Abstract
Background. The aim of this study was to discriminate ischemic cardiomyopathy (ICM) from dilated cardiomyopathy (DCM) based on inter-segmental and transmural differences in ultrasonic tissue characters.
Methods. The study population consisted of 40 patients with DCM and 40 patients with ICM with ejection fraction of <40%. We recorded short-axis integrated backscatter (IBS) images in each patient. We measured the absolute differences in average IBS values between the anterior septum and posterior wall (|A-P|, dB). We also measured the difference of average IBS in the inner layer minus that in the outer layer in either anterior septum or posterior wall that was more dysfunctional (In-Out, dB).
Results. |A-P| was significantly higher in ICM than DCM (5.3 ± 1.7 vs. 2.7 ± 1.4, p<0.001). Receiver-operating characteristic analysis demonstrated that we can differentiate ICM from DCM with sensitivity of 80 % and specificity of 73 % using |A-P| > 4 dB as a cut-off point. (In-Out) was also significantly higher in ICM than DCM (1.6 ± 1.4 vs. -0.9 ± 1.9, p<0.001). We can also differentiate ICM from DCM with sensitivity of 93 % and specificity of 70 % using (In-Out) >0 dB as a cut-off point. Additionally, all patients with |A-P| > 3 dB and (In-Out) >0 dB belonged to the ICM group except for one patient.
Conclusions. Inter-segmental and transmural differences in myocardial IBS are significantly greater in the ICM than in DCM. Using these particular ultrasonic tissue characters, we can discriminate ICM from DCM with favorable sensitivity and specificity.
