DEMONSTRATING THE PERIVASCULAR DISTRIBUTION OF MS LESIONS IN VIVO WITH 7-TESLA MRI

While most white matter (WM) demyelinating lesions in multiple sclerosis (MS) have a perivascular distribution, heterogeneity in lesion pathology has been shown to include a variable relationship between lesions and parenchymal blood vessels.1 Reports that such lesion characteristics at brain biopsy predict treatment response suggest that identifying perivascular lesions in vivo could be clinically relevant.2 It is unclear, however, to what extent the age and topographic location of a lesion influence its vascular anatomy. This pilot study aimed to develop an imaging technique capable of defining the relationship between demyelination and small parenchymal blood vessels in MS. Comparison between T2-weighted MR images at 1.5 tesla with subsequent venography has previously been used to determine the relationship of lesions to blood vessels.3 While this technique can demonstrate an MS lesion and a blood vessel in close proximity, the inability to demonstrate both structures simultaneously means the exact spatial relationship cannot be defined or followed longitudinally. Ultra-high field human MRI offers an increased signal to noise ratio and enhanced spatial resolution compared to clinical MRI scanners, at the expense of increased radiofrequency and static field inhomogeneity which result in a (smooth) variation of intensity across the image and distortions at structural boundaries. T2* contrast observed at ultra high field strengths …