Semiautomatic contour detection in ultrasound M-mode images

We have developed a method for semiautomatic contour detection in M-mode im ages. The method combines tissue Doppler and grey-scale data, It was used t o detect: 1. the left endocardium of the septum, the endocardium and epicar dium of the posterior wall in 16 left ventricular short-axis M-modes, and 2 . the mitral ring in 38 anatomical M-modes extracted pair-wise in 19 apical four-chamber cine-loops (healthy subjects). We validated the results by co mparing the computer-generated contours with contours manually outlined by four echocardiographers. For all boundaries, the average distance between t he computer-generated contours and the manual outlines was smaller than the average distance between the manual outlines. We also calculated left vent ricular wall thickness and diameter at end-diastole and end-systole and lat eral and septal mitral ring excursions, and found, on average, clinically n egligible differences between the computer-generated indices and the same i ndices based on manual outlines (0.8-1.8 mm), The results were also within published normal values. In conclusion, this initial study showed that it w as feasible in a robust and efficient manner to detect continuous wall boun daries in M-mode images so that tracings of left ventricular wall thickness , diameter and long axis could be derived. (C) 2000 World Federation for Ul trasound in Medicine & Biology.