DIPYRIDAMOLE TL-201 SINGLE-PHOTON EMISSION TOMOGRAPHY IN AORTIC-STENOSIS - GENDER DIFFERENCES

Dipyridamole single-photon emission tomography (SPET) is used for the detection of coronary artery disease (CAD) and the method has also bee n applied in patients with aortic stenosis. This study was undertaken to establish the gender-specific normal limits of thallium-201 distrib ution in patients with aortic stenosis and to apply these normal limit s in a larger group of patiens with aortic stenosis to obtain the sens itivity and specificity for coexisting CAD. A low-dose dipyridamole pr otocol was used (0.56 mg/kg during 4 min). Thallium was injected 2 min later and tomographic imaging was performed. Following image reconstr uction a basal, a midventricular and an apical short-axis slice were s elected. The highest activity in each 6 degrees segment was normalised to the maximal acitivity of each slice. The normal uptake for patient s with aortic stenosis was obtained from ten men and ten women with ao rtic stenosis and a normal coronary angiography. Eighty-nine patients were prospectively evaluated. An area reduction of at least 75% in a c oronary artery was considered to be a significant coronary lesion and was found in 57 (64%) patients. With gender-specific curves (-2.5 SD) sensitivity for detecting CAD was 100% and specificity was 75% in men, while sensitivity was 61% and specificity 64% in women. It is conclud ed that the gender-specific normal distribution of (TI)-T-201 uptake i n patients with aortic stenosis, using dipyridamole SPET, yields a hig h: sensitivity and specificity for coronary artery lesions in men but a lower sensitivity and specificity in women with aortic stenosis.