Pediatric Radiology > Abdominal > Neonatal > Hirschsprung Disease - Radiographic Features


Hirschsprung Disease - Radiographic Features

Dilated bowel proximal to "transition zone"
The transition zone is in the mid-descending colon. 		Normally, the rectum is larger than the colon. In Hirschsprung Disease, there is an abnormal rectosigmoid ratio with the rectum smaller than the sigmoid due to denervation hyperspasticity.

Therefore, one see dilation of large and small bowel proximal to the "transition zone."

The "Transition Zone" is the junction between the proximal normally innervated colon and the distal aganglionic segment. The normally innervated proximal colon becomes dilated.

In 33% of cases, there is a normal-appearing rectum.