1. A computer-aided diagnostic (CAD) apparatus comprising: a region of interest (ROI) detector configured to detect an ROI from an image input from a probe; a probe motion determiner configured to determine a motion of the probe in response to the ROI detector detecting the ROI; a diagnostic intention determiner configured to determine a diagnostic intention of a user based on the determined motion of the probe; and a diagnostic intention processor configured to perform a diagnostic procedure based on the determined diagnostic intention of the user.