Role of MRI in the diagnosis of arrhythmic right ventricular dysplasia

Purpose: The arrythmogenic right ventricular dysplasia (ARVD) is often difficult to diagnose. The aim of this study was to evaluate the indications and role of MRI in the diagnosis of ARVD. Material and Methods: Cardiac MRI of 153 with suspected ARVD were retrospectively evaluated; patients were divided into two groups according to the presence of MRI diagnostic criteria (RV dilatation, adipose tissue replacement, kinetic alterations): Group A (111 pts) with only one MRI diagnostic criterion or no criteria at all (unlikely diagnosis); Group B (42 pts) with 2 or more MRI criteria (likely diagnosis). Results: Significant differences were observed either in clinical or instrumental data of the two groups: symptomatic patients were 37,9% in group A and 50% in group B (p= ns); ventricular arrhythmias were 75% in group A and 90% in group B (p < 0.05); ventricular tachycardia was 7% in group A and 26% in group B (p < 0.01); echocardiographic criteria of ARVD were 35% in group A and 61% in group B (p < 0.05). MRI confirmed ARVD diagnosis in 40% of all patients with US criteria. Adipose tissue replacement and kinetic alterations seem to be the most specific MRI findings. Conclusion: MRI exams are often performed without previous significant clinical or instrumental findings; therefore the indications are often misjudged. MRI is a very useful technique in the assessment of tissue and kinetic alterations, which represent the most indicative instrumental features of ARVD; it is also useful to distinguish severe types of the disease from the milder ones.