Abstract: A magnetic resonance imaging system (A) generates an image (16) of a slice or other region of an examined subject. A smoothing filter (B) smooths the generated image to create a smoothed or filtered image representation (30). The filtering of the image, unfortunately, tends to smooth or blur the edges. An edge detecting means (C.sub.1) views the region around each sampled pixel of the filtered image to determine an amount of deviation in the pixel values. A large deviation indicates an edge; whereas, substantial homogeneity indicates the lack of an edge. Analogously, the direction of the maximum deviation is orthogonal to the direction of the edge. A plurality of soft edge directional filters (54) operate on the filtered image data to create a plurality of soft edge directionally filtered image representations (62). A plurality of hard edge directional filters (56) operate on the filtered image data to create a plurality of hard edge directionally filtered image representations (64).

Abstract: A first image (20) and a second image (22) are taken through the patient's heart region at small time displaced intervals. The first and second images are subtracted (24) to generate a difference image which is indicative of the tissue which has moved during the short time interval, i.e. the boundary of the ventricles. Voxels from regions outside the boundary are adjusted to remove lung tissue (40), and ventricle boundary or edge voxels (48) and analyzed to generate a non-blood tissue histogram (62). Voxels within the boundary are analyzed to generate a blood tissue histogram (60). The histograms are fit (66, 74) to smooth curves which represent the probability distribution or confidence that each voxel value represents blood or non-blood tissue. Contiguous voxels within the boundary are counted (96) and adjusted for voxel size (98) to create an indication of left and right ventricle volume (100l, 100r).