Utility of ECG-gated MDCT to differentiate patients with ARVC/D from patients with ventricular tachyarrhythmias

BackgroundThe accuracy of electrocardiogram-gated CT for diagnosing arrhythmogenic right ventricular cardiomyopathy/dysplasia (ARVC/D) is uncertain.ObjectiveWe propose a comprehensive system for scoring characteristic CT findings to diagnose ARVC/D and discuss its utility.MethodsSeventy-seven patients (mean age, 43.1 years; 48 male) diagnosed with ARVC/D or with suspected ARVC/D on the basis of ventricular tachyarrhythmias underwent CT with and without contrast enhancement. We retrospectively graded characteristic CT findings (fatty tissue, bulging appearance, and dilatation of the right ventricle) as minor (1 point) or major (2 points) and then validated our scoring system’s utility for diagnosing ARVC/D with the use of the modified 2010 Task Force criteria as the reference standard.ResultsWe diagnosed 27 of 77 patients with ARVC/D (23 definite, 4 borderline), observing each CT finding more often in patients with ARVC/D than in patients without ARVC/D: fatty tissue, 74.1% versus 12.0%; bulging appearance, 74.1% versus 34.0%; and RV dilatation, 92.6% versus 44.0%. However, observation of each finding in both groups could cause false positive diagnosis. Recursive partitioning analysis showed the superiority of our CT scoring system over methods that used each CT finding and CT findings without fatty tissue for distinguishing ARVC/D and non-ARVC/D. For overall (definite and borderline) and definite ARVC/D diagnosis, sensitivities were 77.8% and 87.0%, specificities were 96.0% and 94.4%, positive predictive values were 91.3% and 87.0%, negative predictive values were 88.9% and 94.4%, and accuracies were 89.6% and 92.2%, respectively.ConclusionsOur CT scoring system showed excellent diagnostic ability and might aid differentiation of ARVC/D from ventricular tachyarrhythmias.