An observational study in Visual Snow Syndrome, sponsored by Universitaire Ziekenhuizen KU Leuven. Completed. Open to participants aged 18 Years to 85 Years, including healthy volunteers. Per ClinicalTrials.gov, last updated 2023-01-27.
Sponsored by Universitaire Ziekenhuizen KU Leuven · Observational
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.
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.
Universitaire Ziekenhuizen KU Leuven is the lead sponsor of 959 studies on the registry; 263 are open to participants now.
Of its 5 completed or terminated interventional studies of FDA-regulated products, 0 (0%) have results posted.
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Group 1 : Visual Snow Syndrome patients Group 2 : Healthy Controls
GROUP 1: VSS Patients
Inclusion Criteria:
Exclusion Criteria:
- other underlying neurological conditions inclusive ophthalmological examinations
GROUP 2 : Controls
Inclusion Criteria:
Exclusion Criteria:
Patients with visual snow syndrome
Diagnostic Test: simultaneous fluor-18 fluorodeoxyglucose (FDG) positron emission tomography with magnetic resonance imaging (PET/MRI)
healthy, screened age-matched controls
Diagnostic Test: simultaneous fluor-18 fluorodeoxyglucose (FDG) positron emission tomography with magnetic resonance imaging (PET/MRI)
All subjects fast at least for 4 hours prior to 18F-FDG injection. 18F-FDG is injected intravenously (150 megabecquerel (MBq)) in standard ambient conditions, supine in a dark, noise free room with eyes and ears open. 18F-FDG PET images are acquired for 20 min on a simultaneous GE Signa 3 Tesla (3T) PET/MR scanner with integrated Time-of-Flight (TOF) (GE Healthcare, Chicago, USA). Simultaneous with the 18F-FDG PET/MR acquisition, zero-echo-time (ZTE) MR data are acquired for attenuation correction and a 3D volumetric T1-weighted BRAVO MR sequence using a vendor supplied high-resolution 8-channel phased array head coil (GE Healthcare, Milwaukee, USA).
Group difference in regional brain metabolism as assessed with 18F-FDG positron emission tomography
Visual, voxel- and volume-of-interest based assessment of of FDG PET
Time frame: analysis done immediately after imaging
Group difference in regional brain volume assessed with volumetric magnetic resonance imaging.
Visual, voxel- and volume-of-interest based assessment of MRI images
Time frame: at baseline
Discriminant analysis of PET metabolic differences
Statistical discriminant analysis of FDG between VSS patients and controls
Time frame: at baseline
Visual scoring of PET metabolic differences
Visual scoring of FDG between VSS patients and controls
Time frame: at baseline
Discriminant analysis of MR volumetric differences
Statistical discriminant analysis of regional MR volumetry between VSS patients and controls
Time frame: at baseline
Visual scoring of MR volumetric differences
Visual scoring of regional MR volumetry between VSS patients and controls
Time frame: at baseline
No study locations are listed for this record.
Plan to share: Yes — Data can be shared on a reasonable request, including full FDG PET and MRI data as well as supporting information.
Supporting information: Study protocol, Informed consent form
Access criteria: Contact PI by email.
Ran from Jan 2017 to primary completion in Sep 2017, 8 months.
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This study is completed, as verified in Sep 2022. You cannot join it, but the record below documents what was studied.
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