Automated assessment of dipyridamole Tl-201 myocardial SPECT perfusion scintigraphy by case-based reasoning

This study evaluated the diagnostic accuracy of case-based reasoning (CBR) to automatically detect significant coronary artery disease from dipyridamo le Tl-201 myocardial SPECT perfusion scintigrams. Methods: The study popula tion included 240 patients (182 men, 58 women; mean age +/- SD, 61 +/- 12 y ) on whom coronary angiography and perfusion scintigraphy were performed wi thin 6 +/- 11 d of each other. The patients were divided into two groups ac cording to the presence or absence of significant coronary disease in any m ajor coronary vessel. Regional myocardial tracer uptake was observed in 84 segments by polar map analysis. For each scintigraphic image, a CBR algorit hm based on a similarity metric was used to identify similar scintigraphic images within the case library. The angiographic results of these similar c ases were used to obtain the CBR reading, which was compared with the true angiographic results. Myocardial scintigrams were also analyzed by a first- generation Cedars-Sinai (CS) method, including a comparison with a referenc e database, and by the visual analysis of an expert reader. Results: By rec eiver-operating-characteristic analysis, the diagnostic accuracy of CBR was not different from the interpretation by the CS algorithm and from visual interpretation (P = not significant [NS]), For detection of significant cor onary disease, the respective sensitivities at 50% and 80% specificity were 90% and 67% for CBR, 88% and 65% for CS polar map analysis, and 91% and 74 % for visual interpretation. For the detection of coronary disease in the V ascular territories assigned to the left anterior descending and the right coronary arteries, CBR and CS polar map analysis showed similar diagnostic accuracy (P = NS). However, for detection of disease in the circumflex arte ry, CS polar map analysis was slightly better than CBR (P = 0.03). Conclusi on: Automated interpretation of dipyridamole Tl-201 myocardial SPECT perfus ion images by CBR has diagnostic accuracy similar to that of visual interpr etation or CS analysis. Thus, use of a case library that includes a variety of normal and abnormal perfusion images does not appear to have greater di agnostic power than use of reference limits.