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Tisell, Anders
Publications (10 of 46) Show all publications
Mellergård, J., Tisell, A., Blystad, I., Grönqvist, A., Blennow,, K., Olsson,, B., . . . Ernerudh, J. (2017). Cerebrospinal fluid levels of neurofilament and tau correlate with brain atrophy in natalizumab-treated multiple sclerosis. European Journal of Neurology, 24(1), 112-121
Open this publication in new window or tab >>Cerebrospinal fluid levels of neurofilament and tau correlate with brain atrophy in natalizumab-treated multiple sclerosis
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2017 (English)In: European Journal of Neurology, ISSN 1351-5101, E-ISSN 1468-1331, Vol. 24, no 1, p. 112-121Article in journal (Refereed) Published
Abstract [en]

Background and purpose

Brain atrophy is related to clinical deterioration in multiple sclerosis (MS) but its association with intrathecal markers of inflammation or neurodegeneration is unclear. Our aim was to investigate whether cerebrospinal fluid (CSF) markers of inflammation or neurodegeneration are associated with brain volume change in natalizumab-treated MS and whether this change is reflected in non-lesional white matter metabolites.

Methods

About 25 patients with natalizumab-treated MS were followed for 3 years with assessment of percentage brain volume change (PBVC) and absolute quantification of metabolites with proton magnetic resonance spectroscopy (1H MRS). Analyses of inflammatory [interleukin 1β (IL-1β), IL-6, C-X-C motif chemokine 8 (CXCL8), CXCL10, CXCL11, C-C motif chemokine 22] and neurodegenerative [neurofilament light protein (NFL), glial fibrillary acidic protein, myelin basic protein, tau proteins] markers were done at baseline and 1-year follow-up.

Results

The mean decline in PBVC was 3% at the 3-year follow-up, although mean 1H MRS metabolite levels in non-lesional white matter were unchanged. CSF levels of NFL and tau at baseline correlated negatively with PBVC over 3 years (r = −0.564, P = 0.012, and r = −0.592, P = 0.010, respectively).

Conclusions

A significant 3-year whole-brain atrophy was not reflected in mean metabolite change of non-lesional white matter. In addition, our results suggest that CSF levels of NFL and tau correlate with brain atrophy development and may be used for evaluating treatment response in inflammatory active MS.

Place, publisher, year, edition, pages
Blackwell Publishing, 2017
Keywords
brain atrophy, magnetic resonance spectroscopy, multiple sclerosis, natalizumab, neurofilament, quantitative magnetic resonance imaging, tau
National Category
Neurology Radiology, Nuclear Medicine and Medical Imaging
Identifiers
urn:nbn:se:liu:diva-134153 (URN)10.1111/ene.13162 (DOI)000392806700007 ()
Note

Funding agencies: Medical Research Council [K2013-61X-22310-01-4]; Swedish Society of Neurologically Disabled; Swedish Society of Medicine; National Research Council (VR/NT); Linkoping University; Linkoping University Hospital; County Council of Ostergotland

Available from: 2017-01-26 Created: 2017-01-26 Last updated: 2018-04-17
Tapper, S., Tisell, A. & Lundberg, P. (2017). How does motion affect GABA-measurements? Order statistic filtering compared to conventional analysis of MEGA-PRESS MRS. PLoS ONE, 12(5), Article ID e0177795.
Open this publication in new window or tab >>How does motion affect GABA-measurements? Order statistic filtering compared to conventional analysis of MEGA-PRESS MRS
2017 (English)In: PLoS ONE, ISSN 1932-6203, E-ISSN 1932-6203, Vol. 12, no 5, article id e0177795Article in journal (Refereed) Published
Abstract [en]

Purpose The aim of this study was to evaluate two post-processing techniques applied to MRS MEGA-PRESS data influenced by motion-induced artifacts. In contrast to the conventional averaging technique, order statistic filtering (OSF) is a known method for artifact reduction. Therefore, this method may be suitable to incorporate in the GABA quantification. Methods Twelve healthy volunteers were scanned three times using a 3 T MR system. One measurement protocol consisted of two MEGA-PRESS measurements, one reference measurement and one measurement including head motions. The resulting datasets were analyzed with the standard averaging technique and with the OSF-technique in two schemes; filtering phase cycles RAW PC and filtering dynamics RAW Dyn. Results The datasets containing artifacts resulted in an underestimation of the concentrations. There was a trend for the OSF-technique to compensate for this reduction when quantifying SNR-intense signals. However, there was no indication that OSF improved the estimated GABA concentrations. Moreover, when only considering the reference measurements, the OSF technique was equally as effective as averaging, which suggests that the techniques are interchangeable. Conclusion OSF performed equally well as the conventional averaging technique for low-SNR signals. For high-SNR signals, OSF performed better and thus could be considered for routine usage.

Place, publisher, year, edition, pages
Public Library of Science, 2017
National Category
Signal Processing
Identifiers
urn:nbn:se:liu:diva-138250 (URN)10.1371/journal.pone.0177795 (DOI)000401485500071 ()28520793 (PubMedID)2-s2.0-85019539851 (Scopus ID)
Note

Funding Agencies|Knut and Alice Wallenberg Foundation [KAW 2013.0076]; NIH [P41 015909, R01 016089]

Available from: 2017-06-14 Created: 2017-06-14 Last updated: 2018-04-17Bibliographically approved
Håkansson, I., Tisell, A., Cassel, P., Blennow, K., Zetterberg, H., Lundberg, P., . . . Ernerudh, J. (2017). Neurofilament light chain in cerebrospinal fluid and prediction of disease activity in clinically isolated syndrome and relapsing-remitting multiple sclerosis. European Journal of Neurology, 24(5), 703-712
Open this publication in new window or tab >>Neurofilament light chain in cerebrospinal fluid and prediction of disease activity in clinically isolated syndrome and relapsing-remitting multiple sclerosis
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2017 (English)In: European Journal of Neurology, ISSN 1351-5101, E-ISSN 1468-1331, Vol. 24, no 5, p. 703-712Article in journal (Refereed) Published
Abstract [en]

Background and purpose: Improved biomarkers are needed to facilitate clinical decision-making and as surrogate endpoints in clinical trials in multiple sclerosis (MS). We assessed whether neurodegenerative and neuroinflammatory markers in cerebrospinal fluid (CSF) at initial sampling could predict disease activity during 2 years of follow-up in patients with clinically isolated syndrome (CIS) and relapsing-remitting MS. Methods: Using multiplex bead array and enzyme-linked immunosorbent assay, CXCL1, CXCL8, CXCL10, CXCL13, CCL20, CCL22, neurofilament light chain (NFL), neurofilament heavy chain, glial fibrillary acidic protein, chitinase-3-like-1, matrix metalloproteinase-9 and osteopontin were analysed in CSF from 41 patients with CIS or relapsing-remitting MS and 22 healthy controls. Disease activity (relapses, magnetic resonance imaging activity or disability worsening) in patients was recorded during 2 years of follow-up in this prospective longitudinal cohort study. Results: In a logistic regression analysis model, NFL in CSF at baseline emerged as the best predictive marker, correctly classifying 93% of patients who showed evidence of disease activity during 2 years of follow-up and 67% of patients who did not, with an overall proportion of 85% (33 of 39 patients) correctly classified. Combining NFL with either neurofilament heavy chain or osteopontin resulted in 87% overall correctly classified patients, whereas combining NFL with a chemokine did not improve results. Conclusions: This study demonstrates the potential prognostic value of NFL in baseline CSF in CIS and relapsing-remitting MS and supports its use as a predictive biomarker of disease activity.

Place, publisher, year, edition, pages
WILEY, 2017
Keywords
biomarker; clinically isolated syndrome; disease activity; multiple sclerosis; neurofilament light chain
National Category
Neurology
Identifiers
urn:nbn:se:liu:diva-137379 (URN)10.1111/ene.13274 (DOI)000399704400010 ()28261960 (PubMedID)
Note

Funding Agencies|Swedish Research Council [K2013-61X-22310-01-4]; Linkoping University, Sweden; University Hospital Linkoping, Sweden; Novartis; Torsten Soderberg foundation; Royal Academy of Sciences, Sweden

Available from: 2017-05-18 Created: 2017-05-18 Last updated: 2018-04-17
Blystad, I., Warntjes, M. J., Smedby, Ö., Lundberg, P., Larsson, E.-M. & Tisell, A. (2017). Quantitative MRI for analysis of peritumoral edema in malignant gliomas. PLoS ONE, 12(5), Article ID e0177135.
Open this publication in new window or tab >>Quantitative MRI for analysis of peritumoral edema in malignant gliomas
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2017 (English)In: PLoS ONE, ISSN 1932-6203, E-ISSN 1932-6203, Vol. 12, no 5, article id e0177135Article in journal (Refereed) Published
Abstract [en]

Background and purpose Damage to the blood-brain barrier with subsequent contrast enhancement is a hallmark of glioblastoma. Non-enhancing tumor invasion into the peritumoral edema is, however, not usually visible on conventional magnetic resonance imaging. New quantitative techniques using relaxometry offer additional information about tissue properties. The aim of this study was to evaluate longitudinal relaxation R-1, transverse relaxation R-2, and proton density in the peritumoral edema in a group of patients with malignant glioma before surgery to assess whether relaxometry can detect changes not visible on conventional images. Methods In a prospective study, 24 patients with suspected malignant glioma were examined before surgery. A standard MRI protocol was used with the addition of a quantitative MR method (MAGIC), which measured R-1, R-2, and proton density. The diagnosis of malignant glioma was confirmed after biopsy/surgery. In 19 patients synthetic MR images were then created from the MAGIC scan, and ROIs were placed in the peritumoral edema to obtain the quantitative values. Dynamic susceptibility contrast perfusion was used to obtain cerebral blood volume (rCBV) data of the peritumoral edema. Voxel-based statistical analysis was performed using a mixed linear model. Results R-1, R-2, and rCBV decrease with increasing distance from the contrast-enhancing part of the tumor. There is a significant increase in R1 gradient after contrast agent injection (Pamp;lt;.0001). There is a heterogeneous pattern of relaxation values in the peritumoral edema adjacent to the contrast-enhancing part of the tumor. Conclusion Quantitative analysis with relaxometry of peritumoral edema in malignant gliomas detects tissue changes not visualized on conventional MR images. The finding of decreasing R-1 and R-2 means shorter relaxation times closer to the tumor, which could reflect tumor invasion into the peritumoral edema. However, these findings need to be validated in the future.

Place, publisher, year, edition, pages
PUBLIC LIBRARY SCIENCE, 2017
National Category
Radiology, Nuclear Medicine and Medical Imaging
Identifiers
urn:nbn:se:liu:diva-138480 (URN)10.1371/journal.pone.0177135 (DOI)000402058800007 ()28542553 (PubMedID)
Note

Funding Agencies|Medical Research Council of Southeast Sweden [FORSS-234551]

Available from: 2017-06-19 Created: 2017-06-19 Last updated: 2018-04-17
Warntjes, M. J., Engström, M., Tisell, A. & Lundberg, P. (2016). Modeling the Presence of Myelin and Edema in the Brain Based on Multi-Parametric Quantitative MRI. Frontiers in Neurology, 7(16)
Open this publication in new window or tab >>Modeling the Presence of Myelin and Edema in the Brain Based on Multi-Parametric Quantitative MRI
2016 (English)In: Frontiers in Neurology, ISSN 1664-2295, E-ISSN 1664-2295, Vol. 7, no 16Article in journal (Refereed) Published
Abstract [en]

The aim of this study was to present a model that uses multi-parametric quantitative MRI to estimate the presence of myelin and edema in the brain. The model relates simultaneous measurement of R-1 and R-2 relaxation rates and proton density to four partial volume compartments, consisting of myelin partial volume, cellular partial volume, free water partial volume, and excess parenchymal water partial volume. The model parameters were obtained using spatially normalized brain images of a group of 20 healthy controls. The pathological brain was modeled in terms of the reduction of myelin content and presence of excess parenchymal water, which indicates the degree of edema. The method was tested on spatially normalized brain images of a group of 20 age-matched multiple sclerosis (MS) patients. Clear differences were observed with respect to the healthy controls: the MS group had a 79 mL smaller brain volume (1069 vs. 1148 mL), a 38 mL smaller myelin volume (119 vs. 157 mL), and a 21 mL larger excess parenchymal water volume (78 vs. 57 mL). Template regions of interest of various brain structures indicated that the myelin partial volume in the MS group was 1.6 +/- 1.5% lower for gray matter (GM) structures and 2.8 +/- 1.0% lower for white matter (WM) structures. The excess parenchymal water partial volume was 9 +/- 10% larger for GM and 5 +/- 2% larger for WM. Manually placed ROls indicated that the results using the template ROls may have suffered from loss of anatomical detail due to the spatial normalization process. Examples of the application of the method on high-resolution images are provided for three individual subjects: a 45-year-old healthy subject, a 72-year-old healthy subject, and a 45-year-old MS patient. The observed results agreed with the expected behavior considering both age and disease. In conclusion, the proposed model may provide clinically important parameters, such as the total brain volume, degree of myelination, and degree of edema, based on a single qMRI acquisition with a clinically acceptable scan time.

Place, publisher, year, edition, pages
FRONTIERS MEDIA SA, 2016
Keywords
quantitative magnetic resonance imaging; brain tissue modeling; myelin; edema; T-1 relaxation; T-2 relaxation; proton density
National Category
Clinical Medicine
Identifiers
urn:nbn:se:liu:diva-126132 (URN)10.3389/fneur.2016.00016 (DOI)000370433200002 ()26925030 (PubMedID)
Note

Funding Agencies|Linkoping University; County Council Ostergotland

Available from: 2016-03-15 Created: 2016-03-15 Last updated: 2017-11-30
Blystad, I., Håkansson, I., Tisell, A., Ernerudh, J., Smedby, Ö., Lundberg, P. & Larsson, E.-M. (2016). Quantitative MRI for Analysis of Active Multiple Sclerosis Lesions without Gadolinium-Based Contrast Agent. American Journal of Neuroradiology, 37(1), 94-100
Open this publication in new window or tab >>Quantitative MRI for Analysis of Active Multiple Sclerosis Lesions without Gadolinium-Based Contrast Agent
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2016 (English)In: American Journal of Neuroradiology, ISSN 0195-6108, E-ISSN 1936-959X, Vol. 37, no 1, p. 94-100Article in journal (Refereed) Published
Abstract [en]

BACKGROUND AND PURPOSE: Contrast-enhancing MS lesions are important markers of active inflammation in the diagnostic work-up of MS and in disease monitoring with MR imaging. Because intravenous contrast agents involve an expense and a potential risk of adverse events, it would be desirable to identify active lesions without using a contrast agent. The purpose of this study was to evaluate whether pre-contrast injection tissue-relaxation rates and proton density of MS lesions, by using a new quantitative MR imaging sequence, can identify active lesions. MATERIALS AND METHODS: Forty-four patients with a clinical suspicion of MS were studied. MR imaging with a standard clinical MS protocol and a quantitative MR imaging sequence was performed at inclusion (baseline) and after 1 year. ROIs were placed in MS lesions, classified as nonenhancing or enhancing. Longitudinal and transverse relaxation rates, as well as proton density were obtained from the quantitative MR imaging sequence. Statistical analyses of ROI values were performed by using a mixed linear model, logistic regression, and receiver operating characteristic analysis. RESULTS: Enhancing lesions had a significantly (P < .001) higher mean longitudinal relaxation rate (1.22 0.36 versus 0.89 +/- 0.24), a higher mean transverse relaxation rate (9.8 +/- 2.6 versus 7.4 +/- 1.9), and a lower mean proton density (77 +/- 11.2 versus 90 +/- 8.4) than nonenhancing lesions. An area under the receiver operating characteristic curve value of 0.832 was obtained. CONCLUSIONS: Contrast-enhancing MS lesions often have proton density and relaxation times that differ from those in nonenhancing lesions, with lower proton density and shorter relaxation times in enhancing lesions compared with nonenhancing lesions.

Place, publisher, year, edition, pages
AMER SOC NEURORADIOLOGY, 2016
National Category
Clinical Medicine
Identifiers
urn:nbn:se:liu:diva-124482 (URN)10.3174/ajnr.A4501 (DOI)000367466500019 ()26471751 (PubMedID)
Note

Funding Agencies|National Science and Engineering Research Council; University of Linkoping; University Hospital Research Funds

Available from: 2016-02-02 Created: 2016-02-01 Last updated: 2017-11-16
Warntjes, M. J., Tisell, A., Landtblom, A.-M. & Lundberg, P. (2014). Effects of Gadolinium Contrast Agent Administration on Automatic Brain Tissue Classification of Patients with Multiple Sclerosis. American Journal of Neuroradiology, 35(7), 1330-1336
Open this publication in new window or tab >>Effects of Gadolinium Contrast Agent Administration on Automatic Brain Tissue Classification of Patients with Multiple Sclerosis
2014 (English)In: American Journal of Neuroradiology, ISSN 0195-6108, E-ISSN 1936-959X, Vol. 35, no 7, p. 1330-1336Article in journal (Refereed) Published
Abstract [en]

BACKGROUND AND PURPOSE:

The administration of gadolinium contrast agent is a common part of MR imaging examinations in patients with MS. The presence of gadolinium may affect the outcome of automated tissue classification. The purpose of this study was to investigate the effects of the presence of gadolinium on the automatic segmentation in patients with MS by using the synthetic tissue-mapping method.

MATERIALS AND METHODS:

A cohort of 20 patients with clinically definite multiple sclerosis were recruited, and the T1 and T2 relaxation times and proton density were simultaneously quantified before and after the administration of gadolinium. Synthetic tissue-mapping was used to measure white matter, gray matter, CSF, brain parenchymal, and intracranial volumes. For comparison, 20 matched controls were measured twice, without gadolinium.

RESULTS:

No differences were observed for the control group between the 2 measurements. For the MS group, significant changes were observed pre- and post-gadolinium in intracranial volume (-13 mL, P < .005) and cerebrospinal fluid volume (-16 mL, P < .005) and the remaining, unclassified non-WM/GM/CSF tissue volume within the intracranial volume (+8 mL, P < .05). The changes in the patient group were much smaller than the differences, compared with the controls, which were -129 mL for WM volume, -22 mL for GM volume, +91 mL for CSF volume, 24 mL for the remaining, unclassified non-WM/GM/CSF tissue volume within the intracranial volume, and -126 mL for brain parenchymal volume. No significant differences were observed for linear regression values against age and Expanded Disability Status Scale.

CONCLUSIONS:

The administration of gadolinium contrast agent had a significant effect on automatic brain-tissue classification in patients with MS by using synthetic tissue-mapping. The observed differences, however, were much smaller than the group differences between MS and controls.

Place, publisher, year, edition, pages
American Society of Neuroradiology, 2014
National Category
Clinical Medicine
Identifiers
urn:nbn:se:liu:diva-109381 (URN)10.3174/ajnr.A3890 (DOI)000339138200015 ()24699093 (PubMedID)
Available from: 2014-08-15 Created: 2014-08-15 Last updated: 2017-12-05Bibliographically approved
Engström, M., Bertus Warntjes, M. J., Tisell, A., Landtblom, A.-M. & Lundberg, P. (2014). Multi-Parametric Representation of Voxel-Based Quantitative Magnetic Resonance Imaging. PLoS ONE, 9(11), e111688
Open this publication in new window or tab >>Multi-Parametric Representation of Voxel-Based Quantitative Magnetic Resonance Imaging
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2014 (English)In: PLoS ONE, ISSN 1932-6203, E-ISSN 1932-6203, Vol. 9, no 11, p. e111688-Article in journal (Refereed) Published
Abstract [en]

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

Place, publisher, year, edition, pages
Public Library of Science, 2014
National Category
Clinical Medicine
Identifiers
urn:nbn:se:liu:diva-114027 (URN)10.1371/journal.pone.0111688 (DOI)000347709300018 ()25393722 (PubMedID)
Note

Funding Agencies|National Research Council [VR/NT 2008-3368]; Linkoping University; County Council of Ostergotland

Available from: 2015-02-05 Created: 2015-02-05 Last updated: 2017-12-05
Engström, M., Jan Bertus Warntje, M., Tisell, A., Landtblom, A.-M. & Lundberg, P. (2014). Multi-Parametric Representation of Voxel-Based Quantitative Magnetic Resonance Imaging. In: : . Paper presented at The International Society for Magnetic Resonance in Medicine (ISMRM) 2014, Milan, Italy (pp. e111688). , 9
Open this publication in new window or tab >>Multi-Parametric Representation of Voxel-Based Quantitative Magnetic Resonance Imaging
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2014 (English)Conference paper, Poster (with or without abstract) (Other academic)
Abstract [en]

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

National Category
Clinical Medicine
Identifiers
urn:nbn:se:liu:diva-114360 (URN)10.1371/journal.pone.0111688 (DOI)25393722 (PubMedID)
Conference
The International Society for Magnetic Resonance in Medicine (ISMRM) 2014, Milan, Italy
Available from: 2015-02-19 Created: 2015-02-19 Last updated: 2018-02-22
Bednarska, O., Tapper, S., Lundberg, P., Tisell, A., Lowén, M. & Walter, S. (2014). Neurotransmittor Concentration in Pregenual ACC in Stool Consistency Patient Subgroups With IBS. In: : . Paper presented at United European Gastroenterology (UEG), Austria. , 2(Supplement 1)
Open this publication in new window or tab >>Neurotransmittor Concentration in Pregenual ACC in Stool Consistency Patient Subgroups With IBS
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2014 (English)Conference paper, Poster (with or without abstract) (Refereed)
Abstract [en]

Introduction

The Anterior Cingulate Cortex (ACC) is a key region of the central autonomic brain network. Irritable Bowel Syndrome (IBS) is characterized abdominal pain and bowel habit disturbances. Autonomic dysregulation has been reported in IBS as well as altered ACC activation in pregenual ACC during visceral stimulation 1 2. Glutamate is the major excitatory and Gamma-aminobutyric acid (GABA) the major inhibitory neurotransmitter in the brain.

Aim & Methods

We aimed to measure neurotransmitter concentration in the pregenual ACC, in stool consistency subgroups with IBS by using quantitative neurotransmitter Magnetic Resonance Spectroscopy (qMRS)Seven patients with IBS-mixed (6 women) and five patients with IBS -diarrhea (4 women) according to Rome 3 were included. Mean age was 34.2 years (SD 5.3) with no significant difference between subgroups.  Patients completed symptom severity score (IBS-SSS). Quantitative MRS was measured in a 3T MRI scanner. A water-suppressed MEGA-PRESS sequence (TR 2.0 s, TE 68 ms) was used with the editing pulses placed at 1.90 ppm (‘ON-dynamics’) and at 7.46 ppm (‘OFF-dynamics’) with a voxel (3x3x3 cm3) placed in the pACC. Each MEGA-PRESS measurement resulted in a sequence of 40 OFF- and ON-dynamics, where each was computed by 8 phase cycles. Directly after each water-suppressed MEGA-PRESS measurement, a shorter 2-dynamic unsuppressed water MEGA-PRESS measurement was performed within the same voxel, which was used to obtain the concentrations in physically well-defined units of [mM]. The GABA concentrations were computed by averaging the difference spectra obtained by subtracting each OFF-dynamic from subsequent ON-dynamic and using LCModel (Version 6.3) for the final quantification. The Glutamate concentrations were obtained by only averaging the OFF-dynamics, which were not affected by the editing pulses. Additionally, all dynamics were phase and frequency corrected prior to the averaging. For group comparison unpaired T-tests were used.

Results

Patients had moderate to severe symptoms with IBS-SSS of 367 (SD 79.7). There was no significant difference between IBS subgroups in terms of IBS-SSS. Mean pACC GABA concentration was 1.66 (SD 0.17) mM in IBS-M and 1.65 (SD 0.27) mM in IBS-D. There was no significant difference between groups (p=0.9). Mean pACC Glutamate concentration was 4.54 (0.35) mM in IBS-M and 5.13 (SD 0.64) mM in IBS-D. There was no significant difference between groups, although a trend with p=0.06 was observed.

Conclusion

Further qMRS data have to be collected in IBS patients as well as healthy controls to evaluate if IBS subgroups demonstrate alterations in pACC glutamate and GABA concentrations

National Category
Clinical Medicine
Identifiers
urn:nbn:se:liu:diva-114346 (URN)
Conference
United European Gastroenterology (UEG), Austria
Available from: 2015-02-19 Created: 2015-02-19 Last updated: 2017-01-19Bibliographically approved
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