Detection of cardiac amyloidosis with ¹⁸F-Florbetaben-PET/CT in comparison to echocardiography, cardiac MRI and DPD-scintigraphy.

Abstract

Cardiac amyloidosis (CA) is a rare cause of heart failure with frequently delayed diagnosis, because specific early signs or symptoms are missing. Recently, direct amyloid imaging using positron emission tomography/computed tomography (PET/CT) has emerged. The aim of this study was to examine the performance of ¹⁸F-florbetaben-PET/CT in detection of CA, and compare it to echocardiography (echo), cardiac MRI (CMR) and scintigraphy. Additionally, the use of ¹⁸F-florbetaben-PET/CT for quantification of amyloid burden and monitoring of treatment response was assessed. Twenty-two patients with proven (n = 5) or clinical suspicion (n = 17) of CA underwent ¹⁸F-florbetaben-PET/CT for diagnostic work-up. Qualitative and quantitative assessment including calculation of myocardial tracer retention (MTR) was performed, and compared to echo (n = 20), CMR (n = 16), scintigraphy (n = 16) and serologic biomarkers (NT-proBNP, cTnT, free light chains). In four patients, follow-up PET/CT was available (after treatment initiation, n = 3; surveillance, n = 1). PET demonstrated myocardial ¹⁸F-florbetaben retention consistent with CA in 14/22 patients. Suspicion of CA was subsequently dropped in all eight PET-negative patients. Amyloid subtypes showed characteristic retention patterns (AL > AA > ATTR; all p < 0.005). MTR correlated with morphologic and functional parameters, as measured by CMR and echo (all r| > 0.47|, all p < 0.05), but not with cardiac biomarkers. Changes in MTR from baseline to follow-up corresponded well to treatment response, as assessed by cardiac biomarkers and performance status. Imaging of cardiac amyloidosis (CA) with ¹⁸F-florbetaben-PET/CT is feasible and might be useful in differentiating CA subtypes.