Sonography of imperforate anus.

Real-time sonography provides a noninvasive method of determining the level of obstruction in patients with imperforate anus. The authors describe one technique for evaluating this anomaly which was employed in 6 neonates. A pouch-perineum distance of less than 1.5 cm is consistent with a low lesion, while a pouch that terminates above the base of the bladder is indicative of a high lesion.