title: Noninvasive measurement of lower extremity muscle oxygen extraction fraction under cuff compression paradigm.
abstract: BACKGROUND
  To demonstrate the feasibility of using a susceptibility-based MRI technique with asymmetric spin-echo (ASE) sequence to assess the lower extremity muscle oxygen extraction fraction (OEF) alternations under cuff compression paradigm.
  
  
  METHODS
  Approved by the local institutional human study committee, nine healthy young volunteers participated in this study. All the ASE scans were conducted using a 3 Tesla clinical MRI scanner during resting state (pre), 1-3 min (post1) and 3-5 min (post2) after a pressure of 50 mmHg above individual systolic blood pressure imposed on the thigh. Moreover, near-infrared spectroscopy (NIRS) measurements were performed on the same day under the same cuff compression protocol to verify the accuracy of this susceptibility-based method.
  
  
  RESULTS
  In all volunteers, the mean MRI based OEF in gastrocnemius (GAS) muscle increased significantly from 0.28 ± 0.02 (pre) to 0.31 ± 0.03 (post1, P < 0.05) and 0.31 ± 0.03 (post2, P < 0.05). In addition, mean OEF in soleus (SOL) muscle went up from 0.31 ± 0.01 (pre) to 0.33 ± 0.03 (post1, P = 0.14) and 0.37 ± 0.04 (post2, P < 0.05). For comparison, NIRS measured 1-%HbO2 (percentage of deoxyhemoglobin concentration within total hemoglobin) in GAS rose significantly from 0.29 ± 0.03 (pre) to 0.31 ± 0.04 (post1, P < 0.05) and 0.31 ± 0.04 (post2, P < 0.05), which confirmed the accuracy of the MRI-based OEF.
  
  
  CONCLUSIONS
  This susceptibility-based OEF quantification technique together with cuff compression paradigm could provide a noninvasive, quantifiable and effective tool for measuring skeletal muscle oxygenation.
authors.affiliation: Academy for Advanced Interdisciplinary Studies, Peking University, Beijing, China.
authors.forename: Chengyan
authors.initials: C
authors.lastname: Wang
authors.affiliation: College of Engineering, Peking University, Beijing, China.
authors.forename: Rui
authors.initials: R
authors.lastname: Zhang
authors.affiliation: Department of Radiology, Peking University First Hospital, Beijing, China.
authors.forename: Xiaodong
authors.initials: X
authors.lastname: Zhang
authors.affiliation: Philips Health Tech, China.
authors.forename: He
authors.initials: H
authors.lastname: Wang
authors.affiliation: Department of Radiology, Peking University First Hospital, Beijing, China.
authors.forename: Kai
authors.initials: K
authors.lastname: Zhao
authors.affiliation: Philips Health Tech, China.
authors.forename: Lixin
authors.initials: L
authors.lastname: Jin
authors.affiliation: Academy for Advanced Interdisciplinary Studies, Peking University, Beijing, China.|College of Engineering, Peking University, Beijing, China.
authors.forename: Jue
authors.initials: J
authors.lastname: Zhang
authors.affiliation: Academy for Advanced Interdisciplinary Studies, Peking University, Beijing, China.|Department of Radiology, Peking University First Hospital, Beijing, China.
authors.forename: Xiaoying
authors.initials: X
authors.lastname: Wang
authors.affiliation: Academy for Advanced Interdisciplinary Studies, Peking University, Beijing, China.|College of Engineering, Peking University, Beijing, China.
authors.forename: Jing
authors.initials: J
authors.lastname: Fang
mesh_terms: D000328:Adult; D044962:Data Compression; D064368:Healthy Volunteers; D006801:Humans; D035002:Lower Extremity / Q000473:pathology*; D008279:Magnetic Resonance Imaging; D008297:Male; D018482:Muscle, Skeletal / Q000473:pathology; D010100:Oxygen / Q000737:chemistry*; D010101:Oxygen Consumption / Q000502:physiology; D015203:Reproducibility of Results; D019265:Spectroscopy, Near-Infrared; D055815:Young Adult
chemical_list: D010100:Oxygen
keywords: cuff compression; near-infrared spectroscopy; oxygen extraction fraction; skeletal muscle; susceptibility