Shear-wave amplitudes measured with cardiac MR elastography for diagnosis of diastolic dysfunction.

Abstract

To test whether shear-wave amplitudes (SWAs) in the myocardium measured with cardiac magnetic resonance (MR) elastography enable diagnosis of myocardial relaxation abnormalities in patients with diastolic dysfunction. Each subject gave written informed consent to participate in this institutional review board-approved prospective study. Electrocardiographically triggered SWA-based cardiac MR elastography with 24.13-Hz external vibration frequency was performed in 50 subjects grouped into asymptomatic young (n = 10, 18-39 years) and asymptomatic old (n = 10, 40-68 years) subjects and patients with echocardiographically proved mild, moderate, or severe diastolic dysfunction (n = 30, 44-73 years). SWA images were analyzed in the left ventricular (LV) region and were normalized against reference SWA of the thoracic wall. Analysis of variance with Bonferroni-corrected pairwise comparison and Pearson correlation were used for statistical evaluation. Young and old control subjects had normalized mean LV SWA of 0.67 ± 0.04 (standard error of the mean) and 0.56 ± 0.04 (P = .18, F test), respectively. Compared with the control groups, patients with mild, moderate, and severe diastolic dysfunction displayed significantly reduced normalized mean LV SWA of 0.37 ± 0.04, 0.34 ± 0.04, and 0.29 ± 0.04 (P < .001, F test), respectively, which was inversely correlated to the severity of diastolic dysfunction (R = -0.61, P < .001). The best cutoff value to differentiate between asymptomatic volunteers and patients was 0.43, yielding an area under the receiver operating characteristic curve of 0.92, with 90% sensitivity and 89.7% specificity. LV SWA measured with cardiac MR elastography provides image contrast sensitive to myocardial relaxation abnormalities and shows significantly lower values in patients with diastolic dysfunction.