title: Semiautomatic contour detection in ultrasound M-mode images.
abstract: We have developed a method for semiautomatic contour detection in M-mode images. The method combines tissue Doppler and grey-scale data. It was used to detect: 1. the left endocardium of the septum, the endocardium and epicardium 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 comparing the computer-generated contours with contours manually outlined by four echocardiographers. For all boundaries, the average distance between the computer-generated contours and the manual outlines was smaller than the average distance between the manual outlines. We also calculated left ventricular wall thickness and diameter at end-diastole and end-systole and lateral and septal mitral ring excursions, and found, on average, clinically negligible differences between the computer-generated indices and the same indices 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 was feasible in a robust and efficient manner to detect continuous wall boundaries in M-mode images so that tracings of left ventricular wall thickness, diameter and long axis could be derived.
authors.affiliation: Department of Physiology and Biomedical Engineering, Norwegian University of Science and Technology, Trondheim, Norway. stein.i.rabben@medisin.ntnu.no
authors.forename: S I
authors.initials: SI
authors.lastname: Rabben
authors.forename: A H
authors.initials: AH
authors.lastname: Torp
authors.forename: A
authors.initials: A
authors.lastname: Støylen
authors.forename: S
authors.initials: S
authors.lastname: Slørdahl
authors.forename: K
authors.initials: K
authors.lastname: Bjørnstad
authors.forename: B O
authors.initials: BO
authors.lastname: Haugen
authors.forename: B
authors.initials: B
authors.lastname: Angelsen
mesh_terms: D001783:Blood Flow Velocity; D015150:Echocardiography, Doppler / Q000379:methods*; D006352:Heart Ventricles / Q000000981:diagnostic imaging*; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods*; D009200:Myocardial Contraction; D017202:Myocardial Ischemia / Q000000981:diagnostic imaging / Q000503:physiopathology; D015588:Observer Variation; D012016:Reference Values; D015203:Reproducibility of Results; D012815:Signal Processing, Computer-Assisted; D016276:Ventricular Function; D016277:Ventricular Function, Left