Quantification of enhancement of left ventricular myocardium in patients with dilated cardiomyopathy using delayed enhanced MR imaging

The purpose is to evaluate delayed enhancement (DE) of the myocardium in patients with dilated cardiomyopathy (DCM), compared with control subjects. We also evaluated the interrelationships of DE and contractile function. DCM patients (n = 42) and 14 control subjects were evaluated by DE MR imaging, acquired using a two-dimensional segmented inversion-recovery prepared gradient-echo sequence (TI = 250 ms), 15 min after intravenous administration of 0.2 mmol/kg gadolinium. For the myocardium of left ventricle (LV), we traced epicardial and endocardial borders, and regions of interest (ROIs) were placed in each slice. For analysis of DE images, the signal-to-noise ratio (SNR) and the contrast-to-noise ratio (CNR) of the LV myocardium were calculated. The averaged SNR (aSNR) and averaged CNR (aCNR) per slice of the LV myocardium were calculated. In the DCM group, we also evaluated the interrelationship of DE and the contractile function of the LV. Mean aSNR was not significantly different between the studied groups; however, mean aCNR was significantly higher in the DCM group (3.5+/-3.1) than in control subjects (-4.1+/-2.1). In the DCM group, aCNR was moderately related to LV ejection fraction (LVEF) (r = 0.52, P<.0001). Mean aCNR was significantly higher in the DCM group with low LVEF (<25%) (6.0+/-2.8) than in the DCM group with high LVEF (>or=25%) (2.0+/-2.3). In DE MR imaging, the LV myocardium of DCM usually has high aCNR, which may suggest fibrosis. Quantification of aCNR may contribute to the diagnosis of DCM. The level of aCNR seems to correlate with LVEF. Using this technique, quantification of aCNR is objective and very useful for the diagnosis of DCM and contractile function of LV.