Simultaneous Fluorodeoxyglucose Positron Emission Tomography (PET) and Magnetic Resonance (MR) in Visual Snow Syndrome

Simultaneous Fluorodeoxyglucose and Magnetic Resonance Imaging (18F-FDG PET/MR) Study of Metabolic and Structural Changes in Visual Snow Syndrome Compared to Healthy Controls

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.

Study Overview

• Status: Completed
• Conditions: Visual Snow Syndrome
• Intervention / Treatment: Diagnostic test: simultaneous fluor-18 fluorodeoxyglucose (FDG) positron emission tomography with magnetic resonance imaging (PET/MRI)

Detailed Description

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.

• Study Type: Observational
• Enrollment (Actual): 22

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years to 85 years (Adult, Older Adult)
• Accepts Healthy Volunteers: No
• Genders Eligible for Study: All

• Sampling Method: Non-Probability Sample

Study Population

Group 1 : Visual Snow Syndrome patients Group 2 : Healthy Controls

Description

GROUP 1: VSS Patients

Inclusion Criteria:

• M/F, age 18-85,
• diagnosis of VSS by an experienced neurologist : dynamic, continuous, black and white tiny dots in the entire visual field lasting longer than 3 months, with at least two additional visual symptoms

Exclusion Criteria:

- other underlying neurological conditions inclusive ophthalmological examinations

GROUP 2 : Controls

Inclusion Criteria:

• age 18-85 years, M/F, in general healthy condition
• normal neurological examination, Mini-Mental State Examination (MMSE) ≥ 28, Beck's Depression Inventory (BDI) score ≤ 9, and a normal structural volumetric MRI.

Exclusion Criteria:

• history of major internal pathology, neurological and/or psychiatric disorders (including psychosis, depression, and anxiety),
• history of frequent migraine attacks, substance abuse or current use of any central acting medication
• first-degree relatives with dementia.

Study Plan

How is the study designed?

Design Details

• Observational Models: Cohort
• Time Perspectives: Prospective

Number of groups / cohorts

2

Cohorts and Interventions

Group / Cohort	Intervention / Treatment
VSS; Patients with visual snow syndrome	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).
controls; 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).

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
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	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	at baseline

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Discriminant analysis of PET metabolic differences	Statistical discriminant analysis of FDG between VSS patients and controls	at baseline
Visual scoring of PET metabolic differences	Visual scoring of FDG between VSS patients and controls	at baseline
Discriminant analysis of MR volumetric differences	Statistical discriminant analysis of regional MR volumetry between VSS patients and controls	at baseline
Visual scoring of MR volumetric differences	Visual scoring of regional MR volumetry between VSS patients and controls	at baseline

Collaborators and Investigators

• Sponsor: Universitaire Ziekenhuizen KU Leuven
• Investigators: Principal Investigator: Koen Van Laere, MD PhD, Head Nuclear Medicine, University Hospitals Leuven

Study record dates

Study Major Dates

• Study Start (Actual): January 2, 2017
• Primary Completion (Actual): September 2, 2017
• Study Completion (Actual): February 1, 2022

Study Registration Dates

• First Submitted: September 27, 2022
• First Submitted That Met QC Criteria: October 3, 2022
• First Posted (Actual): October 6, 2022

Study Record Updates

• Last Update Posted (Actual): January 27, 2023
• Last Update Submitted That Met QC Criteria: January 26, 2023
• Last Verified: September 1, 2022

More Information

Terms related to this study

• Keywords: FDG PET; PET/MR; volumetry; visual analysis; discriminant analysis
• Additional Relevant MeSH Terms: Pathologic Processes; Disease; Syndrome; Molecular Mechanisms of Pharmacological Action; Radiopharmaceuticals; Fluorodeoxyglucose F18
• Other Study ID Numbers: S58764-S58571

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: Yes
• IPD Plan Description: Data can be shared on a reasonable request, including full FDG PET and MRI data as well as supporting information.
• IPD Sharing Access Criteria: Contact PI by email.
• IPD Sharing Supporting Information Type: Study Protocol; Informed Consent Form (ICF)

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No
• product manufactured in and exported from the U.S.: No