[Two-dimensional echocardiographic echo intensity distribution by histographic analysis].

To assess myocardial tissue changes, the distribution of echo intensities of two-dimensional echocardiograms was analyzed using a histogram. The materials were obtained from six normal subjects (N), 29 patients with left ventricular hypertrophy (LVH), and 12 patients one year or more after the onset of anteroseptal myocardial infarction (MI). A transducer with a central frequency of 2.3 MHz was used. Scanner receiver settings, including sensitivity-time control, were kept constant for all subjects. The parasternal long-axis image was digitized and computer-processed. The region of interest was located within the interventricular septum. The mean echo intensity and its distribution were studied. The shape of the histogram was evaluated for skewness and kurtosis. Relative echo intensity: N = 0.23 +/- 0.07 (mean +/- SD) less than LVH = 0.58 +/- 0.18 less than MI = 1.07 +/- 0.25 (p less than 0.01). Skewness: N = 1.58 +/- 0.63 greater than LVH = 0.60 +/- 0.61 greater than MI = -0.14 +/- 0.43 (p less than 0.01). Kurtosis: N = 18.0 +/- 7.3 greater than LVH = 10.5 +/- 3.3 greater than MI = 7.7 +/- 0.9 (p less than 0.01). These differences may closely relate to an increase in collagen fiber content. Consequently, analysis of the myocardial echo intensity distribution, in addition to mean echo intensities, may become a clinically useful approach for identifying myocardial tissue changes.