Evaluation of Reference Regions in [18F]FDG Positron Emission Tomography Image Analysis

• Grant number: 25/14105-6
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: October 01, 2025
• End date: September 30, 2026
• Field of knowledge: Health Sciences - Medicine - Medical Radiology
• Principal Investigator: Daniele de Paula Faria
• Grantee: Luigi Brianesi Ferraz
• Host Institution: Faculdade de Medicina (FM). Universidade de São Paulo (USP). São Paulo , SP, Brazil

Abstract

This study aims to analyze reference regions for the quantification of 18F-fluorodeoxyglucose ([18F]FDG) Positron Emission Tomography (PET) images, comparing elderly human populations (normal aging and Alzheimer's Disease) and animal models (Alzheimer's Disease and Down syndrome mice). PET imaging with the [18F]FDG radiopharmaceutical is used to assess brain metabolic activity. The most commonly used methods for quantifying radiopharmaceutical uptake are SUV (Standardized Uptake Value) and SUVR (the ratio of SUV in the region of interest to SUV in the reference region). The choice of reference region is critical, as it can impact quantification values; however, despite numerous existing studies on optimizing reference region selection, Brazilian data is lacking.The primary objective is to identify ideal reference tissues exhibiting low variability in the context of aging, Alzheimer's Disease, and Down syndrome, thereby validating or refining existing proposals.Methodologically, human and rodent images from the database of the Nuclear Medicine Laboratory (LIM43) at FMUSP (University of São Paulo Faculty of Medicine) will be analyzed. The PMOD software will be used to determine SUVR, categorizing reference regions and evaluating their impact on the analyses. An inter-species comparison will seek common or specific patterns.The results aim to define the optimal reference regions for quantifying [18F]FDG PET images in both preclinical and clinical settings using Brazilian data.