Richard Krauss

For post-evacuation films in Hirschsprung patients, delayed evacuation is seen in those who do have Hirschsprung's, but this is not relied upon for diagnosis. In patients with equivocal findings, the Hirschsprung segment may be spastic and expel contrast, sometimes with huge expulsion.

For post-evacuation films in Hirschsprung contrast studies, delayed evacuation is seen in patients with Hirschsprung, but in equivocal cases, the aganglionic segment can be spastic and expel contrast, so post-evacuation films are not reliable for diagnosis.

In chronic constipation patients (not Hirschsprung), about half of the contrast coming out on post-evacuation films is usually considered normal, though this is a gestalt assessment, not a precise measurement.

When the proximal colon caliber doesn't look bigger than expected, suspect that the transition zone is more proximal than it appears—the remaining colon should be dilated if the transition is truly distal.

In chronic constipation patients, about half of the contrast coming out on post-evacuation films is considered normal, but this is a gestalt assessment, not a precise measurement.

In chronic constipation, the rectosigmoid is usually more dilated than the remainder of the colon, which is characteristic and different from Hirschsprung.