title: Evaluation of Renal Oxygenation Level Changes after Water Loading Using Susceptibility-Weighted Imaging and T2* Mapping.
abstract: OBJECTIVE
  To assess the feasibility of susceptibility-weighted imaging (SWI) while monitoring changes in renal oxygenation level after water loading.
  
  
  METHODS
  Thirty-two volunteers (age, 28.0 ± 2.2 years) were enrolled in this study. SWI and multi-echo gradient echo sequence-based T2(*) mapping were used to cover the kidney before and after water loading. Cortical and medullary parameters were measured using small regions of interest, and their relative changes due to water loading were calculated based on baseline and post-water loading data. An intraclass correlation coefficient analysis was used to assess inter-observer reliability of each parameter. A receiver operating characteristic curve analysis was conducted to compare the performance of the two methods for detecting renal oxygenation changes due to water loading.
  
  
  RESULTS
  Both medullary phase and medullary T2(*) values increased after water loading (p < 0.001), although poor correlations were found between the phase changes and the T2(*) changes (p > 0.05). Interobserver reliability was excellent for the T2(*) values, good for SWI cortical phase values, and moderate for the SWI medullary phase values. The area under receiver operating characteristic curve of the SWI medullary phase values was 0.85 and was not different from the medullary T2(*) value (0.84).
  
  
  CONCLUSIONS
  Susceptibility-weighted imaging enabled monitoring changes in the oxygenation level in the medulla after water loading, and may allow comparable feasibility to detect renal oxygenation level changes due to water loading compared with that of T2(*) mapping.
authors.affiliation: Department of Radiology, Third Affiliated Hospital of Suzhou University, Changzhou, Jiangsu 213003, China.
authors.forename: Jiule
authors.initials: J
authors.lastname: Ding
authors.affiliation: Department of Radiology, Third Affiliated Hospital of Suzhou University, Changzhou, Jiangsu 213003, China.
authors.forename: Wei
authors.initials: W
authors.lastname: Xing
authors.affiliation: Shanghai Key Laboratory of Magnetic Resonance Imaging, East China Normal University, Shanghai 200241, China.
authors.forename: Dongmei
authors.initials: D
authors.lastname: Wu
authors.affiliation: Department of Radiology, Third Affiliated Hospital of Suzhou University, Changzhou, Jiangsu 213003, China.
authors.forename: Jie
authors.initials: J
authors.lastname: Chen
authors.affiliation: Department of Radiology, Third Affiliated Hospital of Suzhou University, Changzhou, Jiangsu 213003, China.
authors.forename: Liang
authors.initials: L
authors.lastname: Pan
authors.affiliation: Department of Radiology, Third Affiliated Hospital of Suzhou University, Changzhou, Jiangsu 213003, China.
authors.forename: Jun
authors.initials: J
authors.lastname: Sun
authors.affiliation: Department of Radiology, Third Affiliated Hospital of Suzhou University, Changzhou, Jiangsu 213003, China.
authors.forename: Shijun
authors.initials: S
authors.lastname: Xing
authors.affiliation: Philips Healthcare, Shanghai 200000, China.
authors.forename: Yongming
authors.initials: Y
authors.lastname: Dai
mesh_terms: D000328:Adult; D005260:Female; D006801:Humans; D007668:Kidney / Q000378:metabolism*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D010100:Oxygen / Q000097:blood / Q000378:metabolism*; D012372:ROC Curve; D015203:Reproducibility of Results; D014867:Water / Q000008:administration & dosage*; D055815:Young Adult
chemical_list: D014867:Water; D010100:Oxygen
keywords: Blood oxygen level dependent; Magnetic resonance imaging; Phase; Renal oxygenation level; Susceptibility-weighted imaging; T2*