To determine quantitatively the location, extent and type of Thallium-201 myocardial perfusion abnormalities from early and late post-exercise scintigrams, a computerized method has been devel-oped. This method is based on : 1) spatial registration of the early and late images using external markers, 2) automated boundary detection of the left ventricular activity structure, 3) bilinear interpolative background subtraction, 4) circumferential profile analysis in the early and late images and 5) computation of washout circumferential profile. Localization, extent and type of abnormalities are identified by automatic computer comparison of a patient's profile with corresponding limits of normal profiles. The single user-interaction consists of indicating the apex in the 3 views of the study (ANT, LA045, LA065). Normal limits have been defined by the 10 and 90 percentiles assessed from a set of 15 normal subjects.