Abstract: An edge detector executes a process to extract a surface of an inner wall of a left ventricle from a binarized image output from a binarization circuit. A telediastolic edge memory stores an intracardial surface image at the end of ventricular diastole from among intracardial surface images for time phases output from the edge detector. A displacement detector unit detects the amount of displacement for each site of the intracardial surface between time phases from the intracardial surface image at the telediastolic which is output from the telediastolic edge memory, a current intracardial surface image which is output from the edge detector, and a center-of-mass coordinate of the intracardial section at the telediastolic point which is stored in a telediastolic center-of-mass memory. A coloring processor unit applies a coloring process to each site of the surface of the current intracardial surface image based on the amount of displacement and outputs the result to an image synthesizer unit.

Abstract: A specific cavity extractor extracts an isolated group corresponding to a left ventricle from among a plurality of isolated groups to which numbers are attached in a labeling section. A major axis slope calculator section sets, as a left ventricle major axis, a straight line passing through a center of mass calculated in a center-of-mass detector section and a major-axis end point detected in a major-axis end detector section. A cavity cross sectional area calculator section calculates a cross sectional area of four cavities for each of a plurality of cutting planes including the left ventricle major-axis. An optimum cross section setter sets, as a four-cavity cross section, a cutting plane in which the cross sectional area of the four cavities becomes maximum.