18F-Florbetaben PET/CT for the Diagnosis and Subtyping of Cardiac Amyloidosis: A Case Series and Review of the Literature.

Objectives: Cardiac amyloidosis (CA) is a type of systemic amyloidosis. Amyloid-targeting positron emission tomography (PET) has shown potential as an imaging method for CA. However, the optimal imaging protocol and role of ¹⁸F-florbetaben (FBB) PET in the diagnosis and subtyping of CA have yet to be determined.

Methods: Patients with suspected CA who had positive or equivocal results of technetium-99m pyrophosphate (PYP) scintigraphy were enrolled for dynamic and late FBB PET imaging. In addition to visual assessment, a kinetic modeling-based approach including target-to-background ratio (TBR) and myocardial retention fraction (RF) of serial images reconstructed from a 20-min dynamic acquisition, and a late image at 110 min post-injection were performed. We compared FBB PET measures of four typical patients with light chain amyloidosis (AL), wild-type transthyretin amyloidosis (ATTRwt), variant transthyretin amyloidosis (ATTRv), and heart failure, respectively. We also reviewed the literature on the clinical use of amyloid PET in CA.

Results: Myocardial tracer retention was only found in the AL patient on the late images. TBR and RF were highest in the AL patient followed by the ATTRwt patient, and lowest in the ATTRv and non-CA patients.

Conclusions: FBB PET has potential in the detection and non-invasive subtyping of CA, especially in subjects with equivocal PYP findings or monoclonal gammopathy.