Evaluation of diagnostic indicators using normalized CT attenuation values of the ovarian wall in contrast-enhanced CT for pediatric ovarian tumor torsion.

PURPOSE: Pediatric ovarian tumor torsion often presents with nonspecific symptoms, and delayed diagnosis can lead to ovarian necrosis. Although contrast-enhanced CT is frequently used, objective quantitative indicators have not been established. This study evaluated normalized ovarian wall CT attenuation (n-OWA) and a combined index incorporating white blood cell count (WBC). METHODS: Among 82 patients with surgically-treated ovarian tumor, 52 who underwent contrast-enhanced CT (15 with torsion and 37 without torsion) were analyzed. The n-OWA was calculated as the ovarian wall CT attenuation divided by the inferior vena cava attenuation. The WBC/n-OWA ratio was also evaluated. Group comparisons were performed using the Wilcoxon test, and diagnostic performance was evaluated by an ROC analysis. RESULTS: The n-OWA was significantly lower in the torsion group (0.25 vs. 0.31, p = 0.02), with an AUC of 0.71. The WBC/n-OWA ratio was significantly higher in the torsion group (44.8 vs. 19.9, p < 0.01) and showed improved diagnostic performance with an AUC of 0.86. At a cutoff of 25.4, the sensitivity and specificity were 1.00 and 0.70, respectively. CONCLUSIONS: The n-OWA is an objective imaging biomarker for pediatric ovarian torsion. The WBC/n-OWA ratio may further improve diagnostic accuracy, particularly for excluding ovarian torsion.