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Background: Fabry disease (FD) is a lysosomal storage disorder that is associated with marked cerebrovascular disease. Conventional MRI shows an extensive load of white matter lesions (WMLs) already at an early stage in FD. Objective: Investigator independent and sensitive quantification of brain structural changes in clinically affected men and women with FD. Methods: The authors performed a voxel-based analysis of diffusion tensor images (DTI) in 25 FD patients and 20 age-matched normal controls. Results: DTI revealed significant increases of cerebral white matter diffusivity (MD) in FD patients that were pronounced in the periventricular white matter. Even the subgroup of patients without significant WMLs-load (n = 18) showed increased diffusivity in the cerebral white matter. In gray matter areas MD elevation could only be detected in the posterior part of the thalamus, independently from visible pulvinar alterations on the T1-weighted images. Voxel-based anisotropy (FA) measurements did not differ significantly between patients and controls. Conclusions: The present study demonstrates the clinical feasibility of voxel-based analysis of DTI as a sensitive tool to quantify brain tissue alterations in FD. The pattern of increased brain tissue diffusivity is probably due to microangiopathic alterations mainly affecting the long perforating arteries.

Background: Magnetic resonance diffusion tensor imaging (DTI) shows promise in the early detection of microstructural pathophysiological changes in the brain. Objectives: To measure microstructural differences in the brains of participants with amnestic mild cognitive impairment (MCI) compared with an age-matched control group using an optimised DTI technique with fully automated image analysis tools and to investigate the correlation between diffusivity measurements and neuropsychological performance scores across groups. Methods: 34 participants (17 participants with MCI, 17 healthy elderly adults) underwent magnetic resonance imaging (MRI)-based DTI. To control for the effects of anatomical variation, diffusion images of all participants were registered to standard anatomical space. Significant statistical differences in diffusivity measurements between the two groups were determined on a pixel-by-pixel basis using gaussian random field theory. Results: Significantly raised mean diffusivity measurements (p

Objectives: Our purpose was to investigate whether differences exist in the values and temporal evolution of mean diffusivity ( ) and fractional anisotropy (FA) of grey and white matter after human ischaemic stroke. Methods: Thirty two patients with lesions affecting both grey and white matter underwent serial diffusion tensor magnetic resonance imaging (DT-MRI) within 24 hours, and at 4–7 days, 10–14 days, 1 month, and 3 months after stroke. Multiple small circular regions of interest (ROI) were placed in the grey and white matter within the lesion and in the contralateral hemisphere. Values of {grey}, {white}, FA{grey} and FA{white} were measured in these ROI at each time point and the ratios of ischaemic to normal contralateral values ( R and FAR) calculated. Results: and FA showed different patterns of evolution after stroke. After an initial decline, the rate of increase of {grey} was faster than {white} from 4–7 to 10–14 days. FA{white} decreased more rapidly than FA{grey} during the first week, thereafter for both tissue types the FA decreased gradually. However, FA{white} was still higher than FA{grey} at three months indicating that some organised axonal structure remained. This effect was more marked in some patients than in others. R{grey} was significantly higher than R{white} within 24 hours and at 10–14 days (p

Current magnetic resonance imaging (MRI) outcome measures such as T2 lesion load correlate poorly with disability in multiple sclerosis. Diffusion tensor imaging (DTI) of the brain can provide unique information regarding the orientation and integrity of white matter tracts in vivo.To use this information to map the pyramidal tracts of patients with multiple sclerosis, investigate the relation between burden of disease in the tracts and disability, and compare this with more global magnetic resonance estimates of disease burden.25 patients with relapsing-remitting multiple sclerosis and 17 healthy volunteers were studied with DTI. An algorithm was used that automatically produced anatomically plausible maps of white matter tracts. The integrity of the pyramidal tracts was assessed using relative anisotropy and a novel measure (L(t)) derived from the compounded relative anisotropy along the tracts. The methods were compared with both traditional and more recent techniques for measuring disease burden in multiple sclerosis (T2 lesion load and "whole brain" diffusion histograms).Relative anisotropy and L(t) were significantly lower in patients than controls (p0.05). Pyramidal tract L(t) in the patients correlated significantly with both expanded disability status scale (r = -0.48, p0.05), and to a greater degree, the pyramidal Kurtzke functional system score (KFS-p) (r = -0.75, p0.0001). T2 lesion load and diffusion histogram parameters did not correlate with disability.Tract mapping using DTI is feasible and may increase the specificity of MRI in multiple sclerosis by matching appropriate tracts with specific clinical scoring systems. These techniques may be applicable to a wide range of neurological conditions.