Figure 5. (a) 67-year-old male with Crohn's disease. The appendix is distended and slightly thickened (curved arrow), but predominantly filled with "clean" air. These findings are consistent with a secondary inflammation of the appendix rather then appendicitis due to obstruction. The appendiceal dilatation and thickening resolved with conservative treatment of the patients underlying disease. (b) 40-year-old male with appendicitis. CT demonstrates a distended appendix with enhancement of the periappendiceal wall and multiple small air bubbles within the lumen (arrow).