Incidence and Diagnostic Performance of Postnatal Ultrasound for Presacral Masses in Pediatric Patients with Anorectal Malformation.

Abstract

Objectives: To determine the incidence of presacral masses in patients with anorectal malformations (ARMs) and evaluate the diagnostic performance of ultrasound to detect presacral masses during the neonatal period.

Methods: Pediatric patients with ARM underwent ultrasonography during the neonatal period, and their magnetic resonance imaging (MRI) results were reviewed. The presence or absence of a presacral mass was assessed employing ultrasonography and compared with MRI results using the Clopper-Pearson method. The type of ARM (low/not-low) and the presence or absence of sacral anomalies were compared between patients with and without a presacral mass using Fisher's exact test.

Results: The incidence of presacral masses in our study cohort was 4.6% (5/109). Ultrasound diagnostic performance for detecting presacral masses had an accuracy of 98.2% (95% confidence interval (CI): 93.5-99.8), sensitivity of 60% (95% CI: 14.7-94.7), specificity of 100% (95% CI: 96.5-100), positive predictive value of 100% (95% CI: 29.3-100), and negative predictive value of 98.1% (95% CI: 93.4-99.8). ARM type and presence or absence of sacral anomalies were significantly different between the presacral mass and without presacral mass groups (low/not-low = 5/0 vs 47/57, P = .022; and presence/absence of sacral anomalies = 3/2 vs 18/86, respectively, P = .048).

Conclusions: The incidence of presacral masses in pediatric patients with ARM was low (5%). Although the positive predictive value was reliable, ultrasonography performed during the neonatal period was not sensitive. Therefore, sonographers should pay attention when evaluating patients with low-type ARMs accompanying sacral anomalies to avoid overlooking them.