title: Arterial spin labeling MRI for assessment of perfusion in native and transplanted kidneys.
abstract: OBJECTIVE
  To apply a magnetic resonance arterial spin labeling (ASL) technique to evaluate kidney perfusion in native and transplanted kidneys.
  
  
  METHODS
  This study was compliant with the Health Insurance Portability and Accountability Act and approved by the institutional review board. Informed consent was obtained from all subjects. Renal perfusion exams were performed at 1.5 T in a total of 25 subjects: 10 with native and 15 with transplanted kidneys. A flow-sensitive alternating inversion recovery (FAIR) ASL sequence was performed with respiratory triggering in all subjects and under free-breathing conditions in five transplant subjects. Thirty-two control/tag pairs were acquired and processed using a single-compartment model. Perfusion in native and transplanted kidneys was compared above and below an estimated glomerular filtration rate (eGFR) threshold of 60 ml/min per 1.73 m² and correlations with eGFR were determined.
  
  
  RESULTS
  In many of the transplanted kidneys, major feeding vessels in the coronal plane required a slice orientation sagittal to the kidney. Renal motion during the examination was observed in native and transplant subjects and was corrected with registration. Cortical perfusion correlated with eGFR in native (r=0.85, P=.002) and transplant subjects (r=0.61, P=.02). For subjects with eGFR >60 ml/min per 1.73 m², native kidneys demonstrated greater cortical (P=.01) and medullary (P=.04) perfusion than transplanted kidneys. For subjects with eGFR <60 ml/min per 1.73 m², native kidneys demonstrated greater medullary perfusion (P=.04) compared to transplanted kidneys. Free-breathing acquisitions provided renal perfusion measurements that were slightly lower compared to the coached/triggered technique, although no statistical differences were observed.
  
  
  CONCLUSIONS
  In conclusion, FAIR-ASL was able to measure renal perfusion in subjects with native and transplanted kidneys, potentially providing a clinically viable technique for monitoring kidney function.
authors.affiliation: Department of Medical Physics, University of Wisconsin-Madison, Wisconsin Institute for Medical Research, Madison, WI 53705-2275, USA.
authors.forename: Nathan S
authors.initials: NS
authors.lastname: Artz
authors.forename: Elizabeth A
authors.initials: EA
authors.lastname: Sadowski
authors.forename: Andrew L
authors.initials: AL
authors.lastname: Wentland
authors.forename: Thomas M
authors.initials: TM
authors.lastname: Grist
authors.forename: Songwon
authors.initials: S
authors.lastname: Seo
authors.forename: Arjang
authors.initials: A
authors.lastname: Djamali
authors.forename: Sean B
authors.initials: SB
authors.lastname: Fain
mesh_terms: D000328:Adult; D000368:Aged; D005260:Female; D006801:Humans; D007677:Kidney Function Tests / Q000379:methods*; D016030:Kidney Transplantation / Q000473:pathology*; D018810:Magnetic Resonance Angiography / Q000379:methods*; D008297:Male; D008875:Middle Aged; D012077:Renal Artery / Q000473:pathology*; D012079:Renal Circulation; D013113:Spin Labels
chemical_list: D013113:Spin Labels