Prevalence of Appendicoliths Detected at CT in Adults With Suspected Appendicitis.

OBJECTIVE. With heightened interest in nonoperative antibiotic management of uncomplicated appendicitis, appendicoliths become a more relevant issue, and because of higher failure rates their presence may be considered a contraindication. The purpose of this study was to investigate the prevalence of appendicoliths at CT in adults with suspected appendicitis. MATERIALS AND METHODS. Among adults undergoing MDCT for suspected appendicitis, 248 patients (134 women, 114 men; mean age, 35.2 years) consecutively registered over a 3-year period constituted a cohort with surgically proven appendicitis. A cohort of 248 patients (175 women, 73 men; mean age, 37.7 years) without appendicitis consecutively registered over a 1-year period served as control subjects. CT examinations were reviewed for the presence, size, and attenuation of appendicoliths and whether the appendicoliths were obstructing. In the cohort with appendicitis, degree of inflammation (3-point scale) and likelihood for perforation (5-point scale) were scored. RESULTS. The prevalence of appendicoliths at CT was 38.7% (96/248) among patients with appendicitis and 4.4% (11/248) among control subjects ( p < .001). Among the 96 patients with appendicitis who had visible appendicoliths, mean width, length, and maximum attenuation of the dominant appendicolith were 6.0 mm, 8.2 mm, and 313 HU, respectively. In 70.8% (68/96) of patients appendicoliths were obstructing, and 32.3% (31/96) of patients had more than one appendicolith. Inflammation (1.75 vs 1.43) and likelihood of perforation (2.07 vs 1.51) ( p < .05) scores were higher among patients with appendicitis who had appendicoliths. Extraluminal appendicoliths were seen in five cases of perforated appendicitis. CONCLUSION. Appendicoliths were identified at CT in nearly 40% of adults with proven appendicitis, compared with slightly more than 4% of those without appendicitis, and were associated with increased inflammation and risk of perforation.