title: The use of ultrasound to diagnose hepatic steatosis in type 2 diabetes: intra- and interobserver variability and comparison with magnetic resonance spectroscopy.
abstract: OBJECTIVE
  To compare ultrasound gradings of steatosis with fat fraction (FF) on magnetic resonance spectroscopy (MRS; the non-invasive reference standard for quantification of hepatic steatosis), and evaluate inter- and intraobserver variability in the ultrasound gradings.
  
  
  METHODS
  Triple grading of hepatic ultrasound examination was performed by three independent graders on 131 people with type 2 diabetes. The stored images of 60 of these individuals were assessed twice by each grader on separate occasions. Fifty-eight patients were pre-selected on the basis of ultrasound grading (normal, indeterminate/mild steatosis, or severe steatosis) to undergo (1)H-MRS. The sensitivity and specificity of the ultrasound gradings were determined with reference to MRS data, using two cut-offs of FF to define steatosis, ≥9% and ≥6.1%.
  
  
  RESULTS
  Median (intraquartile range) MRS FF (%) in the participants graded on ultrasound as normal, indeterminate/mild steatosis, and severe steatosis were 4.2 (1.2-5.7), 4.1 (3.1-8.5) and 19.4 (12.9-27.5), respectively. Using a liver FF of ≥6.1% on MRS to denote hepatic steatosis, the unadjusted sensitivity and specificity of ultrasound gradings (severe versus other grades of steatosis) were 71 and 100%, respectively. Interobserver agreement within one grade was observed in 79% of cases. Exact intraobserver agreement ranged from 62 to 87%.
  
  
  CONCLUSIONS
  Hepatic ultrasound provided a good measure of the presence of significant hepatic steatosis with good intra- and interobserver agreement. The grading of a mildly steatotic liver was less secure and, in particular, there was considerable overlap in hepatic FF with those who had a normal liver on ultrasound.
authors.affiliation: Metabolic Unit, Western General Hospital, Royal Infirmary of Edinburgh, Little France Crescent, Edinburgh, UK. rachel_m_williamson@hotmail.com
authors.forename: R M
authors.initials: RM
authors.lastname: Williamson
authors.forename: E
authors.initials: E
authors.lastname: Perry
authors.forename: S
authors.initials: S
authors.lastname: Glancy
authors.forename: I
authors.initials: I
authors.lastname: Marshall
authors.forename: C
authors.initials: C
authors.lastname: Gray
authors.forename: L D
authors.initials: LD
authors.lastname: Nee
authors.forename: P C
authors.initials: PC
authors.lastname: Hayes
authors.forename: S
authors.initials: S
authors.lastname: Forbes
authors.forename: B M
authors.initials: BM
authors.lastname: Frier
authors.forename: G I
authors.initials: GI
authors.lastname: Johnston
authors.forename: A J
authors.initials: AJ
authors.lastname: Lee
authors.forename: R M
authors.initials: RM
authors.lastname: Reynolds
authors.forename: J F
authors.initials: JF
authors.lastname: Price
authors.forename: M W J
authors.initials: MW
authors.lastname: Strachan
mesh_terms: D000368:Aged; D003924:Diabetes Mellitus, Type 2 / Q000175:diagnosis* / Q000000981:diagnostic imaging; D018450:Disease Progression; D005234:Fatty Liver / Q000175:diagnosis* / Q000000981:diagnostic imaging / Q000473:pathology; D005260:Female; D006801:Humans; D009682:Magnetic Resonance Spectroscopy / Q000379:methods*; D008297:Male; D008875:Middle Aged; D015588:Observer Variation; D012680:Sensitivity and Specificity; D014463:Ultrasonography; D006113:United Kingdom