Background: 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).
Materials and Methods: 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.
Results: 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).
Conclusion: Abnormal signal intensity from first-pass myocardial perfusion and delayed contrast-enhanced MRI are closely related to left ventricular regional contractile function.