First-pass Myocardial Perfusion Defect and Delayed Contrast Enhancement in Hypertrophic Cardiomyopathy Assessed with MRI

Abstract

Gadolinium-diethylenetriamine pentaacetic acid (Gd-DTPA) enhanced magnetic resonance imaging (MRI) is known to be useful for detecting myocardial injury. In this study, we used first-pass myocardial perfusion and delayed contrast-enhanced MRI to determine whether an abnormal signal intensity was related to the left ventricular regional contractile function in patients with hypertrophic cardiomyopathy (HCM). Twelve patients with HCM participated in this study. Four short axial cine images of the left ventricle were acquired. Subsequently, first-pass myocardial perfusion images during the first passage of Gd-DTPA (0.1 mmol/kg), and delayed contrast-enhanced images after a 15-min delay, were acquired in the same orientation as cine imaging. Each image was divided into eight blocks and a total of 384 blocks were analyzed. First-pass myocardial perfusion defects (PD) were detected in nine patients with an average of 11.5+/-11 blocks. Delayed contrast enhancement (DE) was detected in 11 patients with an average of 11.5+/-10 blocks. Mean wall thickness in PD blocks (16.7+/-4.7 mm) was larger than that in normal perfusion blocks (13.6+/-3.9 mm, p<0.001). Mean wall thickness in DE blocks (16.9+/-4.9 mm) was larger than that in normal enhanced blocks (13.4+/-3.6 mm, p<0.001). PD were located at almost the same site as DE, but DE areas were larger than PD areas (p=0.0021). Mean percent wall thickening of blocks with PD (63.1+/-44.7%, p<0.0001) and blocks with DE (75.2+/-81.5%, p<0.01) was lower than that in blocks with neither PD nor DE (103.5+/-66.0%). Significant correlations were found between percent wall thickening and percent PD (r=0.46, p<0.0001) and between percent wall thickening and percent DE (r=0.54, p<0.0001). Abnormal signal intensity from first-pass myocardial perfusion and delayed contrast-enhanced MRI are closely related to left ventricular regional contractile function.