MR evaluation of arrhythmogenic right ventricular cardiomyopathy in pediatric patients

OBJECTIVE. The aim of our study was to correlate the findings of three MR imaging sequences with the clinical findings of possible arrhythmogenic right ventricular cardiomyopathy in pediatric patients. MATERIALS AND METHODS. Twenty-six consecutive pediatric patients underwent MR imaging with ECG-gated non-breath-hold spin-echo T1-weighted non-fat-suppressed and fat-suppressed sequences. The MR images were evaluated for thinning or fat signal in the right ventricular wall and for enlargement or increased trabeculation of the right ventricle or right ventricular outflow tract. Cine MR imaging was used to assess wall motion abnormalities. Cardiac biopsy was performed in 17 patients. Biopsy results and other clinical findings suggesting arrhythmogenic right ventricular cardiomyopathy were tabulated. RESULTS. Two MR imaging studies were of poor quality as a result of arrhythmias, and one study was incomplete. In the 23 remaining patients, there were (mean ± SD) 1.5 ± 1.0 and 0.8 ± 1.0 findings of possible arrhythmogenic right ventricular cardiomyopathy in the non-fat-suppressed and the fat-suppressed sequences, respectively. Fat-compatible signal in the myocardium was detected in 16 (70%) of 23 non-fat-suppressed studies and in five (22%) of 23 fat-suppressed studies (p = 0.003). The non-fat-suppressed sequence had a higher sensitivity (75% vs 43%) and a lower specificity (38% vs 75%) for fatty infiltration than did the fat-suppressed sequence when correlated with the biopsies. The linear correlation between all MR findings and all clinical diagnostic criteria, including biopsy, was better for the combination of cine and both T1 sequences (r = 0.58) than for the non-fat-suppressed (r = 0.53) or fat-suppressed (r = 0.46) T1 sequences alone. CONCLUSION. MR imaging showed moderate correlation with the clinical criteria in the diagnosis of arrhythmogenic right ventricular cardiomyopathy.