Assessment of Glycolytic Metabolism by PET/CT with [18F]FDG in Extraocular Muscles in Patients with Graves' Ophthalmopathy.

• Grant number: 24/18095-2
• Support Opportunities: Scholarships in Brazil - Master
• Start date: April 01, 2025
• End date: September 30, 2026
• Field of knowledge: Health Sciences - Medicine - Medical Radiology
• Principal Investigator: Lauro Wichert Ana
• Grantee: Juliana Sayuri Sakamoto
• Host Institution: Faculdade de Medicina de Ribeirão Preto (FMRP). Universidade de São Paulo (USP). Ribeirão Preto , SP, Brazil

Abstract

Introduction: The extraocular muscles (EOM) are essential for eye function and movement. They are responsible for visual accommodation and reaction to light, as well as controlling eye movement and position. Changes in the size and shape of the muscles can occur due to a number of inflammatory, neoplastic, infectious or vascular conditions. Graves' Ophthalmopathy (GO), considered the most common orbital disease, is an ocular disease defined as an autoimmune inflammatory disorder involving the orbit that affects 25-40% of patients with Graves' disease, ranging from mild eye irritation to loss of vision. Although there are studies investigating Graves' ophthalmopathy, there is still a lack of quantitative knowledge of inflammation in the extraocular muscles. Aim: This project aims to: (a) Determine the reference values for the glycolytic metabolism of the MEO on PET/CT with [18F]FDG in healthy volunteers; (b) Determine the values of glycolytic metabolism on PET/CT with [18F]FDG in the MEO of patients with GO. Methods: To this end, we will carry out a prospective, unpaired case-control study on 30 patients with GO from the Oculoplastics Outpatient Clinic and compare them with 20 healthy volunteers previously obtained with the same imaging methodology from the Nuclear Medicine Department of HCFMRP-USP. Patients with GO will undergo PET/CT scans with [18F]FDG and the images will be analyzed qualitatively by visual inspection and quantitatively using MIM Software (MIM Software Inc., Cleveland, OH, USA). Glycolytic metabolism and its quantitative parameters SUVmax, SUVmean, TLG and MTV will be identified and evaluated in patients with GO and subsequently compared with healthy volunteers. Expected results: Determination of reference values for glycolytic metabolism in healthy volunteers and description of glycolytic metabolic alterations in patients affected by GO.