Purpose: With ANN in stress MPI, whether beginners in cardiology diagnostic imaging can get closer results of experts.
Methods: The subjects were 138 patients who underwent stress MPI (with Tc-labeled agents)at Nagasaki University Hospital. Among them, 45 patients (33%) with multiple vessel disease, 28 patients (20%) with a history of myocardial infarction, and 17 patients (12%) with both multiple vessel disease and a history of myocardial infarction. An expert over 30 years interpretation experience and a beginner within a few years experience interpreted stress MPI with/without software which implemented ANN (cardioREPO) and compared the results. The myocardium was divided into 5 regions of apex, septum, anterior, lateral, and inferior, and the degree of myocardial blood flow was evaluated as 5 stages of 0 to 4, 5 segment model, and Summed Stress Score (SSS), Summed Rest Score (SRS) and Summed Difference Score (SDS). These numbers were obtained with and without help of ANN for both interpreters.
Results: To investigate the influence by ANN, "effect of ANN" expressed as the difference of each score (SSS, SRS, SDS) between with ANN and without ANN ("with" – "without") was calculated both in beginner and expert. "Skill effect" expressed as the difference of each score between expert and beginner ("expert" – "beginner") was also calculated both with ANN and without ANN.
"Effect of ANN" was smaller in expert than in beginner. (For SSS; expert vs. beginner = -0.49 vs. -1.23, p value <0.0001, For SRS; expert vs. beginner SRS - beginner = -0.34 vs. -0.88, p value 0.0003, For SDS; expert vs. beginner = -0.15 vs. -0.36, p value 0.0128). All the effect of ANN showed negative value both of them, which indicates that both interpreters tend to interpret score smaller with ANN than without. With ANN the "Skill effect"became smaller than without. (For SSS; with ANN vs. without = -0.07 vs. -0.8, p value <0.0001?For SRS; with ANN vs. without = -0.17 vs. -0.7, p value 0.0003?For SDS; with ANN vs. without = 0.101 vs. -0.1, p value 0.0128). When the score of expert with ANN was considered as "Standard Expert Score", the score of beginner got closer to "Standard Expert Score" with ANN than without("Standard Expert Score"-beginner with ANN vs. "Standard Expert Score"-beginner without ANN for SSS, SRS and SSS are; -0.07 vs. -0.8, p value <0.0001, -0.17 vs. -0.7, p value 0.0003, 0.101 vs. -0.1, p value 0.0128). However, a beginner may interpret no ischemia for actually ischemia because a beginner is affected strongly by ANN.
Conclusions: In the interpretation of MPI, interpretation of beginner gets closer to expert interpretation with ANN than that without. Interpretation with ANN may be useful in interpretation by beginners.