Multidetector-row CT of the appendix in healthy adults.

The purpose of this study is to characterize the caliber of the normal appendix and the effect of luminal content on appendiceal diameter in adults using thin section intravenous (IV) contrast enhanced multidetector-row computed tomography (MDCT). A retrospective review was conducted using the MDCT datasets from 82 adults being screened as potential renal donors. The four-channel CT technique included IV contrast and 1-mm collimation. Arterial phase scans were reviewed by two radiologists blinded to surgical history, to evaluate the following parameters related to the appendix: quality of visualization, origin and course relative to the cecum, maximum cross-sectional diameter of the lumen and luminal contents at the point of measurement, appearance of the periappendiceal fat, and presence of any luminal calcification. Medical records were reviewed to determine which subjects had reported a previous appendectomy or to confirm the absence of symptoms in any subjects with findings suspicious for appendicitis. The appendix was visualized in 72 of the 77 subjects who did not report an appendectomy (94%). The mean diameter of the collapsed appendix was 5 mm (range: 3-7 mm) and the air-distended appendix, 7 mm (range: 4-10 mm). Sixteen to 17% of the collapsed appendices measured 7 mm in diameter. Minimal periappendiceal stranding was identified in 2/72 subjects (3%). Chart notes from within 24 h of the MDCT confirmed no signs or symptoms of appendicitis in cases that demonstrated any CT finding suspicious for appendicitis. In this healthy, adult population, the collapsed appendix measured up to 7 mm at MDCT. Air distention of the lumen results in a wider diameter, up to 10 mm.