title: Unilocular hepatic echinococcal cysts: sonography and computed tomography findings.
abstract: OBJECTIVE
  In endemic regions, unilocular hepatic echinococcal cysts (HEC) may be difficult to differentiate radiologically from simple non-parasitic cysts, especially if serological tests were negative. The aim of this descriptive study is to elucidate distinctive imaging findings that allow a diagnosis of HEC.
  
  
  METHODS
  The sonographic and computed tomography (CT) findings of 21 patients with proven unilocular HEC were retrospectively analysed. A total of 28 examinations were reviewed, including 14 sonograms (ultrasound; US) of the liver and 14 CT studies.
  
  
  RESULTS
  Seven imaging features that help in the diagnosis of unilocular HEC were identified by US and/or CT in 14 patients (14/21; 66.6%). They are, by order of frequency: hydatid sand (29.2%), focal or segmental thickening of the cyst wall (29.2%), coexistent echinococcal cysts in the spleen or lungs (16.6%), pericystic biliary radicles dilatation (8.3%), atrophy of the right lobe with compensatory hypertrophy of the left hepatic lobe (8.3%), satellite cysts typical of HEC in the liver (4.2%) and pericyst calcification (4.2%).
  
  
  CONCLUSIONS
  These ancillary signs should prompt us to consider HEC as the cause of a unilocular cyst in approximately two-thirds of patients.
authors.affiliation: Department of Diagnostic Radiology, American University of Beirut Medical Center, Beirut, Lebanon. rad@aub.edu.lb
authors.forename: M C
authors.initials: MC
authors.lastname: Haddad
authors.forename: G A
authors.initials: GA
authors.lastname: Birjawi
authors.forename: R A
authors.initials: RA
authors.lastname: Khouzami
authors.forename: N J
authors.initials: NJ
authors.lastname: Khoury
authors.forename: Y R
authors.initials: YR
authors.lastname: El-Zein
authors.forename: A O
authors.initials: AO
authors.lastname: Al-Kutoubi
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D002648:Child; D004444:Echinococcosis, Hepatic / Q000175:diagnosis* / Q000000981:diagnostic imaging; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D014057:Tomography, X-Ray Computed; D014463:Ultrasonography