Ultrasound in the evaluation of necrotic bowel in children: A pictorial essay.

Necrotic bowel is a serious condition involving death of gastrointestinal tissue. The diagnosis is difficult to make clinically, and plain radiography is often inconclusive. Ultrasonography is an inexpensive, portable and readily available complementary diagnostic tool. In some cases, ultrasonography can detect features of necrotic bowel earlier than plain radiography or when plain radiography is equivocal and does not correlate with the clinical findings. This pictorial essay aims to compare the ultrasonography features of normal bowel and necrotic bowel in children. The role of ultrasonography and the ultrasonographic features of necrotic bowel will be illustrated by discussing some of the causes of necrotic bowel in children. Correlation with plain radiographs and pathological specimens is made. Frequent causes of necrotic bowel in neonates include necrotising enterocolitis, malrotation with small bowel volvulus and incarcerated inguinal hernias. Causes in older children include intussusception, complications of Meckel's diverticulum, post-surgical adhesions, internal hernias and vasculitic abnormalities. Ultrasonography features suggestive of necrotic bowel include persistently dilated loops of aperistaltic bowel, increase or decrease of bowel wall thickness, intramural or portal venous gas, loss of bowel wall perfusion, and free intraperitoneal gas and fluid. The diagnosis of necrotic bowel may be made earlier on ultrasonography than on abdominal radiographs alone. This pictorial essay will familiarise the reader with the role of ultrasonography and the ultrasonographic features of necrotic bowel through a wide range of conditions that may cause necrotic bowel in children. Familiarity with these findings will facilitate timely imaging diagnosis of necrotic bowel before complications develop.