1. An image display apparatus comprising: a computer system including at least one central processing unit (CPU) and associated memory, an image data input port and a visual display, said memory containing executable program instructions which, when executed by said CPU, effect: creation of a plurality of segmentation regions, based on analysis of pixel values in the images, by applying a prescribed region extraction processing to each of a plurality of different kinds of images including a same portion of a subject imaged by a diagnostic imaging apparatus; extraction of a plurality of boundaries of the segmentation regions from at least two of the images as displayable visually discernable edges of the segmentation regions; superposition of the extracted plurality of the visually discernable edges of the segmentation regions on respective ones of the images; concurrently displaying the extracted plurality of visually discernable edge boundaries of the segmentation regions in fixed overlapping superimposed respective positions on the visual display; and switching the images in a prescribed order on the visual display causing each image to be displayed in sequence with its segmentation region positioned within a respectively associated one of the concurrently displayed superimposed extracted plurality of visually discernable edge boundaries.