title: Noninvasive measurement of renal oxygen extraction fraction under the influence of respiratory challenge.
abstract: To demonstrate the feasibility of using a susceptibility-based magnetic resonance imaging (MRI) technique for measuring renal oxygen extraction fraction (OEF) changes under the influence of carbogen (97% O2 , 3% CO2 ) breathing.
  
  
  
  Eight New Zealand White rabbits were included in this study with local animal care committee approval. For OEF measurement, an asymmetric spin echo (ASE) sequence was used to acquire source images and a susceptibility model was utilized for OEF estimation at 3.0T. Within-session and between-day tests were conducted to evaluate the reproducibility of this OEF measurement. OEF changes were measured under respiratory challenge with alternated air and carbogen (97% O2 , 3% CO2 ) breathing. For comparison, blood samples were collected for the measurement of pO2 .
  
  
  
  The within-session coefficients of variation (CVs) of renal OEF measurements were 6.62% in cortex and 5.92% in medulla, while between-day CVs were 7.52% in cortex and 8.03% in medulla. Under carbogen breathing, renal OEFs decreased significantly from 0.32 ± 0.03 to 0.28 ± 0.02 (P < 0.01) in cortex, and from 0.34 ± 0.04 to 0.31 ± 0.03 (P < 0.01) in medulla. No statistical difference of relative OEF change was seen between cortex and medulla (P = 0.93). In addition, negative correlation between renal OEF and blood pO2 was found (r = 0.68 (P < 0.05) in cortex, and r = 0.64 (P < 0.05) in medulla).
  
  
  
  This study demonstrates the feasibility of using a susceptibility-based OEF measurement method for the evaluation of renal oxygenation changes induced by carbogen breathing. J. Magn. Reson. Imaging 2016;44:230-237.
authors.affiliation: Academy for Advanced Interdisciplinary Studies, Peking University, Beijing, PR China.
authors.forename: Chengyan
authors.initials: C
authors.lastname: Wang
authors.affiliation: College of Engineering, Peking University, Beijing, PR China.
authors.forename: Rui
authors.initials: R
authors.lastname: Zhang
authors.affiliation: Department of Radiology, Peking University First Hospital, Beijing, PR China.
authors.forename: Rui
authors.initials: R
authors.lastname: Wang
authors.affiliation: Philips Healthcare, Suzhou, Jiangsu, PR China.
authors.forename: Li
authors.initials: L
authors.lastname: Jiang
authors.affiliation: Department of Radiology, Peking University First Hospital, Beijing, PR China.
authors.forename: Xiaodong
authors.initials: X
authors.lastname: Zhang
authors.affiliation: Philips Healthcare, Suzhou, Jiangsu, PR China.
authors.forename: He
authors.initials: H
authors.lastname: Wang
authors.affiliation: Department of Radiology, Peking University First Hospital, Beijing, PR China.
authors.forename: Kai
authors.initials: K
authors.lastname: Zhao
authors.affiliation: Philips Healthcare, Suzhou, Jiangsu, PR China.
authors.forename: Lixin
authors.initials: L
authors.lastname: Jin
authors.affiliation: Academy for Advanced Interdisciplinary Studies, Peking University, Beijing, PR China.|College of Engineering, Peking University, Beijing, PR China.
authors.forename: Jue
authors.initials: J
authors.lastname: Zhang
authors.affiliation: Academy for Advanced Interdisciplinary Studies, Peking University, Beijing, PR China.|Department of Radiology, Peking University First Hospital, Beijing, PR China.
authors.forename: Xiaoying
authors.initials: X
authors.lastname: Wang
authors.affiliation: Academy for Advanced Interdisciplinary Studies, Peking University, Beijing, PR China.|College of Engineering, Peking University, Beijing, PR China.
authors.forename: Jing
authors.initials: J
authors.lastname: Fang
mesh_terms: D000280:Administration, Inhalation; D000818:Animals; D002245:Carbon Dioxide / Q000008:administration & dosage*; D005240:Feasibility Studies; D007090:Image Interpretation, Computer-Assisted / Q000379:methods; D007668:Kidney / Q000000981:diagnostic imaging* / Q000187:drug effects / Q000502:physiology*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D010092:Oximetry / Q000379:methods; D010100:Oxygen / Q000008:administration & dosage / Q000378:metabolism*; D010101:Oxygen Consumption / Q000187:drug effects / Q000502:physiology; D011659:Pulmonary Gas Exchange / Q000187:drug effects / Q000502:physiology*; D011817:Rabbits; D015203:Reproducibility of Results; D012129:Respiratory Function Tests / Q000379:methods*; D012680:Sensitivity and Specificity
chemical_list: D002245:Carbon Dioxide; C011700:carbogen; D010100:Oxygen
keywords: carbogen breathing; renal oxygen extraction; respiratory challenge; susceptibility