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  • 251.
    Tisell, Anders
    et al.
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medical and Health Sciences, Radiation Physics. Östergötlands Läns Landsting, Centre of Surgery and Oncology, Department of Radiation Physics. Linköping University, Center for Medical Image Science and Visualization (CMIV).
    Dahlqvist Leinhard, Olof
    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.
    Warntjes, Marcel, Jan Bertus
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medical and Health Sciences, Clinical Physiology. Östergötlands Läns Landsting, Heart Centre, Department of Clinical Physiology. Linköping University, Center for Medical Image Science and Visualization (CMIV).
    Engström, Maria
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medical and Health Sciences, Radiology. Linköping University, Center for Medical Image Science and Visualization (CMIV).
    Landtblom, Anne-Marie
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Clinical and Experimental Medicine. Östergötlands Läns Landsting, Local Health Care Services in Central Östergötland, Department of Neurology. Linköping University, Center for Medical Image Science and Visualization (CMIV).
    Lundberg, Peter
    Linköping University, Center for Medical Image Science and Visualization (CMIV). Linköping University, Department of Medical and Health Sciences, Radiation Physics. Linköping University, Department of Medical 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.
    Absolute quantification of LCModel water scaled metabolite concentration of 1H magnetic resonance spectroscopy (MRS) using quantitative magnetic resoonance imaging (qMRI)2008In: ESMRMB,2008, 2008Conference paper (Other academic)
    Abstract [en]

      

  • 252.
    Tsolakis, A
    et al.
    Uppsala University.
    Grimelius, L
    Uppsala University.
    Granerus, Göran
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Health Sciences, Clinical Physiology . Östergötlands Läns Landsting, Heart Centre, Department of Clinical Physiology.
    Stridsberg, M
    Uppsala University.
    Falkmer, S
    Uppsala University.
    Expression of histidine decarboxylase and vesicular monoamine transporter 2 in human enterochromaffin-like cells and gastric endocrine tumours2008In: XXVII International Congress of the International Academy of Pathology October 12-17, 2008, Athens, Greece: HISTOPATHOLOGY,ISSN 0309-0167, Volume 53, Sp Iss 1, 2008, Vol. 53, no Sp. Iss. 1, p. 113-114Conference paper (Refereed)
  • 253.
    Tödt, Tim
    et al.
    Linköping University, Department of Medical and Health Sciences, Cardiology. Östergötlands Läns Landsting, Heart and Medicine Center, Department of Cardiology in Linköping. Linköping University, Faculty of Health Sciences.
    Maret, Eva
    Ryhov County Hospital, Jönköping.
    Alfredsson, Joakim
    Linköping University, Department of Medical and Health Sciences, Cardiology. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Heart and Medicine Center, Department of Cardiology in Linköping.
    Janzon, Magnus
    Linköping University, Department of Medical and Health Sciences, Cardiology. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Heart and Medicine Center, Department of Cardiology in Linköping.
    Engvall, Jan
    Linköping University, Center for Medical Image Science and Visualization (CMIV). 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.
    Swahn, Eva
    Linköping University, Department of Medical and Health Sciences, Cardiology. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Heart and Medicine Center, Department of Cardiology in Linköping.
    Relationship between treatment delay and final infarct size in STEMI patients treated with abciximab and primary PCI2012In: BMC Cardiovascular Disorders, ISSN 1471-2261, E-ISSN 1471-2261, Vol. 12, no 9, p. 1-9Article in journal (Refereed)
    Abstract [en]

    Background

    Studies on the impact of time to treatment on myocardial infarct size have yielded   conflicting results. In this study of ST-Elevation Myocardial Infarction (STEMI) treated   with primary percutaneous coronary intervention (PCI), we set out to investigate the   relationship between the time from First Medical Contact (FMC) to the demonstration   of an open infarct related artery (IRA) and final scar size.

    Between February 2006 and September 2007, 89 STEMI patients treated with primary PCI   were studied with contrast enhanced magnetic resonance imaging (ceMRI) 4 to 8 weeks   after the infarction. Spearman correlation was computed for health care delay time   (defined as time from FMC to PCI) and myocardial injury. Multiple linear regression   was used to determine covariates independently associated with infarct size.

    Results

    An occluded artery (Thrombolysis In Myocardial Infarction, TIMI flow 0-1 at initial   angiogram) was seen in 56 patients (63%). The median FMC-to-patent artery was 89 minutes.   There was a weak correlation between time from FMC-to-patent IRA and infarct size,   r = 0.27, p = 0.01. In multiple regression analyses, LAD as the IRA, smoking and an occluded vessel   at the first angiogram, but not delay time, correlated with infarct size.

    Conclusions

    In patients with STEMI treated with primary PCI we found a weak correlation between   health care delay time and infarct size. Other factors like anterior infarction, a   patent artery pre-PCI and effects of reperfusion injury may have had greater influence   on infarct size than time-to-treatment per se.

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  • 254.
    Vågberg, Mattias
    et al.
    Department of Clinical Neurosci, Umeå.
    Lindqvist, Thomas
    Department of Radiation Science, Umeå.
    Warntjes, Marcel Jan Bertus
    Linköping University, Department of Medical and Health Sciences, Clinical Physiology. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Heart and Medicine Centre, Department of Clinical Physiology UHL.
    Sundström, Peter
    Department of Clinical Neurosci, Umeå.
    Birgander, Richard
    Department of Radiation Science, Umeå.
    Svenningsson, Anders
    Department of Clinical Neurosci, Umeå.
    Automated Determination of Brain Parenchymal Fraction in Multiple Sclerosis in NEUROLOGY, vol 78, issue , pp2012In: NEUROLOGY, American Academy of Neurology (AAN) , 2012, Vol. 78Conference paper (Refereed)
    Abstract [en]

    n/a

  • 255.
    Wallby, Lars
    et al.
    Linköping University, Department of Medicine and Health Sciences, Cardiology . Linköping University, Faculty of Health Sciences.
    Janerot Sjöberg, Birgitta
    Linköping University, Department of Medicine and Health Sciences, Clinical Physiology . Linköping University, Faculty of Health Sciences.
    Jonasson, Lena
    Linköping University, Department of Medicine and Health Sciences, Cardiology . Linköping University, Faculty of Health Sciences.
    Locht, H.
    Broqvist, Mats
    Linköping University, Department of Medicine and Health Sciences, Cardiology . Linköping University, Faculty of Health Sciences.
    History and signs of rheumatic disease in patients with significant heart valve disease2008Article in journal (Refereed)
  • 256.
    Wallby, Lars
    et al.
    Linköping University, Department of Medicine and Health Sciences, Cardiology . Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Heart Centre, Department of Clinical Physiology.
    Janerot Sjöberg, Birgitta
    Linköping University, Department of Medicine and Health Sciences, Clinical Physiology . Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Heart Centre, Department of Clinical Physiology.
    Steffensen, Thora
    Östergötlands Läns Landsting, Centre for Laboratory Medicine, Department of Clinical Pathology and Clinical Genetics.
    Broqvist, Mats
    Linköping University, Department of Medicine and Health Sciences, Cardiology . Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Heart Centre, Department of Cardiology.
    T lymphocyte infiltration in non-rheumatic aortic stenosis: a comparative descriptive study between tricuspid and bicuspid aortic valves2002In: Heart, ISSN 1355-6037, Vol. 88, no 4, p. 348-351Article in journal (Refereed)
    Abstract [en]

    Background: The two most common causes of aortic stenosis are primary "degenerative" calcification of tricuspid aortic valves and secondary calcification of congenital bicuspid valves. T lymphocyte infiltration occurs in stenotic tricuspid aortic valves, indicating an inflammatory component, but it has not been shown whether it also occurs in stenotic bicuspid valves.

    Objective: To compare non-rheumatic tricuspid and bicuspid stenotic aortic valves for the presence and distribution of T lymphocytes.

    Setting: University hospital.

    Patients and design: Valve specimens were obtained from 29 patients (15 women, 14 men, mean age 69 years (range 52–81 years)), referred to the hospital for aortic valve replacement because of symptomatic aortic valve stenosis. There were 17 tricuspid valves (from 10 women and seven men, mean age 71 years) and 12 bicuspid valves (from five women and seven men, mean age 67 years). To identify mononuclear inflammatory cells, sections were stained with antibodies for CD3 (pan-T cell antigen, Dako 1:400) and then graded histologically according to the degree of T cell infiltrate.

    Results: T lymphocyte infiltration was present in both tricuspid and bicuspid stenotic aortic valves, without any significant differences in extent or localisation.

    Conclusions: Stenotic bicuspid aortic valves show the same degree of T lymphocyte infiltration as degenerative tricuspid aortic valves. Inflammation needs to be considered in the pathogenesis of acquired aortic stenosis, irrespective of the primary valve anomaly.

  • 257.
    Wallin, Anders
    et al.
    Sahlgrenska University Hospital.
    Ekberg, Stefan
    Linköping University, Department of Medicine and Health Sciences, Radiation Physics . Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Centre of Surgery and Oncology, Department of Radiation Physics.
    Lind, K
    Sahlgrenska University Hospital.
    Milos, V
    Sahlgrenska University Hospital.
    Granérus, Ann-Kathrine
    Linköping University, Department of Clinical and Experimental Medicine, Geriatric . Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Local Health Care Services in Central Östergötland, Department of Geriatric Medicine.
    Granerus, Göran
    Linköping University, Department of Medicine and Health Sciences, Clinical Physiology . Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Heart Centre, Department of Clinical Physiology.
    Posterior cortical brain dysfunction in cognitively impaired patients with Parkinson´s disease - an rCBF scintigraphy study2007In: Acta Neurologica Scandinavica, ISSN 0001-6314, E-ISSN 1600-0404, Vol. 116, no 6, p. 347-354Article in journal (Refereed)
    Abstract [en]

    Objectives: The aim of the study was to visualize cortical function in Parkinson's patients with various degrees of cognitive impairment.

    Materials and methods: Thirty-seven patients with Parkinson's disease and three with Parkinson plus syndromes underwent cognitive assessment and rCBF using 99mTC-HMPAO-SPECT.

    Results: Almost no regional reductions in cerebral blood flow were seen in patients without cognitive impairment (n = 16). Limited, mainly posterior, blood flow reductions were seen in patients with mild cognitive impairment (n = 14), whereas the reductions were extensive and bilaterally symmetric, involving both anterior and posterior brain regions in patients with dementia (n = 10).

    Conclusions: The findings suggest a widespread cortical, mainly posterior type of dysfunction and a relationship between the degree of cognitive impairment and the magnitude of the dysfunction.

  • 258.
    Wanby, Pär
    et al.
    Linköping University, Faculty of Health Sciences.
    Nilsson, I
    Länssjukhuset Kalmar.
    Brudin, Lars
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Health Sciences, Clinical Physiology .
    Nyhammar, I
    Länssjukhuset Kalmar.
    Gustafsson, I
    Länssjukhuset Kalmar.
    Carlsson, M
    Länssjukhuset Kalmar.
    Increased plasma levels of asymmetric dimethylarginine in patients with carotid stenosis: No evidence for the role of the common FABP2 A54T gene polymorphism2007In: Acta Neurologica Scandinavica, ISSN 0001-6314, E-ISSN 1600-0404, Vol. 115, no 2, p. 90-96Article in journal (Refereed)
    Abstract [en]

    Objective - Both asymmetric dimethylarginine (ADMA), which is an inhibitor of endothelial nitric oxide synthase and the fatty acid-binding protein 2 (FABP2) A54T gene polymorphism have been associated with cerebrovascular disease. The objective of the present study was to investigate the role of ADMA and the FABP2 A54T polymorphism in carotid atherosclerosis. Material and methods - 54 patients with severe carotid stenosis and 54 matched controls without significant carotid stenosis were compared. ADMA was analysed with an ELISA method. The FABP2 A54T polymorphism was determined with a polymerase chain reaction-restriction fragment length polymorphism technique. Results - Patients with carotid stenosis had higher ADMA levels (0.76 ± 0.16 μmol/l) than the controls (0.70 ± 0.14 μmol/l, P < 0,01). Allele and genotype frequencies of the FABP2 polymorphism did not differ between patients and controls. Conclusions - ADMA levels in subjects with carotid stenosis are increased which emphasize the role of ADMA as a novel risk factor for atherosclerosis and future cardiovascular risk. The FABP2 A54T polymorphism is not associated with severe carotid stenosis. © 2007 The Authors.

  • 259.
    Wang, Chunliang
    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.
    Persson, Anders
    Linköping University, Department of Medical and Health Sciences, Radiology. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Centre for Diagnostics, Department of Radiology in Linköping. Linköping University, Center for Medical Image Science and Visualization, CMIV.
    Engvall, Jan
    Linköping University, Department of Medical and Health Sciences, Clinical Physiology. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Heart and Medicine Centre, Department of Clinical Physiology UHL.
    de Geer, Jakob
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medical and Health Sciences, Radiology.
    Björkholm, Anders
    Östergötlands Läns Landsting, Centre for Diagnostics, Department of Radiology in Linköping.
    Czekierda, Waldemar
    Östergötlands Läns Landsting, Centre for Diagnostics, Department of Radiology in Linköping.
    Fransson, Sven Göran
    Linköping University, Department of Medical and Health Sciences, Radiology. Linköping University, Faculty of Health Sciences.
    Smedby, Örjan
    Linköping University, Department of Medical and Health Sciences, Radiology. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Centre for Medical Imaging, Department of Radiology in Linköping.
    Can segmented 3D images be used for stenosis evaluation in coronary CT angiography?2012In: Acta Radiologica, ISSN 0284-1851, E-ISSN 1600-0455, Vol. 53, no 8, p. 845-851Article in journal (Refereed)
    Abstract [en]

    Purpose: To retrospectively evaluate the diagnostic accuracy of coronary CT angiography (CCTA) using segmented 3D data for the detection of significant stenoses with catheter angiography (CA) as the reference standard.

    Method: CCTA data sets from 30 patients were acquired with a 64-slice dual source CT scanner and segmented by an independent observer using the region growing (RG) method and the “virtual contrast injection” (VC) method. For every examination, each of the three types of images was  then reviewed by one of three reviewers in a blinded fashion for the presence of stenoses with diameter reduction of 50% or more. For the original series, the reviewer was allowed to use all the 2D or 3D visualization tools available (mixed method). For the segmented results (from RG and VC), the reviewer only used the 3D maximum intensity projection. Evaluation results were compared with CA for each artery.

    Results: Overall, 34 arteries with significant stenosis were identified by CA. The percentage of evaluable arteries, accuracy and negative predictive value (NPV) for detecting stenosis were, respectively, 86%, 74% and 93% for the mixed method, 83%, 71% and 92% for VC, and 64%, 56% and 93% for RG. Accuracy was significantly lower for the RG method than for the other two methods (p<0.01), whereas there was no significant difference in accuracy between the VC method and the mixed method (p = 0.22). Excluding vessels with heavy calcification, all three methods had similar accuracy.

    Conclusion: Diagnostic accuracy when using segmented 3D data was lower than with access to 2D images. However, the high NPV of the 3D methods suggests a potential of using them as an initial step, with access to 2D reviewing techniques for suspected lesions and cases with heavy calcification. The VC method, which generates more evaluable arteries and has higher accuracy, seems more promising for this purpose than the RG method.

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  • 260.
    Warntjes, Marcel
    et al.
    Linköping University, Center for Medical Image Science and Visualization, CMIV. Linköping University, Department of Medical and Health Sciences, Clinical Physiology. Linköping University, Faculty of Health Sciences.
    Blystad, Ida
    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. Östergötlands Läns Landsting, Centre for Diagnostics, Department of Radiology in Linköping.
    Tisell, Anders
    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. Östergötlands Läns Landsting, Centre for Surgery, Orthopaedics and Cancer Treatment, Department of Radiation Physics UHL.
    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.
    Lundberg, Peter
    Linköping University, Center for Medical Image Science and Visualization, CMIV. Linköping University, Department of Medical and Health Sciences, Radiation Physics. Linköping University, Department of Medical and Health Sciences, Radiology. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Centre for Surgery, Orthopaedics and Cancer Treatment, Department of Radiation Physics UHL.
    Multiparametric Quantitative Magnetic Resonance Imaging of the Normal Appearing Brain in Multiple Sclerosis2012Conference paper (Other academic)
  • 261.
    Warntjes, Marcel, Jan Bertus
    et al.
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medical and Health Sciences, Clinical Physiology. Linköping University, Center for Medical Image Science and Visualization (CMIV). Östergötlands Läns Landsting, Heart Centre, Department of Clinical Physiology.
    Dahlqvist, Olof
    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).
    West, Janne
    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.
    Lundberg, Peter
    Linköping University, Center for Medical Image Science and Visualization (CMIV). Linköping University, Department of Medical and Health Sciences, Radiation Physics. Linköping University, Department of Medical 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.
    Rapid magnetic resonance quantification on the brain: Optimization for clinical usage2008In: Magnetic Resonance in Medicine, ISSN 0740-3194, E-ISSN 1522-2594, Vol. 60, no 2, p. 320-329Article in journal (Refereed)
    Abstract [en]

    A method is presented for rapid simultaneous quantification of the longitudinal T1 relaxation, the transverse T2 relaxation, the proton density (PD), and the amplitude of the local radio frequency B 1 field. All four parameters are measured in one single scan by means of a multislice, multiecho, and multidelay acquisition. It is based on a previously reported method, which was substantially improved for routine clinical usage. The improvements comprise of the use of a multislice spin-echo technique, a background phase correction, and a spin system simulation to compensate for the slice-selective RF pulse profile effects. The aim of the optimization was to achieve the optimal result for the quantification of magnetic resonance parameters within a clinically acceptable time. One benchmark was high-resolution coverage of the brain within 5 min. In this scan time the measured intersubject standard deviation (SD) in a group of volunteers was 2% to 8%, depending on the tissue (voxel size = 0.8 x 0.8 x 5 mm). As an example, the method was applied to a patient with multiple sclerosis in whom the diseased tissue could clearly be distinguished from healthy reference values. Additionally it was shown that, using the approach of synthetic MRI, both accurate conventional contrast images as well as quantification maps can be generated based on the same scan. © 2008 Wiley-Liss, Inc.

  • 262.
    Warntjes, Marcel Jan Bertus
    et al.
    Linköping University, Department of Medical and Health Sciences, Clinical Physiology. Linköping University, Faculty of Health Sciences. Linköping University, Center for Medical Image Science and Visualization (CMIV).
    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).
    Tisell, Anders
    Linköping University, Department of Medical and Health Sciences, Radiation Physics. Linköping University, Faculty of Health Sciences. Linköping University, Center for Medical Image Science and Visualization (CMIV).
    Lundberg, Peter
    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. 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.
    Brain Characterization Using Normalized Quantitative Magnetic Resonance Imaging2013In: PLoS ONE, ISSN 1932-6203, E-ISSN 1932-6203, Vol. 8, no 8Article in journal (Refereed)
    Abstract [en]

    Objectives

    To present a method for generating reference maps of typical brain characteristics of groups of subjects using a novel combination of rapid quantitative Magnetic Resonance Imaging (qMRI) and brain normalization. The reference maps can be used to detect significant tissue differences in patients, both locally and globally.

    Materials and Methods

    A rapid qMRI method was used to obtain the longitudinal relaxation rate (R1), the transverse relaxation rate (R2) and the proton density (PD). These three tissue properties were measured in the brains of 32 healthy subjects and in one patient diagnosed with Multiple Sclerosis (MS). The maps were normalized to a standard brain template using a linear affine registration. The differences of the mean value ofR1, R2 and PD of 31 healthy subjects in comparison to the oldest healthy subject and in comparison to an MS patient were calculated. Larger anatomical structures were characterized using a standard atlas. The vector sum of the normalized differences was used to show significant tissue differences.

    Results

    The coefficient of variation of the reference maps was high at the edges of the brain and the ventricles, moderate in the cortical grey matter and low in white matter and the deep grey matter structures. The elderly subject mainly showed significantly lower R1 and R2 and higher PD values along all sulci. The MS patient showed significantly lower R1 and R2 and higher PD values at the edges of the ventricular system as well as throughout the periventricular white matter, at the internal and external capsules and at each of the MS lesions.

    Conclusion

    Brain normalization of rapid qMRI is a promising new method to generate reference maps of typical brain characteristics and to automatically detect deviating tissue properties in the brain.

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  • 263.
    Warntjes, Marcel JB
    et al.
    Linköping University, Center for Medical Image Science and Visualization (CMIV). Linköping University, Department of Medical and Health Sciences, Clinical Physiology. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Heart Centre, Department of Clinical Physiology.
    Kihlberg, Johan
    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. Östergötlands Läns Landsting, Centre for Medical Imaging, Department of Radiology in Linköping.
    Engvall, Jan
    Linköping University, Department of Medical and Health Sciences, Clinical Physiology. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Heart Centre, Department of Clinical Physiology.
    Rapid T1 quantification based on 3D phase sensitive inversion recovery2010In: BMC Medical Imaging, ISSN 1471-2342, E-ISSN 1471-2342, Vol. 10, no 19Article in journal (Refereed)
    Abstract [en]

    BACKGROUND: In Contrast Enhanced Magnetic Resonance Imaging fibrotic myocardium can be distinguished from healthy tissue using the difference in the longitudinal T1 relaxation after administration of Gadolinium, the so-called Late Gd Enhancement. The purpose of this work was to measure the myocardial absolute T1 post-Gd from a single breath-hold 3D Phase Sensitivity Inversion Recovery sequence (PSIR). Equations were derived to take the acquisition and saturation effects on the magnetization into account.

    METHODS: The accuracy of the method was investigated on phantoms and using simulations. The method was applied to a group of patients with suspected myocardial infarction where the absolute difference in relaxation of healthy and fibrotic myocardium was measured at about 15 minutes post-contrast. The evolution of the absolute R1 relaxation rate (1/T1) over time after contrast injection was followed for one patient and compared to T1 mapping using Look-Locker. Based on the T1 maps synthetic LGE images were reconstructed and compared to the conventional LGE images.

    RESULTS: The fitting algorithm is robust against variation in acquisition flip angle, the inversion delay time and cardiac arrhythmia. The observed relaxation rate of the myocardium is 1.2 s-1, increasing to 6 - 7 s-1 after contrast injection and decreasing to 2 - 2.5 s-1 for healthy myocardium and to 3.5 - 4 s-1 for fibrotic myocardium. Synthesized images based on the T1 maps correspond very well to actual LGE images.

    CONCLUSIONS: The method provides a robust quantification of post-Gd T1 relaxation for a complete cardiac volume within a single breath-hold.

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  • 264.
    Warntjes, Marcel
    et al.
    Linköping University, Center for Medical Image Science and Visualization (CMIV). 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.
    Tisell, Anders
    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. Östergötlands Läns Landsting, Center for Surgery, Orthopaedics and Cancer Treatment, Department of Radiation Physics.
    West, Janne
    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, 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.
    Lundberg, Peter
    Linköping University, Center for Medical Image Science and Visualization (CMIV). Linköping University, Department of Medical and Health Sciences, Radiation Physics. Linköping University, Department of Medical and Health Sciences, Radiology. Linköping University, Faculty of Health Sciences. 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.
    Fully Automatic Brain Tissue Mapping on Multiple Sclerosis Based on Quantitative MRI2011Conference paper (Refereed)
  • 265.
    Warntjes, Marcel
    et al.
    Linköping University, Center for Medical Image Science and Visualization (CMIV). 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.
    West, Janne
    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.
    Dahlqvist Leinhard, Olof
    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.
    Helms, G.
    University Medical Center, Göttingen, Germany.
    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. Östergötlands Läns Landsting, Local Health Care Services in West Östergötland, Department of Medical Specialist in Motala.
    Lundberg, Peter
    Linköping University, Center for Medical Image Science and Visualization (CMIV). Linköping University, Department of Medical and Health Sciences, Radiation Physics. Linköping University, Department of Medical and Health Sciences, Radiology. Linköping University, Faculty of Health Sciences. 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.
    Estimation of total myelin volume in the brain2011In: Internationell Society for Magnetic Resonance in Medicin, 2011, 2011, p. 2175-2175Conference paper (Refereed)
  • 266.
    Warntjes, Marcel
    et al.
    Linköping University, Center for Medical Image Science and Visualization (CMIV). 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.
    West, Janne
    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.
    Dahlqvist Leinhard, Olof
    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.
    Helms, G.
    University Medical Center, Göttingen, Germany.
    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. Östergötlands Läns Landsting, Local Health Care Services in West Östergötland, Department of Medical Specialist in Motala.
    Lundberg, Peter
    Linköping University, Center for Medical Image Science and Visualization (CMIV). Linköping University, Department of Medical and Health Sciences, Radiation Physics. Linköping University, Department of Medical and Health Sciences, Radiology. Linköping University, Faculty of Health Sciences. 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.
    Using multi-parametric quantitative MRI to model myelin in the brain2011In: Internationell Society for Magnetic Resonance in Medicin, 2011, 2011, p. 536-536Conference paper (Refereed)
  • 267.
    Warntjes, Marcel
    et al.
    Linköping University, Center for Medical Image Science and Visualization, CMIV. Linköping University, Department of Medical and Health Sciences, Clinical Physiology. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Heart and Medicine Centre, Department of Clinical Physiology UHL.
    West, Janne
    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.
    Tisell, Anders
    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. Östergötlands Läns Landsting, Centre for Surgery, Orthopaedics and Cancer Treatment, Department of Radiation Physics UHL.
    Dahlqvist Leinhard, Olof
    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, Neurology. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Local Health Care Services in Central Östergötland, Department of Neurology.
    Lundberg, Peter
    Linköping University, Center for Medical Image Science and Visualization, CMIV. Linköping University, Department of Medical and Health Sciences, Radiation Physics. Linköping University, Department of Medical and Health Sciences, Radiology. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Centre for Surgery, Orthopaedics and Cancer Treatment, Department of Radiation Physics UHL.
    Fully Automatic Brain Tissue Segmentation on Multiple Sclerosis Patients with a High and a Low Number of White Matter Lesions2012Conference paper (Other academic)
  • 268.
    West, Janne
    et al.
    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.
    Aalto, Anne
    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. Östergötlands Läns Landsting, Centre for Diagnostics, Department of Radiology in Linköping.
    Warntjes, Marcel
    Linköping University, Center for Medical Image Science and Visualization, CMIV. Linköping University, Department of Medical and Health Sciences, Clinical Physiology. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Heart and Medicine Centre, Department of Clinical Physiology UHL.
    Dahlqvist Leinhard, Olof
    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, Neurology. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Local Health Care Services in Central Östergötland, Department of Neurology.
    Smedby, Örjan
    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. Östergötlands Läns Landsting, Centre for Diagnostics, Department of Radiology in Linköping.
    Lundberg, Peter
    Linköping University, Center for Medical Image Science and Visualization, CMIV. Linköping University, Department of Medical and Health Sciences, Radiation Physics. Linköping University, Department of Medical and Health Sciences, Radiology. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Centre for Surgery, Orthopaedics and Cancer Treatment, Department of Radiation Physics UHL.
    Characterizing Normal Appearing White and Diseased Matter in Multiple Sclerosis Using Quantitative MRI2012Conference paper (Other academic)
  • 269.
    West, Janne
    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.
    Blystad, Ida
    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.
    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).
    Warntjes, Marcel Jan Bertus
    Linköping University, Department of Medical and Health Sciences, Clinical Physiology. Linköping University, Faculty of Health Sciences. Linköping University, Center for Medical Image Science and Visualization (CMIV).
    Lundberg, Peter
    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. 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.
    Application of Quantitative MRI for Brain Tissue Segmentation at 1.5 T and 3.0 T Field Strengths2013In: PLoS ONE, ISSN 1932-6203, E-ISSN 1932-6203, Vol. 8, no 9Article in journal (Refereed)
    Abstract [en]

    Background

    Brain tissue segmentation of white matter (WM), grey matter (GM), and cerebrospinal fluid (CSF) are important in neuroradiological applications. Quantitative Mri (qMRI) allows segmentation based on physical tissue properties, and the dependencies on MR scanner settings are removed. Brain tissue groups into clusters in the three dimensional space formed by the qMRI parameters R1, R2 and PD, and partial volume voxels are intermediate in this space. The qMRI parameters, however, depend on the main magnetic field strength. Therefore, longitudinal studies can be seriously limited by system upgrades. The aim of this work was to apply one recently described brain tissue segmentation method, based on qMRI, at both 1.5 T and 3.0 T field strengths, and to investigate similarities and differences.

    Methods

    In vivo qMRI measurements were performed on 10 healthy subjects using both 1.5 T and 3.0 T MR scanners. The brain tissue segmentation method was applied for both 1.5 T and 3.0 T and volumes of WM, GM, CSF and brain parenchymal fraction (BPF) were calculated on both field strengths. Repeatability was calculated for each scanner and a General Linear Model was used to examine the effect of field strength. Voxel-wise t-tests were also performed to evaluate regional differences.

    Results

    Statistically significant differences were found between 1.5 T and 3.0 T for WM, GM, CSF and BPF (p<0.001). Analyses of main effects showed that WM was underestimated, while GM and CSF were overestimated on 1.5 T compared to 3.0 T. The mean differences between 1.5 T and 3.0 T were -66 mL WM, 40 mL GM, 29 mL CSF and -1.99% BPF. Voxel-wise t-tests revealed regional differences of WM and GM in deep brain structures, cerebellum and brain stem.

    Conclusions

    Most of the brain was identically classified at the two field strengths, although some regional differences were observed.

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  • 270.
    West, Janne
    et al.
    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.
    Warntjes, Marcel
    Linköping University, Center for Medical Image Science and Visualization, CMIV. Linköping University, Department of Medical and Health Sciences, Clinical Physiology. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Heart and Medicine Centre, Department of Clinical Physiology UHL.
    Lundberg, Peter
    Linköping University, Center for Medical Image Science and Visualization, CMIV. Linköping University, Department of Medical and Health Sciences, Radiation Physics. Linköping University, Department of Medical and Health Sciences, Radiology. Linköping University, Faculty of Health Sciences. 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.
    Novel whole brain segmentation and volume estimation using quantitative MRI2012In: European Radiology, ISSN 0938-7994, E-ISSN 1432-1084, Vol. 22, no 5, p. 998-1007Article in journal (Refereed)
    Abstract [en]

    OBJECTIVES:

    Brain segmentation and volume estimation of grey matter (GM), white matter (WM) and cerebro-spinal fluid (CSF) are important for many neurological applications. Volumetric changes are observed in multiple sclerosis (MS), Alzheimer's disease and dementia, and in normal aging. A novel method is presented to segment brain tissue based on quantitative magnetic resonance imaging (qMRI) of the longitudinal relaxation rate R(1), the transverse relaxation rate R(2) and the proton density, PD.

    METHODS:

    Previously reported qMRI values for WM, GM and CSF were used to define tissues and a Bloch simulation performed to investigate R(1), R(2) and PD for tissue mixtures in the presence of noise. Based on the simulations a lookup grid was constructed to relate tissue partial volume to the R(1)-R(2)-PD space. The method was validated in 10 healthy subjects. MRI data were acquired using six resolutions and three geometries.

    RESULTS:

    Repeatability for different resolutions was 3.2% for WM, 3.2% for GM, 1.0% for CSF and 2.2% for total brain volume. Repeatability for different geometries was 8.5% for WM, 9.4% for GM, 2.4% for CSF and 2.4% for total brain volume.

    CONCLUSION:

    We propose a new robust qMRI-based approach which we demonstrate in a patient with MS. KEY POINTS : • A method for segmenting the brain and estimating tissue volume is presented • This method measures white matter, grey matter, cerebrospinal fluid and remaining tissue • The method calculates tissue fractions in voxel, thus accounting for partial volume • Repeatability was 2.2% for total brain volume with imaging resolution <2.0 mm.

  • 271.
    West, Janne
    et al.
    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.
    Warntjes, Marcel
    Linköping University, Center for Medical Image Science and Visualization, CMIV. Linköping University, Department of Medical and Health Sciences, Clinical Physiology. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Heart and Medicine Centre, Department of Clinical Physiology UHL.
    Lundberg, Peter
    Linköping University, Center for Medical Image Science and Visualization, CMIV. Linköping University, Department of Medical and Health Sciences, Radiation Physics. Linköping University, Department of Medical and Health Sciences, Radiology. Linköping University, Faculty of Health Sciences. 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.
    Using Quantitative Magnetic Resonance Imaging to Generate Disease Images of Multiple Sclerosis2011Conference paper (Refereed)
  • 272.
    Westin, C.-F.
    et al.
    Surgical Planning Laboratory, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, United States, Surgical Planning Laboratory, Brigham and Women's Hospital, Harvard Medical School, 75 Francis St., Boston, MA 02115, United States.
    Wigström, Lars
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Health Sciences, Clinical Physiology . Östergötlands Läns Landsting, Heart Centre, Department of Clinical Physiology.
    Loock, T.
    Sjoqvist, L.
    Kikinis, R.
    Surgical Planning Laboratory, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, United States.
    Knutsson, Hans
    Linköping University, The Institute of Technology. Linköping University, Department of Biomedical Engineering, Medical Informatics.
    A multielement RF coil for MRI guidance of interventional devices2001In: Journal of Magnetic Resonance Imaging, ISSN 1053-1807, E-ISSN 1522-2586, Vol. 14, no 1, p. 56-62Article in journal (Refereed)
    Abstract [en]

    Accurate localization of minimally invasive devices is critical to the success of interventional procedures. Device orientation and tip position are two of the most important pieces of information needed to define device location for magnetic resonance imaging (MRI)-guided interventional procedures. While a single one-element micro coil incorporated into an interventional device has proven to be effective in some applications, it can only supply tip position information. However, multiple positions on the device are necessary to also determine its orientation. For this purpose, a novel single micro coil design with three separate winding elements that provides both the device orientation and tip position is described in this study. Definition of MR scan planes, by using the device orientation and the target tissue location, permits automatic tracking of the insertion of the device. Furthermore, devices that include this coil design are permitted to bend to a limited extent. This makes the micro coil design appropriate for many flexible interventional devices. Reliable near-real-time tracking of three points on an interventional device is demonstrated on a 0.2T MRI system with modest gradient performance. Phantom and in vivo animal experiments are used to demonstrate the utility of this new coil design. © 2001 Wiley-Liss, Inc.

  • 273.
    Wigström, Lars
    et al.
    Linköping University, Department of Medicine and Care, Clinical Physiology. Linköping University, Faculty of Health Sciences.
    Lindström, Lena
    Linköping University, Department of Medical and Health Sciences, Clinical Physiology. Linköping University, Faculty of Health Sciences.
    Sjöqvist, Lars
    Östergötlands Läns Landsting, Centre of Surgery and Oncology, Department of Radiation Physics. Linköping University, Faculty of Health Sciences.
    Thuomas, K. Å.
    Linköping University, Department of Medicine and Care, Radiology. Linköping University, Faculty of Health Sciences.
    Wranne, Bengt
    Linköping University, Department of Medical and Health Sciences, Clinical Physiology. Linköping University, Faculty of Health Sciences.
    M-mode magnetic resonance imaging: a new modality for assessing cardiac function1995In: Clinical Physiology, ISSN 0144-5979, E-ISSN 1365-2281, Vol. 15, no 4, p. 397-407Article in journal (Refereed)
    Abstract [en]

    Magnetic resonance imaging (MRI) studies of the heart have been used for some years, but there are few tools available to quantify cardiac motion. A method has been developed that creates an M-mode MRI image, analogous to the one used in echocardiography, to display motion along a line as a function of time. The M-mode image is created from MRI images acquired with an ordinary gradient echo cine sequence. In a cinematographic display of the images, a cursor line can be positioned in order to determine the orientation of the measurement. A resampling algorithm then calculates the appearance of the M-mode image along the cursor line. The MRI method has been compared to echocardiographic M-mode in a phantom study and by measuring mitral and tricuspid annulus motion in 20 normal subjects. The phantom study showed no significant differences between MRI and echocardiographic M-mode measurements (difference mm). The annulus motion exhibits a similar pattern using both methods and the measured amplitudes are in close agreement. M-mode MRI provides similar information to echocardiography, but the cursor line can be placed arbitrarily within the image plane and the method is thus not limited to certain acoustic windows. This makes M-mode MRI a promising technique for assessing cardiac motion.

  • 274.
    Wijkman, Magnus
    et al.
    Linköping University, Department of Medicine and Health Sciences, Internal Medicine. Östergötlands Läns Landsting, Local Health Care Services in the East of Östergötland, Department of Internal Medicine VHN. Linköping University, Faculty of Health Sciences.
    Länne, Toste
    Linköping University, Department of Medicine and Health Sciences, Physiology. Östergötlands Läns Landsting, Heart and Medicine Centre, Department of Thoracic and Vascular Surgery in Östergötland. Linköping University, Faculty of Health Sciences.
    Engvall, Jan
    Linköping University, Department of Medicine and Health Sciences, Clinical Physiology. Östergötlands Läns Landsting, Heart and Medicine Centre, Department of Clinical Physiology UHL. Linköping University, Faculty of Health Sciences.
    Lindström, Torbjörn
    Linköping University, Department of Medicine and Health Sciences, Internal Medicine. Östergötlands Läns Landsting, Heart and Medicine Centre, Department of Endocrinology and Gastroenterology UHL. Linköping University, Faculty of Health Sciences.
    Östgren, Carl Johan
    Linköping University, Department of Medicine and Health Sciences, General Practice. Östergötlands Läns Landsting, Local Health Care Services in the West of Östergötland. Linköping University, Faculty of Health Sciences.
    Nystrom, Fredrik
    Linköping University, Department of Medicine and Health Sciences, Internal Medicine. Östergötlands Läns Landsting, Heart and Medicine Centre, Department of Endocrinology and Gastroenterology UHL. Linköping University, Faculty of Health Sciences.
    Masked nocturnal hypertension is associated with decreased estimated glomerular filtration rate according to serum cystatin C levels in type 2 diabetes2010In: Diabetes 2010; 59 suppl 1: A246-47, 2010Conference paper (Refereed)
  • 275.
    Wijkman, Magnus
    et al.
    Linköping University, Department of Medical and Health Sciences, Internal Medicine. Linköping University, Faculty of Health Sciences.
    Länne, Toste
    Linköping University, Department of Medical and Health Sciences, Physiology. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Heart Centre, Department of Thoracic and Vascular Surgery.
    Engvall, Jan
    Linköping University, Department of Medical and Health Sciences, Clinical Physiology. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Heart Centre, Department of Clinical Physiology.
    Lindström, Torbjörn
    Linköping University, Department of Medical and Health Sciences, Internal Medicine. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Centre for Medicine, Department of Endocrinology and Gastroenterology UHL.
    Östgren, Carl Johan
    Linköping University, Department of Medical and Health Sciences, General Practice. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Local Health Care Services in the West of Östergötland, Primary Health Care Centres.
    Nystrom, Fredrik H
    Linköping University, Department of Medical and Health Sciences, Internal Medicine. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Centre for Medicine, Department of Endocrinology and Gastroenterology UHL.
    Masked nocturnal hypertension - a novel marker of risk in type 2 diabetes.2009In: Diabetologia, ISSN 0012-186X, E-ISSN 1432-0428, Vol. 52, no 7, p. 1258-64Article in journal (Refereed)
    Abstract [en]

    AIMS/HYPOTHESIS: This study was designed to evaluate the prevalence of masked nocturnal hypertension (MNHT) and its impact on arterial stiffness and central blood pressure in patients with type 2 diabetes. METHODS: Middle-aged patients (n = 414) with type 2 diabetes underwent clinic and ambulatory BP measurements and applanation tonometry. RESULTS: MNHT (clinic BP < 130/80 mmHg and night-time BP > or = 120/70 mmHg) was found in 7.2% of patients (n = 30). Compared with patients with both clinical and nocturnal normotension (n = 70), patients with MNHT had higher aortic pulse wave velocity (PWV) (10.2 +/- 1.8 m/s vs 9.4 +/- 1.7 m/s; p = 0.03) and higher central BP (117.6 +/- 13.9/74.0 +/- 9.1 mmHg vs 110.4 +/- 16.4/69.7 +/- 9.6 mmHg, p = 0.04). In patients with clinical normotension, night-time systolic BP correlated significantly with PWV. CONCLUSIONS/INTERPRETATION: Thirty per cent of patients with clinical normotension had nocturnal hypertension. This was accompanied by increased arterial stiffness and higher central BP. We conclude that in clinically normotensive patients with type 2 diabetes, ambulatory BP measurement may help clinicians to identify patients with increased cardiovascular risk.

  • 276.
    Wijkman, Magnus
    et al.
    Linköping University, Department of Medical and Health Sciences, Internal Medicine. Linköping University, Faculty of Health Sciences.
    Länne, Toste
    Linköping University, Department of Medical and Health Sciences, Physiology. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Heart and Medicine Centre, Department of Thoracic and Vascular Surgery in Östergötland.
    Engvall, Jan
    Linköping University, Department of Medical and Health Sciences, Clinical Physiology. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Heart and Medicine Centre, Department of Clinical Physiology UHL.
    Lindström, Torbjörn
    Linköping University, Department of Medical and Health Sciences, Internal Medicine. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Heart and Medicine Centre, Department of Endocrinology and Gastroenterology UHL.
    Östgren, Carl Johan
    Linköping University, Department of Medical and Health Sciences, General Practice. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Local Health Care Services in the West of Östergötland, Primary Health Care Centres.
    Nyström, Fredrik
    Linköping University, Department of Medical and Health Sciences, Internal Medicine. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Heart and Medicine Centre, Department of Endocrinology and Gastroenterology UHL.
    Central pulse pressure elevation is common in patients with type 2 diabetes and office normotension, and is associated with markers of atherosclerosisManuscript (preprint) (Other academic)
    Abstract [en]

    The aim of this study was to describe the prevalence of elevated central pulsepressure (CPP) in patients with type 2 diabetes and office normotension, and to investigatewhether elevated CPP was associated with markers of atherosclerosis in these patients. Wedetermined office and central blood pressure, carotid intima-media thickness (IMT) and aorticpulse wave velocity (PWV) in 167 patients with type 2 diabetes and office normotension(<130/80 mmHg). Patients with office normotension and CPP ≥50 mmHg (n=32) hadsignificantly higher carotid IMT (0.76±0.2 mm vs 0.71±0.1 mm, p=0.041) and aortic PWV(11.0±2.5 m/s vs 9.5±1.8 m/s, p<0.01) than patients with office normotension and CPP <50mmHg (n=135). We conclude that almost one in five patients with type 2 diabetes and officenormotension had elevated CPP, and that this was associated with markers of both structuraland functional atherosclerosis.

  • 277.
    Wijkman, Magnus
    et al.
    Linköping University, Department of Medicine and Health Sciences, Internal Medicine . Linköping University, Faculty of Health Sciences.
    Länne, Toste
    Linköping University, Department of Medicine and Health Sciences, Physiology . Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Heart Centre, Department of Thoracic and Vascular Surgery.
    Engvall, Jan
    Linköping University, Department of Medicine and Health Sciences, Clinical Physiology . Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Heart Centre, Department of Clinical Physiology.
    Lindström, Torbjörn
    Linköping University, Department of Medicine and Health Sciences, Internal Medicine . Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Centre for Medicine, Department of Endocrinology and Gastroenterology UHL.
    Östgren, Carl Johan
    Linköping University, Department of Medicine and Health Sciences, General Practice. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Local Health Care Services in the West of Östergötland, West County Primary Health Care.
    Nyström, Fredrik
    Linköping University, Department of Medicine and Health Sciences, Internal Medicine . Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Centre for Medicine, Department of Endocrinology and Gastroenterology UHL.
    MASKED NOCTURNAL HYPERTENSION IN TYPE 2 DIABETES - A NEW MARKER OF RISK2009In: in JOURNAL OF HYPERTENSION, vol 27, 2009, Vol. 27, p. S169-S169Conference paper (Refereed)
    Abstract [en]

    n/a

  • 278.
    Wijkman, Magnus
    et al.
    Linköping University, Department of Medical and Health Sciences, Internal Medicine. Linköping University, Faculty of Health Sciences.
    Länne, Toste
    Linköping University, Department of Medical and Health Sciences, Physiology. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Heart and Medicine Centre, Department of Thoracic and Vascular Surgery in Östergötland.
    Engvall, Jan
    Linköping University, Department of Medical and Health Sciences, Clinical Physiology. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Heart and Medicine Centre, Department of Clinical Physiology UHL.
    Lindström, Torbjörn
    Linköping University, Department of Medical and Health Sciences, Internal Medicine. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Heart and Medicine Centre, Department of Endocrinology and Gastroenterology UHL.
    Östgren, Carl Johan
    Linköping University, Department of Medical and Health Sciences, General Practice. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Local Health Care Services in the West of Östergötland, Primary Health Care Centres.
    Nyström, Fredrik
    Linköping University, Department of Medical and Health Sciences, Internal Medicine. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Heart and Medicine Centre, Department of Endocrinology and Gastroenterology UHL.
    ß-blocker Treatment is Associated with High Augmentation Index and with High Aortic, but not Brachial, Pulse Pressure in Type 2 Diabetes2010In: The journal of clinical metabolism and diabetes, Vol. 1, no 1, p. 55-62Article in journal (Refereed)
    Abstract [en]

    Aims: To explore the associations between ß-blocker treatment and clinic, ambulatory, and central pulse pressure (PP) and central augmentation index (AIx), and left ventricular mass index (LVMI), respectively, in patients with type 2 diabetes.Methods: In 124 middle-aged patients with type 2 diabetes who were treated in primary care and used at least one antihypertensive drug, we measured clinic PP (mean value of three nurse-recorded measurements in the sitting position) and ambulatory PP (24-hour ambulatory measurements with the Spacelab 90217 measurement device). Central PP was measured non-invasively, using applanation tonometry (SphygmoCor), which also yielded values of AIx. LVMI was determined echocardiographically in all patients.Results: Patients whose antihypertensive drug regimen included a ß-blocker (n=67) had significantly higher central PP compared with patients whose antihypertensive drug regimen did not include a ß-blocker (ß-blocker: 49.6±12.2 mmHg, no ß-blocker: 45.1±10.2 mmHg; p=0.03) despite having similar clinic PP (ß-blocker: 60.4±16.3 mmHg, no ß-blocker: 58.9±13.1 mmHg; p=0.59) and similar ambulatory PP (ß-blocker: 55.2±9.1 mmHg, no ß-blocker: 54.8±10.6 mmHg; p=0.40). Patients treated with ß-blockers also had significantly higher AIx (ß-blocker: 30.7±8.4%, no ß-blocker: 25.8±8.8%; p<0.01) and higher LVMI (ß-blocker: 129.5±29.7 g/m2, no ß-blocker: 117.4±27.4 g/m2; p=0.02) compared with patients who were not treated with ß-blockers.Conclusions: In our cohort, ß-blocker use was associated with high central but not brachial PP and with high central AIx and high LVMI. Non-invasive measurement of central hemodynamic parameters may improve the evaluation of antihypertensive treatment efficacy in patients with type 2 diabetes.

  • 279.
    Wijkman, Magnus
    et al.
    Linköping University, Department of Medical and Health Sciences, Internal Medicine. Linköping University, Faculty of Health Sciences.
    Länne, Toste
    Linköping University, Department of Medical and Health Sciences, Physiology. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Heart and Medicine Centre, Department of Thoracic and Vascular Surgery in Östergötland.
    Grodzinsky, Ewa
    Linköping University, Department of Medical and Health Sciences, General Practice. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Local Health Care Services in the West of Östergötland, Unit of Research and Development in Local Health Care, County of Östergötland.
    Östgren, Carl Johan
    Linköping University, Department of Medical and Health Sciences, General Practice. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Local Health Care Services in the West of Östergötland, Primary Health Care Centres.
    Engvall, Jan
    Linköping University, Department of Medical and Health Sciences, Clinical Physiology. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Heart and Medicine Centre, Department of Clinical Physiology UHL.
    Nyström, Fredrik
    Linköping University, Department of Medical and Health Sciences, Internal Medicine. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Heart and Medicine Centre, Department of Endocrinology and Gastroenterology UHL.
    Ambulatory systolic blood pressure predicts left ventricular mass in type 2 diabetes, independently of central systolic blood pressure2012In: Blood Pressure Monitoring, ISSN 1359-5237, E-ISSN 1473-5725, Vol. 17, no 4, p. 139-144Article in journal (Refereed)
    Abstract [en]

    Objectives: Both ambulatory and central blood pressures have been reported to correlate more closely than office blood pressure with left ventricular mass index (LVMI). The aim of this study was to test whether ambulatory systolic blood pressure (SBP) predicts LVMI independently of central SBP in patients with type 2 diabetes.

    Methods: We determined office, ambulatory and central blood pressures and performed echocardiography in 460 patients with type 2 diabetes, who participated in the CARDIPP (Cardiovascular Risk factors in Patients with Diabetes – a Prospective study in Primary care) study (ClinicalTrials.gov number NCT 01049737).

    Results: In separate multivariable regression models, both 24-hour ambulatory SBP, ambulatory day-time SBP, and ambulatory night-time SBP were significantly associated with LVMI, independently of central SBP, age, sex, BMI, ambulatory 24-hour heart rate, duration of known diabetes and presence or absence of any antihypertensive medications (r = 0.19, 0.17 and 0.18, respectively, P <0.01). All ambulatory SBP parameters, but not central SBP, were significantly associated with LVMI independently of office SBP.

    Conclusions: Ambulatory SBP predicted LVMI independently of central SBP in patients with type 2 diabetes. The use of ambulatory blood pressure measurements may be encouraged as a tool for refined risk stratification of patients with type 2 diabetes.

  • 280.
    Wilkenshoff, Ursula M.
    et al.
    Charite - Universitätsmedizin Berlin, Department of Cardiology and Pneumology, Berlin Germany .
    Sovany, Agnes
    Charite - Universitätsmedizin Berlin, Department of Cardiology and Pneumology, Berlin Germany .
    Wigström, Lars
    Linköping University, Department of Medical and Health Sciences, Clinical Physiology. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Heart and Medicine Centre, Department of Clinical Physiology UHL.
    Olstad, Björn
    Lindström, Lena
    County Hospital Ryhov, Department of Clinical Physiology, Jönköping.
    Engvall, Jan
    Linköping University, Department of Medical and Health Sciences, Clinical Physiology. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Heart and Medicine Centre, Department of Clinical Physiology UHL.
    Janerot-Sjöberg, Birgitta
    Linköping University, Department of Biomedical Engineering, Physiological Measurements. Linköping University, The Institute of Technology. Östergötlands Läns Landsting, Heart and Medicine Centre, Department of Clinical Physiology UHL.
    Wranne, Bengt
    Linköping University, Department of Medical and Health Sciences, Clinical Physiology. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Heart and Medicine Centre, Department of Clinical Physiology UHL.
    Hatle, Liv
    Norwegian University of Science and Technology, Faculty of Medicine, Trondheim Norway .
    Sutherland, George R.
    St George's Hospital, London, Department of Cardiology, London United Kingdom .
    Regional mean systolic myocardial velocity estimation by real-time color Doppler Myocardial Imaging: A new technique for quantifying regional systolic function1998In: Journal of the American Society of Echocardiography, ISSN 0894-7317, E-ISSN 1097-6795, Vol. 11, no 7, p. 683-692Article in journal (Refereed)
    Abstract [en]

    A new color Doppler myocardial imaging (CDMI) system with high spatial and temporal resolution and novel postprocessing modalities has been developed that could allow quantifiable stress echocardiography. The purpose of this study was to determine whether regional myocardial systolic velocities could be accurately and reproducibly measured both at rest and during bicycle ergometry by using CDMI. Thirty normal subjects were examined with CDMI at rest, and peak mean systolic myocardial velocities (MSV) were measured for 34 predetermined left ventricular myocardial segments. Interobserver variability and intraobserver variability were established for all segments. Submaximal bicycle ergometry was performed in 20 normal subjects by using standardized weight-related increases in workload. MSV were measured at each step of exercise for 16 left ventricular stress echo segments. At rest, a base-apex gradient in regional MSV was recorded with highest longitudinal shortening velocities at the base. A similar pattern was noted for circumferential shortening MSV. Measurements were predictable and highly reproducible with low interobserver and intraobserver variability for 26 of 34 segments. Reproducibility was poor for basal anteroseptal segments in all views and mid anterior, anteroseptal, and septal segments in the short-axis views. During exercise, mid and basal segments of all walls showed a significant increase of MSV between each workload step and for apical segments between alternate steps. The resting base-apex velocity gradient observed at rest remained in all walls throughout ergometry. Thus a CDMI system with improved spatial and temporal resolution and postprocessing analysis modalities provided reproducible and accurate quantification of segmental left ventricular circumferential and longitudinal contraction both at rest and during exercise.

  • 281.
    Wisten, A.
    et al.
    Medicinkliniken, Sunderby sjukhus, Luleå, Sweden.
    Jernelov, L.
    Jernelöv, L., Pliktverket, Regionkontor, Stockholm, Sweden.
    Bäckstrand, B.
    n/a.
    Lovgren, T.
    Lövgren, T., Avdelningen för planering och urval, De båda sist nämn da Pliktverket, Karlstad, Sweden.
    Lofmark, R.
    Löfmark, R., Centrum för bioetik, Karolinska institutet, Stockholm, Sweden.
    Nylander, Eva
    Linköping University, Department of Medicine and Health Sciences, Clinical Physiology . Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Heart Centre, Department of Clinical Physiology.
    Service Administration continues to take an ECG at conscription draft board [Pliktverket fortsätter ta EKG vid värnpliktsmönstring]2009In: Läkartidningen, ISSN 0023-7205, E-ISSN 1652-7518, Vol. 106, no 10Article in journal (Refereed)
    Abstract [en]

    [No abstract available]

  • 282. Wisten, Aase
    et al.
    Jernelöv, Leif
    Bäckstrand, Björn
    Lövgren, Thomas
    Löfmark, Rurik
    Nylander, Eva
    Linköping University, Department of Medicine and Health Sciences, Clinical Physiology . Östergötlands Läns Landsting, Heart Centre, Department of Clinical Physiology. Linköping University, Faculty of Health Sciences.
    Pliktverket fortsätter ta EKG vid värnpliktsmönstring.2009In: Läkartidningen, ISSN 0023-7205, E-ISSN 1652-7518, Vol. 10, no 672, p. 675-Article in journal (Other academic)
  • 283. Xiong, Changsheng
    et al.
    Sjöberg, Birgitta Janero
    Linköping University, Department of Medical and Health Sciences, Clinical Physiology. 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.
    Sveider, Per
    Linköping University, Department of Biomedical Engineering.
    Ask, Per
    Linköping University, Department of Biomedical Engineering, Physiological Measurements. Linköping University, The Institute of Technology.
    Loyd, Dan
    Linköping University, Department of Management and Engineering, Applied Thermodynamics and Fluid Mechanics. Linköping University, The Institute of Technology.
    Wranne, Bengt
    Linköping University, Department of Medicine and Care, Clinical Physiology. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Heart and Medicine Center, Department of Clinical Physiology in Linköping.
    Problems in timing of respiration with the nasal thermistor technique.1993In: Journal of the American Society of Echocardiography, ISSN 0894-7317, E-ISSN 1097-6795, Vol. 6, no 2, p. 210-216Article in journal (Refereed)
    Abstract [en]

    When one analyzes transvalvular and venous flow velocity patterns, it is important to relate them to respiration. For this reason a nasal thermistor technique is often used, although it is known that this signal is delayed in relation to intrathoracic pressure changes. The magnitude and variation in delay have not been investigated previously and were, therefore, studied in a model experiment in 10 normal subjects, in 10 patients with obstructive, and in 10 patients with restrictive pulmonary disease. Esophageal pressure variations measured with an air-filled balloon served as a gold standard for intrathoracic pressure changes. During basal conditions there was, for both patient groups and normal subjects, a considerable delay of the thermistor signal. The average delay for all subjects was 370 msec with a wide variation (from 120 to 720 msec). At higher breathing frequencies the delay shortened to 310 msec (P < 0.01) but there was still a wide variation (ranging from 200 to 470 msec). Theoretic calculations show that the delay caused by the respiratory system accounts for only a minor portion of the total delay. Model experiments confirmed that the response characteristics of the thermistor probes limit the accuracy in timing of respiration. The total delay with the investigated thermistor technique is too long and variable to fulfil clinical demands.

  • 284.
    Yoon, EJ
    et al.
    Univ Calif San Francisco, San Francisco, CA 94143 USA Linkoping Univ, Linkoping, Sweden.
    Engvall, J
    Ebbers, Tino
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Health Sciences, Clinical Physiology . Östergötlands Läns Landsting, Heart Centre, Department of Clinical Physiology.
    Brandt, E
    Univ Calif San Francisco, San Francisco, CA 94143 USA Linkoping Univ, Linkoping, Sweden.
    Wigström, Lars
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Health Sciences, Clinical Physiology . Östergötlands Läns Landsting, Heart Centre, Department of Clinical Physiology.
    Wranne, Bengt
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Health Sciences, Clinical Physiology . Östergötlands Läns Landsting, Heart Centre, Department of Clinical Physiology.
    Bolger, A
    Reversal of blood flow in the descending aorta: Implications for Doppler quantitation of aortic insufficiency2002In: Journal of the American College of Cardiology, ISSN 0735-1097, E-ISSN 1558-3597, Vol. 39, no 5, p. 425A-425AConference paper (Other academic)
  • 285.
    Yousif, MHM
    et al.
    Kuwait Univ, Fac Med, Dept Pharmacol & Toxicol, Safat 13110, Kuwait Linkoping Univ, Fac Hlth Sci, S-58183 Linkoping, Sweden.
    Thulesius, Olav
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Health Sciences, Clinical Physiology .
    A pharmacological study of bronchodilator properties of NKH477, forskolin, and beta-agonists on guinea pig and ovine isolated bronchioles2000In: Drug development research (Print), ISSN 0272-4391, E-ISSN 1098-2299, Vol. 51, no 3, p. 169-176Article in journal (Refereed)
    Abstract [en]

    In this study we assessed the relaxant responses of two direct adenylate cyclase activators, NKH477 and forskolin, in comparison with two beta -adrenoceptor agonists, salbutamol and isoprenaline. The possible potentiation effect of NKH477 and forskolin on beta -agonist-induced bronchodilatation was examined. The effectiveness of NKH477 and forskolin in reversing tachyphylaxis development to salbutamol or isoprenaline was also investigated. We tested the in vitro bronchodilator effect of salbutamol, NKH477, and forskolin (10(-9)-10(-4) M) On isolated guinea pig bronchiolar ring segments precontracted with carbachol (3 muM). Salbutamol, NKH477, and forskolin produced a concentration-dependent relaxation. Potency values (pD(2)) were determined from cumulative concentration-response curves. The rank order for their potencies was salbutamol > NKH477 > forskolin (7.3 +/- 0.3, 6.4 +/- 0.3, and 5.4 +/- 0.1, respectively). The bronchodilator effects of salbutamol, isoprenaline, NKH477, and forskolin (10(-9)-10(-4) M) were examined on isolated ovine bronchioles precontracted with carbachol (0.3 muM). Isoprenaline, NKH477, and forskolin produced a concentration-dependent relaxation with pot values of 6.1 +/- 0.2, 5.4 +/- 0.2, and 5.3 +/- 0.2, respectively. Tachyphylaxis to the relaxant effects of salbutamol on guinea pig isolated bronchioles was experimentally induced and the potency of salbutamol was reduced to 5.9 +/- 0.2 after 24 h incubation with salbutamol (10(-5) M). NKH477 and forskolin (10(-6) M) produced a partial reversal of tachyphylaxis to salbutamol-induced relaxation using salbutamol pretreated tissues. The potency of salbutamol was increased to 6.6 +/- 0.2 and 5.9 +/- 0.2 after incubation with NKH477 or forskolin (10(-6) M), respectively Tachyphylaxis to the relaxant effects of isoprenaline resulted in a reduced potency of 5.7 +/- 0.2. Forskolin (10-6 M) Produced a partial reversal of tachyphylaxis, while NKH477 (10(-6) M) produced a complete reversal of tachyphylaxis to isoprenaline-induced relaxation with an pot value of 6.3 +/- 0.1. In conclusion, the guinea pig and sheep isolated bronchioles serve as good models to study the relaxant effects of the bronchodilator agents salbutamol, isoprenaline, NKH477, and forskolin. The beta -agonists examined had higher potencies than NKH477 or forskolin. However, the two adenylate cyclase activators, with greater effectiveness of NKH477, when used in combination with the beta -agonists, could produce an increase in the potency of the beta -agonists. Furthermore, the effectiveness of NKH477 and forskolin in reversing tachyphylaxis to the bronchodilator effects of the beta -agonists, particularly salbutamol, may provide an advantage in long-term use of beta -agonists in bronchial asthma therapy. Drug Dev. Res. 51:169-176, 2000. (C) 2001 Wiley-Liss, Inc.

  • 286.
    Yousif, MHM
    et al.
    Kuwait Univ, Fac Med, Dept Pharmacol & Toxicol, Safat 13110, Kuwait Linkoping Univ, Fac Hlth Sci, S-58183 Linkoping, Sweden.
    Thulesius, Olav
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Health Sciences, Clinical Physiology .
    NKH477: A novel bronchodilator produces potentiation and tachyphylaxis reversal to salbutamol in isolated guinea pig trachea1999In: Drug development research (Print), ISSN 0272-4391, E-ISSN 1098-2299, Vol. 48, no 4, p. 154-159Article in journal (Refereed)
    Abstract [en]

    The relaxant responses of the beta(2)-adrenoceptor agonist salbutamol and NKH477, an activator of adenylate cyclase, were compared and the possible potentiating effect of NKH477 on salbutamol-induced bronchodilatation was measured together with the effectiveness of NKH477 in reversing tachyphylaxis development to salbutamol. The in vitro bronchodilator effect of salbutamol and NKH477 (10(-9) - 10(-5) M) was measured on isolated guinea pig tracheal ring segments precontracted with carbachol (10(-6) M). Both salbutamol and NKH477 produced a concentration-dependent relaxation. EC50 values were determined from cumulative concentration-response curves. Salbutamol was more potent than NKH477 in relaxing the tracheal preparations (7.1 +/- 0.1 compared to 6.1 +/- 0.2, respectively). NKH477 produced a significant increase in the salbutamol-induced bronchodilator effect. The potency values recorded for salbutamol were 7.1 +/- 0.1, 7.4 +/- 0.2, 7.6 +/- 0.1, and 8.6 +/- 0.4 in the absence and presence of NKH477 (3 x 10(-8) M, 10(-7) M, and 3 x 10(-7) M, respectively). Reproducible relaxant responses could be elicited to salbutamol and NKH477 after 24 h incubation in Krebs' solution. Tachyphylaxis to the relaxant effects of salbutamol was experimentally induced by 24-h incubation of the preparations in Krebs' solution containing salbutamol (10(-6), 3 X 10(-6) or 10(-5) M). The potency of salbutamol was reduced to 6.9 +/- 0.2, 6.8 +/- 0.2, and 6.0 +/- 0.2 after 24 h incubation with salbutamol 10(-6) M, 3 X 10(-6) M or 10(-5) M, respectively. NKH477 (3 x 10(-7) M) produced a complete reversal of tachyphylaxis to salbutamol-induced relaxation in salbutamol pretreated tissues. The potency of salbutamol was increased to 7.4 +/- 0.2, 7.1 +/- 0.1, and 7.3 +/- 0.1 after the addition of NKH477 (3 x 10(-7) M) to the preparations preincubated (24 h) with salbutamol 10(-6), 3 X 10(-6), or 10(-5) M, respectively. NKH477 shares with salbutamol the ability to relax airway smooth muscle and produces an apparent increase of the bronchodilator effects of salbutamol and reverses tachyphylaxis. Drug Dev. Res. 48:154-159, 1999. (C) 1999 Wiley-Liss, Inc.

  • 287.
    Zachrisson, Helene
    Linköping University, Department of Medical and Health Sciences, Clinical Physiology. 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.
    Transkraniell doppler/duplex2002In: Klinisk fysiologisk kärldiagnostik / [ed] Tomas Jogestrand och Stefan Rosfors, Lund: Studentlitteratur AB, 2002, p. 212-221Chapter in book (Other academic)
  • 288.
    Zachrisson, Helene
    et al.
    Linköping University, Department of Medical and Health Sciences, Clinical Physiology. 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.
    Berthelsen, B
    Blomstrand, C
    Holm, J
    Volkmann, R
    Influence of poststenotic collateral pressure on blood flow velocities within high-grade carotid artery stenosis: differences between morphologic and functional measurements.2001In: Journal of Vascular Surgery, ISSN 0741-5214, E-ISSN 1097-6809, Vol. 34, no 2, p. 263-8Article in journal (Refereed)
    Abstract [en]

    PURPOSE: The driving force for blood flow through a high-grade stenosis in the internal carotid artery can be expressed as the pressure gradient over the stenosis itself, which, however, might be reduced by the back pressure exerted by distal collateral vessels. Theoretically the maximum blood flow velocity as a measure of the functional grade of obstruction may therefore be lower than what is expected from morphologic gradations of the stenosis. This study was designed to test prospectively the influence of intracranial collateral vessels on blood flow velocities within high-grade internal carotid artery stenoses.

    PATIENTS AND METHODS: Forty-five consecutive patients (age 66 +/- 11) with high-grade internal carotid artery stenoses were investigated before and during carotid endarterectomy. The preoperative investigations included duplex ultrasound scanning of the neck vessels, transcranial Doppler scanning for assessment of collateral flow to the middle cerebral artery and angiography. Carotid endarterectomy was performed with patients under deep general anesthesia without a shunt. Systolic and diastolic internal carotid artery blood pressures were measured before and during intraoperative cross-clamping (ie, stump pressure) of the carotid arteries.

    RESULTS: Within high-grade internal carotid artery stenoses, maximum systolic and end-diastolic blood flow velocities showed a significant inverse correlation to the corresponding systolic and diastolic stump blood internal carotid artery blood pressures. All patients with spontaneous collateral flow to the ipsilateral anterior part of the circle of Willis were divided into a group with relatively high and another one with low end-diastolic blood flow velocities. The stump pressure was significantly lower in patients with high end-diastolic blood flow velocities in spite of the fact that the mean angiographic grade of stenosis did not differ significantly between the groups.

    CONCLUSIONS: Flow velocities within a high-grade internal carotid artery stenosis are inversely dependent on the stump pressure, that is the poststenotic collateral perfusion pressure. This should be taken into consideration in case of discrepancies between angiography and ultrasound outcome.

  • 289.
    Zachrisson, Helene
    et al.
    Linköping University, Department of Medical and Health Sciences, Clinical Physiology. 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.
    Berthelsen, Brigitte
    Blomstrand, Christian
    Holm, Jan
    Kjällman, Lena
    Volkmann, Reinhard
    High diastolic flow velocities in severe internal carotid artery stenosis: a sign of increased surgical risk?2000In: Journal of Vascular Surgery, ISSN 0741-5214, E-ISSN 1097-6809, Vol. 31, no 3, p. 477-83Article in journal (Refereed)
    Abstract [en]

    PURPOSE: We reviewed the history and preoperative investigations of patients with early postoperative neurologic events after carotid thromboendarterectomy in an attempt to identify risk factors for neurologic complications.

    METHODS: Patients with neurologic events/complications (S group, n = 14 patients) were compared with an age- and disease-matched control group (C group, n = 42 patients) selected from the whole carotid thromboendarterectomy material between 1987 and 1996. In this retrospective study, we re-evaluated the maximum systolic and end diastolic flow velocities within the internal carotid artery (ICA) using video recordings of preoperative Duplex ultrasound scan investigations. The flow velocity variables were compared with preoperative carotid angiography and intraoperative ICA stump pressure measurement.

    RESULTS: S-group did not differ from C-group concerning either cardiovascular risk factors or diseases, ipsilateral and contralateral angiographic grade of ICA stenosis, or history of cerebral infarctions. Nevertheless, in contrast to control subjects, patients with early postoperative major stroke had higher end diastolic flow velocities and lower ICA stump pressures. Patients with postoperative minor stroke, transient ischemic attack, or amaurosis fugax did not differ significantly from the control subjects. Among patients with ICA stenosis of 75% or more, end diastolic flow velocities were correlated to the diastolic stump pressures.

    CONCLUSION: Diastolic flow velocities within severe internal carotid artery stenosis are dependent on the level of the collateral perfusion pressure distally to the stenosis (ie, high values indicate a low internal carotid artery stump pressure), which seems to be a risk factor for early postoperative strokes.

  • 290.
    Zachrisson, Helene
    et al.
    Linköping University, Department of Medical and Health Sciences, Clinical Physiology. 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.
    Blomstrand, C
    Holm, J
    Mattsson, E
    Volkmann, R
    Changes in middle cerebral artery blood flow after carotid endarterectomy as monitored by transcranial Doppler.2002In: Journal of Vascular Surgery, ISSN 0741-5214, E-ISSN 1097-6809, Vol. 36, no 2, p. 285-90Article in journal (Refereed)
    Abstract [en]

    OBJECTIVE: By using transcranial Doppler (TCD) it is possible to measure blood flow velocities within the circle of Willis. In this study, TCD was performed before and after carotid endarterectomy (CEA) with the aim to describe cerebral hemodynamics after normalization of the carotid artery blood flow.

    METHODS: Thirty CEA patients were consecutively entered into the TCD study, whereas 15 patients were referred for postoperative TCD for various clinical reasons. All 45 patients were investigated by using TCD: first preoperatively, then during the first few days after CEA before discharge from the hospital, and finally 3 to 12 months later. In addition, all patients underwent duplex investigation of the internal carotid artery the day before surgery and 3 months postoperatively. For the analysis, the patients were divided into two groups, one with (S-group), suspected postoperative neurologic complications/symptoms and another one without (C-group). Six patients were assigned to the S-group and 37 to the C-group, the latter including two patients who underwent bilateral CEAs.

    RESULTS: In the whole study group,a significant postoperative increase in systolic flow velocity was recorded bilaterally in the middle cerebral artery (MCA) as measured some days after surgery. The patients in the S-group showed high blood flow velocities mainly in the MCA on the ipsilateral side. A contralateral flow velocity increase did not occur in patients with very severe contralateral stenosis or occlusion (n = 9) if the late follow-up investigation was chosen as a reference value. Twenty patients in the C-group formed a subgroup with high blood pressure and/or headache postoperatively (CB-group) The other 19 patients were referred to as the CA-group. The CB- and S-groups showed more pronounced vessel disease in internal carotid artery on the contralateral side combined with lower collateral capacity in the circle of Willis compared to the CA-group. In the S-group the mean +/- standard deviation peak systolic velocity in ipsilateral MCA increased from a preoperative value of 0.71 +/- 0.22 m/sec to 2.23 +/- 0.72 m/sec (P <.005). In the CB-group, we observed a bilateral MCA blood flow velocity increase from 0.72 +/- 0.18 to 1.35 +/- 0.56 m/sec (P <.0001) on the ipsilateral side and from 0.82 +/- 0.37 to 1.28 +/- 0.66 m/sec (P < 0.001) on the contralateral side. In the CA-group, we observed minor bilateral blood flow velocity increases in the MCA, from 0.79 +/- 0.25 m/sec to 1.03 +/- 0.33 m/sec on the ipsilateral (P <.001) and from 0.70 +/- 0.17 m/sec to 0.93 +/- 0.26 m/sec on the contralateral side (P <.005). At the follow-up 3 to 12 months after surgery, the MCA flow velocities had returned to normal.

    CONCLUSIONS: Soon after surgery, blood flow velocity increases often bilaterally in the MCA. However a contralateral flow velocity increase did not occur in patients with very severe contralateral stenosis or occlusion if the late follow-up investigation was chosen as a reference value. The clinical significance of bilateral flow velocity increases is uncertain, but very high blood flow velocities might be a signal for cerebrovascular hyperperfusion. In those patients, increased postoperative surveillance is recommended.

  • 291.
    Zachrisson, Helene
    et al.
    Linköping University, Center for Medical Image Science and Visualization, CMIV. Linköping University, Department of Medicine and Health Sciences, Clinical Physiology . Linköping University, Faculty of Health Sciences.
    Engström, E
    Linköping University, Department of Medicine and Health Sciences, Clinical Physiology . Linköping University, Faculty of Health Sciences.
    Engvall, Jan
    Linköping University, Center for Medical Image Science and Visualization, CMIV. Linköping University, Department of Medicine and Health Sciences, Clinical Physiology . Linköping University, Faculty of Health Sciences.
    Wigström, Lars
    Linköping University, Center for Medical Image Science and Visualization, CMIV. Linköping University, Department of Medicine and Health Sciences, Clinical Physiology . Linköping University, Faculty of Health Sciences.
    Smedby, Örjan
    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.
    Persson, Anders
    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.
    Soft tissue discrimination ex vivo by dual energy computed tomography2010In: European Journal of Radiology, ISSN 0720-048X, E-ISSN 1872-7727, Vol. 75, no 2, p. E124-E128Article in journal (Refereed)
    Abstract [en]

    PURPOSE: Dual Energy Computed Tomography (DECT) may provide additional information about the chemical composition of tissues compared to examination with a single X-ray energy. The aim of this in vitro study was to test whether combining two energies may significantly improve the detection of soft tissue components commonly present in arterial plaques. METHODS: Tissue samples of myocardial and psoas muscle, venous and arterial thrombus as well as fat from different locations were scanned using a SOMATOM Definition Dual Source CT system (Siemens AG, Medical Solutions, Forchheim, Germany) with simultaneous tube voltages of 140 and 80kV. The attenuation (Hounsfield units, HU) at 80 and 140kV was measured in representative regions of interest, and the association between measured HU values and tissue types was tested with logistic regression. RESULTS: The combination of two energy levels (80 and 140kV) significantly improved (p<0.001) the ability to correctly classify venous thrombus vs arterial thrombus, myocardium or psoas; arterial thrombus vs myocardium or psoas; myocardium vs psoas; as well as the differentiation between fat tissue from various locations. Single energy alone was sufficient for distinguishing fat from other tissues. CONCLUSION: DECT offers significantly improved in vitro differentiation between soft tissues occurring in plaques. If this corresponds to better tissue discrimination in vivo needs to be clarified in future studies.

  • 292.
    Zachrisson, Helene
    et al.
    Linköping University, Department of Medical and Health Sciences, Clinical Physiology. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Heart and Medicine Centre, Department of Clinical Physiology UHL.
    Fouladiun, Marita
    Sahlgrens Academy.
    Blomstrand, Christian
    Sahlgrens Academy.
    Volkmann, Reinhard
    Sahlgrens Academy.
    Functional assessment of high-grade ICA stenosis with duplex ultrasound and transcranial Doppler2012In: Clinical Physiology and Functional Imaging, ISSN 1475-0961, E-ISSN 1475-097X, Vol. 32, no 3, p. 241-246Article in journal (Refereed)
    Abstract [en]

    Background: Duplex ultrasound (DUS) has shown a andgt;90% accuracy compared to angiography, concerning the degree of internal carotid artery (ICA) stenosis. However, uncertainty may occur in a severe stenosis, in which peak systolic velocity (PSV) may decrease owing to high flow resistance or high backward pressure. We investigated intracranial collateral flows using transcranial Doppler (TCD) to further evaluate the hemodynamic significance of high-grade ICA stenosis. Methods: In this retrospective study, 320 consecutive symptomatic patients were examined. The degree of ICA stenosis and collateral capacity in the circle of Willis was investigated by DUS and TCD. In addition, magnetic resonance angiography (MRA) was added in a subgroup of 204 patients. The criterion for hemodynamic significant ICA stenosis was established collateral flow. Results: In 91% of all symptomatic vessels (291 vessels), an ICA stenosis of 70% was found. Established collateral flow always indicated precerebral carotid artery disease of 70%. Furthermore, in 11% of the whole study material, collateral reserve capacity was found despite high-grade (70%) ICA stenosis. PSV in ICA andlt; 2 5 m s) 1 was combined with established collateral flow and MRA stenosis of 70% in 9% (19 arterial systems). In 4%, doubt existed concerning the degree of stenosis after DUS. Conclusion: Transcranial Doppler helps to determine whether an ICA stenosis is of hemodynamic significance and to assess collateral patterns. Established collateral blood flow will help to identify patients with 70% (ECST) carotid artery disease. TCD might be of value when flow velocity criteria combined with plaque assessment by DUS are inclusive. Other diagnostic methods may also be considered.

  • 293.
    Zachrisson, Helene
    et al.
    Linköping University, Department of Medical and Health Sciences, Clinical Physiology. 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.
    Jatuzis, D
    Blomstrand, C
    Holm, J
    Volkmann, R
    Middle cerebral artery circulation during carotid surgery. A transcranial Doppler study.2000In: Scandinavian Cardiovascular Journal, ISSN 1401-7431, E-ISSN 1651-2006, Vol. 34, no 6, p. 597-602Article in journal (Refereed)
    Abstract [en]

    OBJECTIVE: Perioperative carotid cross-clamping might induce low stump pressures as well as hypoperfusion of the middle cerebral artery. In this study blood flow velocities in the middle cerebral artery were compared with intraoperative measurements of the poststenotic carotid blood pressure.

    DESIGN: Forty-one patients with internal carotid artery stenosis were operated on without shunting, under general anesthesia. Poststenotic carotid pressures and middle cerebral artery flow velocities were measured before and during cross-clamping. The hemodynamic responses to preoperative carotid compressions and intraoperative cross-clamping were evaluated.

    RESULTS: In seven patients the poststenotic carotid blood pressure decreased on clamping despite unchanged or even increased middle cerebral artery blood flow velocities. In all other patients, pressure changes were significantly correlated to the decrease in middle cerebral artery blood flow velocities. Autoregulatory blood flow velocity responses after preoperative common carotid artery compression were not reproducible by cross-clamping.

    CONCLUSIONS: Stump blood pressure measurements may not reflect middle cerebral artery perfusion in about 20% of thrombendarterectomies performed under general anesthesia. A possible explanation might be dimished cerebral autoregulation and changes in collateral flow distributions.

  • 294.
    Zachrisson, Helene
    et al.
    Linköping University, Department of Medical and Health Sciences, Clinical Physiology. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Heart and Medicine Centre, Department of Clinical Physiology UHL.
    Lindenberger, Marcus
    Linköping University, Department of Medical and Health Sciences, Physiology. Linköping University, Faculty of Health Sciences.
    Hallman, Daniel
    Linköping University, Department of Medical and Health Sciences, Physiology. Linköping University, Faculty of Health Sciences.
    Ekman, M.
    Biomed Data AB, Gothenburg, Sweden.
    Neider, Daniel
    Linköping University, Department of Medical and Health Sciences, Physiology. Linköping University, Faculty of Health Sciences.
    Länne, Toste
    Linköping University, Department of Medical and Health Sciences, Physiology. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Heart and Medicine Centre, Department of Thoracic and Vascular Surgery in Östergötland.
    Diameter and compliance of the greater saphenous vein - effect of age and nitroglycerine2011In: Clinical Physiology and Functional Imaging, ISSN 1475-0961, E-ISSN 1475-097X, Vol. 31, no 4, p. 300-306Article in journal (Refereed)
    Abstract [en]

    Objectives: The greater saphenous vein (GSV) is commonly used in autologous vein graft surgery. GSV diameter has proven to influence graft patency, and furthermore venous compliance might be of importance. The purpose of the study was to evaluate the effect of age on GSV diameter and compliance, and to evaluate the effect of nitroglycerine (NTG). Methods: The diameter and compliance of the GSV, with and without NTG, were examined with B-mode ultrasound in 12 elderly (70.3 +/- 1.2 year) and 15 young (25.1 +/- 0.6 year) men. The GSV diameter at the thigh and calf level was measured at rest, after 6 min of venous stasis (60 mmHg) and after NTG administration. Pressure-area curves during a linear venous pressure decrease were produced. Venous compliance was calculated using the quadratic regression equation (area) = beta(0) + beta(1) (cuff pressure) + beta(2) (cuff pressure)(2). Results: GVS diameter between the groups showed significant lower diameter in elderly compared to young men (Pless than0.05). Venous occlusion increased GSV diameter in elderly men (Pless than0.01) as well as young men (Pless than0.001). NTG increased GSV diameter in elderly men (Pless than0.01) with an equal trend in young men. During venous occlusion, after administration of NTG, GSV diameter increased further in both elderly (Pless than0.01) and young men (Pless than0.001). GSV compliance was decreased in elderly (beta(1), 0.037 +/- 0019, beta(2), -0.000064 +/- 00017) versus young men (beta(1), 0.128 +/- 0.013, beta(2), -0.00010 +/- 000018) [Pless than0.001 (beta(1)), Pless than0.02 (beta(2))]. Conclusions: Baseline GSV diameter as well as GSV compliance is decreased in elderly men compared to the young subjects. As reduced GSV diameter as well as reduced compliance is related to decreased graft patency, these findings might be of importance for the uses of GSV as graft material in cardiovascular bypass surgery. The clinical value has to be clarified in future studies.

  • 295.
    Zachrisson, Helene
    et al.
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Health Sciences, Clinical Physiology . Östergötlands Läns Landsting, Heart Centre, Department of Clinical Physiology.
    Lindenberger, Marcus
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Health Sciences, Physiology .
    Hallman, Daniel
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Health Sciences.
    Länne, Toste
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Health Sciences, Physiology . Östergötlands Läns Landsting, Heart Centre, Department of Thoracic and Vascular Surgery.
    Diameter and compliance of the great saphenous vein2008In: Experimental Biology,2008, 2008Conference paper (Refereed)
  • 296.
    Zachrisson, Helene
    et al.
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Health Sciences, Clinical Physiology . Östergötlands Läns Landsting, Heart Centre, Department of Clinical Physiology.
    Persson, Anders
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Health Sciences, Radiology . Östergötlands Läns Landsting, Centre for Medical Imaging, Department of Radiology UHL. Linköping University, Center for Medical Image Science and Visualization, CMIV.
    Engvall, Jan
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Health Sciences, Clinical Physiology . Östergötlands Läns Landsting, Heart Centre, Department of Clinical Physiology. Linköping University, Center for Medical Image Science and Visualization, CMIV.
    Stenestrand, Ulf
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Health Sciences, Cardiology . Östergötlands Läns Landsting, Heart Centre, Department of Cardiology.
    Janzon, Magnus
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Health Sciences, Cardiology . Östergötlands Läns Landsting, Heart Centre, Department of Cardiology.
    CT angiography - clinical experience from Linköping University Hospital2008In: X Svenska Kardiovaskulära Vårmötet,2008, 2008, p. 40-Conference paper (Refereed)
  • 297.
    Zachrisson, Helene
    et al.
    Linköping University, Department of Medical and Health Sciences, Clinical Physiology. 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.
    Volkmann, R
    Bergerheim, T
    Holm, J
    Selectivity of superficial vein occlusion at the ankle and calf level: a methodological study in healthy volunteers.1998In: Clinical Physiology, ISSN 0144-5979, E-ISSN 1365-2281, Vol. 18, no 1, p. 55-60Article in journal (Refereed)
    Abstract [en]

    Judgement of deep venous function may be necessary before surgery for superficial vein incompetence is performed. Assessment of deep venous function needs selective entrapment of superficial venous compartments between the ankle and knee, which may not be guaranteed if conventional tourniquets are used. This study was, therefore, aimed at modifying the technique of selective compression of superficial vein compartments. Twenty apparently normal legs of 10 volunteers were investigated on two study days. The subjects were in a supine position with the feet resting 30 cm above heart level. Ankle cuffs (3 cm wide) were placed just above the malleoli and stepwise inflated with air. The steady-state venous volume of the forefoot as a function of the pressure within the ankle cuff was measured with a mercury-in-rubber strain gauge. The maximum venous outflow velocity from the foot was also measured at each cuff pressure step after the addition of conventional thigh vein occlusion. The same protocol was used on the second study day: calf cuffs (3 cm wide) were then used instead of the ankle cuffs. In the forefoot, venous volume increased and the maximum venous outflow velocity decreased significantly either at ankle cuff pressures > 30 mmHg or at calf cuff pressures of > 60 mmHg. By using small cuffs, selective superficial vein occlusion seems to occur at cuff pressures ranging between 10 and 30 mmHg (ankle) and between 30 and 60 mmHg (calf), provided the feet are 30 cm above heart level. Higher cuff pressures seem to interact with deep venous function.

  • 298. Order onlineBuy this publication >>
    Åström Aneq, Meriam
    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.
    Arrhythmogenic right ventricular cardiomyopathy: Is it right?2011Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Arrhythmogenic right ventricular cardiomyopathy (ARVC) is an inherited heart disease, where sudden cardiac death in young seemingly healthy persons may be the first symptom. There is a need for more sensitive and accurate diagnostic methods to detect signs of disease, at an early stage and in relatives of affected individuals. The aim of this thesis is the evaluation of new non-invasive modalities in assessment of right ventricular (RV) volume and function with focus on patients with ARVC.

    Clinical and non-invasive follow-up of fifteen patients with ARVC during a mean period of 8 years permitted the evaluation of disease progression. RV volume analysis by magnetic resonance imaging relies on short axis (SA) views. A new axially rotated modality acquisition was tested and its feasibility in assessment of RV volume was evaluated. This acquisition seems to be able to improve the assessment of RV volume and function by reducing the uncertainty in defining the basal slice of the RV. A third study concentrated on analysis of RV regional and general function by echocardiography, using tissue Doppler imaging as well as two dimensional (2D) longitudinal strain based on speckle tracking in patients with ARVC, their first degree relatives and in healthy subjects. 2D strain showed a good feasibility in analysis of the RV function in relatives and controls but less in ARVC patients probably due to the progressive myocardial cell death with fibro-fatty replacement of the RV wall. In order to detect and follow up echocardiographic changes an index was developed combining dimensional and functional parameters for the left and for the right ventricle. Advances in the molecular genetics of ARVC have provided new insights into the understanding of the disease. Hitherto, 9 candidate genes have been identified. A new mutation in the plakophilin 2 gene was detected in a three generation family. The clinical phenotype related to this mutation was investigated.

    The studies have evaluated and developed methods for studying the right ventricle with special emphasis on ARVC. With the ultimate goal of preventing sudden death in ARVC, a combination of genetic testing and improved diagnostic methods may create an improved algorithm for risk stratification and selection to prophylactic treatment.

    List of papers
    1. Long-term follow-up in arrhythmogenic right ventricular cardiomyopathy using Tissue Doppler Imaging
    Open this publication in new window or tab >>Long-term follow-up in arrhythmogenic right ventricular cardiomyopathy using Tissue Doppler Imaging
    2008 (English)In: Scandinavian Cardiovascular Journal, ISSN 1401-7431, E-ISSN 1651-2006, Vol. 42, no 6, p. 368-374Article in journal (Refereed) Published
    Abstract [en]

    Aim: To study patients with arrhythmogenic right ventricular cardiomyopathy (ARVC) and describe different echocardiographic parameters and their change over time during almost 10 years follow-up period.

    Methods: Fifteen patients (9 male, 6 female), aged 22-58 years (mean 40) with a diagnosis of ARVC, were followed up for a period of 6-10 years (mean 8.7). Twelve-lead and a signal- averaged ECG was recorded. Tricuspid and mitral annular motion and tissue Doppler imaging were registered by echocardiography. Wall motion score index (WMSI) was calculated for the left and right ventricles.

    Results: We registered significant reduction in systolic tissue velocity on right ventricle free wall between the first and last investigations: 7-17cm/s (mean 11.8) to 4-15 (mean 9.1), p=0.005. WMSI increased by at least 0.2 in 10/14 patients for the right and in 8/15 patients for the left ventricle. A decrease in velocity time integral for the left ventricular outflow was observed (16-30 to 13-21, p=0.009).

    Conclusion: ARVC is a progressive disease with individual variation. Left ventricular involvement may occur early in the disease. Tissue Doppler imaging is a useful tool to follow-up right ventricular abnormalities.

    Keywords
    Arrhythmogenic right ventricular cardiomyopathy, Doppler tissue imaging, progression, right ventricular function
    National Category
    Medical and Health Sciences
    Identifiers
    urn:nbn:se:liu:diva-16180 (URN)10.1080/14017430802372384 (DOI)
    Available from: 2009-01-09 Created: 2009-01-09 Last updated: 2017-12-14
    2. Determination of right ventricular volume and function using multiple axially rotated MRI slices
    Open this publication in new window or tab >>Determination of right ventricular volume and function using multiple axially rotated MRI slices
    2011 (English)In: Clinical Physiology and Functional Imaging, ISSN 1475-0961, E-ISSN 1475-097X, Vol. 31, no 3, p. 233-239Article in journal (Refereed) Published
    Abstract [en]

    Pandgt;Background: The conventional magnetic resonance imaging (MRI) method for right ventricular (RV) volume and motion, using short-axis (SA) orientation, is limited by RV anatomy and shape. We suggest an orientation based on six slices rotated around the long axis of the RV, rotated long axis (RLA). Materials and methods: Three phantoms were investigated in SA and RLA using cine balanced steady-state free precession MRI. Volumes were calculated based on segmentation and checked against true volumes. In 23 healthy male volunteers, we used six long-axis planes from the middle of the tricuspid valve to the RV apex, rotated in 30 degrees increments. For comparison, short-axis slices were acquired. Imaging parameters were identical in both acquisitions. Results: Right ventricular end-diastolic (EDV), end-systolic (ESV) and stroke volumes (SV) determined in the RLA 179 center dot 1 +/- 29 center dot 3; 80 center dot 1 +/- 17 center dot 1; 99 center dot 3 +/- 16 center dot 9 ml and in the SA were 174 center dot 0 +/- 21 center dot 1; 78 center dot 8 +/- 13 center dot 6; 95 center dot 3 +/- 14 center dot 5 ml with P-values for the difference from 0 center dot 17 to 0 center dot 64 (ns). Interobserver variability ranged between 3 center dot 2% and 6 center dot 6% and intraobserver variability between 2 center dot 8% and 6 center dot 8%. In SA views, consensus for the definition of the basal slice was necessary in 39% of the volunteers for whom the average volume change was 20% in ESV and 10% in EDV. Conclusions: The RLA method results in better visualization and definition of the RV inflow, outflow and apex. Accurate measurement of RV volumes for diagnosis and follow-up of cardiac diseases are enhanced by the RLA orientation, even though additional acquisition time is required.

    Place, publisher, year, edition, pages
    Blackwell Publishing Ltd, 2011
    Keywords
    axial rotation, cine MRI, heart volumes, methodological comparison, normal values
    National Category
    Medical and Health Sciences
    Identifiers
    urn:nbn:se:liu:diva-67837 (URN)10.1111/j.1475-097X.2011.01006.x (DOI)000289258100012 ()
    Note
    This is the authors’ version of the following article: Meriam Aneq Åström, Eva Nylander, Tino Ebbers and Jan Engvall, Determination of right ventricular volume and function using multiple axially rotated MRI slices, 2011, CLINICAL PHYSIOLOGY AND FUNCTIONAL IMAGING, (31), 3, 233-239. which has been published in final form at: http://dx.doi.org/10.1111/j.1475-097X.2011.01006.x Copyright: Blackwell Publishing Ltd http://eu.wiley.com/WileyCDA/Brand/id-35.htmlAvailable from: 2011-04-29 Created: 2011-04-29 Last updated: 2017-12-11Bibliographically approved
    3. Evaluation of Right and Left Ventricular Function Using Speckle Tracking Echocardiography in Patients with Arrhythmogenic Right Ventricular Cardiomyopathy and Their First Degree Relatives
    Open this publication in new window or tab >>Evaluation of Right and Left Ventricular Function Using Speckle Tracking Echocardiography in Patients with Arrhythmogenic Right Ventricular Cardiomyopathy and Their First Degree Relatives
    (English)Manuscript (preprint) (Other academic)
    Abstract [en]

    Introduction and aim: The identification of right ventricular abnormalities in patients with arrhythmogenic right ventricular cardiomyopathy (ARVC) in early stages is still difficult. The aim of this study was to investigate if longitudinal strain based on speckle tracking can detect subtle right (RV) or left ventricular (LV) dysfunction as an early sign of ARVC.

    Methods and results: Seventeen male patients, fulfilling Task force criteria for ARVC, 49 (32-70) years old, nineteen male first degree relatives 29 (19-73) y.o. and twenty-two healthy male volunteers 36 (24-66) y.o participated in the study. Twelve-lead and signal-averaged electrocardiograms were recorded. All subjects underwent echocardiography. LV and RV diameters, peak systolic velocity from tissue Doppler and longitudinal strain based on speckle tracking were measured from the basal and mid segments in both ventricles. RV longitudinal strain measurement was successful in first degree relatives and controls (95 resp. 86%) but less feasible in patients (59%). Results were not systematically different between first degree relatives and controls. Using discriminant analysis, we then developed an index based on echocardiographic parameters. All normal controls had an index <l while patients with abnormal ventricles had an index between 1-4. Some of the first degree relatives deviated from the normal pattern.

    Conclusion: Longitudinal strain of LV and RV segments was significantly lower in patients than in relatives and controls. An index was developed incorporating dimensional and functional echocardiographic parameters. In combination with genetic testing this index might help to detect early phenotype expression in mutation carriers.

    National Category
    Medical and Health Sciences
    Identifiers
    urn:nbn:se:liu:diva-70401 (URN)
    Available from: 2011-09-06 Created: 2011-09-06 Last updated: 2011-09-06Bibliographically approved
    4. Novel plakophilin2 mutation. Three generation family with arrhythmogenic right ventricular cardiomyopathy
    Open this publication in new window or tab >>Novel plakophilin2 mutation. Three generation family with arrhythmogenic right ventricular cardiomyopathy
    Show others...
    2012 (English)In: Scandinavian Cardiovascular Journal, ISSN 1401-7431, E-ISSN 1651-2006, Vol. 46, no 2, p. 72-75Article in journal (Refereed) Published
    Abstract [en]

    Objectives: The autosomal dominant form of arrhythmogenic right ventricular cardiomyopathy (ARVC)has been linked to mutations in desmosomal proteins. Different studies have shown that amutation in plakophilin-2 (PKP 2) is a frequent genetic cause for ARVC. We describe a newmutation in the PKP2 gene, the genotype-phenotype variation in this mutation and its clinicalconsequences.

    Design: Individuals in a three generation family were investigated after the sudden cardiac death of a young male. Clinical evaluation, electrocardiography, echocardiography, magnetic resonance imaging, endomyocardial biopsy and genetic testing were performed.

    Results: A novel heterozygote mutation, a c.368G>A transition, located in exon 3 of the PKP2 gene was found (p.Trp123X). The phenotype was characterized by arrhythmia at an early age in some individuals, with mild abnormalities on imaging. However a relative carrying this mutation, with positive findings on endomyocardial biopsy had an otherwise normal phenotype, for 16 years, whereas a relative fulfilling the modified Task Force Criteria for ARVC turned out to be a non-carrier.

    Conclusions: This shows the variable penetrance and phenotypic expression in ARVC and highlights the need of genetic testing as well as a thorough phenotype examination as a part of the investigations in ARVC pedigrees.

    Place, publisher, year, edition, pages
    Informa Healthcare, 2012
    National Category
    Medical and Health Sciences
    Identifiers
    urn:nbn:se:liu:diva-70402 (URN)10.3109/14017431.2011.636068 (DOI)000301496200002 ()
    Note
    Funding agencies|FORSS||Medical Research Council of Southeast Sweden| 12043 |Swedish Heart-Lung foundation| 20070864 |Available from: 2011-09-06 Created: 2011-09-06 Last updated: 2017-12-08Bibliographically approved
    Download full text (pdf)
    Arrhythmogenic right ventricular cardiomyopathy: Is it right?
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  • 299.
    Åström Aneq, Meriam
    et al.
    Linköping University, Department of Medicine and Health Sciences, Clinical Physiology . Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Heart Centre, Department of Clinical Physiology.
    Lindström, Lena
    Linköping University, Department of Medicine and Health Sciences, Clinical Physiology . Linköping University, Faculty of Health Sciences.
    Nylander, Eva
    Linköping University, Department of Medicine and Health Sciences, Clinical Physiology . Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Heart Centre, Department of Clinical Physiology.
    Long-term follow-up in arrhythmogenic right ventricular cardiomyopathy using Tissue Doppler Imaging2008In: Scandinavian Cardiovascular Journal, ISSN 1401-7431, E-ISSN 1651-2006, Vol. 42, no 6, p. 368-374Article in journal (Refereed)
    Abstract [en]

    Aim: To study patients with arrhythmogenic right ventricular cardiomyopathy (ARVC) and describe different echocardiographic parameters and their change over time during almost 10 years follow-up period.

    Methods: Fifteen patients (9 male, 6 female), aged 22-58 years (mean 40) with a diagnosis of ARVC, were followed up for a period of 6-10 years (mean 8.7). Twelve-lead and a signal- averaged ECG was recorded. Tricuspid and mitral annular motion and tissue Doppler imaging were registered by echocardiography. Wall motion score index (WMSI) was calculated for the left and right ventricles.

    Results: We registered significant reduction in systolic tissue velocity on right ventricle free wall between the first and last investigations: 7-17cm/s (mean 11.8) to 4-15 (mean 9.1), p=0.005. WMSI increased by at least 0.2 in 10/14 patients for the right and in 8/15 patients for the left ventricle. A decrease in velocity time integral for the left ventricular outflow was observed (16-30 to 13-21, p=0.009).

    Conclusion: ARVC is a progressive disease with individual variation. Left ventricular involvement may occur early in the disease. Tissue Doppler imaging is a useful tool to follow-up right ventricular abnormalities.

  • 300.
    Åström, Meriam Aneq
    et al.
    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.
    Engvall, Jan
    Linköping University, Department of Medical and Health Sciences, Division of Cardiovascular Medicine. Linköping University, Faculty of Health Sciences.
    Brudin, Lars
    Kalmar County Hospital, Sweden .
    Nylander, Eva
    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.
    Evaluation of right and left ventricular function using speckle tracking echocardiography in patients with arrhythmogenic right ventricular cardiomyopathy and their first degree relatives2012In: Cardiovascular Ultrasound, ISSN 1476-7120, E-ISSN 1476-7120, Vol. 10, no 37Article in journal (Refereed)
    Abstract [en]

    Introduction and aim: The identification of right ventricular abnormalities in patients with arrhythmogenic right ventricular cardiomyopathy (ARVC) in early stages is still difficult. The aim of this study was to investigate if longitudinal strain based on speckle tracking can detect subtle right (RV) or left ventricular (LV) dysfunction as an early sign of ARVC. Methods and results: Seventeen male patients, fulfilling Task force criteria for ARVC, 49 (32-70) years old, nineteen male first degree relatives 29 (19-73) y.o. and twenty-two healthy male volunteers 36 (24-66) y.o participated in the study. Twelve-lead and signal-averaged electrocardiograms were recorded. All subjects underwent echocardiography. LV and RV diameters, peak systolic velocity from tissue Doppler and longitudinal strain based on speckle tracking were measured from the basal and mid segments in both ventricles. RV longitudinal strain measurement was successful in first degree relatives and controls (95 resp. 86%) but less feasible in patients (59%). Results were not systematically different between first degree relatives and controls. Using discriminant analysis, we then developed an index based on echocardiographic parameters. All normal controls had an index less thanl while patients with abnormal ventricles had an index between 1-4. Some of the first degree relatives deviated from the normal pattern. Conclusion: Longitudinal strain of LV and RV segments was significantly lower in patients than in relatives and controls. An index was developed incorporating dimensional and functional echocardiographic parameters. In combination with genetic testing this index might help to detect early phenotype expression in mutation carriers.

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