The Usefulness of ¹⁸F-FDG PET to Differentiate Subtypes of Dementia: The Systematic Review and Meta-Analysis

Background and Purpose: Dementia subtypes, including Alzheimer's dementia (AD), dementia with Lewy bodies (DLB), and frontotemporal dementia (FTD), pose diagnostic challenges.This review examines the effectiveness of 18 F-Fluorodeoxyglucose Positron Emission Tomography ( 18 F-FDG PET) in differentiating these subtypes for precise treatment and management.Methods: A systematic review following Preferred Reporting Items for Systematic reviews and Meta-Analyses guidelines was conducted using databases like PubMed and Embase to identify studies on the diagnostic utility of 18 F-FDG PET in dementia.The search included studies up to November 16, 2022, focusing on peer-reviewed journals and applying the goldstandard clinical diagnosis for dementia subtypes.Results: From 12,815 articles, 14 were selected for final analysis.For AD versus FTD, the sensitivity was 0.96 (95% confidence interval [CI], 0.88-0.98)and specificity was 0.84 (95% CI, 0.70-0.92).In the case of AD versus DLB, 18F-FDG PET showed a sensitivity of 0.93 (95% CI 0.88-0.98)and specificity of 0.92 (95% CI, 0.70-0.92).Lastly, when differentiating AD from non-AD dementias, the sensitivity was 0.86 (95% CI, 0.80-0.91)and the specificity was 0.88 (95% CI, 0.80-0.91).The studies mostly used case-control designs with visual and quantitative assessments.Conclusions: 18 F-FDG PET exhibits high sensitivity and specificity in differentiating dementia subtypes, particularly AD, FTD, and DLB.This method, while not a standalone diagnostic tool, significantly enhances diagnostic accuracy in uncertain cases, complementing clinical assessments and structural imaging.