title: Quantification of liver perfusion using multidelay pseudocontinuous arterial spin labeling.
abstract: OBJECTIVE
  To develop a free-breathing multidelay pseudocontinuous arterial spin labeling (pCASL) technique for quantitative measurement of liver perfusion of the hepatic artery and portal vein, respectively.
  
  
  METHODS
  A navigator-gated pCASL sequence with balanced steady-state free precession (bSSFP) readout was developed and applied on five healthy young volunteers at 3T. Two labeling schemes were performed with the labeling plane applied on the descending aorta above the liver, and perpendicular to the portal vein before its entry to liver to label the hepatic artery and portal vein, respectively. For each labeling scheme, pCASL scans were performed at five or six postlabeling delays between 200 and 2000 msec or 2500 msec with an interval of 400 or 500 msec. Multidelay pCASL images were processed offline with nonrigid motion correction, outlier removal, and fitted for estimation of liver perfusion and transit time.
  
  
  RESULTS
  Estimated liver perfusion of the hepatic artery and hepatic portal vein were 21.8 ± 1.9 and 95.1 ± 8.9 mL/100g/min, with the corresponding transit time of 1227.3 ± 355.5 and 667.2 ± 85.0 msec, respectively. The estimated liver perfusion and transit time without motion correction were less reliable with greater residual variance compared to those processed with motion correction (P < 0.05).
  
  
  CONCLUSIONS
  The liver perfusion measurement using multidelay pCASL showed good correspondence with values noted in the literature. The capability to noninvasively and selectively label the hepatic artery and portal vein is a unique strength of pCASL as compared to other liver perfusion imaging techniques, such as computed tomography perfusion and dynamic contrast-enhanced MRI.
authors.affiliation: Department of Biomedical Engineering, Tsinghua University, Beijing, China.
authors.forename: Xinlei
authors.initials: X
authors.lastname: Pan
authors.affiliation: Siemens Healthcare, MR Collaboration NE Asia, Beijing, China.
authors.forename: Tianyi
authors.initials: T
authors.lastname: Qian
authors.affiliation: Neuroimaging Laboratory, Division of Neuroscience, Center for Applied Medical Research, University of Navarra, Spain.
authors.forename: Maria A
authors.initials: MA
authors.lastname: Fernandez-Seara
authors.affiliation: Laboratory of Functional MRI Technology (LOFT), Department of Neurology, University of California Los Angeles, Los Angeles, California, USA.
authors.forename: Robert X
authors.initials: RX
authors.lastname: Smith
authors.affiliation: Department of Radiology, Xuanwu Hospital of Capital Medical University, Beijing, China.
authors.forename: Kuncheng
authors.initials: K
authors.lastname: Li
authors.affiliation: Department of Engineering Physics, Tsinghua University, Beijing, China.
authors.forename: Kui
authors.initials: K
authors.lastname: Ying
authors.affiliation: Department of Radiology, University of California Los Angeles, Los Angeles, California, USA.
authors.forename: Kyunghyun
authors.initials: K
authors.lastname: Sung
authors.affiliation: Laboratory of Functional MRI Technology (LOFT), Department of Neurology, University of California Los Angeles, Los Angeles, California, USA.|Department of Radiology, University of California Los Angeles, Los Angeles, California, USA.
authors.forename: Danny J J
authors.initials: DJ
authors.lastname: Wang
mesh_terms: D000328:Adult; D001158:Arteries / Q000000981:diagnostic imaging*; D003287:Contrast Media / Q000737:chemistry; D005260:Female; D064368:Healthy Volunteers; D006499:Hepatic Artery / Q000000981:diagnostic imaging*; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods; D008099:Liver / Q000098:blood supply / Q000000981:diagnostic imaging*; D008279:Magnetic Resonance Imaging; D008297:Male; D015233:Models, Statistical; D009038:Motion; D010477:Perfusion; D011169:Portal Vein / Q000000981:diagnostic imaging*; D013113:Spin Labels; D055815:Young Adult
chemical_list: D003287:Contrast Media; D013113:Spin Labels
keywords: hepatic artery; liver perfusion; multidelay; nonrigid motion correction; portal vein; pseudocontinuous arterial spin labeling (pCASL)