EXERCISE GATED PLANAR MYOCARDIAL PERFUSION IMAGING USING TC-99M SESTAMIBI FOR THE DIAGNOSIS OF CORONARY-ARTERY DISEASE - AN ALTERNATIVE TO EXERCISE TOMOGRAPHIC IMAGING

Single-photon emission tomography (SPET) using technetium-99m labelled myocardial tracers (e.g, Tc-99m-sestamibi) has become one of the most popular myocardial imaging methods for the diagnosis of coronary arte ry disease (CAD). This prospective study was designed to evaluate the diagnostic performance of Tc-99m-sestamibi exercise gated planar myoca rdial imaging by comparison with both visual and quantitative analyses of SPET. The study was conducted in 115 consecutive patients with kno wn or suspected CAD, including 54 patients with a previous myocardial infarction (MI), referred for exercise testing prior to coronary angio graphy. Multi-gated planar imaging and SPET were performed after bicyc le exercise. The end-diastolic (ED) and SPET images were visually scor ed (SVi). Myocardial uptake was quantitated on SPET slices using maxim um count circumferential profiles (SQu) and defect extent was measured by comparison with gender-matched data sets obtained from 27 controls (<5% likelihood of CAD). CAD was defined as coronary artery stenosis >50% and/or regional wall motion abnormality. The cut-off criteria for positivity of the three procedures were determined from receiver oper ating characteristic (ROC) curves derived from the data of patients wi thout previous MI. The area under the ROC curves was similar for ED, S Vi and SQu. This was confirmed by the analysis of sensitivity performe d using the ROC curve-derived cut-off criteria, in patients with or wi thout previous MI. SVi was more sensitive than ED in identifying the d iseased vessel(s) (ED: 41% vs SVi: 80%; P<0.0005) but ED was more spec ific in this respect (ED: 79% vs SVi: 61%; P<0.0005). We conclude that visual analysis of ED images obtained from gated Tc-99m-sestamibi str ess planar imaging is a valuable alternative to SPET imaging for the d iagnosis of CAD. SPET is, however, more accurate for the evaluation of the disease extent and localization and therefore remains the method of choice for the assessment of myocardial perfusion.