The aim of this study was to determine and localize culprit lesion by myocardial perfusion imaging (MPI) in cases of angiographically detected coronary narrowing >or= 75% of at least one coronary artery.
Material and methods: One hundred and thirty-two (132) patients with angiographically detected significant coronary narrowing (>or= 75% luminal stenosis of at least one major coronary artery) were studied. All the patients submitted MPI (99m)Tc-MIBI, with pharmacologic dipyridamole stress protocol with concomitant low level bicycle exercise 50W (DipyEX). We measured relative uptake (99m)Tc-MIBI for each myocardial segment using short-axis myocardial tomogram study. A 5-point scoring system was used to assess the difference between uptake degree in stress and rest studies for the same segments, and we created two indices: Sum reversibility score (SRS), Index of sum reversibility score (ISRS).
Results: A total of 396 vascular territories (2244 segments) were analyzed before elective percutaneous coronary intervention (ePCI). Overall sensitivity, specificity and accuracy using SRS were 90.2%, 87.5%, and 89.4%, with a positive predictive value of 94.1%. Overall sensitivity, specificity, and accuracy using ISRS were 94.4%, 90.6%, 93.2% and the positive predictive value was 95.7%.
Conclusion: DipyEX MPI with the two indices created, SRS and ISRS, significantly improves sensitivity, specificity and accuracy in the determination and localization of culprit lesions in patients undergoing elective PCI.