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  • 1.
    Ahrén, Maria
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Molecular Surface Physics and Nano Science. Linköping University, The Institute of Technology.
    Selegård, Linnéa
    Linköping University, Department of Physics, Chemistry and Biology, Molecular Surface Physics and Nano Science. Linköping University, The Institute of Technology.
    Klasson, Anna
    Linköping University, Center for Medical Image Science and Visualization (CMIV). Linköping University, Department of Medical and Health Sciences, Radiology. Linköping University, Faculty of Health Sciences.
    Söderlind, Fredrik
    Linköping University, Department of Physics, Chemistry and Biology, Chemistry. Linköping University, The Institute of Technology.
    Abrikossova, Natalia
    Linköping University, Department of Physics, Chemistry and Biology, Molecular Surface Physics and Nano Science. Linköping University, The Institute of Technology.
    Skoglund, Caroline
    Linköping University, Department of Physics, Chemistry and Biology, Molecular Surface Physics and Nano Science. Linköping University, Faculty of Science & Engineering.
    Bengtsson, Torbjörn
    Linköping University, Department of Medical and Health Sciences, Division of Drug Research. Linköping University, The Institute of Technology.
    Engström, Maria
    Linköping University, Center for Medical Image Science and Visualization (CMIV). Linköping University, Department of Medical and Health Sciences, Radiology. Linköping University, Faculty of Health Sciences.
    Käll, Per-Olov
    Linköping University, Department of Physics, Chemistry and Biology, Chemistry. Linköping University, The Institute of Technology.
    Uvdal, Kajsa
    Linköping University, Department of Physics, Chemistry and Biology, Molecular Surface Physics and Nano Science. Linköping University, The Institute of Technology.
    Synthesis and Characterization of PEGylated Gd2O3 Nanoparticles for MRI Contrast Enhancement2010In: Langmuir, ISSN 0743-7463, E-ISSN 1520-5827, Vol. 26, no 8, p. 5753-5762Article in journal (Refereed)
    Abstract [en]

    Recently, much attention has been given to the development of biofunctionalized nanoparticles with magnetic properties for novel biomedical imaging. Guided, smart, targeting nanoparticulate magnetic resonance imaging (MRI) contrast agents inducing high MRI signal will be valuable tools for future tissue specific imaging and investigation of molecular and cellular events. In this study, we report a new design of functionalized ultrasmall rare earth based nanoparticles to be used as a positive contrast agent in MRI. The relaxivity is compared to commercially available Gd based chelates. The synthesis, PEGylation, and dialysis of small (3−5 nm) gadolinium oxide (DEG-Gd2O3) nanoparticles are presented. The chemical and physical properties of the nanomaterial were investigated with Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, transmission electron microscopy, and dynamic light scattering. Neutrophil activation after exposure to this nanomaterial was studied by means of fluorescence microscopy. The proton relaxation times as a function of dialysis time and functionalization were measured at 1.5 T. A capping procedure introducing stabilizing properties was designed and verified, and the dialysis effects were evaluated. A higher proton relaxivity was obtained for as-synthesized diethylene glycol (DEG)-Gd2O3 nanoparticles compared to commercial Gd-DTPA. A slight decrease of the relaxivity for as-synthesized DEG-Gd2O3 nanoparticles as a function of dialysis time was observed. The results for functionalized nanoparticles showed a considerable relaxivity increase for particles dialyzed extensively with r1 and r2 values approximately 4 times the corresponding values for Gd-DTPA. The microscopy study showed that PEGylated nanoparticles do not activate neutrophils in contrast to uncapped Gd2O3. Finally, the nanoparticles are equipped with Rhodamine to show that our PEGylated nanoparticles are available for further coupling chemistry, and thus prepared for targeting purposes. The long term goal is to design a powerful, directed contrast agent for MRI examinations with specific targeting possibilities and with properties inducing local contrast, that is, an extremely high MR signal at the cellular and molecular level.

  • 2.
    Bednarska, Olga
    et al.
    Linköping University, Department of Clinical and Experimental Medicine, Division of Surgery, Orthopedics and Oncology. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Heart and Medicine Center, Department of Gastroentorology.
    Icenhour, Adriane
    Linköping University, Center for Medical Image Science and Visualization (CMIV). Linköping University, Department of Clinical and Experimental Medicine. Linköping University, Faculty of Medicine and Health Sciences. Institute of Medical Psychology and Behavioral Immunobiology, University Hospital Essen, University of Duisburg-Essen, Essen, Germany.
    Tapper, Sofie
    Linköping University, Department of Medical and Health Sciences, Division of Radiological Sciences. Linköping University, Faculty of Medicine and Health Sciences. Linköping University, Center for Medical Image Science and Visualization (CMIV).
    Witt, Suzanne Tyson
    Linköping University, Faculty of Medicine and Health Sciences. Linköping University, Center for Medical Image Science and Visualization (CMIV).
    Tisell, Anders
    Linköping University, Department of Medical and Health Sciences, Division of Radiological Sciences. Linköping University, Faculty of Medicine and Health Sciences. Linköping University, Center for Medical Image Science and Visualization (CMIV). Region Östergötland, Center for Diagnostics, Medical radiation physics.
    Lundberg, Peter
    Linköping University, Department of Medical and Health Sciences, Division of Radiological Sciences. Linköping University, Faculty of Medicine and Health Sciences. Linköping University, Center for Medical Image Science and Visualization (CMIV). Region Östergötland, Center for Diagnostics, Medical radiation physics.
    Elsenbruch, Sigrid
    Institute of Medical Psychology and Behavioral Immunobiology, University Hospital Essen, University of Duisburg-Essen, Essen, Germany.
    Engström, Maria
    Linköping University, Department of Medical and Health Sciences, Division of Radiological Sciences. Linköping University, Faculty of Medicine and Health Sciences. Linköping University, Center for Medical Image Science and Visualization (CMIV).
    Walter, Susanna
    Linköping University, Department of Clinical and Experimental Medicine, Division of Neuro and Inflammation Science. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Heart and Medicine Center, Department of Gastroentorology. Linköping University, Center for Medical Image Science and Visualization (CMIV).
    Reduced excitatory neurotransmitter levels in anterior insulae are associated with abdominal pain in irritable bowel syndrome2019In: Pain, ISSN 0304-3959, E-ISSN 1872-6623, Vol. 160, no 9, p. 2004-2012Article in journal (Refereed)
    Abstract [en]

    Irritable bowel syndrome (IBS) is a visceral pain condition with psychological comorbidity. Brain imaging studies in IBS demonstratealtered function in anterior insula (aINS), a key hub for integration of interoceptive, affective, and cognitive processes. However,alterations in aINS excitatory and inhibitory neurotransmission as putative biochemical underpinnings of these functional changesremain elusive. Using quantitative magnetic resonance spectroscopy, we compared women with IBS and healthy women (healthycontrols [HC]) with respect to aINS glutamate 1 glutamine (Glx) and g-aminobutyric acid (GABA1) concentrations and addressedpossible associations with symptoms. Thirty-nine women with IBS and 21 HC underwent quantitative magnetic resonancespectroscopy of bilateral aINS to assess Glx and GABA1 concentrations. Questionnaire data from all participants and prospectivesymptom-diary data from patients were obtained for regression analyses of neurotransmitter concentrations with IBS-related andpsychological parameters. Concentrations of Glx were lower in IBS compared with HC (left aINS P , 0.05, right aINS P , 0.001),whereas no group differences were detected for GABA1concentrations. Lower right-lateralized Glx concentrations in patients weresubstantially predicted by longer pain duration, while less frequent use of adaptive pain‐coping predicted lower Glx in left aINS. Ourfindings provide first evidence for reduced excitatory but unaltered inhibitory neurotransmitter levels in aINS in IBS. The results alsoindicate a functional lateralization of aINS with a stronger involvement of the right hemisphere in perception of abdominal pain and ofthe left aINS in cognitive pain regulation. Our findings suggest that glutaminergic deficiency may play a role in pain processing in IBS.

  • 3.
    Bergstrand, Sara
    et al.
    Linköping University, Department of Medical and Health Sciences, Division of Nursing Science. Linköping University, Faculty of Health Sciences.
    Källman, Ulrika
    Linköping University, Department of Medical and Health Sciences, Division of Nursing Science. Linköping University, Faculty of Health Sciences. Department of Dermatology, Södra Älvsborgs Sjukhus, Borås, Sweden.
    Ek, Anna-Christina
    Linköping University, Department of Medical and Health Sciences, Division of Nursing Science. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Local Health Care Services in Central Östergötland, Department of Acute Health Care in Linköping.
    Engström, Maria
    Linköping University, Department of Medical and Health Sciences, Division of Radiological Sciences. Linköping University, Center for Medical Image Science and Visualization (CMIV). Linköping University, Faculty of Health Sciences.
    Lindgren, Margareta
    Linköping University, Department of Medical and Health Sciences, Division of Nursing Science. Linköping University, Faculty of Health Sciences.
    Microcirculatory responses of sacral tissue in healthy individuals and inpatients on different pressure-redistribution mattresses2015In: Journal of Wound Care, ISSN 0969-0700, E-ISSN 2052-2916, Vol. 24, no 8, p. 346-358Article in journal (Refereed)
    Abstract [en]

    Objective: The aim of this study was to explore the interaction between interface pressure and pressure-induced vasodilation and reactive hyperemia with different pressureredistribution mattresses.

    Method: A cross-sectional study was performed with a convenience sample of 42 healthy individuals between 18 and 64 years of age, 38 healthy individuals 65 years or older, and 35 inpatients 65 years or older at a university hospital in Sweden. Blood flow was measured at depths of 1 mm, 2 mm, and 10 mm using a combined system of laser Doppler flowmetry and photoplethysmography. The blood flow, interface pressure and skin temperature were measured in the sacral tissue before, during, and after load while lying on one standard hospital mattress and three different pressure-redistribution mattresses.

    Results: There were significant differences between the three foam mattresses with regard to average sacral pressure, peak sacral pressure, and local probe pressure with the lowest values at the visco-elastic foam/air mattress (23.5 ± 2.5 mmHg, 49.3 ± 11.1 mmHg, 29.2 ± 14.0 mmHg respectively). A greater proportion of subjects had affected blood flow in terms of lack of pressure-induced vasodilation on the visco-elastic foam/air mattress compared to the alternating pressure mattress at tissue depths of 2 mm (39.0% vs. 20.0%, respectively) and 10 mm (56.9 % vs. 35.1%, respectively). Eleven individuals, including subjects in all three subject groups were identified with no pressure-induced vasodilation or reactive hyperemia in any mattress, and this was considered a high-risk blood flow response.

    Conclusion: Interface pressure magnitudes considered not harmful during pressure-exposure lying on different pressure-redistribution mattresses can affect the microcirculation in different tissue structures. Despite having the lowest pressure values compared to the other mattresses, the visco-elastic foam/air mattress had the highest proportion of subjects with decreased blood flow indicating a more affected blood flow. Three young healthy individuals were identified with the high-risk blood flow response, indicating an innate vulnerability to pressure exposure and may not benefit from pressure-redistribution mattresses. Finally it was shown that the evaluation of pressure-redistribution support surfaces in terms of mean blood flow during and after tissue exposure is not feasible but assessment of pressure-induced vasodilation and reactive hyperemia could be a new possibility to assess individualized physiological measurements of mechanisms known to be related to pressure ulcer development.

  • 4.
    Bergstrand, Sara
    et al.
    Linköping University, Department of Medical and Health Sciences, Division of Nursing Science. Linköping University, Faculty of Health Sciences.
    Källman, Ulrika
    Linköping University, Department of Medical and Health Sciences, Division of Nursing Science. Linköping University, Faculty of Health Sciences. Department of Dermatology, Södra Älvsborgs Sjukhus, Borås, Sweden.
    Ek, Anna-Christina
    Linköping University, Department of Medical and Health Sciences, Division of Nursing Science. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Local Health Care Services in Central Östergötland, Department of Acute Health Care in Linköping.
    Lindberg, Lars-Göran
    Linköping University, The Institute of Technology. Linköping University, Department of Biomedical Engineering, Physiological Measurements.
    Engström, Maria
    Linköping University, Department of Medical and Health Sciences, Division of Radiological Sciences. Linköping University, Faculty of Health Sciences. Linköping University, Center for Medical Image Science and Visualization (CMIV).
    Sjöberg, Folke
    Linköping University, Department of Clinical and Experimental Medicine, Division of Clinical Sciences. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Anaesthetics, Operations and Specialty Surgery Center, Department of Hand and Plastic Surgery. Östergötlands Läns Landsting, Anaesthetics, Operations and Specialty Surgery Center, Department of Anaesthesiology and Intensive Care in Linköping.
    Lindgren, Margareta
    Linköping University, Department of Medical and Health Sciences, Division of Nursing Science. Linköping University, Faculty of Health Sciences.
    Pressure-induced vasodilation and reactive hyperemia at different depths in sacral tissue under clinically relevant conditions2014In: Microcirculation, ISSN 1073-9688, E-ISSN 1549-8719, Vol. 21, no 8, p. 761-771Article in journal (Refereed)
    Abstract [en]

    OBJECTIVE: To characterize pressure-induced vasodilatation and reactive hyperemia at different sacral tissue depths in different populations under clinically relevant pressure exposure.

    METHODS: Forty-two subjects (< 65 years), 38 subjects (≥ 65 years), and 35 patients (≥ 65 years) participated. Interface pressure, skin temperature, and blood flow at tissue depths of 1 mm, 2 mm, and 10 mm (using laser Doppler flowmetry and photoplethysmography) were measured in the sacral tissue before, during, and after load in a supine position.

    RESULTS: pressure-induced vasodilatation and reactive hyperemia were observed at three tissue depths. At 10 mm depth, the proportion of subjects with a lack of pressure-induced vasodilatation was higher compared to superficial depths. The patients had higher interface pressure during load than the healthy individuals, but there were no significant differences in blood flow. Twenty-nine subjects in all three study groups were identified with a lack of pressure-induced vasodilatation and reactive hyperemia.

    CONCLUSIONS: pressure-induced vasodilatation and reactive hyperemia can be measured at different tissue depths. A lack of these responses was found in healthy individuals as well as in patients indicating an innate susceptibility in some individuals, and are potential important factors to evaluate in order to better understand the etiology of pressure ulcers.

  • 5.
    Engstrom, Maria
    et al.
    Linköping University, Department of Physics, Chemistry and Biology. Linköping University, The Institute of Technology.
    Himo, F
    Linkoping Univ, Inst Phys & Measurement Technol, SE-58183 Linkoping, Sweden Univ Stockholm, Dept Phys, SE-11385 Stockholm, Sweden Royal Inst Technol, SE-10044 Stockholm, Sweden.
    Agren, H
    Linkoping Univ, Inst Phys & Measurement Technol, SE-58183 Linkoping, Sweden Univ Stockholm, Dept Phys, SE-11385 Stockholm, Sweden Royal Inst Technol, SE-10044 Stockholm, Sweden.
    Ab initio g-tensor calculations of the thioether substituted tyrosyl radical in galactose oxidase2000In: Chemical Physics Letters, ISSN 0009-2614, E-ISSN 1873-4448, Vol. 319, no 3-4, p. 191-196Article in journal (Refereed)
    Abstract [en]

    The tyrosyl radical in galactose oxidase is covalently cross-linked to a neighboring cysteine residue through a thioether bond. The role of this sulfur cross-link has been discussed ever since the crystal structure of the enzyme was solved. In the present work, the ab initio multiconfigurational linear response method is applied to calculate the g-tensor of unsubstituted and thioether substituted phenoxyl radicals. In contrast to some previous interpretations, but in agreement with recent EPR measurements, we find that the sulfur substitution induces only minor shifts in the g-tensor components. The spin distribution retains the odd-alternant pattern of the unsubstituted radical and only a small amount of spin is localized to the sulfur center. (C) 2000 Elsevier Science B.V. All rights reserved.

  • 6.
    Engstrom, Maria
    et al.
    Linköping University, Department of Physics, Chemistry and Biology. Linköping University, The Institute of Technology.
    Himo, F
    Linkoping Univ, Dept Phys, SE-58183 Linkoping, Sweden.
    Graslund, A
    Linkoping Univ, Dept Phys, SE-58183 Linkoping, Sweden.
    Minaev, B
    Linkoping Univ, Dept Phys, SE-58183 Linkoping, Sweden.
    Vahtras, O
    Linkoping Univ, Dept Phys, SE-58183 Linkoping, Sweden.
    Agren, H
    Linkoping Univ, Dept Phys, SE-58183 Linkoping, Sweden.
    Hydrogen bonding to tyrosyl radical analyzed by ab initio g-tensor calculations2000In: Journal of Physical Chemistry A, ISSN 1089-5639, E-ISSN 1520-5215, Vol. 104, no 21, p. 5149-5153Article in journal (Refereed)
    Abstract [en]

    Hydrogen bonding to the tyrosyl radical in ribonucleotide reductase (RNR) has been simulated by a complex between the phenoxyl radical and a water molecule. Multiconfigurational self-consistent field linear response theory was used to calculate the g-tensor of the isolated phenoxyl radical and of the phenoxyl-water model. The relevance of the model was motivated by the fact that spin density distributions and electron paramagnetic resonance (EPR) spectra of the phenoxyl and tyrosyl radicals are very similar. The calculated g-tensor anisotropy of the phenoxyl radical was comparable with experimental findings for tyrosyl in those RNRs where the H-bond is absent: g(x) = 2.0087(2.0087), g(y) = 2.0050(2.0042), and g(z) = 2.0025(2.0020), where the tyrosyl radical EPR data from Escherichia coli RNR are given in parentheses. The hydrogen bonding models reproduced a shift toward a lower g(x) value that was observed experimentally for mouse and herpes simplex virus RNR where the H-bond was detected by electron-nuclear double resonance after deuterium exchange. This decrease could be traced to lower angular momentum and spin-orbit coupling matrix elements between the ground B-2(1) and the first excited B-2(2) states (oxygen lone-pair n to pi(SOMO) excitation) upon hydrogen bonding in a linear configuration. The g(x) value was further decreased by hydrogen bonding in bent configurations due to a blue shift of this excitation.

  • 7.
    Engstrom, Maria
    et al.
    Linköping University, Department of Physics, Chemistry and Biology. Linköping University, The Institute of Technology.
    Owenius, Rikard
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology.
    Vahtras, O.
    PDC, Roy. Inst. of Technology, SE-100 44, Stockholm, Sweden.
    Ab initio g-tensor calculations of hydrogen bond effects on a nitroxide spin label2001In: Chemical Physics Letters, ISSN 0009-2614, E-ISSN 1873-4448, Vol. 338, no 4-6, p. 407-413Article in journal (Refereed)
    Abstract [en]

    Hydrogen bonding effects on the electron paramagnetic resonance (EPR) g-tensor of a nitroxide spin label was investigated by quantum chemical calculations. The restricted open-shell Hartree-Fock (ROHF) linear response method with the atomic mean field approximation (AMFI) was used in the calculations. The results show that hydrogen bonding reduces the g-tensor component directed along the NO bond, gxx. This decrease is traced to higher excitation energy and lower spin-orbit coupling and angular momentum matrix elements for the n-p* excitation. The calculations show that the g-tensor is practically invariable when hydrogen bonding was modeled with methanol instead of water. © 2001 Elsevier Science B.V.

  • 8.
    Engstrom, Maria
    et al.
    Linköping University, Department of Physics, Chemistry and Biology. Linköping University, The Institute of Technology.
    Vaara, J.
    Department of Chemistry, University of Helsinki, A.I. Virtasen aukio 1, FIN-00014 Helsinki, Finland.
    Schimmelpfennig, B.
    Department of Biotechnology, Laboratory of Theoretical Chemistry, Royal Institute of Technology, S-10691 Stockholm, Sweden.
    Agren, H.
    Ågren, H., Department of Biotechnology, Laboratory of Theoretical Chemistry, Royal Institute of Technology, S-10691 Stockholm, Sweden.
    Density functional theory calculations of electron paramagnetic resonance parameters of a nitroxide spin label in tissue factor and factor VIIa protein complex2002In: Journal of Physical Chemistry B, ISSN 1089-5647, Vol. 106, no 47, p. 12354-12360Article in journal (Refereed)
    Abstract [en]

    The electron paramagnetic resonance (EPR) g and 14N hyperfine coupling (A) tensors of a nitroxide spin label are calculated with density-functional theory (DFT). The influence on the spin label from nearby amino acids in the extracellular part of tissue factor (sTF) and activated factor VII (FVIIa) protein complex is investigated. For that purpose, the nitroxide unit and six surrounding amino acids within 5 Å are selected on the basis of a molecular mechanics structure of the protein complex. The effects of the surroundings on the EPR parameters of the spin label can be divided into indirect effects caused by the induced structure changes of the spin label and direct effects. The structural changes are larger in the present case. The experimentally measurable hyperfine tensor component perpendicular to the molecular plane of the spin label, Azz, as well as the g tensor component along the NO direction, gxx, are significant probes of the intramolecular structure of the spin label. This indicates the possibility of relating EPR properties to the geometric structure of radical sites. The direct environmental effects on the g tensor from the surrounding amino acids mainly affect the second-order spin-orbit/orbital Zeeman cross-term contributions from the spin label itself. The direct effects originating elsewhere in the model are small. Neither the g nor A tensors display additivity of the effects of individual amino acids on the final observable. The results underline the feasibility of DFT calculations of the EPR parameters in large molecular systems, such as spin labels and other radicals in proteins.

  • 9.
    Engstrom, Maria
    et al.
    Linköping University, Department of Physics, Chemistry and Biology. Linköping University, The Institute of Technology.
    Vahtras, O
    Linkoping Univ, Inst Phys & Measurement Technol, SE-58183 Linkoping, Sweden Royal Inst Technol, PDC, SE-10044 Stockholm, Sweden.
    Agren, H
    Linkoping Univ, Inst Phys & Measurement Technol, SE-58183 Linkoping, Sweden Royal Inst Technol, PDC, SE-10044 Stockholm, Sweden.
    MCSCF and DFT calculations of EPR parameters of sulfur centered radicals2000In: Chemical Physics Letters, ISSN 0009-2614, E-ISSN 1873-4448, Vol. 328, no 4-6, p. 483-491Article in journal (Refereed)
    Abstract [en]

    The EPR parameters of sulfur centered radicals are different depending on the radical structure, charge and solvent. That is, the g- and A-tensor components provide significant patterns which may distinguish sulfur radical structures from each other. In the present work, these EPR parameters were calculated for monosulfide radicals (RS'), disulfide radicals (RSS.), radical cations ((RSSR+)-S-.) and anions ((RSSR-)-S-.), with R = CH3, using the MCSCF linear response and DFT/B3LYP methods. Results were in agreement with experimental data for the cases when well-resolved EPR spectra are available. Especially, the assignment of the disulfide anion in ribonucleotide reductase was confirmed. The results indicate that investigations with the present computational methods on refined structures and solvent modeling may provide interpretations of experimental data on unassigned radical species. (C) 2000 Elsevier Science B.V. All rights reserved.

  • 10.
    Engström, Maria
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Care, Medical Radiology. Linköping University, Center for Medical Image Science and Visualization (CMIV).
    Funktionella områden i hjärnan2004In: Forskning för livet, Vol. 6Article in journal (Other academic)
  • 11.
    Engström, Maria
    et al.
    Linköping University, Department of Medical and Health Sciences, Division of Radiological Sciences. Linköping University, Faculty of Health Sciences. Linköping University, Center for Medical Image Science and Visualization (CMIV).
    Bertus Warntjes, Marcel, Jan
    Linköping University, Department of Medical and Health Sciences, Division of Cardiovascular Medicine. Linköping University, Faculty of Health Sciences. Linköping University, Center for Medical Image Science and Visualization (CMIV). Östergötlands Läns Landsting, Heart and Medicine Center, Department of Clinical Physiology in Linköping. SyntheticMR AB, Linkoping, Sweden.
    Tisell, Anders
    Linköping University, Department of Medical and Health Sciences, Division of Radiological Sciences. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Center for Surgery, Orthopaedics and Cancer Treatment, Department of Radiation Physics. Linköping University, Center for Medical Image Science and Visualization (CMIV).
    Landtblom, Anne-Marie
    Linköping University, Department of Clinical and Experimental Medicine, Division of Neuroscience. Linköping University, Faculty of Health Sciences. Linköping University, Center for Medical Image Science and Visualization (CMIV). Östergötlands Läns Landsting, Local Health Care Services in Central Östergötland, Department of Neurology. Östergötlands Läns Landsting, Local Health Care Services in West Östergötland, Department of Medical Specialist in Motala.
    Lundberg, Peter
    Linköping University, Department of Medical and Health Sciences, Division of Radiological Sciences. Linköping University, Faculty of Health Sciences. Linköping University, Center for Medical Image Science and Visualization (CMIV). Östergötlands Läns Landsting, Center for Surgery, Orthopaedics and Cancer Treatment, Department of Radiation Physics. Östergötlands Läns Landsting, Center for Diagnostics, Department of Radiology in Linköping.
    Multi-Parametric Representation of Voxel-Based Quantitative Magnetic Resonance Imaging2014In: PLoS ONE, ISSN 1932-6203, E-ISSN 1932-6203, Vol. 9, no 11, p. e111688-Article in journal (Refereed)
    Abstract [en]

    The aim of the study was to explore the possibilities of multi-parametric representations of voxel-wise quantitative MRI data to objectively discriminate pathological cerebral tissue in patients with brain disorders. For this purpose, we recruited 19 patients with Multiple Sclerosis (MS) as benchmark samples and 19 age and gender matched healthy subjects as a reference group. The subjects were examined using quantitative Magnetic Resonance Imaging (MRI) measuring the tissue structure parameters: relaxation rates, R-1 and R-2, and proton density. The resulting parameter images were normalized to a standard template. Tissue structure in MS patients was assessed by voxel-wise comparisons with the reference group and with correlation to a clinical measure, the Expanded Disability Status Scale (EDSS). The results were visualized by conventional geometric representations and also by multi-parametric representations. Data showed that MS patients had lower R-1 and R-2, and higher proton density in periventricular white matter and in wide-spread areas encompassing central and sub-cortical white matter structures. MS-related tissue abnormality was highlighted in posterior white matter whereas EDSS correlation appeared especially in the frontal cortex. The multi-parameter representation highlighted disease-specific features. In conclusion, the proposed method has the potential to visualize both high-probability focal anomalies and diffuse tissue changes. Results from voxel-based statistical analysis, as exemplified in the present work, may guide radiologists where in the image to inspect for signs of disease. Future clinical studies must validate the usability of the method in clinical practice.

  • 12.
    Engström, Maria
    et al.
    Linköping University, Department of Medical and Health Sciences, Radiology. Linköping University, Center for Medical Image Science and Visualization, CMIV. Linköping University, Faculty of Health Sciences.
    Flensner, Gullvi
    Linköping University, Department of Medical and Health Sciences, Nursing Science. Linköping University, Faculty of Health Sciences.
    Landtblom, Anne-Marie
    Linköping University, Center for Medical Image Science and Visualization, CMIV. Linköping University, Department of Clinical and Experimental Medicine, Psychiatry. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Sinnescentrum, Department of Neurosurgery UHL.
    Ek, Anna-Christina
    Linköping University, Department of Medical and Health Sciences, Nursing Science. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Local Health Care Services in Central Östergötland, Department of Acute Health Care.
    Karlsson, Thomas
    Linköping University, Department of Behavioural Sciences and Learning. Linköping University, Faculty of Arts and Sciences.
    Fatigue and cognitive effort in multiple sclerosis: an fMRI study2011Conference paper (Other academic)
    Abstract [en]

    Despite recent advances in therapy and diagnosis, fatigue remains a mayor challenge in multiple sclerosis (MS).  To further the understanding of the neural underpinnings of fatigue, we undertook a study using functional magnetic resonance imaging (fMRI) to investigate neural networks that may be affected by MS-related fatigue. Twelve MS patients and 12 age- and sex matched controls were administered the Fatigue Impact Scale (FIS) to assess clinically significant fatigue, and underwent a neuropsychological examination. The participants performed a working memory task (Daneman’s  ‘Reading Span’ task) while being monitored by means of a 1.5 T Philips Achieva MR scanner. We have previously shown that this task triggers an executive network comprising frontal and parietal areas typically involved in working memory. In addition, the task engages a core network involving the anterior insula and the anterior cingulate cortex.  This latter network may be implicated in allocation of mental resources and monitoring of the present state of the individual. There were two main findings. MS participants evidenced less activation than controls in the anterior cingulate and the left parietal cortex (Brodmann area 7) and more activation in left hemisphere language areas as well as the anterior insula. The second main finding was that clinical ratings of fatigue were strongly correlated with activity in wide areas of the core network, as well as posterior language areas. We take this finding to indicate that fatigue is related to compensatory involvement of the core network, and that excess activity in the core network possibly could be used as an objective marker of fatigue in MS.

  • 13.
    Engström, Maria
    et al.
    Linköping University, Department of Medical and Health Sciences, Radiology. Linköping University, Faculty of Health Sciences. Linköping University, Center for Medical Image Science and Visualization (CMIV).
    Flensner, Gullvi
    Linköping University, Department of Medical and Health Sciences, Nursing Science. Linköping University, Faculty of Health Sciences. University West, Trollhättan, Sweden.
    Landtblom, Anne-Marie
    Linköping University, Department of Clinical and Experimental Medicine, Neurology. Linköping University, Faculty of Health Sciences. Linköping University, Center for Medical Image Science and Visualization (CMIV). Östergötlands Läns Landsting, Local Health Care Services in Central Östergötland, Department of Neurology.
    Ek, Anna-Christina
    Linköping University, Department of Medical and Health Sciences, Nursing Science. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Local Health Care Services in Central Östergötland, Department of Acute Health Care in Linköping.
    Karlsson, Thomas
    Linköping University, Department of Behavioural Sciences and Learning, Disability Research. Linköping University, Faculty of Arts and Sciences. Linköping University, Center for Medical Image Science and Visualization (CMIV).
    Thalamo-striato-cortical determinants to fatigue in multiple sclerosis2013In: Brain and Behavior, ISSN 2162-3279, E-ISSN 2162-3279, Vol. 3, no 6, p. 715-728Article in journal (Refereed)
    Abstract [en]

    Background

    The aim was to explore the thalamo-striato-cortical theory of central fatigue in multiple sclerosis (MS) patients with self-reported fatigue. If the theory correctly predicted fatigue based on disruptions of the thalamo-striato-cortical network, we expected altered brain activation in this network in MS participants while performing a complex cognitive task that challenged fatigue.

    Methods

    MS participants with self-reported fatigue were examined by functional magnetic resonance imaging (fMRI) during the performance of a complex working memory task. In this task, cognitive effort was challenged by a parametric design, which modeled the cerebral responses at increasing cognitive demands. In order to explore the theory of central fatigue in MS we also analyzed the cerebral responses by adding perceived fatigue scores as covariates in the analysis and by calculating the functional connectivity between regions in the thalamo-striatocortical network. The main findings were that MS participants elicited altered brain responses in the thalamo-striato-cortical network, and that brain activation in the left posterior parietal cortex and the right substantia nigra was positively correlated to perceived fatigue ratings. MS participants had stronger cortical-to-cortical and subcortical-to-subcortical connections, whereas they had weaker cortical-to-subcortical connections.

    Conclusions

    The findings of the present study indicate that the thalamo-striato-cortical network is involved in the pathophysiology of fatigue in MS, and provide support for the theory of central fatigue. However, due to the limited number of participants and the somewhat heterogeneous sample of MS participants, these results have to be regarded as tentative, though they might serve as a basis for future studies.

  • 14.
    Engström, Maria
    et al.
    Linköping University, Department of Medical and Health Sciences, Radiology. Linköping University, Center for Medical Image Science and Visualization, CMIV. Linköping University, Faculty of Health Sciences.
    Flensner, Gullvi
    Linköping University, Department of Medical and Health Sciences. Linköping University, Faculty of Health Sciences.
    Landtblom, Anne-Marie
    Linköping University, Center for Medical Image Science and Visualization, CMIV. Linköping University, Department of Clinical and Experimental Medicine, Psychiatry. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Sinnescentrum, Department of Neurosurgery UHL.
    Karlsson, Thomas
    Linköping University, Department of Behavioural Sciences and Learning, Cognition, Development and Disability. Linköping University, Faculty of Arts and Sciences.
    Aberrant brain activation in the core control network for cognitive function in MS2011Conference paper (Other academic)
    Abstract [en]

    Purpose: The purpose of this study was to investigate if patients with multiple sclerosis (MS) and fatigue have aberrant brain activation in the anterior insular cortex (AIC) and the anterior cingulate cortex (ACC), which are regions in the brain that are suggested to be a core network for cognitive control (Cole and Schneider, 2007; Sridharan et al., 2008).

     Materials and Methods: Twelve patients with MS and eleven healthy controls were examined with functional Magnetic Resonance Imaging (fMRI) while performing a complex working memory task. The task was to indicate if words presented in video goggles had appeared in previously presented sentences. Axial blood oxygen level dependent (BOLD) images were analyzed with SPM8 software. Images were realigned for movement correction, normalised to standard brain template, and smoothed with 8mm Gaussian kernel. We used a parametric contrast that tapped brain activation as a function of difficulty level of the task, i.e. words presented after 1, 2, 3, or 4 consecutive sentences.

    Results: Healthy controls elicited more activation in the left superior parietal lobe (p<0.001 family wise error (FWE) corrected for multiple comparisons), the right caudate head (p=0.002), and ACC (p=0.004) compared to MS patients. The MS patients had more activity in the left and right inferior parietal lobe (p=0.001 and p=0.029, respectively). In addition, in a region of interest analysis the MS patients had more activation in the left dorsal and ventral AIC (p=0.011 and p=0.009, respectively). The figure shows brain activation at working memory across both healthy controls and MS.

     Conclusion: MS patients elicited, as predicted, aberrant activation in the AIC-ACC network in that they had activation depletion in ACC and increased activity in the left AIC. It has recently been proposed that the AIC engenders awareness and the ACC engenders volitional action (Craig, 2009). The abnormal activation in this region could therefore explain the frequent symptoms of fatigue and cognitive impairment in MS.

     Clinical Relevance statement: Cognitive impairment occurs in 40-70% of individuals with MS and the patophysiology is unknown. Increased knowledge might contribute to novel strategies for symptomatic treatment.

  • 15.
    Engström, Maria
    et al.
    Linköping University, Department of Medical and Health Sciences, Division of Radiological Sciences. Linköping University, Faculty of Health Sciences. Linköping University, Center for Medical Image Science and Visualization (CMIV).
    Hallböök, Tove
    Sahlgrenska Academy, University of Gothenburg, Sweden.
    Szakacs, Attila
    Sahlgrenska Academy, University of Gothenburg. Sweden; Halmstad County Hospital, Sweden.
    Karlsson, Thomas
    Linköping University, Department of Behavioural Sciences and Learning, Disability Research. Linköping University, Faculty of Arts and Sciences. Linköping University, Center for Medical Image Science and Visualization (CMIV).
    Landtblom, Anne-Marie
    Linköping University, Department of Clinical and Experimental Medicine, Division of Neuroscience. Linköping University, Faculty of Health Sciences. Linköping University, Center for Medical Image Science and Visualization (CMIV). Östergötlands Läns Landsting, Local Health Care Services in Central Östergötland, Department of Neurology. Östergötlands Läns Landsting, Local Health Care Services in West Östergötland, Department of Medical Specialist in Motala.
    Functional magnetic resonance imaging in narcolepsy and the Kleine–Levin syndrome2014In: Frontiers in Neurology, ISSN 1664-2295, E-ISSN 1664-2295, Vol. 5, no 105Article in journal (Refereed)
    Abstract [en]

    This work aims at reviewing the present state of the art when it comes to understanding the pathophysiology of narcolepsy and the Kleine–Levin syndrome (KLS) from a neuroimaging point of view. This work also aims at discussing future perspectives of functional neuroimaging in these sleep disorders. We focus on functional magnetic resonance imaging (fMRI), which is a technique for in vivo measurements of brain activation in neuronal circuitries under healthy and pathological conditions. fMRI has significantly increased the knowledge on the affected neuronal circuitries in narcolepsy and the Kleine–Levin syndrome. It has been shown that narcolepsy is accompanied with disturbances of the emotional and the closely related reward systems. In the Kleine Levin syndrome, fMRI has identified hyperactivation of the thalamus as a potential biomarker that could be used in the diagnostic procedure. The fMRI findings in both narcolepsy and the Kleine–Levin syndrome are in line with previous structural and functional imaging studies. We conclude that fMRI in combination with multi-modal imaging can reveal important details about the pathophysiology in narcolepsy and the Kleine–Levin syndrome. In the future, fMRI possibly gives opportunities for diagnostic support and prediction of treatment response in individual patients.

  • 16.
    Engström, Maria
    et al.
    Linköping University, Department of Medical and Health Sciences, Division of Radiological Sciences. Linköping University, Faculty of Health Sciences. Linköping University, Center for Medical Image Science and Visualization (CMIV).
    Jan Bertus Warntje, Marcel
    Linköping University, Department of Medical and Health Sciences, Division of Cardiovascular Medicine. Linköping University, Faculty of Health Sciences. Linköping University, Center for Medical Image Science and Visualization (CMIV). Östergötlands Läns Landsting, Heart and Medicine Center, Department of Clinical Physiology in Linköping.
    Tisell, Anders
    Linköping University, Department of Medical and Health Sciences, Division of Radiological Sciences. Linköping University, Faculty of Health Sciences. Linköping University, Center for Medical Image Science and Visualization (CMIV). Östergötlands Läns Landsting, Center for Surgery, Orthopaedics and Cancer Treatment, Department of Radiation Physics.
    Landtblom, Anne-Marie
    Linköping University, Department of Clinical and Experimental Medicine, Division of Neuroscience. Linköping University, Faculty of Health Sciences. Linköping University, Center for Medical Image Science and Visualization (CMIV). Östergötlands Läns Landsting, Local Health Care Services in Central Östergötland, Department of Neurology.
    Lundberg, Peter
    Linköping University, Department of Medical and Health Sciences, Division of Radiological Sciences. Linköping University, Faculty of Health Sciences. Linköping University, Center for Medical Image Science and Visualization (CMIV). Östergötlands Läns Landsting, Center for Surgery, Orthopaedics and Cancer Treatment, Department of Radiation Physics. Östergötlands Läns Landsting, Center for Diagnostics, Department of Radiology in Linköping.
    Multi-Parametric Representation of Voxel-Based Quantitative Magnetic Resonance Imaging2014Conference paper (Other academic)
    Abstract [en]

    The aim of the study was to explore the possibilities of multi-parametric representations of voxel-wise quantitative MRI data to objectively discriminate pathological cerebral tissue in patients with brain disorders. For this purpose, we recruited 19 patients with Multiple Sclerosis (MS) as benchmark samples and 19 age and gender matched healthy subjects as a reference group. The subjects were examined using quantitative Magnetic Resonance Imaging (MRI) measuring the tissue structure parameters: relaxation rates, R and R, and proton density. The resulting parameter images were normalized to a standard template. Tissue structure in MS patients was assessed by voxel-wise comparisons with the reference group and with correlation to a clinical measure, the Expanded Disability Status Scale (EDSS). The results were visualized by conventional geometric representations and also by multi-parametric representations. Data showed that MS patients had lower R and R, and higher proton density in periventricular white matter and in wide-spread areas encompassing central and sub-cortical white matter structures. MS-related tissue abnormality was highlighted in posterior white matter whereas EDSS correlation appeared especially in the frontal cortex. The multi-parameter representation highlighted disease-specific features. In conclusion, the proposed method has the potential to visualize both high-probability focal anomalies and diffuse tissue changes. Results from voxel-based statistical analysis, as exemplified in the present work, may guide radiologists where in the image to inspect for signs of disease. Future clinical studies must validate the usability of the method in clinical practice.

  • 17.
    Engström, Maria
    et al.
    Linköping University, Department of Medical and Health Sciences, Radiology. Linköping University, Faculty of Health Sciences.
    Karlsson, Marie
    Linköping University, Department of Clinical and Experimental Medicine. Linköping University, Faculty of Health Sciences.
    Crone, Marie
    Linköping University, Department of Clinical and Experimental Medicine. Linköping University, The Institute of Technology.
    Ragnehed, Mattias
    Linköping University, Department of Medical and Health Sciences, Radiology. Linköping University, Faculty of Health Sciences.
    Antepohl, Wolfram
    Linköping University, Department of Clinical and Experimental Medicine, Rehabilitation Medicine. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Reconstruction Centre, Department of Rehabilitation Medicine UHL.
    Landtblom, Anne-Marie
    Linköping University, Department of Clinical and Experimental Medicine, Neurology. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Local Health Care Services in Central Östergötland, Department of Neurology. Östergötlands Läns Landsting, Local Health Care Services in the West of Östergötland, Department of Medical Specialist.
    Lundberg, Peter
    Linköping University, Department of Medical and Health Sciences, Radiology. Linköping University, Faculty of Health Sciences.
    Clinical fMRI of language function in aphasic patients: Reading paradigm successful, while word generation paradigm fails2010In: Acta Radiologica, ISSN 0284-1851, E-ISSN 1600-0455, Vol. 51, no 6, p. 679-686Article in journal (Refereed)
    Abstract [en]

    Background: In fMRI examinations, it is very important to select appropriate paradigms assessing the brain function of interest. In addition, the patients ability to perform the required cognitive tasks during fMRI must be taken into account. Purpose: To evaluate two language paradigms, word generation and sentence reading for their usefulness in examinations of aphasic patients and to make suggestions for improvements of clinical fMRI. Material and Methods: Five patients with aphasia after stroke or trauma sequelae were examined by fMRI. The patients language ability was screened by neurolinguistic tests and elementary pre-fMRI language tests. Results: The sentence-reading paradigm succeeded to elicit adequate language-related activation in perilesional areas whereas the word generation paradigm failed. These findings were consistent with results on the behavioral tests in that all patients showed very poor performance in phonemic fluency, but scored well above mean at a reading comprehension task. Conclusion: The sentence-reading paradigm is appropriate to assess language function in this patient group, while the word-generation paradigm seems to be inadequate. In addition, it is crucial to use elementary pre-fMRI language tests to guide the fMRI paradigm decision.

  • 18.
    Engström, Maria
    et al.
    Linköping University, Department of Medicine and Health Sciences, Radiology . Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Centre for Medical Imaging, Department of Radiology in Linköping.
    Karlsson, Thomas
    Linköping University, Department of Behavioural Sciences and Learning. Linköping University, Faculty of Arts and Sciences.
    An fMRi investigation of mental effort in a complex working memory task2010In: 16th Annual Meeting of the Organization for Human Brain Mapping, Barcelona 2010: Abstract No 1116, 2010Conference paper (Other academic)
    Abstract [en]

     

    A fundamental component of attention and working memory is the ability to allocate sufficient amount of mental resources to ongoing activity. Despite the fact that ’effort’ is a key ingredient to current theories about attention and memory, little is known about the brain’s regulation of cognitive effort. In this fMRI study, we employed the momentous Daneman reading span task (Daneman & Carpenter, 1980) to induce cognitive effort. We have previously used complex working memory tasks to study deficits with respect to effortful processing in patients with sleep disorders (Engström, et al., 2009). We have noted profound involvement of the anterior cingulate cortex in relation to cognitive effort. We now wish to corroborate this finding in a larger group of healthy participants.

     

     

  • 19.
    Engström, Maria
    et al.
    Linköping University. Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Health Sciences. Linköping University, Department of Medicine and Health Sciences, Radiology . Östergötlands Läns Landsting, Centre for Medical Imaging, Department of Radiology in Linköping.
    Karlsson, Thomas
    Linköping University. Linköping University, Faculty of Arts and Sciences. Linköping University, Department of Behavioural Sciences and Learning.
    Disorganised working memory functional connectivity in periodic hypersomnia2010In: 16th Annual Meeting of the Organization for Human Brain Mapping, Barcelona 2010: 16th Annual Meeting of the Organization for Human Brain Mapping, Abstract No 1771, 2010Conference paper (Other academic)
    Abstract [en]

    The Kleine–Levin Syndrome (KLS) is a rare but relatively well-defined disorder characterised by excessive sleep periods (periodic hypersomnia) associated with cognitive deficits and behavioural disturbances such as binge eating and hypersexuality [1]. The etiology of KLS is unknown and several neuroimagning methods have been applied to investigate the neural corrlates to KLS. A functional Magnetic Resonance Imaging (fMRI) study by us implicated hyperactivity in the thalamus and hypoactivity in the anterior cingulate cortex and the right anterior insula in a working memory task [2], which imply the involvement of a recently proposed anterior cingulate-insular control network in KLS [3]. As we expected less coherent organisation in KLS, we compared the connectivity of the anterior cingulate-insular and thalamic (AIT) network and the well-known, working memory-related, dorsal attention network (involving the dorsolateral prefrontal cortex and parietal areas) between KLS and controls.

  • 20.
    Engström, Maria
    et al.
    Linköping University, Department of Medical and Health Sciences, Radiology. Linköping University, Faculty of Health Sciences. Linköping University, Center for Medical Image Science and Visualization (CMIV).
    Karlsson, Thomas
    Linköping University, Department of Behavioural Sciences and Learning. Linköping University, Faculty of Arts and Sciences.
    Landtblom, Anne-Marie
    Linköping University, Department of Clinical and Experimental Medicine, Neurology. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Local Health Care Services in Central Östergötland, Department of Neurology. Linköping University, Center for Medical Image Science and Visualization (CMIV).
    Abnormal thalamic activation and complex working memory in Kleine-Levin Syndrome2013Conference paper (Other academic)
  • 21.
    Engström, Maria
    et al.
    Linköping University, Department of Medical and Health Sciences, Division of Radiological Sciences. Linköping University, Faculty of Health Sciences. Linköping University, Center for Medical Image Science and Visualization (CMIV).
    Karlsson, Thomas
    Linköping University, Department of Behavioural Sciences and Learning, Disability Research. Linköping University, Faculty of Arts and Sciences. Linköping University, Center for Medical Image Science and Visualization (CMIV).
    Landtblom, Anne-Marie
    Linköping University, Department of Clinical and Experimental Medicine, Division of Neuroscience. Linköping University, Faculty of Health Sciences. Linköping University, Center for Medical Image Science and Visualization (CMIV). Östergötlands Läns Landsting, Local Health Care Services in Central Östergötland, Department of Neurology. Östergötlands Läns Landsting, Local Health Care Services in West Östergötland, Department of Medical Specialist in Motala.
    Reduced thalamic and pontine connectivity in Kleine–Levin syndrome2014In: Frontiers in Neurology, ISSN 1664-2295, E-ISSN 1664-2295, Vol. 5, no 42Article in journal (Refereed)
    Abstract [en]

    The Kleine–Levin syndrome (KLS) is a rare sleep disorder, characterized by exceptionally long sleep episodes. The neuropathology of the syndrome is unknown and treatment is often inadequate. The aim of the study was to improve understanding of the underlying neuropathology, related to cerebral networks, in KLS during sleep episodes. One patient with KLS and congenital nystagmus was investigated by resting state functional magnetic resonance imaging during both asymptomatic and hypersomnic periods. Fourteen healthy subjects were also investigated as control samples. Functional connectivity was assessed from seed regions of interest in the thalamus and the dorsal pons. Thalamic connectivity was normal in the asymptomatic patient whereas the connectivity between the brain stem, including dorsal pons, and the thalamus was diminished during hypersomnia. These results suggest that the patient’s nystagmus and hypersomnia might have their pathological origin in adjacent dorsal pontine regions. This finding provides additional knowledge of the cerebral networks involved in the neuropathology of this disabling disorder. Furthermore, these findings regarding a rare syndrome have broad implications, and results could be of interest to researchers and clinicians in the whole field of sleep medicine.

  • 22.
    Engström, Maria
    et al.
    Linköping University, Department of Medical and Health Sciences, Division of Radiological Sciences. Linköping University, Faculty of Health Sciences. Linköping University, Center for Medical Image Science and Visualization (CMIV).
    Karlsson, Thomas
    Linköping University, Department of Behavioural Sciences and Learning, Disability Research. Linköping University, Faculty of Arts and Sciences. Linköping University, Center for Medical Image Science and Visualization (CMIV).
    Landtblom, Anne-Marie
    Linköping University, Department of Clinical and Experimental Medicine, Division of Neuroscience. Linköping University, Faculty of Health Sciences. Linköping University, Center for Medical Image Science and Visualization (CMIV). Östergötlands Läns Landsting, Local Health Care Services in Central Östergötland, Department of Neurology. Östergötlands Läns Landsting, Local Health Care Services in West Östergötland, Department of Medical Specialist in Motala.
    Thalamic Activation in the Kleine-Levin Syndrome2014In: Sleep, ISSN 0161-8105, E-ISSN 1550-9109, Vol. 37, no 2, p. 379-386Article in journal (Refereed)
    Abstract [en]

    STUDY OBJECTIVES:

    The objective of this study was to investigate if combined measures of activation in the thalamus and working memory capacity could guide the diagnosis of Kleine-Levin Syndrome (KLS). A second objective was to obtain more insight into the neurobiological causes of KLS.

    DESIGN:

    Matched group and consecutive recruitment.

    SETTING:

    University hospital neurology department and imaging center.

    PATIENTS OR PARTICIPANTS:

    Eighteen patients with KLS diagnosed according to the International Classification of Sleep Disorders and 26 healthy controls were included.

    INTERVENTIONS:

    N/A.

    MEASUREMENTS AND RESULTS:

    Working memory capacity was assessed by the listening span task. A version of this task (reading span) was presented to the participants during functional magnetic resonance imaging (fMRI). Activation in the thalamus was measured in a region of interest analysis. A combination of the working memory capacity and the thalamic activation measures resulted in 80% prediction accuracy, 81% sensitivity, and 78% specificity regarding the ability to separate KLS patients from healthy controls. The controls had an inverse relation between working memory capacity and thalamic activation; higher performing participants had lower thalamic activation (r = -0.41). KLS patients showed the opposite relationship; higher performing participants had a tendency to higher thalamic activation (r = -0.35).

    CONCLUSIONS:

    This study shows that functional neuroimaging of the thalamus combined with neuropsychological assessment of working memory function provides a means to guide diagnosis of Kleine-Levin Syndrome. Results in this study also indicate that imaging of brain function and evaluation of cognitive capacity can give insights into the neurobiological mechanisms of Kleine-Levin Syndrome.

  • 23.
    Engström, Maria
    et al.
    Linköping University, Center for Medical Image Science and Visualization, CMIV. Linköping University, Department of Medical and Health Sciences, Radiology. Linköping University, Faculty of Health Sciences.
    Karlsson, Thomas
    Linköping University, Center for Medical Image Science and Visualization, CMIV. Linköping University, Department of Behavioural Sciences and Learning, Disability Research. Linköping University, Faculty of Arts and Sciences.
    Landtblom, Anne-Marie
    Linköping University, Center for Medical Image Science and Visualization, CMIV. Linköping University, Department of Clinical and Experimental Medicine, Neurology. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Local Health Care Services in Central Östergötland, Department of Neurology.
    Craig, A. D. (Bud)
    Atkinson Research Laboratory, Barrow Neurological Institute, Phoenix, AZ.
    Mental energy – an fMRI investigation of the anterior insular and the anterior cingulate network2012Conference paper (Other academic)
  • 24.
    Engström, Maria
    et al.
    Linköping University, Department of Medical and Health Sciences, Division of Radiological Sciences. Linköping University, Faculty of Health Sciences. Linköping University, Center for Medical Image Science and Visualization (CMIV).
    Karlsson, Thomas
    Linköping University, Department of Behavioural Sciences and Learning, Disability Research. Linköping University, Faculty of Arts and Sciences. Linköping University, Center for Medical Image Science and Visualization (CMIV). Linköping University, The Swedish Institute for Disability Research.
    Landtblom, Anne-Marie
    Linköping University, Center for Medical Image Science and Visualization (CMIV). Linköping University, Department of Clinical and Experimental Medicine, Division of Neuro and Inflammation Science. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Local Health Care Services in Central Östergötland, Department of Neurology.
    Craig, Arthur
    Linköping University, Department of Clinical and Experimental Medicine, Division of Cell Biology. Linköping University, Faculty of Health Sciences. Barrow Neurol Institute, AZ 85013 USA.
    Evidence of conjoint activation of the anterior insular and cingulate cortices during effortful tasks2015In: Frontiers in Human Neuroscience, ISSN 1662-5161, E-ISSN 1662-5161, Vol. 8, no 1071Article in journal (Refereed)
    Abstract [en]

    The ability to perform effortful tasks is a topic that has received considerable interest in the research of higher functions of the human brain. Neuroimaging studies show that the anterior insular and the anterior cingulate cortices are involved in a multitude of cognitive tasks that require mental effort. In this study, we investigated brain responses to effort using cognitive tasks with task-difficulty modulations and functional magnetic resonance imaging (fMRI). We hypothesized that effortful performance involves modulation of activation in the anterior insular and the anterior cingulate cortices, and that the modulation correlates with individual performance levels. Healthy participants performed tasks probing verbal working memory capacity using the reading span task, and visual perception speed using the inspection time task. In the fMRI analysis, we focused on identifying effort-related brain activation. The results showed that working memory and inspection time performances were directly related. The bilateral anterior insular and anterior cingulate cortices showed significantly increased activation during each task with common portions that were active across both tasks. We observed increased brain activation in the right anterior insula and the anterior cingulate cortex in participants with low working memory performance. In line with the reported results, we suggest that activation in the anterior insular and cingulate cortices is consistent with the neural efficiency hypothesis (Neubauer).

  • 25.
    Engström, Maria
    et al.
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Care, Medical Radiology. Linköping University, Center for Medical Image Science and Visualization, CMIV.
    Karlsson, Thomas
    Linköping University, Faculty of Arts and Sciences. Linköping University, Department of Behavioural Sciences and Learning. Linköping University, Center for Medical Image Science and Visualization, CMIV.
    Vigren, Patrick
    Neurology INR.
    Landtblom, Anne-Marie
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Neuroscience and Locomotion, Neurology. Östergötlands Läns Landsting, Local Health Care Services in Central Östergötland, Department of Neurology. Linköping University, Center for Medical Image Science and Visualization, CMIV.
    Subcortical and frontal determinants to working memory deficits in patients with Kleine-Levin syndrome.2007In: 13th Annual Meeting of the Organization for Human Brain Mapping,2007, NeuroImage: Elsevier , 2007, p. S78-Conference paper (Refereed)
  • 26.
    Engström, Maria
    et al.
    Linköping University, Department of Medical and Health Sciences, Radiology. Linköping University, Faculty of Health Sciences. Linköping University, Center for Medical Image Science and Visualization (CMIV).
    Klasson, Anna
    Linköping University, Department of Medical and Health Sciences, Radiology. Linköping University, Faculty of Health Sciences. Linköping University, Center for Medical Image Science and Visualization (CMIV).
    Pedersen, Henrik
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Vahlberg, Cecillia
    Linköping University, Department of Physics, Chemistry and Biology, Sensor Science and Molecular Physics. Linköping University, The Institute of Technology.
    Käll, Per-Olov
    Linköping University, Department of Physics, Chemistry and Biology, Physical Chemistry. Linköping University, The Institute of Technology.
    Uvdal, Kajsa
    Linköping University, Department of Physics, Chemistry and Biology, Sensor Science and Molecular Physics. Linköping University, The Institute of Technology.
    High Proton Relaxivity for Gadolinium Oxide Nanoparticles2006In: Magnetic Resonance Materials in Physics, Biology and Medicine, ISSN 0968-5243, E-ISSN 1352-8661, Vol. 19, no 4, p. 180-186Article in journal (Refereed)
    Abstract [en]

    Objective: Nanosized materials of gadolinium oxide can provide high-contrast enhancement in magnetic resonance imaging (MRI). The objective of the present study was to investigate proton relaxation enhancement by ultrasmall (5 to 10 nm) Gd2O3 nanocrystals.

    Materials and methods: Gd2O3 nanocrystals were synthesized by a colloidal method and capped with diethylene glycol (DEG). The oxidation state of Gd2O3 was confirmed by X-ray photoelectron spectroscopy. Proton relaxation times were measured with a 1.5-T MRI scanner. The measurements were performed in aqueous solutions and cell culture medium (RPMI).

    Results: Results showed a considerable relaxivity increase for the Gd2O3–DEG particles compared to Gd-DTPA. Both T 1 and T 2 relaxivities in the presence of Gd2O3–DEG particles were approximately twice the corresponding values for Gd–DTPA in aqueous solution and even larger in RPMI. Higher signal intensity at low concentrations was predicted for the nanoparticle solutions, using experimental data to simulate a T1-weighted spin echo sequence.

    Conclusion: The study indicates the possibility of obtaining at least doubled relaxivity compared to Gd–DTPA using Gd2O3–DEG nanocrystals as contrast agent. The high T 1 relaxation rate at low concentrations of Gd2O3 nanoparticles is very promising for future studies of contrast agents based on gadolinium-containing nanocrystals.

  • 27.
    Engström, Maria
    et al.
    Linköping University, Center for Medical Image Science and Visualization, CMIV. Linköping University, Department of Medical and Health Sciences, Radiology. Linköping University, Faculty of Health Sciences.
    Landtblom, Anne-Marie
    Linköping University, Center for Medical Image Science and Visualization, CMIV. Linköping University, Department of Clinical and Experimental Medicine, Neurology. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Local Health Care Services in Central Östergötland, Department of Neurology.
    Karlsson, Thomas
    Linköping University, Center for Medical Image Science and Visualization, CMIV. Linköping University, Department of Behavioural Sciences and Learning, Disability Research. Linköping University, Faculty of Arts and Sciences.
    Brain and effort: brain activation and effort-related working memory in healthy participants and patients with working memory deficits2013In: Frontiers in Human Neuroscience, ISSN 1662-5161, E-ISSN 1662-5161, Vol. 7, no 140, p. 1-17Article in journal (Refereed)
    Abstract [en]

    Despite the interest in the neuroimaging of working memory, little is still known about the neurobiology of complex working memory in tasks that require simultaneous manipulation and storage of information. In addition to the central executive network, we assumed that the recently described salience network [involving the anterior insular cortex (AIC) and the anterior cingulate cortex (ACC)] might be of particular importance to working memory tasks that require complex, effortful processing.

    Method: Healthy participants (n = 26) and participants suffering from working memory problems related to the Kleine–Levin syndrome (KLS) (a specific form of periodic idiopathic hypersomnia; n = 18) participated in the study. Participants were further divided into a high- and low-capacity group, according to performance on a working memory task (listening span). In a functional magnetic resonance imaging (fMRI) study, participants were administered the reading span complex working memory task tapping cognitive effort.

    Principal findings: The fMRI-derived blood oxygen level dependent (BOLD) signal was modulated by (1) effort in both the central executive and the salience network and (2) capacity in the salience network in that high performers evidenced a weaker BOLD signal than low performers. In the salience network there was a dichotomy between the left and the right hemisphere; the right hemisphere elicited a steeper increase of the BOLD signal as a function of increasing effort. There was also a stronger functional connectivity within the central executive network because of increased task difficulty.

    Conclusion: The ability to allocate cognitive effort in complex working memory is contingent upon focused resources in the executive and in particular the salience network. Individual capacity during the complex working memory task is related to activity in the salience (but not the executive) network so that high-capacity participants evidence a lower signal and possibly hence a larger dynamic response.

  • 28.
    Engström, Maria
    et al.
    Linköping University, Department of Medical and Health Sciences, Division of Radiological Sciences. Linköping University, Faculty of Medicine and Health Sciences. Linköping University, Center for Medical Image Science and Visualization (CMIV).
    Landtblom, Anne-Marie
    Linköping University, Department of Clinical and Experimental Medicine, Division of Neuro and Inflammation Science. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Local Health Care Services in Central Östergötland, Department of Neurology. Linköping University, Center for Medical Image Science and Visualization (CMIV). Uppsala University, Sweden.
    Karlsson, Thomas
    Linköping University, Department of Behavioural Sciences and Learning, Disability Research. Linköping University, Faculty of Arts and Sciences. Linköping University, Center for Medical Image Science and Visualization (CMIV).
    New hypothesis on pontine-frontal eye field connectivity in Kleine-Levin syndrome2016In: Journal of Sleep Research, ISSN 0962-1105, E-ISSN 1365-2869, Vol. 25, no 6, p. 716-719Article in journal (Refereed)
    Abstract [en]

    Previous studies have indicated involvement of the thalamus and the pons in Kleine-Levin syndrome. In the present study, functional connectivity of the thalamus and the pons was investigated in asymptomatic patients with Kleine-Levin syndrome and healthy controls. Twelve patients and 14 healthy controls were investigated by functional magnetic resonance imaging during rest. Resting state images were analysed using seed regions of interest in the thalamus and the pons. The results showed significantly lower functional connectivity between the pons and the frontal eye field in persons with Kleine-Levin syndrome compared with healthy controls. There were no connectivity differences involving the thalamus. Based on these findings, a relation is proposed between the sleep disorder Kleine-Levin syndrome and cerebral control of eye movements, which in turn is related to visual attention and working memory. This hypothesis has to be tested in future studies of oculomotor control in Kleine-Levin syndrome.

  • 29.
    Engström, Maria
    et al.
    Linköping University, Department of Medical and Health Sciences, Division of Radiological Sciences. Linköping University, Faculty of Medicine and Health Sciences. Linköping University, Center for Medical Image Science and Visualization (CMIV).
    Latini, Francesco
    Department of Neuroscience, Section of Neurosurgery, Uppsala University, Uppsala, Sweden.
    Landtblom, Anne-Marie
    Linköping University, Center for Medical Image Science and Visualization (CMIV). Region Östergötland, Local Health Care Services in Central Östergötland, Department of Neurology. Linköping University, Department of Clinical and Experimental Medicine, Division of Neuro and Inflammation Science. Linköping University, Faculty of Medicine and Health Sciences. Department of Neuroscience, Section of Neurology, Uppsala University, Uppsala, Sweden.
    Neuroimaging in the Kleine-Levin Syndrome2018In: Current Neurology and Neuroscience Reports, ISSN 1528-4042, E-ISSN 1534-6293, Vol. 18, no 9, article id 58Article, review/survey (Refereed)
    Abstract [en]

    The purpose was to review the most recent literature on neuroimaging in the Kleine-Levin syndrome (KLS). We aimed to investigate if frontotemporal and thalamic dysfunction are key KLS signatures, and if recent research indicates other brain networks of interest that elucidate KLS symptomatology and aetiology. In a comprehensive literature search, we found 12 original articles published 2013-2018. Most studies report deviations related to cerebral perfusion, glucose metabolism, or blood-oxygen-level-dependent responses in frontotemporal areas and/or the thalamus. Studies also report dysfunction in the temporoparietal junction and the oculomotor network that also were related to clinical parameters. We discuss these findings based on recent research on thalamocortical networks and brain stem white matter tracts. The hypothesis of frontotemporal and thalamic involvement in KLS was confirmed, and additional findings in the temporoparietal junction and the oculomotor system suggest a broader network involvement, which can be investigated by future high-resolution and multimodal imaging.

  • 30.
    Engström, Maria
    et al.
    Linköping University, Department of Physics, Chemistry and Biology. Linköping University, The Institute of Technology.
    Minaev, Boris
    Linköping University, Department of Physics, Chemistry and Biology. Linköping University, The Institute of Technology.
    Vahtras, Olav
    Linköping University, Department of Physics, Chemistry and Biology. Linköping University, The Institute of Technology.
    Ņgren, Hans
    Linköping University, Department of Physics, Chemistry and Biology. Linköping University, The Institute of Technology.
    Linear response calculations of electronic g-factors and spin-rotational coupling constants for diatomic molecules with a triplet ground state1998In: Chemical Physics, ISSN 0301-0104, E-ISSN 1873-4421, Vol. 237, no 1-2, p. 149-158Article in journal (Refereed)
    Abstract [en]

    Electronic g-factors for ESR spectra of a number of diatomic molecules with a ground X3Σ- state and their electronic spin-rotational coupling constants have been calculated by a linear response method. General expressions are used for the second order correction to the electronic g-factor which account for spin-orbit coupling induced admixtures from all excited triplet states to the ground state orbital magnetism. First order corrections - the spin-Zeeman kinetic energy contribution and the one-electron spin-Zeeman gauge contribution - to the g-factor are also accounted for. Calculated g-factors and spin-rotational coupling constants are in a good agreement with available experimental data. In particular, the positive, anomalous, sign of the spin-rotational coupling constant of the PF radical is reproduced.

  • 31.
    Engström, Maria
    et al.
    Linköping University, Department of Medical and Health Sciences, Radiology. Linköping University, Faculty of Health Sciences. Linköping University, Center for Medical Image Science and Visualization (CMIV).
    Pihlsgård, Johan
    Linköping University, Center for Medical Image Science and Visualization (CMIV). Linköping University, Department of Medical and Health Sciences. Linköping University, Faculty of Health Sciences.
    Lundberg, Peter
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medical and Health Sciences, Radiology. Linköping University, Department of Medical and Health Sciences, Radiation Physics. Linköping University, Center for Medical Image Science and Visualization (CMIV). Östergötlands Läns Landsting, Center for Diagnostics, Department of Radiology in Linköping. Östergötlands Läns Landsting, Center for Surgery, Orthopaedics and Cancer Treatment, Department of Radiation Physics.
    Axelsson Söderfeldt, Birgitta
    Linköping University, Department of Clinical and Experimental Medicine, Neurology. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Local Health Care Services in Central Östergötland, Department of Neurology. Linköping University, Center for Medical Image Science and Visualization (CMIV).
    Functional Magnetic Resonance Imaging of Hippocampal Activation During Silent Mantra Meditation2010In: Journal of Alternative and Complementary Medicine, ISSN 1075-5535, E-ISSN 1557-7708, Vol. 16, no 12, p. 1253-1258Article in journal (Refereed)
    Abstract [en]

    Objectives: The objective of the present study was to investigate whether moderately experienced meditators activate hippocampus and the prefrontal cortex during silent mantra meditation, as has been observed in earlier studies on subjects with several years of practice. Methods: Subjects with less than 2 years of meditation practice according to the Kundalini yoga or Acem tradition were examined by functional magnetic resonance imaging during silent mantra meditation, using an on-off block design. Whole-brain as well as region-of-interest analyses were performed. Results: The most significant activation was found in the bilateral hippocampus/parahippocampal formations. Other areas with significant activation were the bilateral middle cingulate cortex and the bilateral precentral cortex. No activation in the anterior cingulate cortex was found, and only small activation clusters were observed in the prefrontal cortex. Conclusions: In conclusion, the main finding in this study was the significant activation in the hippocampi, which also has been correlated with meditation in several previous studies on very experienced meditators. We propose that the hippocampus is activated already after moderate meditation practice and also during different modes of meditation, including relaxation. The role of hippocampal activity during meditation should be further clarified in future studies, especially by investigating whether the meditation-correlated hippocampal activity is related to memory consolidation.

  • 32.
    Engström, Maria
    et al.
    Linköping University, Center for Medical Image Science and Visualization, CMIV. Linköping University, Department of Medicine and Health Sciences, Radiology . Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Centre for Medical Imaging, Department of Radiology in Linköping.
    Ragnehed, Mattias
    Linköping University, Department of Medicine and Health Sciences, Radiology . Linköping University, Faculty of Health Sciences.
    Lundberg, Peter
    Linköping University, Center for Medical Image Science and Visualization, CMIV. Linköping University, Department of Medicine and Health Sciences, Radiation Physics . Linköping University, Department of Medicine and Health Sciences, Radiology . Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Centre of Surgery and Oncology, Department of Radiation Physics. Östergötlands Läns Landsting, Centre for Medical Imaging, Department of Radiology in Linköping.
    On the Advantage of Data Driven Analysis in Aphasic Patients with Severe Language Latncy2010Conference paper (Other academic)
  • 33.
    Engström, Maria
    et al.
    Linköping University, Department of Medical and Health Sciences, Radiology. Linköping University, Center for Medical Image Science and Visualization, CMIV. Linköping University, Faculty of Health Sciences.
    Ragnehed, Mattias
    Linköping University, Department of Medical and Health Sciences, Radiology. Linköping University, Center for Medical Image Science and Visualization, CMIV. Linköping University, Faculty of Health Sciences.
    Lundberg, Peter
    Linköping University, Department of Medical and Health Sciences, Radiation Physics. Linköping University, Center for Medical Image Science and Visualization, CMIV. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Centre of Surgery and Oncology, Department of Radiation Physics.
    Projection screen or video goggles as stimulus modality in functional magnetic resonance imaging2005In: Magnetic Resonance Imaging, ISSN 0730-725X, E-ISSN 1873-5894, Vol. 23, no 5, p. 695-699Article in journal (Refereed)
    Abstract [en]

    The purpose of this study was to investigate the reliability of functional magnetic resonance imaging (fMRI) by using either a projection screen or video goggles as stimulus modality. A sequence of visual stimuli were presented to the same subject at different occasions. The sequence was optimized with a genetic algorithm. In five sessions the stimuli were presented using a projection screen viewed through a mirror in the head coil and in five sessions using video goggles. Failure to detect visual activation in the medial left hemisphere was observed in sessions using the projection screen as stimulus modality. Decreased thresholds for P values and cluster size resulted in activation outside the occipital lobe and did not significantly increase activated areas in this region. Results in this study indicate that presentation of fMRI tasks with visual routes is more reliable with direct input through video goggles than with the conventional use of projection screens. Failure to detect crucial visual areas has severe consequences for tumor surgery in the visual cortex. Inferior visual impression might also have negative consequences for cognitive tests with high demand on attention and perception.

  • 34.
    Engström, Maria
    et al.
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Care, Medical Radiology. Linköping University, Center for Medical Image Science and Visualization (CMIV).
    Ragnehed, Mattias
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Care, Medical Radiology. Linköping University, Center for Medical Image Science and Visualization (CMIV).
    Lundberg, Peter
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Care, Radiation Physics. Östergötlands Läns Landsting, Centre of Surgery and Oncology, Department of Radiation Physics. Linköping University, Center for Medical Image Science and Visualization (CMIV).
    Axelsson Söderfeldt, Birgitta
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Neuroscience and Locomotion, Neurology. Östergötlands Läns Landsting, Local Health Care Services in Central Östergötland, Department of Neurology. Linköping University, Center for Medical Image Science and Visualization (CMIV).
    Paradigm design of sensory–motor and language tests in clinical fMRI2004In: Neurophysiologie clinique, ISSN 0987-7053, E-ISSN 1769-7131, Vol. 34, no 6, p. 267-277Article in journal (Refereed)
    Abstract [en]

    Functional magnetic resonance imaging (fMRI) paradigms on sensory–motor and language functions are reviewed from a clinical user’s perspective. The objective was to identify special requirements regarding the design of fMRI paradigms for clinical applications. A wide range of methods for setting up fMRI examinations were found in the literature. It was concluded that there is a need for standardised procedures adapted for clinical settings. Sensory–motor activation patterns do not vary much at different hand motion tasks. Nevertheless it is one of the most important clinical tests. In contrast, the language system is much more complex. In several studies it has been observed that word production tasks are preferable in determination of language lateralisation. Broca’s area is activated by most tasks, whereas sentence processing and semantic decision also involve activation in temporoparietal and frontal areas. However, combined task analysis (CTA) of several different tasks has been found to be more robust and reliable for clinical fMRI compared to separate task analysis.

  • 35.
    Engström, Maria
    et al.
    Linköping University, Department of Medicine and Health Sciences, Radiology . Östergötlands Läns Landsting, Centre for Medical Imaging. Östergötlands Läns Landsting, Centre for Medical Imaging, Department of Radiology in Linköping. Linköping University, Faculty of Health Sciences.
    Söderfeldt, Birgitta
    Karolinska institutet, Stockholm.
    Brain Activation During Compassion Meditation: A Case Study2010In: Journal of Alternative and Complementary Medicine, ISSN 1075-5535, E-ISSN 1557-7708, Vol. 16, no 5, p. 597-599Article in journal (Refereed)
    Abstract [en]

    Objectives: B.L. is a Tibetan Buddhist with many years of compassion meditation practice. During meditation B.L. uses a technique to generate a feeling of love and compassion while reciting a mantra. The aim of the present study was to investigate the neural correlates of compassion meditation in 1 experienced meditator.

    Methods: B.L. was examined by functional magnetic resonance imaging during compassion meditation, applying a paradigm with meditation and word repetition blocks.

    Results: The most significant finding was the activation in the left medial prefrontal cortex extending to the anterior cingulate gyrus. Other significant loci of activation were observed in the right caudate body extending to the right insula and in the left midbrain close to the hypothalamus.

    Conclusions: The results in this study are in concordance with the hypothesis that compassion meditation is accompanied by activation in brain areas involved with empathy as well as with happy and pleasant feelings (i.e., the left medial prefrontal cortex and the anterior cingulate gyrus).

  • 36.
    Engström, Maria
    et al.
    Linköping University, Department of Medicine and Health Sciences, Radiology. Linköping University, Center for Medical Image Science and Visualization, CMIV. Linköping University, Faculty of Health Sciences.
    Tisell, Anders
    Linköping University, Center for Medical Image Science and Visualization, CMIV. Linköping University, Department of Medicine and Health Sciences, Radiation Physics. Östergötlands Läns Landsting, Centre for Surgery, Orthopaedics and Cancer Treatment, Department of Radiation Physics UHL. Linköping University, Faculty of Health Sciences.
    Dahlqvist Leinhard, Olof
    Linköping University, Center for Medical Image Science and Visualization, CMIV. Linköping University, Department of Medicine and Health Sciences, Radiation Physics. Linköping University, Faculty of Health Sciences.
    Karlsson, T
    Vigren, P
    Lundberg, Peter
    Linköping University, Center for Medical Image Science and Visualization, CMIV. Linköping University, Department of Medicine and Health Sciences, Radiation Physics. Linköping University, Department of Medicine and Health Sciences, Radiology. Östergötlands Läns Landsting, Centre for Surgery, Orthopaedics and Cancer Treatment, Department of Radiation Physics UHL. Östergötlands Läns Landsting, Centre for Diagnostics, Department of Radiology in Linköping.
    Landtblom, Anne-Marie
    Linköping University, Center for Medical Image Science and Visualization, CMIV. Linköping University, Department of Clinical and Experimental Medicine, Psychiatry. Östergötlands Läns Landsting, Sinnescentrum, Department of Neurosurgery UHL. Linköping University, Faculty of Health Sciences.
    Kleine-Levin Syndrom (KLS) – A bipolar disorder?2009Conference paper (Other academic)
  • 37.
    Engström, Maria
    et al.
    Linköping University, Department of Physics, Chemistry and Biology. Linköping University, The Institute of Technology.
    Vahtras, Olav
    Linköping University, Department of Physics, Chemistry and Biology. Linköping University, The Institute of Technology.
    Ågren, Hans
    Linköping University, Department of Physics, Chemistry and Biology. Linköping University, The Institute of Technology.
    Hartree-Fock linear response calculations of g-tensors of substituted benzene radicals1999In: Chemical Physics, ISSN 0301-0104, E-ISSN 1873-4421, Vol. 243, no 3, p. 263-271Article in journal (Refereed)
    Abstract [en]

    Linear response theory has been applied for calculations of g-tensors of organic radicals in order to test the range of validity of restricted Hartree-Fock reference states. The g-values were calculated for the benzene cation (C6H6+), the benzene anion (C6H6-), hydropyrazine (C4H5N2), the dihydropyrazine cation (C4H6N2+), the aniline radical (C6H5NH), the p-benzoquinone anion (C6H4O2-), phenoxyl (C6H5O), the nitrobenzene anion (C6H5NO2-), and the nitropyridine anion (C5H4N2O2-). Influence of variations of structural parameters on the g-tensor components were investigated. Calculated g-values were in excellent agreement with experiment for six out of nine radicals. Two radicals - the p-benzoquinone anion and aniline radical - showed minor discrepancies, while the g-tensor of the phenoxyl radical was incorrect. The problem with the phenoxyl radical was traced to a complex electronic structure and optical spectrum. Results consistent with experiment could in that case only be obtained with electron correlated calculations.

  • 38.
    Engström, Maria
    et al.
    Linköping University, Department of Medical and Health Sciences, Radiology. Linköping University, Faculty of Health Sciences. Linköping University, Center for Medical Image Science and Visualization (CMIV). Östergötlands Läns Landsting, Centre for Medical Imaging, Department of Radiology in Linköping.
    Vigren, Patrick
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Clinical and Experimental Medicine, Neurology.
    Karlsson, Thomas
    Linköping University, Department of Behavioural Sciences and Learning. Linköping University, Faculty of Arts and Sciences. Linköping University, Center for Medical Image Science and Visualization (CMIV).
    Landtblom, Anne-Marie
    Linköping University, Department of Clinical and Experimental Medicine, Neurology. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Local Health Care Services in Central Östergötland, Department of Neurology. Östergötlands Läns Landsting, Local Health Care Services in West Östergötland, Department of Medical Specialist in Motala. Linköping University, Center for Medical Image Science and Visualization (CMIV).
    Working Memory in 8 Kleine-Levin Syndrome Patients: An fMRI Study2009In: SLEEP, ISSN 0161-8105, Vol. 32, no 5, p. 681-688Article in journal (Refereed)
    Abstract [en]

    Study Objectives: The objectives of this study were to investigate possible neuropathology behind the Kleine-Levin Syndrome (KLS), a severe form of hypersomnia with onset during adolescence.

    Design: Functional magnetic resonance imaging (fMRI) applying a verbal working memory task was used in conjunction with a paper-and-pencil version of the task. Participants: Eight patients with KLS and 12 healthy volunteers participated in the study.

    Results: The results revealed a pattern of increased thalamic activity and reduced frontal activity (involving the anterior cingulate and adjacent prefrontal cortex) while performing a reading span task.

    Discussion: This finding may explain the clinical symptoms observed in KLS, in that the thalamus is known to be involved in the control of sleep. Given the increasing access to fMRI, this investigation may aid clinicians in the diagnosis of patients suffering from severe forms of hypersomnia.

  • 39.
    Fornander, Lotta
    et al.
    Region Östergötland, Center for Surgery, Orthopaedics and Cancer Treatment, Department of Orthopaedics in Norrköping. Department of Clinical Neuroscience, Karolinska Institutet, Stockholm, Sweden.
    Nyman, Torbjörn
    Region Östergötland, Anaesthetics, Operations and Specialty Surgery Center, Department of Anaesthesiology and Intensive Care in Norrköping.
    Hansson, Thomas
    Linköping University, Department of Clinical and Experimental Medicine, Division of Clinical Sciences. Region Östergötland, Anaesthetics, Operations and Specialty Surgery Center, Department of Hand and Plastic Surgery. Linköping University, Center for Medical Image Science and Visualization (CMIV). Linköping University, Faculty of Medicine and Health Sciences.
    Brismar, Tom
    Department of Clinical Neuroscience, Karolinska Institutet, Stockholm, Sweden.
    Engström, Maria
    Linköping University, Department of Medical and Health Sciences, Division of Radiological Sciences. Linköping University, Faculty of Medicine and Health Sciences. Linköping University, Center for Medical Image Science and Visualization (CMIV).
    Inter-hemispheric plasticity in patients with median nerve injury2016In: Neuroscience Letters, ISSN 0304-3940, E-ISSN 1872-7972, Vol. 628, p. 59-66Article in journal (Refereed)
    Abstract [en]

    Peripheral nerve injuries result in reorganization within the contralateral hemisphere. Furthermore, recent animal and human studies have suggested that the plastic changes in response to peripheral nerve injury also include several areas of the ipsilateral hemisphere. The objective of this study was to map the inter-hemispheric plasticity in response to median nerve injury, to investigate normal differences in contra- and ipsilateral activation, and to study the impact of event-related or blocked functional magnetic resonance imaging (fMRI) design on ipsilateral activation. Four patients with median nerve injury at the wrist (injured and epineurally sutured amp;gt;2 years earlier) and ten healthy volunteers were included. 3T fMRI was used to map the hemodynamic response to brain activity during tactile stimulation of the fingers, and a laterality index (LI) was calculated. Stimulation of Digits II-III of the injured hand resulted in a reduction in contralateral activation in the somatosensory area SI. Patients had a lower LI (0.21 +/- 0.15) compared to healthy controls (0.60 +/- 0.26) indicating greater ipsilateral activation of the primary somatosensory cortex. The spatial dispersion of the coordinates for areas SI and SII was larger in the ipsilateral than in the contralateral hemisphere in the healthy controls, and was increased in the contralateral hemisphere of the patients compared to the healthy controls. There was no difference in LI between the event-related and blocked paradigms. In conclusion, patients with median nerve injury have increased ipsilateral SI area activation, and spatially more dispersed contralateral SI activation during tactile stimulation of their injured hand. In normal subjects ipsilateral activation has larger spatial distribution than the contralateral. Previous findings in patients performed with the blocked fMRI paradigm were confirmed. The increase in ipsilateral SI activation may be due to an interhemispheric disinhibition associated with changes in the afferent signal inflow to the contralateral primary somatosensory cortex.

  • 40.
    Fortin, Marc-Andre
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology.
    Petoral, Rodrigo Jr
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Sensor Science and Molecular Physics .
    Söderlind, Fredrik
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology.
    Käll, Per-Olov
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Physical Chemistry .
    Engström, Maria
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Care, Medical Radiology. Linköping University, Center for Medical Image Science and Visualization, CMIV.
    Uvdal, Kajsa
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Sensor Science and Molecular Physics .
    Synthesis of gadolinium oxide nanoparticles as a contrast agent in MRI2006In: Trends in Nanotechnology,2006, 2006Conference paper (Other academic)
    Abstract [en]

           

  • 41.
    Fortin, Marc-André
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Molecular Surface Physics and Nano Science. Linköping University, Faculty of Science & Engineering.
    Petoral Jr, Rodrigo M.
    Linköping University, Department of Physics, Chemistry and Biology, Molecular Surface Physics and Nano Science. Linköping University, Faculty of Science & Engineering.
    Söderlind, Fredrik
    Linköping University, Department of Physics, Chemistry and Biology, Physical Chemistry. Linköping University, Faculty of Science & Engineering.
    Klasson, Anna
    Linköping University, Center for Medical Image Science and Visualization (CMIV). Linköping University, Department of Medical and Health Sciences, Radiology. Linköping University, Faculty of Health Sciences.
    Engström, Maria
    Linköping University, Center for Medical Image Science and Visualization (CMIV). Linköping University, Department of Medical and Health Sciences, Radiology. Linköping University, Faculty of Health Sciences.
    Veres, Teodor
    National Research Council of Canada (CNRC-IMI) 75, Boucherville, QC, Canada.
    Käll, Per-Olov
    Linköping University, Department of Physics, Chemistry and Biology, Physical Chemistry. Linköping University, The Institute of Technology.
    Uvdal, Kajsa
    Linköping University, Department of Physics, Chemistry and Biology, Molecular Surface Physics and Nano Science. Linköping University, Faculty of Science & Engineering.
    Polyethylene glycol-cover ultra-small Gd2O3 nanoparticles for positive contras at 1.5 T magnetic resonance clinical scanning2007In: Nanotechnology, ISSN 0957-4484, Vol. 18, no 39, p. 395501-Article in journal (Refereed)
    Abstract [en]

    The size distribution and magnetic properties of ultra-small gadolinium oxide crystals (US-Gd2O3) were studied, and the impact of polyethylene glycol capping on the relaxivity constants (r1, r2) and signal intensity with this contrast agent was investigated. Size distribution and magnetic properties of US-Gd2O3 nanocrystals were measured with a TEM and PPMS magnetometer. For relaxation studies, diethylene glycol (DEG)-capped US-Gd2O3 nanocrystals were reacted with PEG-silane (MW 5000). Suspensions were adequately dialyzed in water to eliminate traces of Gd3+ and surfactants. The particle hydrodynamic radius was measured with dynamic light scattering (DLS) and the proton relaxation times were measured with a 1.5 T MRI scanner. Parallel studies were performed with DEG–Gd2O3 and PEG-silane–SPGO (Gd2O3,< 40 nm diameter). The small and narrow size distribution of US-Gd2O3 was confirmed with TEM (~3 nm) and DLS. PEG-silane–US-Gd2O3 relaxation parameters were twice as high as for Gd–DTPA and the r2/r1 ratio was 1.4. PEG-silane–SPGO gave low r1 relaxivities and high r2/r1 ratios, less compatible with positive contrast agent requirements. Higher r1 were obtained with PEG-silane in comparison to DEG–Gd2O3. Treatment of DEG–US-Gd2O3 with PEG-silane provides enhanced relaxivity while preventing aggregation of the oxide cores. This study confirms that PEG-covered Gd2O3 nanoparticles can be used for positively contrasted MR applications requiring stability, biocompatible coatings and nanocrystal functionalization.

  • 42.
    Gauffin, Helena
    et al.
    Linköping University, Department of Clinical and Experimental Medicine, Neurology. Linköping University, Faculty of Health Sciences.
    van Ettinger-Veenstra, Helene
    Linköping University, Center for Medical Image Science and Visualization, CMIV. Linköping University, Department of Medical and Health Sciences, Radiation Physics. Linköping University, Faculty of Health Sciences.
    Landtblom, Anne-Marie
    Linköping University, Center for Medical Image Science and Visualization, CMIV. Linköping University, Department of Clinical and Experimental Medicine, Neurobiology. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Local Health Care Services in Central Östergötland, Department of Neurology.
    Ulrici, Daniel
    Linköping University, Department of Clinical and Experimental Medicine, Neurology. Linköping University, Faculty of Health Sciences.
    McAllister, Anita
    Linköping University, Department of Clinical and Experimental Medicine, Speech and Language Pathology. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Sinnescentrum, Department of ENT - Head and Neck Surgery UHL.
    Karlsson, Thomas
    Linköping University, Center for Medical Image Science and Visualization, CMIV. Linköping University, The Swedish Institute for Disability Research. Linköping University, Faculty of Arts and Sciences.
    Engström, Maria
    Linköping University, Center for Medical Image Science and Visualization, CMIV. Linköping University, Department of Medical and Health Sciences, Radiology. Linköping University, Faculty of Health Sciences.
    Cognitive problems in young adults with epilepsy: Language deficits correlate to brain activation and self-esteemManuscript (preprint) (Other academic)
    Abstract [en]

    People with epilepsy often display cognitive decline. Language function in epilepsy has been most thoroughly studied in temporal lobe epilepsy, but the impact of language deficits in epilepsy is not fully understood. The aim of this study was to evaluate the effect of epilepsy on language function with functional magnetic resonance imaging of brain activation, with behavioral methods and to relate language performance to demographic data, self-esteem and Quality of life. We specifically aimed to investigate if variation in epilepsy origin would relate to differences in language performance and if these differences could be associated with specific language activation patterns in the brain. We recruited people with epilepsy (29 in total), with focal onset seizures in either the left or right hemispheres or with generalized epilepsy; and 27 matching healthy controls. The participants’ language skills were measured with a phonemic word fluency test and a broader test measuring higher language functions. Functional magnetic resonance images of the brain were obtained during a word fluency and a sentence reading paradigm. Questionnaires on self-esteem and quality of life were collected. People with epilepsy of both focal and generalized origin had impaired function in semantic and verbal fluency tasks compared to the controls. The causes of language impairment were multifactorial; the most important determinants were education and onset age of epilepsy. Impaired language function was correlated to low self-esteem for participants with focal onset seizures; however Quality of life did not seem to be affected by language impairment. The functional magnetic resonance imaging investigation demonstrated altered functional activity during language tasks for participants with epilepsy compared to healthy controls. In epilepsy with focal seizures originating in the left hemisphere we found increased bilateral  activation of supporting areas in the anterior mid-cingulate cortex and the left anterior ventral insula, indicating a compensational functional reorganization. In generalized epilepsy, the functional language network showed an imbalance expressed as an inadequate  suppression of activation in the left anterior temporal lobe during semantic processing. Our study shows not only that reduced language functioning is present in people with epilepsy other than in the temporal lobe, but also that frequency of convulsive seizures correlates to language impairment. For patients with focalized seizures, low self esteem correlated also to language impairment. Our results highlight the importance of addressing the negative consequences of language decline in people with epilepsy of both focal and generalized origin.

  • 43.
    Gauffin, Helena
    et al.
    Linköping University, Center for Medical Image Science and Visualization (CMIV). Linköping University, Department of Clinical and Experimental Medicine, Neurology. Linköping University, Faculty of Health Sciences.
    van Ettinger-Veenstra, Helene
    Linköping University, Center for Medical Image Science and Visualization (CMIV). Linköping University, Department of Medical and Health Sciences, Radiology. Linköping University, Faculty of Health Sciences.
    Landtblom, Anne-Marie
    Linköping University, Center for Medical Image Science and Visualization (CMIV). Linköping University, Department of Clinical and Experimental Medicine, Neurology. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Local Health Care Services in Central Östergötland, Department of Neurology.
    Ulrici, Daniel
    Linköping University, Department of Clinical and Experimental Medicine, Neurology. Linköping University, Faculty of Health Sciences.
    McAllister, Anita
    Linköping University, Department of Clinical and Experimental Medicine, Speech and Language Pathology. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Anaesthetics, Operations and Specialty Surgery Center, Department of Otorhinolaryngology in Linköping.
    Karlsson, Thomas
    Linköping University, Center for Medical Image Science and Visualization (CMIV). Linköping University, Department of Behavioural Sciences and Learning, Disability Research. Linköping University, Faculty of Arts and Sciences.
    Engström, Maria
    Linköping University, Center for Medical Image Science and Visualization (CMIV). Linköping University, Department of Medical and Health Sciences, Radiology. Linköping University, Faculty of Health Sciences.
    Impaired language function in generalized epilepsy: Inadequate suppression of the default mode network2013In: Epilepsy & Behavior, ISSN 1525-5050, E-ISSN 1525-5069, Vol. 28, no 1, p. 26-35Article in journal (Refereed)
    Abstract [en]

    We aimed to study the effect of a potential default mode network (DMN) dysfunction on language performance in epilepsy. Language dysfunction in focal epilepsy has previously been connected to brain damage in language-associated cortical areas. In this work, we studied generalized epilepsy (GE) without focal brain damage to see if the language function was impaired. We used functional magnetic resonance imaging (fMRI) to investigate if the DMN was involved. Eleven persons with GE and 28 healthy controls were examined with fMRI during a sentence-reading task. We demonstrated impaired language function, reduced suppression of DMN, and, specifically, an inadequate suppression of activation in the left anterior temporal lobe and the posterior cingulate cortex, as well as an aberrant activation in the right hippocampal formation. Our results highlight the presence of language decline in people with epilepsy of not only focal but also generalized origin.

  • 44.
    Georgiopoulos, Charalampos
    et al.
    Linköping University, Department of Medical and Health Sciences, Division of Radiological Sciences. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Center for Diagnostics, Department of Radiology in Linköping.
    Davidsson, Anette
    Linköping University, Department of Medical and Health Sciences, Division of Cardiovascular Medicine. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Heart and Medicine Center, Department of Clinical Physiology in Linköping.
    Engström, Maria
    Linköping University, Department of Medical and Health Sciences, Division of Radiological Sciences. Linköping University, Faculty of Health Sciences. Linköping University, Center for Medical Image Science and Visualization (CMIV).
    Larsson, Elna-Marie
    Uppsala University, Sweden.
    Zachrisson, Helene
    Linköping University, Department of Medical and Health Sciences, Division of Cardiovascular Medicine. Linköping University, Faculty of Health Sciences. Region Östergötland, Heart and Medicine Center, Department of Clinical Physiology in Linköping. Linköping University, Center for Medical Image Science and Visualization (CMIV).
    Dizdar (Dizdar Segrell), Nil
    Linköping University, Department of Clinical and Experimental Medicine, Division of Neuro and Inflammation Science. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Local Health Care Services in Central Östergötland, Department of Neurology.
    The diagnostic value of dopamine transporter imaging and olfactory testing in patients with parkinsonian syndromes2015In: Journal of Neurology, ISSN 0340-5354, E-ISSN 1432-1459, Vol. 262, no 9, p. 2154-2163Article in journal (Refereed)
    Abstract [en]

    The aim of the study was to compare the efficacy of olfactory testing and presynaptic dopamine imaging in diagnosing Parkinsons disease (PD) and atypical parkinsonian syndromes (APS); to evaluate if the combination of these two diagnostic tools can improve their diagnostic value. A prospective investigation of 24 PD patients, 16 APS patients and 15 patients with non-parkinsonian syndromes was performed during an 18-month period. Single photon emission computed tomography with the presynaptic radioligand I-123-FP-CIT (DaTSCAN (R)) and olfactory testing with the Brief 12-item Smell Identification Test (B-SIT) were performed in all patients. DaTSCAN was analysed semi-quantitatively, by calculating two different striatal uptake ratios, and visually according to a predefined ranking scale. B-SIT score was significantly lower for PD patients, but not significantly different between APS and non-parkinsonism. The visual assessment of DaTSCAN had higher sensitivity, specificity and diagnostic accuracy compared to olfactory testing. Most PD patients (75 %) had visually predominant dopamine depletion in putamen, while most APS patients (56 %) had visually severe dopamine depletion both in putamen and in caudate nucleus. The combination of DaTSCAN and B-SIT led to a higher rate of correctly classified patients. Olfactory testing can distinguish PD from non-parkinsonism, but not PD from APS or APS from non-parkinsonism. DaTSCAN is more efficient than olfactory testing and can be valuable in differentiating PD from APS. However, combining olfactory testing and DaTSCAN imaging has a higher predictive value than these two methods separately.

  • 45.
    Georgiopoulos, Charalampos
    et al.
    Linköping University, Department of Medical and Health Sciences, Division of Radiological Sciences. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Center for Diagnostics, Department of Radiology in Linköping.
    Warntjes, Marcel Jan Bertus
    Linköping University, Department of Medical and Health Sciences, Division of Cardiovascular Medicine. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Heart and Medicine Center, Department of Clinical Physiology in Linköping. Linköping University, Center for Medical Image Science and Visualization (CMIV). SyntheticMR AB, Linkoping, Sweden.
    Dizdar Segrell, Nil
    Linköping University, Department of Clinical and Experimental Medicine, Division of Neuro and Inflammation Science. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Local Health Care Services in Central Östergötland, Department of Neurology.
    Zachrisson, Helene
    Linköping University, Department of Medical and Health Sciences, Division of Cardiovascular Medicine. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Heart and Medicine Center, Department of Clinical Physiology in Linköping. Linköping University, Center for Medical Image Science and Visualization (CMIV).
    Engström, Maria
    Linköping University, Department of Medical and Health Sciences, Division of Radiological Sciences. Linköping University, Faculty of Medicine and Health Sciences. Linköping University, Center for Medical Image Science and Visualization (CMIV).
    Haller, Sven
    Affidea CDRC Centre Diagnost Radiol Carouge SA, Switzerland; Uppsala University, Sweden.
    Larsson, Elna-Marie
    Uppsala University, Sweden.
    Olfactory Impairment in Parkinsons Disease Studied with Diffusion Tensor and Magnetization Transfer Imaging2017In: Journal of Parkinson's Disease, ISSN 1877-7171, E-ISSN 1877-718X, Vol. 7, no 2, p. 301-311Article in journal (Refereed)
    Abstract [en]

    Background: Olfactory impairment is an early manifestation of Parkinsons disease (PD). Diffusion Tensor Imaging (DTI) and Magnetization Transfer (MT) are two imaging techniques that allow noninvasive detection of microstructural changes in the cerebral white matter. Objective: To assess white matter alterations associated with olfactory impairment in PD, using a binary imaging approach with DTI and MT. Methods: 22 PD patients and 13 healthy controls were examined with DTI, MT and an odor discrimination test. DTI data were first analyzed with tract-based spatial statistics (TBSS) in order to detect differences in fractional anisotropy, mean, radial and axial diffusivity between PD patients and controls. Voxelwise randomized permutation was employed for the MT analysis, after spatial and intensity normalization. Additionally, ROI analysis was performed on both the DTI and MT data, focused on the white matter adjacent to olfactory brain regions. Results: Whole brain voxelwise analysis revealed decreased axial diffusivity in the left uncinate fasciculus and the white matter adjacent to the left olfactory sulcus of PD patients. ROI analysis demonstrated decreased axial diffusivity in the right orbitofrontal cortex, as well as decreased mean diffusivity and axial diffusivity in the white matter of the left entorhinal cortex of PD patients. There were no significant differences regarding fractional anisotropy, radial diffusivity or MT between patients and controls. Conclusions: ROI analysis of DTI could detect microstructural changes in the white matter adjacent to olfactory areas in PD patients, whereas MT imaging could not.

  • 46.
    Georgiopoulos, Charalampos
    et al.
    Linköping University, Department of Medical and Health Sciences, Division of Radiological Sciences. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Center for Diagnostics, Department of Radiology in Linköping. Linköping University, Center for Medical Image Science and Visualization (CMIV).
    Witt, Suzanne Tyson
    Linköping University, Center for Medical Image Science and Visualization (CMIV).
    Haller, Sven
    Affidea CDRC Ctr Diagnost Radiol Carouge SA, Switzerland; Uppsala Univ, Sweden.
    Dizdar Segrell, Nil
    Linköping University, Department of Clinical and Experimental Medicine, Division of Neuro and Inflammation Science. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Local Health Care Services in Central Östergötland, Department of Neurology.
    Zachrisson, Helene
    Linköping University, Department of Medical and Health Sciences, Division of Cardiovascular Medicine. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Heart and Medicine Center, Department of Clinical Physiology in Linköping.
    Engström, Maria
    Linköping University, Department of Medical and Health Sciences, Division of Radiological Sciences. Linköping University, Faculty of Medicine and Health Sciences. Linköping University, Center for Medical Image Science and Visualization (CMIV).
    Larsson, Elna-Marie
    Uppsala Univ, Sweden.
    Olfactory fMRI: Implications of Stimulation Length and Repetition Time2018In: Chemical Senses, ISSN 0379-864X, E-ISSN 1464-3553, Vol. 43, no 6, p. 389-398Article in journal (Refereed)
    Abstract [en]

    Studying olfaction with functional magnetic resonance imaging (fMRI) poses various methodological challenges. This study aimed to investigate the effects of stimulation length and repetition time (TR) on the activation pattern of 4 olfactory brain regions: the anterior and the posterior piriform cortex, the orbitofrontal cortex, and the insula. Twenty-two healthy participants with normal olfaction were examined with fMRI, with 2 stimulation lengths (6 s and 15 s) and 2 TRs (0.901 s and 1.34 s). Data were analyzed using General Linear Model (GLM), Tensorial Independent Component Analysis (TICA), and by plotting the event-related time course of brain activation in the 4 olfactory regions of interest. The statistical analysis of the time courses revealed that short TR was associated with more pronounced signal increase and short stimulation was associated with shorter time to peak signal. Additionally, both long stimulation and short TR were associated with oscillatory time courses, whereas both short stimulation and short TR resulted in more typical time courses. GLM analysis showed that the combination of short stimulation and short TR could result in visually larger activation within these olfactory areas. TICA validated that the tested paradigm was spatially and temporally associated with a functionally connected network that included all 4 olfactory regions. In conclusion, the combination of short stimulation and short TR is associated with higher signal increase and shorter time to peak, making it more amenable to standard GLM-type analyses than long stimulation and long TR, and it should, thus, be preferable for olfactory fMRI.

  • 47.
    Gustafsson, Håkan
    et al.
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medical and Health Sciences, Radiation Physics. Linköping University, Center for Medical Image Science and Visualization (CMIV).
    Ahrén, Maria
    Linköping University, Department of Physics, Chemistry and Biology, Molecular Surface Physics and Nano Science. Linköping University, Faculty of Science & Engineering.
    Söderlind, Fredrik
    Linköping University, Department of Physics, Chemistry and Biology, Chemistry. Linköping University, Faculty of Science & Engineering.
    Córdoba Gallego, José M.
    Linköping University, Department of Physics, Chemistry and Biology, Nanostructured Materials. Linköping University, The Institute of Technology.
    Käll, Per-Olov
    Linköping University, Department of Physics, Chemistry and Biology, Physical Chemistry. Linköping University, Faculty of Science & Engineering.
    Nordblad, Per
    Uppsala Universitet.
    Westlund, Per-Olof
    Umeå Universitet.
    Uvdal, Kajsa
    Linköping University, Department of Physics, Chemistry and Biology, Molecular Surface Physics and Nano Science. Linköping University, Faculty of Science & Engineering.
    Engström, Maria
    Linköping University, Department of Medical and Health Sciences, Radiology. Linköping University, Center for Medical Image Science and Visualization (CMIV). Linköping University, Faculty of Health Sciences.
    Magnetic and Electron Spin Relaxation Properties of (GdxY1-x)2O3 (0 ≤ x ≤ 1) Nanoparticles Synthesized by the Combustion Method. Increased Electron Spin Relaxation Times with Increasing Yttrium Content2011In: The Journal of Physical Chemistry C, ISSN 1932-7447, E-ISSN 1932-7455, Vol. 115, no 13, p. 5469-5477Article in journal (Refereed)
    Abstract [en]

    The performance of a magnetic resonance imaging contrast agent (CA) depends on several factors, including the relaxation times of the unpaired electrons in the CA. The electron spin relaxation time may be a key factor for the performance of new CAs, such as nanosized Gd2O3 particles. The aim of this work is, therefore, to study changes in the magnetic susceptibility and the electron spin relaxation time of paramagnetic Gd2O3 nanoparticles diluted with increasing amounts of diamagnetic Y2O3. Nanoparticles of (GdxY1-x)2O3 (0 e x e 1) were prepared by the combustion method and thoroughly characterized (by X-ray di.raction, transmission electron microscopy, thermogravimetry coupled with mass spectroscopy, photoelectron spectroscopy, Fourier transform infrared spectroscopy, and magnetic susceptibility measurements). Changes in the electron spin relaxation time were estimated by observations of the signal line width in electron paramagnetic resonance spectroscopy, and it was found that the line width was dependent on the concentration of yttrium, indicating that diamagnetic Y2O3 may increase the electron spin relaxation time of Gd2O3 nanoparticles.

  • 48.
    Gustafsson, Håkan
    et al.
    Linköping University, Department of Medical and Health Sciences, Radiology. Linköping University, Faculty of Health Sciences. Linköping University, Center for Medical Image Science and Visualization (CMIV).
    Berg, Kirsti
    Norwegian University of Science and Technology.
    Lindgren, Mikael
    Norwegian University of Science and Technology.
    Engström, Maria
    Linköping University, Department of Medical and Health Sciences, Radiology. Linköping University, Faculty of Health Sciences. Linköping University, Center for Medical Image Science and Visualization (CMIV).
    De Muinck, Ebo
    Linköping University, Department of Medical and Health Sciences. Linköping University, Faculty of Health Sciences. Linköping University, Center for Medical Image Science and Visualization (CMIV).
    Zachrisson, Helene
    Linköping University, Department of Medical and Health Sciences, Clinical Physiology. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Heart and Medicine Center, Department of Clinical Physiology in Linköping. Linköping University, Center for Medical Image Science and Visualization (CMIV).
    Fe(3+) Heterogeneity in Ex Vivo Carotid Atherosclerotic Plaques2011In: Free Radical Biology & Medicine, ISSN 0891-5849, E-ISSN 1873-4596, Vol. 51, no Suppl. 1, p. S40-S40Article in journal (Other academic)
    Abstract [en]

    n/a

  • 49.
    Gustafsson, Håkan
    et al.
    Linköping University, Department of Medical and Health Sciences, Division of Radiological Sciences. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Center for Diagnostics, Department of Biomedical Engineering. Linköping University, Center for Medical Image Science and Visualization (CMIV).
    Hallbeck, Martin
    Linköping University, Department of Clinical and Experimental Medicine, Division of Neuro and Inflammation Science. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Center for Diagnostics, Department of Clinical Pathology and Clinical Genetics.
    Lindgren, Mikael
    Linköping University, Department of Physics, Chemistry and Biology, Chemistry. Linköping University, The Institute of Technology. Norwegian University of Science and Technology, Norway.
    Kolbun, Natallia
    Linköping University, Department of Medical and Health Sciences, Division of Radiological Sciences. Linköping University, Faculty of Health Sciences. Linköping University, Center for Medical Image Science and Visualization (CMIV).
    Jonson, Maria
    Linköping University, Department of Physics, Chemistry and Biology, Chemistry. Linköping University, The Institute of Technology.
    Engström, Maria
    Linköping University, Department of Medical and Health Sciences, Division of Radiological Sciences. Linköping University, Faculty of Health Sciences. Linköping University, Center for Medical Image Science and Visualization (CMIV).
    de Muinck, Ebo
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medical and Health Sciences, Division of Cardiovascular Medicine. Region Östergötland, Heart and Medicine Center, Department of Cardiology in Linköping.
    Zachrisson, Helene
    Linköping University, Department of Medical and Health Sciences, Division of Cardiovascular Medicine. Linköping University, Faculty of Health Sciences. Region Östergötland, Heart and Medicine Center, Department of Clinical Physiology in Linköping.
    Visualization of oxidative stress in ex vivo biopsies using electron paramagnetic resonance imaging2015In: Magnetic Resonance in Medicine, ISSN 0740-3194, E-ISSN 1522-2594, Vol. 73, no 4, p. 1682-1691Article in journal (Refereed)
    Abstract [en]

    PURPOSE: The purpose of this study was to develop an X-Band electron paramagnetic resonance imaging protocol for visualization of oxidative stress in biopsies.

    METHODS: The developed electron paramagnetic resonance imaging protocol was based on spin trapping with the cyclic hydroxylamine spin probe 1-hydroxy-3-methoxycarbonyl-2,2,5,5-tetramethylpyrrolidine and X-Band EPR imaging. Computer software was developed for deconvolution and back-projection of the EPR image. A phantom containing radicals of known spatial characteristic was used for evaluation of the developed protocol. As a demonstration of the technique electron paramagnetic resonance imaging of oxidative stress was performed in six sections of atherosclerotic plaques. Histopathological analyses were performed on adjoining sections.

    RESULTS: The developed computer software for deconvolution and back-projection of the EPR images could accurately reproduce the shape of a phantom of known spatial distribution of radicals. The developed protocol could successfully be used to image oxidative stress in six sections of the three ex vivo atherosclerotic plaques.

    CONCLUSIONS: We have shown that oxidative stress can be imaged using a combination of spin trapping with the cyclic hydroxylamine spin probe cyclic hydroxylamine spin probe 1-hydroxy-3-methoxycarbonyl-2,2,5,5-tetramethylpyrrolidine and X-Band EPR imaging. A thorough and systematic evaluation on different types of biopsies must be performed in the future to validate the proposed technique. Magn Reson Med, 2014.

  • 50.
    Gustafsson, Håkan
    et al.
    Linköping University, Center for Medical Image Science and Visualization (CMIV). Linköping University, Department of Medical and Health Sciences, Division of Radiological Sciences. Linköping University, Faculty of Health Sciences.
    Hallbeck, Martin
    Linköping University, Department of Clinical and Experimental Medicine, Division of Inflammation Medicine. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Center for Diagnostics, Department of Clinical Pathology and Clinical Genetics.
    Norell, M.
    Linköping University, Department of Medical and Health Sciences, Division of Cardiovascular Medicine. Linköping University, Faculty of Health Sciences.
    Lindgren, Mikael
    Norwegian University of Science and Technology, Trondheim, Norway.
    Engström, Maria
    Linköping University, Center for Medical Image Science and Visualization (CMIV). Linköping University, Department of Medical and Health Sciences, Division of Radiological Sciences. Linköping University, Faculty of Health Sciences.
    Rosén, Anders
    Linköping University, Department of Clinical and Experimental Medicine, Division of Cell Biology. Linköping University, Faculty of Health Sciences.
    Zachrisson, Helene
    Linköping University, Center for Medical Image Science and Visualization (CMIV). Linköping University, Department of Medical and Health Sciences, Division of Cardiovascular Medicine. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Heart and Medicine Center, Department of Clinical Physiology in Linköping.
    Fe(III) distribution varies substantially within and between atherosclerotic plaques2014In: Magnetic Resonance in Medicine, ISSN 0740-3194, E-ISSN 1522-2594, Vol. 2, no 71, p. 885-892Article in journal (Refereed)
    Abstract [en]

    PURPOSE:

    Vulnerable atherosclerotic plaques are structurally weak and prone to rupture, presumably due to local oxidative stress. Redox active iron is linked to oxidative stress and the aim of this study was to investigate the distribution of Fe(III) in carotid plaques and its relation to vulnerability for rupture.

    METHODS:

    Atherosclerotic plaques from 10 patients (three asymptomatic and seven symptomatic) were investigated. Plaque vulnerability was classified using ultrasound and immunohistochemistry and correlated to Fe(III) measured by electron paramagnetic resonance spectroscopy.

    RESULTS:

    Large intra-plaque Fe(III) variations were found. Plaques from symptomatic patients had a higher Fe(III) concentration as compared with asymptomatic plaques (0.36 ± 0.21 vs. 0.06 ± 0.04 nmol Fe(III)/mg tissue, P < 0.05, in sections adjoining narrowest part of the plaques). All but one plaque from symptomatic patients showed signs of cap rupture. No plaque from asymptomatic patients showed signs of cap rupture. There was a significant increase in cap macrophages in plaques from symptomatic patients compared with asymptomatic patients (31 ± 11% vs. 2.3 ± 2.3%, P < 0.01).

    CONCLUSION:

    Fe(III) distribution varies substantially within atherosclerotic plaques. Plaques from symptomatic patients had significantly higher concentrations of Fe(III), signs of cap rupture and increased cap macrophage activity.

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