Myocardial texture analysis in idiopathic dilated cardiomyopathy: Prediction of contractile reserve on dobutamine echocardiography

Abstract

Conventional resting echocardiography is not able to predict contractile reserve (CR) of patients with idiopathic dilated cardiomyopathy. The aim of this study was to investigate whether the videodensitometric myocardial texture analysis could predict the CR of these patients. Myocardial texture analysis was performed on echocardiographic digitized images of 27 patients with IDC through a calibrated 256 gray level digitization system. Cyclic variation (CV) index of myocardial mean gray level (MGL) was calculated according to the formula: (MGLdiast − MGLsyst)/ MGLdiast × 100. CR was defined as the %-change of ejection fraction by 10 μg/kg per minute dobutamine infusion. A clinical follow-up was also performed for all patients for an average of 8 ± 3 months. CR ranged from −1.8% to 50.3%. CV index of both septum and posterior wall (PW) was the single parameter significantly correlated to CR (r = 0.69 and r = 0.77, respectively, P <.0001 for both). The mean resting CV index of septum and PW were significantly lower in patients with CR less than 17%—median value of all subjects—(5.7 ± 5.6 vs 16.9 ± 7.9 and 5.4 ± 5.9 vs 16.1 ± 6.4, respectively, P <.0001 for both). A CV index of 10% for both septum and PW yielded a sensitivity of 77% and 84%, and a specificity of 84% and 84% for predicting diminished CR, respectively. The event-free survival rate was significantly lower in patients with CR less than 17% (61.5% vs 92.8%, P <.05). The CV index of both septum and PW were also significantly lower in patients with cardiac events (13.6 ± 8 vs 4.3 ± 6, P <.05 and 14.7 ± 7 vs 4.1 ± 7, P <.01, respectively). Ultrasonic myocardial texture analysis in idiopathic dilated cardiomyopathy has a high ability to discriminate the patients with and without preserved CR, and patients with unfavorable outcome as well. (J Am Soc Echocardiogr 2002;15:36-42.)