title: Trends in the Use of Medical Imaging to Diagnose Appendicitis at an Academic Medical Center.
abstract: 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.
authors.affiliation: BerbeeWalsh Department of Emergency Medicine, University of Wisconsin-Madison, Madison, Wisconsin; Department of Radiology, University of Wisconsin-Madison, Madison, Wisconsin. Electronic address: mdreppli@medicine.wisc.edu.
authors.forename: Michael D
authors.initials: MD
authors.lastname: Repplinger
authors.affiliation: BerbeeWalsh Department of Emergency Medicine, University of Wisconsin-Madison, Madison, Wisconsin.
authors.forename: Andrew C
authors.initials: AC
authors.lastname: Weber
authors.affiliation: Department of Radiology, University of Wisconsin-Madison, Madison, Wisconsin.
authors.forename: Perry J
authors.initials: PJ
authors.lastname: Pickhardt
authors.affiliation: Department of Biostatistics & Medical Informatics, University of Wisconsin-Madison, Madison, Wisconsin.
authors.forename: Victoria P
authors.initials: VP
authors.lastname: Rajamanickam
authors.affiliation: BerbeeWalsh Department of Emergency Medicine, University of Wisconsin-Madison, Madison, Wisconsin.
authors.forename: James E
authors.initials: JE
authors.lastname: Svenson
authors.affiliation: Department of Medicine, University of Wisconsin-Madison, Madison, Wisconsin.
authors.forename: William J
authors.initials: WJ
authors.lastname: Ehlenbach
authors.affiliation: Department of Medicine, University of Wisconsin-Madison, Madison, Wisconsin.
authors.forename: Ryan P
authors.initials: RP
authors.lastname: Westergaard
authors.affiliation: BerbeeWalsh Department of Emergency Medicine, University of Wisconsin-Madison, Madison, Wisconsin; Department of Radiology, University of Wisconsin-Madison, Madison, Wisconsin; Department of Medicine, University of Wisconsin-Madison, Madison, Wisconsin; Department of Medical Physics, University of Wisconsin-Madison, Madison, Wisconsin; Department of Biomedical Engineering, University of Wisconsin-Madison, Madison, Wisconsin.
authors.forename: Scott B
authors.initials: SB
authors.lastname: Reeder
authors.affiliation: BerbeeWalsh Department of Emergency Medicine, University of Wisconsin-Madison, Madison, Wisconsin; Department of Medicine, University of Wisconsin-Madison, Madison, Wisconsin.
authors.forename: Elizabeth A
authors.initials: EA
authors.lastname: Jacobs
mesh_terms: D000046:Academic Medical Centers / Q000706:statistics & numerical data / Q000639:trends*; D000328:Adult; D017677:Age Distribution; D000368:Aged; D000369:Aged, 80 and over; D001064:Appendicitis / Q000000981:diagnostic imaging* / Q000453:epidemiology*; D015992:Body Mass Index; D002648:Child; D002675:Child, Preschool; D000066491:Clinical Decision-Making; D003952:Diagnostic Imaging / Q000706:statistics & numerical data* / Q000639:trends*; D005260:Female; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D008875:Middle Aged; D010818:Practice Patterns, Physicians' / Q000706:statistics & numerical data / Q000639:trends; D017678:Sex Distribution; D014600:Utilization Review; D014922:Wisconsin / Q000453:epidemiology; D055815:Young Adult
keywords: Appendicitis; CT; MRI; resource utilization; ultrasound