Hydrosonography in the evaluation of colorectal polyps.

Prewarmed saline enemas and transabdominal ultrasound (hydrosonography) were used to evaluate 17 consecutive children with rectal bleeding before colonoscopy. Twelve patients with polyps were identified (10 by ultrasound, 10 by endoscopy): these included multiple hyperplastic polyps (1), multiple polyps (1), solitary polyps (9), and pseudopolyps (1). Ultrasound identified 11 polyps in 10 patients, missing two patients with small polyps less than 0.5 cm in diameter. The polyps were hyperechoic ovoid masses fixed to the colonic wall, with a stalk (7), submucosal infolding (5), and intraluminal floating (5). There was one false positive. Colonoscopy was refused by one patient and failed to reach beyond the distal sigmoid in another following previous surgery for malrotation. Colonoscopy was superior in identifying finer mucosal detail (colitis, ulcers, proctitis, anal fissure) and in detecting smaller polyps (sessile polyps, hyperplastic polyps). Hydrosonography of the colon is a simple, relatively non-invasive procedure that provides an alternative, radiation-free examination of the whole colon before colonoscopy. It is complementary to colonoscopy in the management of rectal bleeding in children.