Comparison of diagnostic efficacy in males with high/intermediate typed anorectal malformations between ultrasound and inverted X-ray exam

To compare the diagnostic efficacy of ultrasound and inverted X-ray in differentiating high and intermediate types of male anorectal malformations（ARMs）.

A fully paired diagnostic accuracy study was conducted on 146 male children with intermediate/high type ARMs who were treated in our hospital from March 2013 to March 2022. According to their postoperative diagnosis after anorectal plasty, 55 cases（including 12 with bladder-neck fistula and 43 with urethral-prostatic fistula）were assigned into high type group and 91 cases（including 65 with urethral-bulbar fistula and 26 without fistula）into intermediate type group. The accuracy, sensitivity, specificity, and area under the curve（AUC）were used as evaluation indicators to compare the diagnostic efficacy of 2 examinations and the optimal diagnostic cutoff values by receiver operating characteristic（ROC）curve analysis. And the diagnostic efficacy of ultrasound and inverted X-ray was then compared in different time periods after birth.

Both examinations effectively differentiated high and intermediate types of male ARMs（P<0.05）. The ROC curve analysis showed that the AUC of ultrasound（0.835, 95%CI: 0.764~0.891）was higher than that of inverted X-ray（0.759, 95%CI: 0.681~0.826）, though without significant difference（P=0.061）. The cut-off value of ultrasound（15.0 mm）was shorter than that of inverted X-ray（24.0 mm）. The diagnostic efficacy of ultrasound（0.940, 95%CI: 0.799~0.993）was significant higher than that of inverted X-ray（0.758, 95%CI: 0.578~0.890）when inspection time was longer than 48 h after birth（P=0.032）.

Both ultrasound and inverted X-ray can differentiate intermediate and high type ARMs in male neonates. Ultrasound is more recommended for the neonates older than 48 h.