Table 1: The value of using binary logistic stepwise regression analysis to detect viable myocardium using different S and Sr parameters in the resting state.
Subsequently, LS, LSr and ROC curves were plotted to determine the optimal cutoff points for detecting viable myocardium using STE. Accordingly, sensitivity, specificity, and accuracy were calculated (Fig. 2A-D, Table 2 and 3).
In the DM group, the cutoff point for LSrest was determined to be -13.27, with 46 out of 117 segments classified as viable myocardium (LSrest ≤ -13.27) and 71 segments as non-viable myocardium (LSrest> -13.27) according to the gold standard. Similarly, for LSLDDSE in the DM group, the cutoff point was -13.81, with 83 segments classified as viable myocardium (LSLDDSE ≤ -13.81) and 34 segments as non-viable myocardium (LSLDDSE > -13.81). In terms of LSrrest, the cutoff point was -0.875, resulting in 98 segments classified as viable myocardium (LSrrest ≤ -0.875) and 19 segments as non-viable myocardium (LSrrest > -0.875) according to the gold standard. In the DM group, LSrLDDSE had a cutoff point of -1.12, with 108 segments classified as viable myocardium (LSrLDDSE ≤ -1.12) and 9 segments as non-viable myocardium (LSrLDDSE > -1.12).
In the non-DM group, the cutoff point for LSrestwas -12.33, with 123 out of 248 segments classified as viable myocardium (LSrest ≤ -12.33) and 125 segments as non-viable myocardium (LSrest > -12.33) according to the gold standard. Similarly, for LSLDDSE in the non-DM group, the cutoff point was -14.075, with 171 segments classified as viable myocardium (LSLDDSE ≤ -14.075) and 77 segments as non-viable myocardium (LSLDDSE> -14.075). Regarding LSrrest , the cutoff point was -1.075, resulting in 156 segments classified as viable myocardium (LSrrest ≤ -1.075) and 92 segments as non-viable myocardium (LSrrest > -1.075) according to the gold standard. In the non-DM group, LSrLDDSE had a cutoff point of -1.305, with 192 segments classified as viable myocardium (LSrLDDSE ≤ -1.305) and 56 segments as non-viable myocardium (LSrLDDSE > -1.305) according to the gold ststandard.