The cardiac magnetic resonance sphericity index in the dilated cardiomyopathy: New diagnostic and prognostic marker

Abstract

Cardiac magnetic resonance (CMR) plays an increasingly important role in the exploration and management of heart failure. The purpose of this study is to assess the diagnostic and prognostic value of left ventricular sphericity in dilated cardiomyopathy. We conducted a retrospective study including 132 patients: 44 diagnosed with dilated cardiomyopathy (DCM+ group) and 88 control patients with normal ventricular function and volumes (DCM− group). All patients underwent a cardiac CMR with standardized clinical protocol: cine-acquisition in short axis, 4-chamber and long axis views and late enhancement data sets acquired 10 minutes after intravenous administration of extracellular gadolinium contrast agent. We determined the sphericity index (SI) = left ventricular short axis end-diastolic length/long axis end-diastolic length × 100. We calculated the sensitivity and specificity of SI as a diagnostic tool of dilated cardiomyopathy and determined its relation to occurrence of cardiac events defined as hospitalization or arrhythmia occurrence or death. In our study SI was inversely correlated with LVEF ( P < 0.001), and positively correlated with end-systolic LV volume ( P = 0.03). The mean SI in the DCM + group was 72.2 ± 7%. An SI ≤ 63.5% had a sensitivity = 90.9% and specificity = 92% in the prediction of dilated cardiomyopathy. Occurrence of a cardiac event was noted in 45% of patients and it was correlated to a high SI ( P < 0.001). Few studies have investigated the SI by CMR. Our study noted that SI was a good diagnostic marker reflecting cardiac dysfunction and prognostic predictor cardiac events occurrence.