[Digital image processing of the two-dimensional echocardiogram for the evaluation of regional contractility of the left ventricular wall (author's transl)].

Short-axis cross-sectional images of the left ventricle at the levels of the mitral valve, papillary muscles and apex were recorded on video tape by using a phased-array sector scanner. Endocardial and epicardial outlines of the cross-sectional left ventricular wall were determined automatically by a computer tracing process including digital image processing system. Short axis cross-sectional left ventricular walls of upper-, middle- and lower parts of the left ventricle were divided into eight segments, the center of gravity of end-diastolic left ventricular cavity being used as the reference point. Various parameters such as segmental radius, segmental wall thickness, cross-sectional area, left ventricular circumference and those changes during the cardiac cycle were determined in eight segments at three levels of the left ventricle. Regional contractility of the left ventricular wall was evaluated by systolic shortening of segmental radius and systolic thickening of segmental wall thickness. Contractility and pumping function of the overall left ventricle was assessed by shortening velocity of left ventricular circumference and fractional changes of cross-sectional area at three levels of the left ventricle. These were significantly and diffusely reduced in a patient with congestive cardiomyopathy (CCM), contrasting with a normal subject. Systolic changes in segmental radius and segmental wall thickness were significantly reduced in infarcted myocardium. Digital image processing system and segmental analysis of the left ventricular short-axis two-dimensional echocardiogram are very useful to evaluate the regional contractility of the left ventricle, quantitatively and automatically, especially in patients with myocardial disease including CCM and myocardial infarction with left ventricular asynergy.