COMPARATIVE DIAGNOSTIC-ACCURACY OF TL-201 AND TC-99M SESTAMIBI SPECT IMAGING (PERFUSION AND EGG-GATED SPECT) IN DETECTING CORONARY-ARTERY DISEASE IN WOMEN

Objectives. This prospective study was conducted in 115 women to direc tly compare the sensitivity and specificity of thallium-201 (Tl-201), technetium-99m (Tc-99m) sestamibi perfusion and Tc-99m sestamibi elect rocardiographic (ECG)-gated single photon emission computed tomographi c (SPECT) studies for detection of coronary artery disease (CAD). Back ground. Data on the comparative diagnostic accuracy of Tl-201 and Tc-9 9m sestamibi perfusion imaging for the detection of CAD, specifically in women, are very limited. Methods. Eighty-five patients,vith suspect ed CBD, scheduled for coronary angiography, and 30 volunteers,vith a p retest likelihood of less than or equal to 5% for CAD were evaluated. Within 1 week, each patient underwent Tl-201 and Tc-99m sestamibi SPEC T imaging procedures (both perfusion and gated SPECT imaging). Treadmi ll stress testing was used in 78 patients and dipyridamole in the rema ining 37 patients. All images were interpreted by three observers in a blinded manner (consensus reading). Technetium 99m sestamibi SPECT st udies were read without and then with ECG gating. Technetium-99m sesta mibi gated SPECT studies were used to differentiate scar tissue from s oft tissue attenuation artifact. Results. The overall sensitivities fo r detecting greater than or equal to 50% and greater than or equal to 70% stenoses were 75.0% and 84.3%, respectively, for Tl-201, and 71.9% and 80.4%, respectively, for Tc-99m sestamibi perfusion studies (p = 0.48). The specificity for lesions greater than or equal to 50% was 61 .9% for Tl-201 and 85.7% for Tc-99m sestamibi perfusion (p = 0.07), wh ereas for lesions greater than or equal to 70% it was 58.8% for Tl-201 and 82.4% for Tc-99m sestamibi perfusion (p = 0.01). When the 34 pati ents with a normal coronary angiogram were added to the group of 30 no rmal volunteers, the ''specificity'' for lesions greater than or equal to 70% was 67.2% for Tl-201, 84.4% for Tc-99m sestamibi SPECT perfusi on (p = 0.02) and 92.2% for Tc-99m sestamibi gated SPECT (p = 0.0004). Conclusions. Both Tl-201 SPECT and Tc-99m sestamibi SPECT perfusion s tudies had a similar sensitivity for the detection of CAD in women. Ho wever, Tc-99m sestamibi SPECT perfusion imaging shows a significantly better specificity, which is further enhanced by the use of ECG gating .