Arrhythmogenic right ventricular dysplasia: MRI findings.

Arrhythmogenic right ventricular dysplasia (ARVD) is a heart muscle disorder of unknown cause that is characterized pathologically by fibrofatty replacement of the right ventricular myocardium. Clinical manifestations include structural and functional malformations of the right ventricle, electrocardiographic abnormalities, and presentation with ventricular tachycardias with left bundle branch pattern or sudden death. The disease is often familial with an autosomal inheritance. In addition to right ventricular dilatation, right ventricular aneurysms are typical deformities of ARVD and they are distributed in the so-called "triangle of dysplasia", i.e., right ventricular outflow tract, apex, and infundibulum. Ventricular aneurysms at these sites can be considered pathognomonic of ARVD. Another typical hallmark of ARVD is fibrofatty infiltration of the right ventricular free wall. These functional and morphologic characteristics are relevant to clinical imaging investigations such as contrast angiography, echocardiography, radionuclide angiography, ultrafast computed tomography, and magnetic resonance imaging (MRI). Among these techniques, MRI allows the clearest visualization of the heart, in particular because the right ventricle is involved, which is usually more difficult to explore with the other imaging modalities. Furthermore, MRI offers the specific advantage of visualizing adipose infiltration as a bright signal of the right ventricular myocardium. MRI provides the most important anatomic, functional, and morphologic criteria for diagnosis of ARVD within one single study. As a result, MRI appears to be the optimal imaging technique for detecting and following patients with clinical suspicion of ARVD.