Echocardiographic texture analysis using the wavelet transform: Differentiation of early heart muscle disease

Echocardiographic quantitation of myocardial texture for diagnosis of early cardiomyopathy (CMP) remains problematic. Conventional statistical methods are limited, contributed by a small image region-of-interest (ROI) and dif ficulty in discrimination from noise. This study was performed to evaluate the 2-D Haar wavelet decomposition method as a tool to identify textural ch anges in a rat model of early CMP, focusing on changes that occur before de velopment of hi-mode structural abnormalities. Early diabetic CMP, ethanol CR IP and diabetic-ethanol CR;IP rat models were evaluated. Echocardiograph y was performed on two groups of rats. Group I (5 week cohort, n = 4 per su bgroup) included controls, rats on 12% ethanol, a diabetic subgroup, and di abetic rats on 4% ethanol. Group II (10 week cohort, a = 5 per subgroup) in cluded the same categories as group I with an additional subgroup taking 4% ethanol was also studied. M-mode left ventricular measurements were compar able in all subgroups of group I. However, diabetic rats in group II had an increased left ventricular dimension (LVD) compared to all others and an i ncreased septal dimension (IVSD) and posterior wall dimension (PWD) were no ted in the 4% and 12% ethanol groups. End-diastolic digital images of all r ats in the parasternal short axis view, at the papillary muscle level, were downloaded to a computer. A 16 x 16 (ROI) was selected from the anterior i nterventricular septum. Although standard statistical methods could not dif ferentiate any of the groups, calculation of textural energy and normalized textural energy with the 2-D Haar wavelet decomposition method found at 5 weeks increased normalized texture energy in diabetics compared to all othe rs. At 10 weeks increased texture energy was noted in diabetics. Diabetic-e thanol rats at both 5 and 10 weeks revealed a blunted textural energy compa red to diabetic rats. In a rat model of diabetic cardiomyopathy, the 2-D wa velet decomposition method identified textural energy changes before develo pment of echocardiographic structural changes. Ethanol-associated blunting of textural changes in diabetic rats was also noted. This method for quanti tation of ventricular texture may be relevant for diagnosis of early cardio myopathy. (C) 2001 World Federation for Ultrasound in Medicine & Biology.