title: Cerebral blood flow measured by arterial-spin labeling MRI: a useful biomarker for characterization of minimal hepatic encephalopathy in patients with cirrhosis.
abstract: OBJECTIVE
  To investigate the role of arterial-spin labeling (ASL) MRI to non-invasively characterize the patterns of cerebral blood flow (CBF) changes in cirrhotic patients and to assess the potential of ASL MRI to characterize minimal hepatic encephalopathy (MHE).
  
  
  METHODS
  This study was approved by the local ethics committee, and written informed consent was obtained from all participants. Thirty six cirrhosis patients without overt hepatic encephalopathy (16 MHE patients and 20 non hepatic encephalopathy (non-HE) patients) and 25 controls underwent ASL MRI, and CBF was measured for each subject. One-way ANOCOVA test with age and gender as covariences was used to compare CBF difference among three groups, and post hoc analysis was performed between each two groups. Region-based correlation analysis was applied between Child-Pugh score, venous blood ammonia level, neuropsychological tests and CBF values in cirrhosis patients. Receiver operator characteristic (ROC) analysis was used for assessing CBF measurements in ASL MRI to differentiate MHE from non-HE patients.
  
  
  RESULTS
  The gray matter CBF of MHE patients (71.09 ± 11.88 mL min(-1)100g(-1)) was significantly higher than that of non-HE patients (55.28 ± 12.30 mL min(-1)100g(-1), P<0.01) and controls (52.09 ± 9.27 mL min(-1)100g(-1), P<0.001). Voxel-wise ANOCOVA results showed that CBFs were significantly different among three groups in multiple gray matter areas (P<0.05, Bonferroni corrected). Post hoc comparisons showed that CBF of these brain regions was increased in MHE patients compared with controls and non-HE patients (P<0.05, Bonferroni corrected). CBF of the right putamen was of the highest sensitivity (93.8%) and moderate specificity (75.0%) for characterization of MHE when using the cutoff value of 50.57 mL min(-1)100g(-1). CBFs in the bilateral median cingulate gyri, left supramarginal gyrus, right angular gyrus, right heschl gyrus and right superior temporal gyrus have both sensitivity and specificity of approximately 80% for the diagnosis of MHE.
  
  
  CONCLUSIONS
  Higher CBF was found in many brain regions in cirrhotic patients than controls and gradually increased with the progress of disease. CBF measured with ASL MRI can be a useful marker for differentiating MHE from non-HE patients.
authors.affiliation: Department of Medical Imaging, Jinling Hospital, Clinical School of Medical College, Nanjing University, Nanjing, Jiangsu, 210002, China; College of Civil Aviation, Nanjing University of Aeronautics and Astronautics, Nanjing, Jiangsu, 210016, China.
authors.forename: Gang
authors.initials: G
authors.lastname: Zheng
authors.forename: Long Jiang
authors.initials: LJ
authors.lastname: Zhang
authors.forename: Jianhui
authors.initials: J
authors.lastname: Zhong
authors.forename: Ze
authors.initials: Z
authors.lastname: Wang
authors.forename: Rongfeng
authors.initials: R
authors.lastname: Qi
authors.forename: Donghong
authors.initials: D
authors.lastname: Shi
authors.forename: Guang Ming
authors.initials: GM
authors.lastname: Lu
mesh_terms: D015415:Biomarkers; D001783:Blood Flow Velocity; D002536:Cerebral Arteries / Q000473:pathology / Q000503:physiopathology; D002560:Cerebrovascular Circulation; D005260:Female; D006501:Hepatic Encephalopathy / Q000473:pathology* / Q000503:physiopathology*; D006801:Humans; D008103:Liver Cirrhosis / Q000150:complications / Q000473:pathology* / Q000503:physiopathology*; D018810:Magnetic Resonance Angiography / Q000379:methods*; D008297:Male; D008875:Middle Aged; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013113:Spin Labels
chemical_list: D015415:Biomarkers; D013113:Spin Labels
keywords: ASL; Arterial-spin labeling; CBF; Cerebral blood flow; Cirrhosis; DST; HE; Hepatic encephalopathy; MCC; MHE; NCT-A; OHE; PET; ROC; SPECT; TIPS; arterial spin labeling; cerebral blood flow; digit symbol test; hepatic encephalopathy; median cingulate cortex; minimal hepatic encephalopathy; non hepatic encephalopathy; non-HE; number-connection test type A; overt hepatic encephalopathy; positron emission tomography; receiver operator characteristic; single photon emission computed tomography; transjugular intrahepatic portosystemic shunt.