Cecal apical changes with appendicitis: diagnosing appendicitis when the appendix is borderline abnormal or not seen.

In most cases, CT of appendicitis shows a distended appendix with periappendiceal inflammation. A distended appendix, however, is not always visualized. In these patients, identifying changes at the anatomic cecal apex can secure a diagnosis of appendicitis. Cecal apical changes with appendicitis include focal cecal apical thickening, the arrowhead sign, and the cecal bar. This pictorial essay describes and illustrates the spectrum of CT appearances of cecal apical changes that can be seen with appendicitis.