title: An interdisciplinary initiative to reduce radiation exposure: evaluation of appendicitis in a pediatric emergency department with clinical assessment supported by a staged ultrasound and computed tomography pathway.
abstract: OBJECTIVE
  In the emergency department (ED), a significant amount of radiation exposure is due to computed tomography (CT) scans performed for the diagnosis of appendicitis. Children are at increased risk of developing cancer from low-dose radiation and it is therefore desirable to utilize CT only when appropriate. Ultrasonography (US) eliminates radiation but has sensitivity inferior to that of CT. We describe an interdisciplinary initiative to use a staged US and CT pathway to maximize diagnostic accuracy while minimizing radiation exposure.
  
  
  METHODS
  This was a retrospective outcomes analysis of patients presenting after hours for suspected appendicitis at an academic children's hospital ED over a 6-year period. The pathway established US as the initial imaging modality. CT was recommended only if US was equivocal. Clinical and pathologic outcomes from ED diagnosis and disposition, histopathology and return visits, were correlated with the US and CT. ED diagnosis and disposition, pathology, and return visits were used to determine outcome.
  
  
  RESULTS
  A total of 680 patients met the study criteria. A total of 407 patients (60%) followed the pathway. Two-hundred of these (49%) were managed definitively without CT. A total of 106 patients (26%) had a positive US for appendicitis; 94 (23%) had a negative US. A total of 207 patients had equivocal US with follow-up CT. A total of 144 patients went to the operating room (OR); 10 patients (7%) had negative appendectomies. One case of appendicitis was missed (<0.5%). The sensitivity, specificity, negative predictive value, and positive predictive values of our staged US-CT pathway were 99%, 91%, 99%, and 85%, respectively. A total of 228 of 680 patients (34%) had an equivocal US with no follow-up CT. Of these patients, 10 (4%) went to the OR with one negative appendectomy. A total of 218 patients (32%) were observed clinically without complications.
  
  
  CONCLUSIONS
  Half of the patients who were treated using this pathway were managed with definitive US alone with an acceptable negative appendectomy rate (7%) and a missed appendicitis rate of less than 0.5%. Visualization of a normal appendix (negative US) was sufficient to obviate the need for a CT in the authors' experience. Emergency physicians (EPs) used an equivocal US in conjunction with clinical assessment to care for one-third of study patients without a CT and with no known cases of missed appendicitis. These data suggest that by employing US first on all children needing diagnostic imaging for diagnosis of acute appendicitis, radiation exposure may be substantially decreased without a decrease in safety or efficacy.
authors.affiliation: Division of Pediatric Emergency Medicine, Stanford University School of Medicine, Stanford, CA, USA.
authors.forename: Naresh
authors.initials: N
authors.lastname: Ramarajan
authors.forename: Rajesh
authors.initials: R
authors.lastname: Krishnamoorthi
authors.forename: Richard
authors.initials: R
authors.lastname: Barth
authors.forename: Pejman
authors.initials: P
authors.lastname: Ghanouni
authors.forename: Claudia
authors.initials: C
authors.lastname: Mueller
authors.forename: Bernard
authors.initials: B
authors.lastname: Dannenburg
authors.forename: N Ewen
authors.initials: NE
authors.lastname: Wang
mesh_terms: D000293:Adolescent; D001064:Appendicitis / Q000175:diagnosis* / Q000000981:diagnostic imaging; D002140:California; D002648:Child; D002675:Child, Preschool; D019091:Critical Pathways; D004636:Emergency Service, Hospital / Q000458:organization & administration*; D005260:Female; D006776:Hospitals, Pediatric; D006801:Humans; D007223:Infant; D008297:Male; D010808:Physical Examination; D011859:Radiography; D011878:Radiotherapy / Q000706:statistics & numerical data; D012189:Retrospective Studies; D014463:Ultrasonography; D055815:Young Adult