title: T(1) independent, T(2) (*) corrected chemical shift based fat-water separation with multi-peak fat spectral modeling is an accurate and precise measure of hepatic steatosis.
abstract: OBJECTIVE
  To determine the precision and accuracy of hepatic fat-fraction measured with a chemical shift-based MRI fat-water separation method, using single-voxel MR spectroscopy (MRS) as a reference standard.
  
  
  METHODS
  In 42 patients, two repeated measurements were made using a T(1) -independent, T 2*-corrected chemical shift-based fat-water separation method with multi-peak spectral modeling of fat, and T(2) -corrected single voxel MR spectroscopy. Precision was assessed through calculation of Bland-Altman plots and concordance correlation intervals. Accuracy was assessed through linear regression between MRI and MRS. Sensitivity and specificity of MRI fat-fractions for diagnosis of steatosis using MRS as a reference standard were also calculated.
  
  
  RESULTS
  Statistical analysis demonstrated excellent precision of MRI and MRS fat-fractions, indicated by 95% confidence intervals (units of absolute percent) of [-2.66%,2.64%] for single MRI ROI measurements, [-0.81%,0.80%] for averaged MRI ROI, and [-2.70%,2.87%] for single-voxel MRS. Linear regression between MRI and MRS indicated that the MRI method is highly accurate. Sensitivity and specificity for detection of steatosis using averaged MRI ROI were 100% and 94%, respectively. The relationship between hepatic fat-fraction and body mass index was examined.
  
  
  CONCLUSIONS
  Fat-fraction measured with T(1) -independent T 2*-corrected MRI and multi-peak spectral modeling of fat is a highly precise and accurate method of quantifying hepatic steatosis.
authors: Department of Radiology, University of Wisconsin, Madison, WI, USA.
authors: Catherine D G
authors: CD
authors: Hines
authors: Alex
authors: A
authors: Frydrychowicz
authors: Gavin
authors: G
authors: Hamilton
authors: Dana L
authors: DL
authors: Tudorascu
authors: Karl K
authors: KK
authors: Vigen
authors: Huanzhou
authors: H
authors: Yu
authors: Charles A
authors: CA
authors: McKenzie
authors: Claude B
authors: CB
authors: Sirlin
authors: Jean H
authors: JH
authors: Brittain
authors: Scott B
authors: SB
authors: Reeder
mesh_terms: D000273:Adipose Tissue / Q000473:pathology*; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001834:Body Water / Q000737:chemistry*; D005234:Fatty Liver / Q000473:pathology*; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted; D009682:Magnetic Resonance Spectroscopy / Q000379:methods*; D008297:Male; D008875:Middle Aged; D012044:Regression Analysis; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity