title: Diagnostic value of maximal-outer-diameter and maximal-mural-thickness in use of ultrasound for acute appendicitis in children.
abstract: OBJECTIVE
  To evaluate the maximal-outer-diameter (MOD) and the maximal-mural-thickness (MMT) of the appendix in children with acute appendicitis and to determine their optimal cut-off values to diagnose acute appendicitis.
  
  
  METHODS
  In total, 164 appendixes from 160 children between 1 and 17 years old (84 males, 76 females; mean age, 7.38 years) were examined by high-resolution abdominal ultrasound for acute abdominal pain and the suspicion of acute appendicitis. We measured the MOD and the MMT at the thickest point of the appendix. Patients were categorized into two groups according to their medical records: patients who had surgery (surgical appendix group) and patients who did not have surgery (non-surgical appendix group). Data were analyzed by MedCalc v.9.3. The rank sum test (Mann-Whitney test) was used to evaluate the difference in the MOD and the MMT between the two groups. ROC curve analysis was used to determine the optimal cut-off value of the MOD and the MMT on diagnosis of acute appendicitis.
  
  
  RESULTS
  There were 121 appendixes (73.8%) in the non-surgical appendix group and 43 appendixes (26.2%) in the surgical appendix group. The median MOD differed significantly between the two groups (0.37 cm vs 0.76 cm, P < 0.0001), and the median MMT also differed (0.15 cm vs 0.33 cm, P < 0.0001). The optimal cut-off value of the MOD and the MMT for diagnosis of acute appendicitis in children was > 0.57 cm (sensitivity 95.4%, specificity 93.4%) and > 0.22 cm (sensitivity 90.7%, specificity 79.3%), respectively.
  
  
  CONCLUSIONS
  The MOD and the MMT are reliable criteria to diagnose acute appendicitis in children. An MOD > 0.57 cm and an MMT > 0.22 cm are the optimal criteria.
authors.affiliation: Department of Radiology, College of Medicine, Korea University, Ansan-City, Gyeonggi-Do, South Korea.
authors.forename: Bo-Kyung
authors.initials: BK
authors.lastname: Je
authors.forename: Sung-Bum
authors.initials: SB
authors.lastname: Kim
authors.forename: Seung Hwa
authors.initials: SH
authors.lastname: Lee
authors.forename: Ki Yeol
authors.initials: KY
authors.lastname: Lee
authors.forename: Sang Hoon
authors.initials: SH
authors.lastname: Cha
mesh_terms: D000293:Adolescent; D001064:Appendicitis / Q000175:diagnosis* / Q000000981:diagnostic imaging* / Q000601:surgery; D001065:Appendix / Q000033:anatomy & histology / Q000000981:diagnostic imaging / Q000473:pathology; D002648:Child; D002675:Child, Preschool; D005260:Female; D006801:Humans; D007223:Infant; D008297:Male; D014463:Ultrasonography