Diagnostic Value of Late Gadolinium Enhancement at Cardiac Magnetic Resonance to distinguish Arrhythmogenic Right Ventricular Cardiomyopathy from Differentials.

ABSTRACT

BACKGROUND: While late gadolinium enhancement (LGE) is proposed as a diagnostic criterion for arrhythmogenic right ventricular cardiomyopathy (ARVC), the potential of LGE to distinguish ARVC from differentials remains unknown. We aimed to assess the diagnostic value of LGE for ARVC diagnosis. METHODS: We included 132 subjects (60% male, 47±11 years) who had undergone cardiac magnetic resonance imaging with LGE assessment present for ARVC or ARVC-differentials. ARVC was diagnosed as per 2010 Task Force Criteria (n=55). ARVC-differentials consisted of familial/genetic dilated cardiomyopathy (n=25), myocarditis (n=13), sarcoidosis (n=20), and amyloidosis (n=19). The diagnosis of all differentials was based upon the most current golden standard. Presence of LGE was evaluated using a 7-segment RV and 17-segment LV model. Subsequently, we assessed LGE patterns for every patient individually for fulfilling LV- and/or RV-LGE per Padua criteria, independent of their clinical diagnosis (i.e. phenotype). Diagnostic values were analysed using sensitivity and specificity for any RV-LGE, any LV-LGE, RV-LGE per Padua criteria, and prevalence graphs for LV-LGE per Padua criteria. Optimal integration of LGE for ARVC diagnosis was determined using classification-and-regression-tree analysis. RESULTS: one-third (38%) of ARVC patients had RV-LGE, while half (51%) had LV-LGE. RV-LGE was less frequently observed in ARVC vs. non-ARVC patients (38% vs. 58%, p=0.034) leading to a poor discriminatory potential (any RV-LGE sensitivity 38%, specificity 42%; RV-LGE per Padua criteria sensitivity 36%, specificity 44%). Compared to ARVC patients, non-ARVC patients more often had LV-LGE (91% vs. 51%, p<0.001) which was also more globally distributed (median 9 [IQR 3-13] vs. 0 [IQR 0-3] segments, p<0.001). Absence of anteroseptal and absence of extensive (≥5 segments) mid- mid-myocardial LV-LGE, and absence of moderate (≥2 segments) mid-myocardial LV-LGE predicted ARVC with good diagnostic performance (sensitivity 93%, specificity 78%). CONCLUSIONS: LGE is often present in ARVC differentials and may lead to false positive diagnoses when used without knowledge of LGE patterns. Moderate RV-LGE without anteroseptal and mid-myocardial LV-LGE is typically observed in ARVC.