title: Sonographic detection of normal and abnormal appendix.
abstract: OBJECTIVE
  The aim of the study was to assess the value of sonography in detecting the normal appendix and in identifying abnormality.
  
  
  METHODS
  The appendiceal wall thickness (normal: <3 mm) and ultraluminal contents (abnormal: large appendicolith, non-expressible fluid) were used as the primary criteria to determine the appendiceal status in 716 appendices. In patients who underwent appendicectomy (n = 166), surgical and histopathological findings were correlated with the ultrasound (US) findings; in patients who did not have surgery the reference standard was the clinical consensus based on follow-up.
  
  
  RESULTS
  Thirty-four patients out of 179 with abnormal sonographic findings did not undergo appendicectomy and recovered spontaneously; in 22 of these, the US changes were confined to the appendiceal tip. A normal appendix was identified in 537 patients (45.9% of all patients without appendicitis), with histologic verification subsequently obtained in 21. In 76 normal appendices (14.2% out of all normal appendices), luminal dilatation due to non-expressible inspissated faeces resulted in appendiceal outer diameter >6 mm (range, 6.2-12 mm); a histopathologic proof of non-inflamed appendix was obtained in seven of these.
  
  
  CONCLUSIONS
  A normal appendix can be visualized in a high percentage of cases and it may present with an outer diameter >6 mm (the widely-accepted upper limit of normal) due to the inspissated faecal material within the lumen. A significant percentage of early appendicitis can resolve spontaneously, especially when confined to the appendiceal tip.
authors.affiliation: Clinic of Imaging Methods, Faculty Hospital Motol, Praha, Czech Republic.
authors.forename: V
authors.initials: V
authors.lastname: Simonovský
mesh_terms: D000208:Acute Disease; D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001063:Appendiceal Neoplasms / Q000000981:diagnostic imaging; D001064:Appendicitis / Q000000981:diagnostic imaging*; D001065:Appendix / Q000000981:diagnostic imaging*; D002276:Carcinoid Tumor / Q000000981:diagnostic imaging; D002648:Child; D002675:Child, Preschool; D005189:False Positive Reactions; D005260:Female; D006801:Humans; D007223:Infant; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D014463:Ultrasonography