title: MRI vs. ultrasound for suspected appendicitis during pregnancy.
abstract: OBJECTIVE
  To compare the sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of ultrasound (US) and MRI in evaluation of pregnant patients with a clinical suspicion of appendicitis.
  
  
  METHODS
  A total of 33 pregnant patients with suspected appendicitis underwent US and MRI. The original imaging reports generated at the time of presentation were used for data analysis. Pathology reports were used for disease confirmation in patients who underwent appendectomy. When surgery was not performed, a medical record review was performed. The sensitivity, specificity, PPV, and NPV were calculated for US and MRI in the diagnosis of appendicitis.
  
  
  RESULTS
  Five of the 33 patients had pathologically-proven appendicitis. Four of the five patients with appendicitis were correctly diagnosed at MRI while one was interpreted as indeterminate (appendix not seen). At US, one was correctly diagnosed, one was incorrectly diagnosed as normal, and three were interpreted as indeterminate (appendix not seen). In 13 patients, a normal appendix was diagnosed at MRI, none of whom had appendicitis. In three patients, a normal appendix was diagnosed at US, one of whom had appendicitis. When the appendix was visualized at MRI, the sensitivity, specificity, PPV, and NPV for the diagnosis of appendicitis was 100% for all parameters. When the appendix was visualized at US, the sensitivity, specificity, PPV, and NPV for the diagnosis of appendicitis was 50%, 100%, 100%, and 66%, respectively.
  
  
  CONCLUSIONS
  Based on a relatively small number of true-positives, our data suggests that MRI is very useful for the diagnosis and exclusion of appendicitis in pregnant women.
authors.affiliation: Department of Diagnostic Radiology, Yale University School of Medicine, New Haven, Connecticut 06520-8042, USA. gary.israel@yale.edu
authors.forename: Gary M
authors.initials: GM
authors.lastname: Israel
authors.forename: Nagina
authors.initials: N
authors.lastname: Malguria
authors.forename: Shirley
authors.initials: S
authors.lastname: McCarthy
authors.forename: Josh
authors.initials: J
authors.lastname: Copel
authors.forename: Jeffrey
authors.initials: J
authors.lastname: Weinreb
mesh_terms: D000293:Adolescent; D000328:Adult; D001062:Appendectomy; D001064:Appendicitis / Q000175:diagnosis* / Q000000981:diagnostic imaging / Q000601:surgery; D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods*; D011237:Predictive Value of Tests; D011247:Pregnancy; D011248:Pregnancy Complications / Q000175:diagnosis* / Q000000981:diagnostic imaging / Q000601:surgery; D012189:Retrospective Studies; D012680:Sensitivity and Specificity; D014463:Ultrasonography