Comparative ability of myocardial perfusion single-photon emission computed tomography to detect coronary artery disease in patients with and withoutdiabetes mellitus

Background Diabetics generally have more frequent and extensive silent myoc ardial ischemia than nondiabetics, increasing the importance of noninvasive detection of coronary artery disease (CAD) in this cohort. However, little is known regarding the diagnostic accuracy of myocardial perfusion single- photon emission computed tomography (SPECT) in patients with diabetes. This study was undertaken to compare the diagnostic value of rest thallium-201/ stress technetium-99m sestamibi dual-isotope myocardial perfusion SPECT in patients with and without diabetes. Methods of the 203 patients with diabetes and 260 patients without diabetes who underwent dual-isotope myocardial perfusion SPECT with exercise or pha rmacologic stress testing, 138 diabetics (12% type 1 diabetics) and 188 non diabetics had coronary angiography within 6 months of the nuclear test, and 65 diabetics and 72 nondiabetics had a low likelihood (<10%, mean 6% +/- 3 % and 6% +/- 3%) of CAD. Results The angiographic data showed that patients with diabetes had less i ncidence of 1-vessel disease and a higher incidence of 3-vessel/left main a rtery disease than patients without diabetes (P < .05). The overall sensiti vity and specificity, respectively, of SPECT For detecting CAD with the cri terion of greater than or equal to 50% diameter stenosis were 86% (95 of 11 1) and 56% (15 of 27) in diabetics, 86% (122 of 142) and 46% (21 of 46) in nondiabetics (P = not significant). With the criterion of greater than or e qual to 70% diameter stenosis the corresponding results were 90% (86 of 96) and 50% (21 of 42) in diabetics, and 91% (108 of 119) and 43% (30 of 69) i n nondiabetics, respectively (P = not significant). The normalcy rate For l ow likelihood patients was 89% (58 of 65) in diabetics and 90% (65 of 72) i n nondiabetics (P = not significant). The sensitivity and specificity for i ndividual vessel detection were also similar in patients with and without d iabetes (P = not significant) except for a lower sensitivity and a higher s pecificity for detecting left anterior descending coronary artery disease i n the diabetic group (P < .05). Conclusion Dual-isotope myocardial perfusion SPECT has comparable accuracy for the diagnosis of CAD in diabetic and nondiabetic patients.