1. A Computer Aided Diagnosis (CAD) comprising: a Region of Interest (ROI) detector configured to detect an ROI from image frames; a categorizer configured to create groups of image frames having successive ROI sections from among the image frames based on a result of the detection; a classifier configured to classify an ROI detected from each of the image frames belonging to the groups; and a result combiner configured to combine classification results for the image frames belonging to each group from the groups and to calculate a group resultfor the each group.