Figure 2.
ROC curve of LAA of ≤−860 or ≤−950 HU, and average HU estimated by binomial distribution. AUC of LAA of ≤−860 or ≤−950 HU, and average HU are 0.207, 0.267 and 0.771, respectively. The cut-off value is determined as –850 HU, which is closest distance from the maximum vertical (0,1) point. AUC of average HU is significantly higher than those of ≤−860 (p < 0.0001) or ≤−950 HU (p < 0.0001). AUC, Area under curve; HU, Hounsfield unit; LAA, low attenuation area; ROC, Receiver operating characteristic.