A new method for quantification of spatial and temporal parameters of endocardial motion: Evaluation of experimental infarction using magnetic resonance imaging

BACKGROUND: With the development of high-resolution myocardial imaging ther e has evolved a need for automated techniques that can accurately quantify regional function. OBJECTIVE: To develop a new method for quantification of spatial and tempor al parameters of endocardial motion. DESIGN: Magnetic resonance images were analyzed using a unique, shape-based approach that tracks endocardial surface motion at defined points through the cardiac cycle by minimizing the bending energy. SETTING: Animal instrumentation was performed in the Nuclear Cardiology Exp erimental Research Laboratory at Yale University, New Haven, Connecticut. M agnetic resonance imaging was performed at the Yale New Haven Hospital Cent er. ANIMALS: Eight mongrel canines were used. INTERVENTIONS: Electrocardiograph gated, gradient-echo magnetic resonance i mages were obtained before and after occlusion of the left anterior descend ing coronary artery. Thirty-two points along automatically defined endocard ial contours were tracked. Average displacements and cumulative path length s were computed from end-diastole for each point over the entire cardiac cy cle. The average cumulative path length was computed for each of four quart ers of systole for the normal, border and infarct zones. Shape-based parame ters of systolic motion were compared with the centreline approach. Infarct zone was defined by postmortem histochemical staining. MAIN RESULTS: Displacement and cumulative path length over the cardiac cycl e decreased significantly in the infarct and border zones (P<0.05), but did not change in the normal zone (P was not significant). Temporal changes in motion were observed in all zones. Displacement measured using the shape b ased algorithm was more consistent than cumulative path length when compare d with systolic motion measured using the centreline method. CONCLUSIONS: An automated, shape-based approach permits quantitative evalua tion of both spatial and temporal parameters of regional endocardial motion from high-resolution electrocardiograph gated images. Analysis of endocard ial motion and cumulative motion over the entire cardiac cycle discriminate d infarcted from normal and border regions.