18F-FDG PET/CT for assessing of disease activity of idiopathic inflammatory myopathies. A systematic review and meta-analysis

Abstract

Objective: The purpose of current investigation was to evaluate the diagnostic accuracy of fluorine-18-fluorodeoxyglucose (¹⁸F-FDG) positron emission tomography/computed tomography (PET/CT) for the determination of disease activity of idiopathic inflammatory myopathies (IM) using diagnostic accuracy test.

Subjects and methods: The PubMed and EMBASE database, from the earliest available date of indexing through August 31, 2020, were searched for results investigating the diagnostic accuracy of ¹⁸F-FDG PET/CT for the determination of disease activity of IM. We calculated the pooled sensitivities and specificities of included studies, calculated positive and negative likelihood ratios (LR+ and LR-), and obtained summary receiver operating characteristic (SROC) curves.

Results: Across 4 studies with 5 results (90 patients), the pooled sensitivity was 0.94 (95% CI; 0.87-0.97) without heterogeneity (I²=0.0, P=0.8) and a pooled specificity was 0.90 (95% CI; 0.72-0.97) with heterogeneity (I²=65.1, P=0.02). Likelihood ratio (LR) syntheses showed an overall positive likelihood ratio (LR+) of 9.2 (95% CI; 3.1-28.0) and negative likelihood ratio (LR-) of 0.07 (95% CI; 0.03-0.16). The pooled DOR was 131 (95% CI; 26-664). The hierarchical SROC curve shows the areas under the curve of 0.96 (95% CI; 0.94-0.98).

Conclusion: Fluorine-18-FDG PET/CT has a good performance for the detection of active disease status in patients with IM. Although there are no guidelines for adopting imaging techniques, more objective and updated criteria for the assessment of disease activity incorporated with ¹⁸F-FDG PET/CT should be introduced and validated. Further studies are necessary to determine if 18F-FDG PET/CT-based treatment of IM can improve outcomes.