First in-human study of 64Cu-DOTATATE positron emission tomography/computed tomography(PET/CT) in infective endocarditis: a prospective head-to-head comparison with 18-FDG PET/CT

Abstract Background Infective endocarditis (IE) is a severe and potentially fatal condition, which can be challenging to diagnose. Positron emission tomography/computed tomography (PET/CT) with [18F]fluorodeoxyglucose ([18F]FDG) is proposed as a diagnostic tool in the ESC endocarditis guidelines, but holds limitations. Purpose To compare the tracer uptake between [64Cu]Cu-DOTATATE and [18F]FDG in patients with IE, and to examine sensitivity and specificity in patients with prosthetic valve endocarditis (PVE) or native valve endocarditis (NVE). Methods The CuDOS-study was a prospective study including 20 cases with IE (10 with PVE and 10 with NVE) and 20 controls. [64Cu]Cu-DOTATATE and [18F]FDG PET/CT were performed in all participants. Scans were read blinded to clinical data. Tracer uptakes were measured as maximum standardized uptake values (SUVmax) in each heart valve. A visual interpretation of the presence or absence of IE was recorded for [64Cu]Cu-DOTATATE and [18F]FDG, respectively. Results The median age of the cases and controls was 68 years [IQR 53-71] and 61 years [IQR 56-67], respectively. In cases and controls, 85% and 70% were men, respectively. [64Cu]Cu-DOTATATE uptake (median SUVmax [IQR]) in patients with IE was higher than in controls (2.38 [1.87-2.90] vs. 1.43 [1.30-1.56], p<0.001), although this difference was mainly driven by PVE-cases (2.99 [2.22-3.75] vs. 1.43 [1.30-1.56 (controls), p<0.001) and to a lesser extent the NVE-cases (1.78 [1.22-2.33] vs. 1.43 [1.30-1.56 (controls), p=0.079), Figure 1. The sensitivity of [64Cu]Cu-DOTATATE and [18F]FDG PET/CT in 20 cases and the 20 controls were comparable, and the specificity was 90% and 75%, respectively. The analysis of PVE versus the 20 controls showed equal sensitivity (80%) for [64Cu]Cu-DOTATATE and [18F]FDG PET/CT and a specificity of 90% and 75%, respectively. The difference in the specificity between [64Cu]Cu-DOTATATE and [18F]FDG was 15% [IQR -5.9-36%], p=0.38. Conclusion [64Cu]Cu-DOTATATE PET/CT showed relevant uptake in the infected valve in patients with infective endocarditis. [64Cu]Cu-DOTATATE had a numerically higher specificity than [18F]FDG in prosthetic valve endocarditis, although the difference was not statistically significant. Both tracers were limited in the detection of native valve endocarditis.Figure 1 [64Cu]Cu-DOTATATE and [18F]FDG