Aim : Prospective measurement of brain glucose metabolism and structural integrity in the brain of subjects with visual snow syndrome (VSS). Voxel-based and volume-of interest comparison to age matched healthy controls retrospectively obtained on the same simultaneous PET/MR imaging system.~Hypothesis : 1/ VSS patients show overactivation of parts of the visual system, in particular the lingual gyrus, which is likely related to larger volume of the gyrus on structural imaging. 2/ Discrimination of VSS patients versus controls can be done by visual read of FDG PET and/or volume-of-interest based discriminant analysis.~Methods : Recruitment through neurology practice specialised in VSS, detailed history taking and assessment of in/exclusion criteria, scanning with simultaneous18F-FDG PET/MR Signa GE Healthcare.~Analysis : visual assessment, group-based voxel and volume-of-interest based analysis (FDG PET, volumetry T1 MRI) with appropriate statistics and corrections for multiple regional comparisons. Discriminant analysis on VOI based data. Dual observer scoring of visual data and assessment of accuracy, sensitivity and specificity of visual image analysis compared to clinical final diagnosis.
Visual snow syndrome (VSS) is a neurologic condition where patients experience tiny flickering dots in their entire visual field. It has been reported that the brain consumes more glucose in the lingual gyrus (a subdivision of the occipital cortex) and that this also shows increased volume of grey matter (neurons and supporting cells). In this study, the investigators apply fluor-18 fluorodeoxyglucose positron emission tomography with magnetic resonance imaging (18F-FDG PET/MR) in patients with VSS and compare this to healthy controls. Aside from an analysis in each brain volume element (voxel), the accuracy of classifying groups based on a volume-of-interest (VOI) analysis of both PET and MR is studied, Lastly, this is also compared to a visual assessment of the PET and MR images.