Fourier amplitude image circumferential profile analysis in the evaluation of the dipyridamole test

The aim of this study was to evaluate a circumferential profile method of analysis (CPA) of the Fourier image of amplitude (FA), obtained by equilibrium gated radionuclide angiocardiography (EGRA) in the assessment of the response to the dipyridamole (DIP) test in patients with previous myocardial infarction. The changes in regional wall motion (RWM) induced by DIP in a group of 29 patients with previous MI were compared with those of a ten-patient control group. On the basis of SPECT thallium-201 standard stress-rest scintigraphy the infarcted patients were divided into 9 patients with fixed perfusion defects at four hours and 20 patients with both fixed and reversible perfusion defects. The quantitative CPA was carried out on the FA image normalized by the mean amplitude calculated for the left ventricle (LV) area. A circular ROI was drawn around the FA left ventricle image and two curves (basal and post-DIP) with 60 points were obtained. We compared this method with a five-sector method of analysis applied to the same FA images. An increase of 2 or more SD in the basal post-DIP ratio curve, compared with the average of the ratios in the control group, was found in 16 of 20 patients with reversible perfusion defects (sensitivity: 80%) and an increase in the same ratio was found in 2 of 9 MI patients with fixed perfusion defects (specificity: 78%). A sensitivity and specificity of 60% and 78% respectively were found using sectorial analysis.