title: Quantitative evaluation of liver function with T1 relaxation time index on Gd-EOB-DTPA-enhanced MRI: comparison with signal intensity-based indices.
abstract: OBJECTIVE
  To evaluate whether the reduction rate of T1 relaxation time of the liver (T1 relaxation time index) before and 20 minutes after gadolinium-ethoxybenzyl-diethylenetriaminepentaacetic acid (Gd-EOB-DTPA) injection has the potential to serve as an magnetic resonance imaging (MRI)-based liver function test in comparison with signal intensity-based indices.
  
  
  METHODS
  Ninety-nine patients with suspected liver lesions underwent Gd-EOB-DTPA-enhanced MRI. T1 maps using 3D T1-weighted gradient-echo volumetric interpolated examination with two different flip angles were also performed before and 20 minutes after Gd-EOB-DTPA administration. T1 relaxation time index was compared with four signal intensity-based indices in terms of the ability to discriminate Child-Pugh A (CPA) and Child-Pugh B (CPB) from normal liver function (NLF), and in terms of its correlation with indocyanine green (ICG) clearance.
  
  
  RESULTS
  Twenty-four patients were classified as NLF, 64 patients were classified as CPA, and 11 were classified as CPB group. The T1 relaxation time index was significantly lower for CPA (0.62 ± 0.08 vs. 0.68 ± 0.07, P = 0.021) and CPB (0.55 ± 0.15 vs. 0.68 ± 0.07, P < 0.001) than for NLF. All signal intensity-based indices showed significant differences only when comparing NLF and CPB. The correlation coefficient with ICG clearance was the highest for T1 relaxation time index (r = -0.605, P < 0.001).
  
  
  CONCLUSIONS
  The T1 relaxation time index has the potential to serve as an MRI-based liver function test, and is most strongly correlated with ICG clearance among the Gd-EOB-DTPA MRI-based indices investigated.
authors.affiliation: Department of Radiology, Kagoshima University Graduate School of Medical and Dental Sciences, Kagoshima, Japan.
authors.forename: Kiyohisa
authors.initials: K
authors.lastname: Kamimura
authors.forename: Yoshihiko
authors.initials: Y
authors.lastname: Fukukura
authors.forename: Tomohide
authors.initials: T
authors.lastname: Yoneyama
authors.forename: Koji
authors.initials: K
authors.lastname: Takumi
authors.forename: Akihiro
authors.initials: A
authors.lastname: Tateyama
authors.forename: Aya
authors.initials: A
authors.lastname: Umanodan
authors.forename: Toshikazu
authors.initials: T
authors.lastname: Shindo
authors.forename: Yuichi
authors.initials: Y
authors.lastname: Kumagae
authors.forename: Shin-ichi
authors.initials: S
authors.lastname: Ueno
authors.forename: Chihaya
authors.initials: C
authors.lastname: Koriyama
authors.forename: Masayuki
authors.initials: M
authors.lastname: Nakajo
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000465:Algorithms; D003198:Computer Simulation; D003287:Contrast Media / Q000493:pharmacokinetics; D005260:Female; D019786:Gadolinium DTPA / Q000493:pharmacokinetics*; D006801:Humans; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D008111:Liver Function Tests / Q000379:methods*; D008113:Liver Neoplasms / Q000175:diagnosis* / Q000378:metabolism*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D008954:Models, Biological; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D055815:Young Adult
chemical_list: D003287:Contrast Media; C073590:gadolinium ethoxybenzyl DTPA; D019786:Gadolinium DTPA
keywords: Gd-EOB-DTPA; T1 relaxation time; indocyanine green; liver failure; liver function tests; magnetic resonance imaging