I have grouped these to diseases together in recognition to the possible similarities to their appearances on abdominal plain film. They are not the same disease process.

Plain Film Appearances

Crohn's disease (also known as granulomatous colitis when confined to the colon) may be indistinguishable from ulcerative colitis when confined to the colon. The plain film signs of Crohn's disease are as follows:

Abdominal Plain Film Signs	Comment
long gas-filled stricture	can also be seen in other diseases including ulcerative colitis
narrowed small bowel lumen	not seen in ulcerative colitis
small bowel obstruction	indication of marked stenosis causing obstruction

Small

	The transverse colon is dilated and shows evidence of thumbprinting (black arrow) The descending colon has a thickened featureless wall and pockets of inta-mural gas (white arrow) Patient has known Crohn's disease Appearances consistent with toxic megacolon