Receiver operating characteristics of ex vivo margin assessment.
Receiver operating characteristics for the detection of tumor-positive margins (An SBR cut-off of ≥1.5 was optimal for the detection of close margins (1–5 mm) based on Youden’s index. We detected close margins with a sensitivity of 70.3% (95% CI 53.3–83.0), a specificity of 76.1% (95% CI 58.6–87.7%), 60.5% (95% CI 44.7–74.3%) PPV, 83.1% (95% CI 65.8–92.6%) NPV, and an AUC of 0.72 (95% CI 0.62–0.82). To determine the diagnostic accuracy of the technique more precisely, we divided the close margins into two groups: 1–3 mm (