(99)TC(M)-SESTAMIBI SPECT WITH COMBINED DIPYRIDAMOLE AND EXERCISE STRESS IN CORONARY-ARTERY DISEASE

In order to evaluate the clinical value of Tc-99m-methoxyisobutylisoni trile (sestamibi) single photon emission computed tomography (SPECT) a fter dipyridamole infusion in combination with low level bicycle exerc ise for the assessment of the presence, localization and extent of cor onary artery disease (CAD), myocardial perfusion imaging was performed in 76 patients. Low level bicycle exercise was used to supplement the standard dipyridamole infusion protocol because of the lower incidenc e of non-cardiac side effects. The results were compared to arteriogra phic findings obtained within 3 months of the SPECT studies. The overa ll sensitivity of detection of coronary artery disease (i.e. a luminal stenosis >50%) was 81%, specificity 80%, positive predictive value 96 %, negative predictive value 40% and accuracy 82%. The diagnostic valu es for the detection of significant stenoses in the three major corona ry arteries were: left anterior descending artery sensitivity 72%, spe cificity 87% and accuracy 76%; right coronary artery sensitivity 75%, specificity 90% and accuracy 80%; left circumflex coronary artery sens itivity 57%, specificity 85% and accuracy 71%. Scintigraphic evidence of multivessel disease was found in 31 (65%) patients with two- or thr ee-vessel involvement assessed by arteriography. False negative test r esults were mainly found in patients with relatively mild CAD (one-ves sel disease, branch and distal disease). 99Tc--sestamibi SPECT after d ipyridamole infusion in combination with low level bicycle exercise is shown to be a valuable diagnostic tool for the evaluation of CAD.