201Tl myocardial SPECT detects significant coronary artery disease between 50% and 75% angiogram stenosis

Coronary angiography is the "gold standard" for the diagnosis of coronary artery disease (CAD). The aim of this work was to compare 201Thallium SPECT with different coronary angiographic cutoff values.

Data pertaining to 145 patients were tabulated. All patients underwent stress ECG, 201Thallium SPECT and coronary angiography. To assess the cutoff impact, two criteria for coronary angiography diagnosis were used: a) > or = 50% and b) > or = 75% stenosis, and applied to data from patients and vessels.

On a patient basis, 201Thallium SPECT sensitivity, specificity and accuracy were 87%, 57% and 81% with > or = 50% cutoff and 93%, 51% and 79% with > or = 75% cutoff, respectively (NS). When performing individual vessel analysis, sensitivity, specificity and accuracy were 59%, 78% and 68% for > or = 50% cutoff and 70%, 75% and 74% for > or = 75% cutoff, respectively (p < 0.029 for sensitivity). As expected, the severer the stenosis the higher the detection rate. There were 19 patients who had stenosis between 50% and 74%. Of these, 21% had abnormal stress ECG and 58% abnormal Thallium-201 SPECT.

201Thallium SPECT results support the use of > or = 50% stenosis cutoff criteria for CAD diagnosis and evaluation. Combined with coronary angiography, myocardial SPECT offers an excellent management strategy to patients.