Cardiac MR findings and potential diagnostic pitfalls in patients evaluated for arrhythmogenic right ventricular cardiomyopathy

Arrhythmogenic right ventricular cardiomyopathy (ARVC) is a familial cardiomyopathy characterized by fibrofatty replacement of the myocardium, ventricular tachycardia, and ventricular dysfunction that affects primarily the right ventricle (RV). This disease is not common but can be seen more frequently in young adults, and clinical manifestations range from no symptoms to lethal arrhythmia and sudden death. The diagnosis of ARVC is challenging and is based on the recently revised international task force criteria. Given the strengths of cardiac magnetic resonance (MR) imaging for depicting the RV, this modality plays an important role in the diagnosis of ARVC. Functional and structural abnormalities of the RV depicted with cardiac MR imaging constitute major and minor criteria in the revised task force criteria. Since the ARVC program was established at our center in 1998, there has been an increased awareness of a number of normal variants that are commonly mis-interpreted as showing evidence for ARVC. On the basis of our clinical experience, the overdiagnosis of ARVC appears to reflect two fundamental problems: (a) a lack of awareness of diagnostic criteria that identify major and minor variables to be used for the diagnosis of ARVC, and (b) a lack of familiarity with the normal variants and mimics that may be misinterpreted as showing evidence of ARVC. The purpose of this article is to review the typical patterns of ventricular involvement in ARVC at cardiac MR imaging and to compare those with the patterns of normal variants and other diseases that can mimic ARVC.