title: Quantitative evaluation of liver cirrhosis using T1 relaxation time with 3 tesla MRI before and after oxygen inhalation.
abstract: OBJECTIVE
  To quantify liver T1 relaxation times before and after oxygen inhalation in patients with and without liver cirrhosis using a 3 Tesla (T) MRI.
  
  
  METHODS
  Institutional Review Board approval and written informed consent were obtained. Ninety-two noncirrhotic patients and 87 patients with hepatitis B viral liver cirrhosis (72 Child-Pugh class A and 15 Child-Pugh class B or C) underwent MRI with a 3.0T system before and after the supply of 100% oxygen at a rate of 15 L/min by means of a nonrebreather ventilation mask for 3 min. T1 maps were acquired using three-dimensional spoiled gradient echo sequences with two different flip angles (2° and 14°) and a fixed TR/TE (2.54 ms/0.95 ms). Liver T1 values were obtained using a T1 processing tool (MapIT software). The mean baseline T1 values of three groups (control, Child-Pugh class A, and Child-Pugh class B/C) were compared using an analysis of variance test. Liver T1 value before and after oxygenation was compared using a paired t-test for each group.
  
  
  RESULTS
  The baseline liver T1 value was significantly higher in the control group (941 ± 136 ms) than in Child-Pugh A (858 ± 143 ms) and Child-Pugh B/C (783 ± 164 ms) group (P < 0.001 and P < 0.0001). The reduction in the liver T1 value after oxygen inhalation was significant in the control group (P = 0.012) but not significant in Child-Pugh class A (P = 0.079) and Child-Pugh class B/C (P = 0.752).
  
  
  CONCLUSIONS
  The baseline liver T1 relaxation time was significantly different between the patients with and without liver cirrhosis. The shortening effect of oxygen on the liver T1 value was significant in the control group but not in the cirrhotic patients.
authors.affiliation: Department of Diagnostic Radiology, Research Institute of Radiological Science, Yonsei University College of Medicine, Seoul, Korea.
authors.forename: Kyung Ah
authors.initials: KA
authors.lastname: Kim
authors.forename: Mi-Suk
authors.initials: MS
authors.lastname: Park
authors.forename: In-Seong
authors.initials: IS
authors.lastname: Kim
authors.forename: Berthold
authors.initials: B
authors.lastname: Kiefer
authors.forename: Woo-Suk
authors.initials: WS
authors.lastname: Chung
authors.forename: Myeong-Jin
authors.initials: MJ
authors.lastname: Kim
authors.forename: Ki Whang
authors.initials: KW
authors.lastname: Kim
mesh_terms: D000280:Administration, Inhalation; D000328:Adult; D000368:Aged; D003287:Contrast Media / Q000008:administration & dosage; D005260:Female; D006801:Humans; D008099:Liver / Q000187:drug effects / Q000503:physiopathology*; D008103:Liver Cirrhosis / Q000473:pathology* / Q000503:physiopathology*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D010100:Oxygen / Q000008:administration & dosage*
chemical_list: D003287:Contrast Media; D010100:Oxygen