[18F]Florbetapir positron emission tomography: identification of muscle amyloid in inclusion body myositis and differentiation from polymyositis. Issue 5 (11th May 2019)

• Record Type: Journal Article
• Authors: Lilleker, James B; Hodgson, Richard; Roberts, Mark; Herholz, Karl; Howard, James; Hinz, Rainer; Chinoy, Hector
• Is Part Of: Annals of the rheumatic diseases. Volume 78:Issue 5(2019)
• Page Start: 657
• Publication Date: 2019-05-11
• Subjects: inclusion body myositis -- polymyositis -- amyloid -- positron emission tomography -- diagnostics; Rheumatism -- Periodicals; 616.723005
• DOI: 10.1136/annrheumdis-2018-214644
• Languages: English
• ISSNs: 0003-4967

Abstract

Abstract : Objectives: With the tools available currently, confirming the diagnosis of inclusion body myositis (IBM) can be difficult. Many patients are initially misdiagnosed with polymyositis (PM). In this observational study at a UK adult neuromuscular centre, we investigated whether amyloid positron emission tomography could differentiate between IBM and PM. Methods: Ten patients with IBM and six with PM underwent clinical review, [18F]florbetapir positron emission tomography and MRI of skeletal musculature. Differences in [18F]florbetapir standardised uptake value ratios in skeletal muscle regions of interest were evaluated. Relationships between [18F]florbetapir standardised uptake value ratios and measures of disease severity (clinical and by MRI of skeletal muscle) were assessed. Results: [18F]florbetapir standardised uptake value ratios were significantly higher in those with IBM compared with PM for all assessed regions (total-[18F]florbetapir standardised uptake value ratio 1.45 (1.28 to 2.05) vs 1.01 (0.80 to 1.22), p=0.005). For total-[18F]florbetapir standardised uptake value ratios≥1.28, sensitivity and specificity for IBM was 80% and 100%, respectively. Conclusions: [18F]florbetapir amyloid positron emission tomography differentiates IBM from PM. Successful development could facilitate accurate diagnosis, inclusion in clinical trials and help avoid unnecessary exposure to potentially harmful treatments.