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- Larsson, Mats, et al.
(author)
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Brain Responses to Visceral Stimuli Reflect Visceral Sensitivity Thresholds in Patients With Irritable Bowel Syndrome
- 2012
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In: Gastroenterology. - : Elsevier. - 0016-5085 .- 1528-0012. ; 142:3, s. 463-472
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Journal article (peer-reviewed)abstract
- BACKGROUND & AIMS:Only a fraction of patients with irritable bowel syndrome (IBS) have increased perceptual sensitivity to rectal distension, indicating differences in processing and/or modulation of visceral afferent signals. We investigated the brain mechanisms of these perceptual differences.METHODS:We analyzed data from 44 women with IBS and 20 female healthy subjects (controls). IBS symptom severity was determined by a severity scoring system. Anxiety and depression symptoms were assessed using the hospital anxiety and depression score. Blood oxygen level-dependent signals were measured by functional magnetic resonance imaging during expectation and delivery of high (45 mmHg) and low (15 mmHg) intensity rectal distensions. Perception thresholds to rectal distension were determined in the scanner. Brain imaging data were compared among 18 normosensitive and 15 hypersensitive patients with IBS and 18 controls. Results were reported significant if peak P-values were ≤.05, with family-wise error correction in regions of interest.RESULTS:The subgroups of patients with IBS were similar in age, symptom duration, psychological symptoms, and IBS symptom severity. Although brain responses to distension were similar between normosensitive patients and controls, hypersensitive patients with IBS had greater activation of insula and reduced deactivation in pregenual anterior cingulate cortex during noxious rectal distensions, compared to controls and normosensitive patients with IBS. During expectation of rectal distension, normosensitive patients with IBS had more activation in right hippocampus than controls.CONCLUSIONS:Despite similarities in symptoms, hyper- and normosensitive patients with IBS differ in cerebral responses to standardized rectal distensions and their expectation, consistent with differences in ascending visceral afferent input.
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- van Ettinger-Veenstra, Helene, 1982-, et al.
(author)
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Language deficits in Epilepsy, an fMRI study
- 2012
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Conference paper (other academic/artistic)abstract
- Cognitive functions in people with epilepsy are affected by focality, number of generalized seizures, side effects of antiepileptic drugs (AEDs) or the underlying disease (Kwan, 2001). Newly diagnosed patients have cognitive deficits even before starting on AEDs. Performance declines already in the first year after diagnosis and the impairment continues in the following years (Taylor, 2010; Baker, 2011). In mesial temporal lobe epilepsy (TLE) the hippocampal damage seems to be progressive and accompanied by thinning of neocortex (Briellmann, 2002; Bernhardt, 2009). Widespread structural and functional abnormalities in left TLE can affect more distant networks (Bonilha, 2009); a damage pattern also seen in right TLE (Karunanayaka, 2011).
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- van Ettinger-Veenstra, Helene, 1982-, et al.
(author)
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Right-hemispheric cortical contributions to language ability in healthy adults
- 2012
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In: Brain and Language. - : Elsevier. - 0093-934X .- 1090-2155. ; 120:3, s. 395-400
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Journal article (peer-reviewed)abstract
- In this study we investigated the correlation between individual linguistic ability based on performance levels and their engagement of typical and atypical language areas in the brain. Eighteen healthy subjects between 21 and 64 years participated in language ability tests, and subsequent functional MRI scans measuring brain activity in response to a sentence completion and a word fluency task. Performance in both reading and high-level language tests correlated positively with increased right-hemispheric activation in the inferior frontal gyrus (specifically Brodmann area 47), the dorsolateral prefrontal cortex (DLPFC), and the medial temporal gyrus (Brodmann area 21). In contrast, we found a negative correlation between performance and left-hemispheric DLPFC activation. Our findings indicate that the right lateral frontal and right temporal regions positively modulate aspects of language ability.
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- Warntjes, Marcel Jan Bertus, et al.
(author)
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Brain Characterization Using Normalized Quantitative Magnetic Resonance Imaging
- 2013
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In: PLOS ONE. - United States : Public Library of Science. - 1932-6203. ; 8:8
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Journal article (peer-reviewed)abstract
- ObjectivesTo 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 MethodsA 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.ResultsThe 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.ConclusionBrain 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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- West, Janne, 1982-, et al.
(author)
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Application of Quantitative MRI for Brain Tissue Segmentation at 1.5 T and 3.0 T Field Strengths
- 2013
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In: PLOS ONE. - United States : Public Library of Science. - 1932-6203. ; 8:9
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Journal article (peer-reviewed)abstract
- BackgroundBrain 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.MethodsIn 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.ResultsStatistically 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.ConclusionsMost of the brain was identically classified at the two field strengths, although some regional differences were observed.
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