Trends in the Use of Medical Imaging to Diagnose Appendicitis at an Academic Medical Center.

OBJECTIVE: To quantify the trends in imaging use for the diagnosis of appendicitis.
METHODS: A retrospective study covering a 22-year period was conducted at an academic medical center. Patients were identified by International Classification of Diseases-9 diagnosis code for appendicitis. Medical record data extraction of these patients included imaging test used (ultrasound, CT, or MRI), gender, age, and body mass index (BMI). The proportion of patients undergoing each scan was calculated by year. Regression analysis was performed to determine whether age, gender, or BMI affected imaging choice.
RESULTS: The study included a total of 2,108 patients, including 967 (43.5%) females and 599 (27%) children (<18 years old). CT use increased over time for the entire cohort (2.9% to 82.4%, P < .0001), and each subgroup (males, females, adults, children; P < .0001 for each). CT use increased more in females and adults than in males and children, but differences in trends were not statistically significant (male versus female, P = .8; adult versus child, P = .1). The percentage of patients who had no imaging used for the diagnosis of appendicitis decreased over time (P < .0001 overall and for each subgroup), and no difference was found in trends between complementary subgroups (male versus female, P = .53; adult versus child, P = .66). No statistically significant changes were found in use of ultrasound or MRI over the study period. With increasing BMI, CT was more frequently used.
CONCLUSIONS: Of those diagnosed with appendicitis at an academic medical center, CT use increased more than 20-fold. However, no statistically significant trend was found for increased use of ultrasound or MRI.