CMR-based differentiation of AL and ATTR cardiac amyloidosis.

Objectives This study was devised to describe the different cardiac magnetic resonance (CMR) appearances in light chain amyloid (AL) and transthyretin-related amyloidosis (ATTR). Background CMR is increasingly used to investigate patients with suspected amyloidosis. Global subendocardial late gadolinium enhancement (LGE) has been reported as typical of AL amyloidosis, whereas different patterns have been noted in ATTR amyloidosis. Methods We performed de novo analyses on original DICOM magnetic resonance imaging in 46 patients with cardiac AL amyloidosis and 51 patients with ATTR type who had been referred to a specialist amyloidosis center between 2007 and 2012 after CMR. Histological examination was performed in all cases, with immunohistochemistry, to confirm systemic amyloidosis. Results Patients' median age was 68 ± 10 years, and 74% were male. Left ventricular mass was markedly increased in ATTR amyloidosis (228 g [202 to 267 g]) compared with AL type (167 g [137 to 191 g]) (p Conclusions Transmural patterns of LGE distinguished ATTR from AL cardiac amyloidosis with high accuracy in this real-world analysis of CMR. Precise diagnosis of cardiac amyloidosis is crucial given the role of chemotherapy in AL type and with novel therapies for ATTR type currently in development.