title: Magnetic resonance elastography of liver: influence of intravenous gadolinium administration on measured liver stiffness.
abstract: OBJECTIVE
  To evaluate the effect of intravenous gadolinium-diethylenetriamine penta-acetic acid (Gd-DTPA) on estimation of liver stiffness using magnetic resonance elastography (MRE) for detection of liver fibrosis.
  
  
  METHODS
  Liver MRI with MRE was performed in 210 subjects on a single 1.5 Tesla clinical MRI scanner. Liver MRE was performed before intravenous Gd-DTPA injection (NC-MRE) and 5 minutes post injection (PC-MRE) using a modified phase-contrast gradient-echo sequence (TR/TE=100/27 ms, FOV = 30-46 cm, 4 x 10 mm slices, gap 5 mm) which automatically generated stiffness maps. Two readers' blinded to clinical details independently performed liver stiffness measurements (LSM) by drawing 2 or more regions of interest (ROI) on the stiffness maps on each of the four slices of NC-MRE and PC-MRE obtained for each patient. The mean LSM in kilopascals (kPa) for NC-MRE and PC-MRE was calculated. The correlation between NC-MRE and PC-MRE LSM was evaluated with a paired t test and Pearson's correlation analysis, and the inter-observer correlation was evaluated using intra class coefficient (ICC) analysis. A receiver operating curve analysis (ROC) was performed to compare accuracies for detection and staging of liver fibrosis in a subgroup of 72 subjects with histological confirmation of liver fibrosis.
  
  
  RESULTS
  There was an excellent correlation between NC-MRE and PC-MRE LSM (R(2)=0.98, p<0.001) with no significant differences. The interobserver agreement was also excellent (ICC, 0.94-0.99). There were no significant differences in the cut-off LSM value/accuracy/sensitivity/specificity for detection of significant liver fibrosis with NC-MRE and PC-MRE (2.98 kPa/98.5%/100%/88%, p<0.001 and 3.1 kPa/98.2%/98%/88%, p<0.001 respectively).
  
  
  CONCLUSIONS
  Intravenous Gd-DTPA had no significant influence on LSM with MRE and does not significantly affect the diagnostic performance of MRE for fibrosis detection.
authors.affiliation: Diagnostic Imaging, National University Health System, Singapore, Singapore.
authors.forename: James Thomas Patrick Decourcy
authors.initials: JT
authors.lastname: Hallinan
authors.forename: Hind Saif
authors.initials: HS
authors.lastname: Alsaif
authors.forename: Aileen
authors.initials: A
authors.lastname: Wee
authors.forename: Sudhakar Kundapur
authors.initials: SK
authors.lastname: Venkatesh
mesh_terms: D061605:Administration, Intravenous; D003287:Contrast Media / Q000008:administration & dosage*; D054459:Elasticity Imaging Techniques; D005260:Female; D019786:Gadolinium DTPA / Q000008:administration & dosage*; D006801:Humans; D007089:Image Enhancement / Q000379:methods*; D008099:Liver / Q000473:pathology; D008103:Liver Cirrhosis / Q000473:pathology*; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D015588:Observer Variation; D012372:ROC Curve; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity
chemical_list: D003287:Contrast Media; D019786:Gadolinium DTPA