title: The utility of Xenon-133 liver scan in the diagnosis and management of nonalcoholic fatty liver disease.
abstract: BACKGROUND
  Nonalcoholic fatty liver disease (NAFLD) is an important and common condition affecting approximately 20% of the general population. Given the limitation of radiological investigations, diagnosis often requires a liver biopsy.
  
  
  OBJECTIVE
  To compare Xenon-133 (Xe-133) liver scanning with ultrasonography in the diagnosis of NAFLD.
  
  
  METHODS
  From January 2003 to February 2007, 258 consecutive patients with suspected NAFLD underwent Xe-133 liver scanning at Royal Victoria Hospital (Montreal, Quebec). Of these, 43 patients underwent ultrasonography and liver biopsy for the evaluation of NAFLD. Patients with other liver diseases and significant alcohol consumption were excluded. Two nuclear medicine physicians assessed liver Xe-133 uptake and measured the grade of steatosis using a standardized protocol. The degree of steatosis was determined from biopsy specimens assessed by two hepatopathologists.
  
  
  RESULTS
  NAFLD was identified by liver biopsy in 35 of 43 patients (81.4%). Xe-133 scan demonstrated 94.3% sensitivity (95% CI 81.4% to 98.4%) and 87.5% specificity (95% CI 52.9% to 99.4%) for the presence of NAFLD. The positive and negative predictive values for detection of steatosis by Xe-133 scan were 97.1% (95% CI 85.1% to 99.8%) and 77.8% (95% CI 45.3% to 93.7%), respectively. The positive and negative likelihood ratios were 7.54 (95% CI 1.20 to 47.26) and 0.07 (95% CI 0.02 to 0.26), respectively. Two patients with NAFLD (5.7%) who had a negative Xe-133 scan result had histologically mild steatosis (<10%). The grade of steatosis on liver biopsy was highly correlated with the results of the Xe-133 scan (r=0.87; P<0.001). The sensitivity and specificity of ultrasound in diagnosing steatosis were 62.9% and 75%, respectively.
  
  
  CONCLUSIONS
  Xe-133 liver scan proved to be a safe, reliable, noninvasive method for diagnosing and quantifying hepatic steatosis, and was superior to ultrasound.
authors.affiliation: Department of Gastroenterology, McGill University Health Centre, Montreal, Quebec, Canada. said-albusafi@yahoo.com
authors.forename: Said A
authors.initials: SA
authors.lastname: Al-Busafi
authors.forename: Peter
authors.initials: P
authors.lastname: Ghali
authors.forename: Philip
authors.initials: P
authors.lastname: Wong
authors.forename: Javier A
authors.initials: JA
authors.lastname: Novales-Diaz
authors.forename: Marc
authors.initials: M
authors.lastname: Deschênes
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001706:Biopsy; D005234:Fatty Liver / Q000000981:diagnostic imaging* / Q000473:pathology; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D065626:Non-alcoholic Fatty Liver Disease; D011237:Predictive Value of Tests; D011877:Radionuclide Imaging; D012189:Retrospective Studies; D014463:Ultrasonography; D014980:Xenon Radioisotopes
chemical_list: D014980:Xenon Radioisotopes