TC-99M TETROFOSMIN MYOCARDIAL SPECT PERFUSION IMAGING - COMPARISON OFREST-STRESS AND STRESS-REST PROTOCOLS

Aim. The purpose of this study was to evaluate the diagnostic value of Tc-99m tetrofosmin SPECT myocardial perfusion scintigraphy rest/stres s and stress/rest protocols for the assessment of coronary artery dise ase (CAD). Methods. 65 patients underwent both rest and stress SPECT i maging in a one-day protocol and coronary angiography within 2 months before or after scintigraphy. Scintigraphic data was obtained accordin g to two different protocols; 1) rest-stress (n=18) and 2) stress-rest (n=47). Results. Scintigraphic evidence for myocardial ischaemia was found in 36 patients (55%). The overall sensitivity to detect CAD (>50 % luminal stenosis) was 94% (34/36), specificity 66% (19/24), positive predictive value 77%, negative predictive value 90%. The sensitivity to detect CAD for protocols 1 and 2 were 100% and 93%, specificity 56% and 70%, positive predictive value 69% and 81% and negative predictiv e value 100% and 88%, respectively. The left anterior descending coron ary artery showed a sensitivity (overall, protocol. 1 & 2) of 78%, 75% (3/4) and 79% (15/19) and a specificity of 71%, 64% (9/14) and 75% (2 1/28). The right coronary artery showed a sensitivity (overall, protoc ol 1 & 2) of 91%, 100% (6/6) and 88% (14/16) and a specificity of 70%, 92% (11/12) and 61% (19/31). The left circumflex coronary artery show ed a sensitivity (overall, protocol 1 & 2) of 50%, 67% (2/3) and 46% ( 6/13) and a specificity of 94%, 100% (15/15) and 91% (31/34). Conclusi on. Tc-99m tetrofosmin appears to be a valuable tool in predicting sig nificant CAD. The sensitivity and the positive predictive value are hi gh, making this test highly appropriate for the diagnosis of CAD. The diagnostic value of the individual coronary arteries is high to modera te. No significant differences were found between both protocols.