Abnormal Cardiac PET Imaging in ATTR Amyloidosis

Transthyretin amyloidosis (ATTR) is an infiltrative cardiomyopathy caused by deposition of misfolded transthyretin protein in the myocardium. Diagnosis typically relies on technetium-99m-based imaging or magnetic resonance imaging.

A 72-year-old man presented for evaluation of multifocal premature ventricular contractions and nonsustained ventricular tachycardia after atrial fibrillation ablation. Cardiac positron emission tomography (PET) was highly suggestive of cardiac sarcoidosis. However, voltage-guided endomyocardial biopsy revealed a tissue diagnosis of ATTR.

Although PET typically identifies inflammatory disease, this case suggests that fluorodeoxyglucose uptake may also occur in ATTR.

Diagnosis of ATTR often requires multimodality imaging to identify and differentiate from other infiltrative cardiomyopathies. Cardiac PET, although not classically used for this application, may have utility in the diagnostic pathway.