title: Renal plasma flow (RPF) measured with multiple-inversion-time arterial spin labeling (ASL) and tracer kinetic analysis: Validation against a dynamic contrast-enhancement method.
abstract: To propose and validate a method for accurately quantifying renal plasma flow (RPF) with arterial spin labeling (ASL).
  
  
  
  The proposed method employs a tracer-kinetic approach and derives perfusion from the slope of the ASL difference signal sampled at multiple inversion-times (TIs). To validate the method's accuracy, we performed a HIPAA-compliant and IRB-approved study with 15 subjects (9 male, 6 female; age range 24-73) to compare RPF estimates obtained from ASL to those from a more established dynamic contrast-enhanced (DCE) MRI method. We also investigated the impact of TI-sampling density on the accuracy of estimated RPF.
  
  
  
  Good agreement was found between ASL- and DCE-measured RPF, with a mean difference of 9±30ml/min and a correlation coefficient R=0.92 when ASL signals were acquired at 16 TIs and a mean difference of 9±57ml/min and R=0.81 when ASL signals were acquired at 5 TIs. RPF estimated from ASL signals acquired at only 2 TIs (400 and 1200ms) showed a low correlation with DCE-measured values (R=0.30).
  
  
  
  The proposed ASL method is capable of measuring RPF with an accuracy that is comparable to DCE MRI. At least 5 TIs are recommended for the ASL acquisition to ensure reliability of RPF measurements.
authors.affiliation: Department of Radiology and Imaging Sciences, University of Utah, 729 Arapeen Drive, Salt Lake City, UT 84108, USA; Department of Bioengineering, University of Utah, 36 S Wasatch Drive, Rm 3100, Salt Lake City, UT 84112, USA. Electronic address: christopher.conlin@utah.edu.
authors.forename: Christopher C
authors.initials: CC
authors.lastname: Conlin
authors.affiliation: Siemens Medical Solutions, Inc., 660 First Avenue, 4th Floor, New York, NY 10016, USA. Electronic address: niels.oesingmann@siemens.com.
authors.forename: Niels
authors.initials: N
authors.lastname: Oesingmann
authors.affiliation: Siemens Medical Solutions, Inc., 729 Arapeen Drive, Salt Lake City, UT 84108, USA. Electronic address: bradley.bolster@siemens.com.
authors.forename: Bradley
authors.initials: B
authors.lastname: Bolster
authors.affiliation: Division of Nephrology, Department of Internal Medicine, University of Utah, 30 N 1900 E, Rm 4R312, Salt Lake City, UT 84132, USA. Electronic address: yufeng.huang@hsc.utah.edu.
authors.forename: Yufeng
authors.initials: Y
authors.lastname: Huang
authors.affiliation: Department of Radiology and Imaging Sciences, University of Utah, 729 Arapeen Drive, Salt Lake City, UT 84108, USA. Electronic address: vivian.lee@hsc.utah.edu.
authors.forename: Vivian S
authors.initials: VS
authors.lastname: Lee
authors.affiliation: Department of Radiology and Imaging Sciences, University of Utah, 729 Arapeen Drive, Salt Lake City, UT 84108, USA; Department of Bioengineering, University of Utah, 36 S Wasatch Drive, Rm 3100, Salt Lake City, UT 84112, USA. Electronic address: lei.zhang@hsc.utah.edu.
authors.forename: Jeff L
authors.initials: JL
authors.lastname: Zhang
mesh_terms: D000328:Adult; D000368:Aged; D001158:Arteries; D003287:Contrast Media; D005260:Female; D005682:Gadolinium / Q000494:pharmacology; D006801:Humans; D007091:Image Processing, Computer-Assisted; D007700:Kinetics; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D010477:Perfusion; D017595:Renal Plasma Flow; D015203:Reproducibility of Results; D013113:Spin Labels
chemical_list: D003287:Contrast Media; D013113:Spin Labels; D005682:Gadolinium
keywords: Arterial spin labeling; Renal perfusion; Tracer kinetic analysis