title: Assessment of relevant hepatic steatosis in obese adolescents by rapid fat-selective GRE imaging with spatial-spectral excitation: a quantitative comparison with spectroscopic findings.
abstract: OBJECTIVE
  To test the feasibility of fat-selective GRE imaging using a spectral-spatial excitation technique for determination of intrahepatic lipid content (IHL) in obese adolescents.
  
  
  METHODS
  Fat-selective MR imaging (1.5 T) was applied to record a single axial slice through a representative liver region within a single breath-hold. The sequence uses six equidistant slice-selective excitation pulses with binomial amplitude ratios to achieve high selectivity for lipid signals after appropriate shimming. IHL(MRI) content was quantified using signal intensity of adjacent subcutaneous adipose tissue. As the gold standard for IHL quantification, single-voxel stimulated echo magnetic resonance spectroscopy (MRS) was applied. IHL(MRS) was quantified using the water peak as a reference.
  
  
  RESULTS
  Forty-five MR examinations could be performed, and IHL(MRS) content ranged from 0.7% to 19.1%. Results from MRS and fat-selective imaging correlated well with Spearman coefficients between r = 0.78 and r = 0.86. There were no relevant regional differences in IHL within the liver parenchyma (p > 0.6359). Fat-selective imaging was able to reliably identify patients with IHL content above 5% with positive/negative likelihood ratio of 11.8 and 0.05, respectively.
  
  
  CONCLUSIONS
  Fat-selective MR imaging provides both a reliable and a convenient method of rapidly quantifying IHL content in obese adolescents.
authors.affiliation: Section on Experimental Radiology, Department of Diagnostic and Interventional Radiology, University Hospital Tübingen, Hoppe-Seyler-Str. 3, 72076 Tübingen, Germany. Fabian.Springer@med.uni-tuebingen.de
authors.forename: Fabian
authors.initials: F
authors.lastname: Springer
authors.forename: Stefan
authors.initials: S
authors.lastname: Ehehalt
authors.forename: Julia
authors.initials: J
authors.lastname: Sommer
authors.forename: Verena
authors.initials: V
authors.lastname: Ballweg
authors.forename: Jürgen
authors.initials: J
authors.lastname: Machann
authors.forename: Gerhard
authors.initials: G
authors.lastname: Binder
authors.forename: Claus D
authors.initials: CD
authors.lastname: Claussen
authors.forename: Fritz
authors.initials: F
authors.lastname: Schick
mesh_terms: D000273:Adipose Tissue / Q000166:cytology / Q000473:pathology; D000293:Adolescent; D015992:Body Mass Index; D002648:Child; D003251:Constriction, Pathologic / Q000473:pathology*; D003952:Diagnostic Imaging / Q000379:methods; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted; D016013:Likelihood Functions; D008055:Lipids / Q000737:chemistry; D008099:Liver / Q000473:pathology*; D008279:Magnetic Resonance Imaging / Q000379:methods; D009682:Magnetic Resonance Spectroscopy / Q000379:methods; D008297:Male; D009765:Obesity / Q000150:complications* / Q000473:pathology*; D012044:Regression Analysis; D014867:Water / Q000737:chemistry
chemical_list: D008055:Lipids; D014867:Water