Table 5.

Accuracy analyses of volume-ratio-based clinical cutoffs at differentiating severities of the Erlenmeyer flask deformity, with the best performing ratio in italics

Ratio	Severity cutoff	Accuracy (95% CI)
$\frac{\mathit{\text{Volume}}4-6\mathit{cm}}{\mathit{\text{Volume}}0-2\mathit{cm}}$	Normal ≥ mild (cutoff = 0.57)	Sensitivity: 96.8% (83.3–99.9%)
		Specificity: 84.2% (60.4–96.6%)
		PPV: 90.9% (77.9–96.6%)
		NPV: 94.1% (69.7–99.1%)
		Accuracy: 92.0% (80.8–97.8%)
	Mild ≥ severe (cutoff = 0.68)	Sensitivity: 82.4% (65.5–93.2%)
		Specificity: 90.3% (74.3–98.0%)
		PPV: 90.3% (75.9–96.5%)
		NPV: 82.4% (69.1–90.7%)
		Accuracy: 86.2% (75.3–93.5%)
$\frac{\text{Volume}4-6\mathrm{cm}}{\text{Volume}2-4\mathrm{cm}}$	Normal ≥ mild (cutoff = 0.79)	Sensitivity: 77.4% (58.9–90.4%)
		Specificity: 73.7% (48.8–90.9%)
		PPV: 82.8% (68.8–91.3%)
		NPV: 66.7% (49.7–80.2%)
		Accuracy: 76.0% (61.8–86.9%)
	Mild ≥ severe (cutoff = 0.85)	Sensitivity: 61.8% (43.6–77.8%)
		Specificity: 71.0% (52.0–85.8%)
		PPV: 70.0% (55.9–81.1%)
		NPV: 62.9% (51.1–73.3%)
		Accuracy: 66.2% (53.4–77.4%)
$\frac{\text{Volume}2-4\mathrm{cm}}{\text{Volume}0-2\mathrm{cm}}$	Normal ≥ mild (cutoff = 0.72)	Sensitivity: 83.9% (66.3–94.6%)
		Specificity: 79.0% (54.4–94.0%)
		PPV: 86.7% (72.9–94.0%)
		NPV: 75.0% (56.5–87.4%)
		Accuracy: 82.0% (68.6–91.4%)
	Mild ≥ severe (cutoff = 0.80)	Sensitivity: 76.5% (58.8–89.3%)
		Specificity: 96.8% (83.3–99.9%)
		PPV: 96.3% (78.9–99.5%)
		NPV: 79.0% (67.1–87.3%)
		Accuracy: 86.2% (75.3–93.5%)