Figure 2. Chart shows ROC curves and area under the curve (AUC), or Az values, for the three observers in the detection of fistula tracks, abscesses, horseshoe fistulas, and internal openings. The 95% CIs of the estimated Az values for fistula tracks were as follows: Az1: 0.97, 1.00; Az2: 0.92, 1.00; and Az3: 0.94, 1.00. For abscesses, Az1: 0.92, 1.00; Az2: 0.88, 1.00; and Az3: 0.88, 1.00. For horseshoe fistulas, Az1: 1.00, 1.00; Az2: 0.88, 1.00; and Az3: 0.82, 1.00. For internal openings, Az1: 0.89, 0.99; Az2: 0.85, 0.97; and Az3: 0.86, 0.97.