title: Diffusion- and T₂-weighted MR imaging of the liver: effect of intravenous administration of gadoxetic acid disodium.
abstract: OBJECTIVE
  We evaluated the effect of intravenous administration of gadoxetic acid disodium to hepatic lesions and liver parenchyma on T₂-weighted (T₂WI) and diffusion-weighted imaging (DWI).
  
  
  METHODS
  One hundred and one consecutive patients with 259 hepatic lesions underwent T₂WI and DWI (b-values of 500 and 1000 s/mm²) before and after gadoxetic acid administration. We compared the ratio of signal intensity (SIR) of the liver parenchyma and hepatic lesions, the ratio of contrast intensity of the lesion to the liver (CIR), the apparent diffusion coefficients (ADCs) of the liver and lesions, and lesion detectability between pre- and post-contrast images.
  
  
  RESULTS
  SIRs, CIRs, and ADC of focal hepatic lesions were comparable on pre- and post-contrast images, and lesion detectability did not differ significantly between pre- and post-contrast T₂WI and DWI. The SIRs of the liver parenchyma were significantly lower on post-contrast DWI (1.4±0.68 [b=500 s/mm²] and 1.71±0.67 [b=1000 s/mm²]) than pre-contrast images (1.89±0.68 [b=500 s/mm²] and 2.26±0.78 [b=1000 s/mm²]) (P<0.001). ADCs of the liver parenchyma were also significantly decreased on post-contrast DWI (0.77±0.32 mm²/s) than pre-contrast images (0.64±0.33 mm²/s) (P=0.001).
  
  
  CONCLUSIONS
  T₂WI and DWI after administration of gadoxetic acid are feasible and do not compromise the SIR, CIR, and ADC of focal hepatic lesions. However, the signal intensity of DWI and ADC value of the liver parenchyma were decreased on gadoxetic acid-enhanced hepatocyte phase images.
authors.affiliation: Department of Radiology, University of Yamanashi, Yamanashi, Japan.
authors.forename: Ali
authors.initials: A
authors.lastname: Muhi
authors.forename: Tomoaki
authors.initials: T
authors.lastname: Ichikawa
authors.forename: Utaroh
authors.initials: U
authors.lastname: Motosugi
authors.forename: Hironobu
authors.initials: H
authors.lastname: Sou
authors.forename: Katsuhiro
authors.initials: K
authors.lastname: Sano
authors.forename: Tsutomu
authors.initials: T
authors.lastname: Araki
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D003287:Contrast Media / Q000008:administration & dosage; D005260:Female; D019786:Gadolinium DTPA / Q000008:administration & dosage*; D006801:Humans; D007089:Image Enhancement / Q000379:methods*; D007275:Injections, Intravenous; D008113:Liver Neoplasms / Q000473:pathology*; D008297:Male; D008875:Middle Aged; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity
chemical_list: D003287:Contrast Media; C073590:gadolinium ethoxybenzyl DTPA; D019786:Gadolinium DTPA