title: Evaluation of transplanted kidneys using blood oxygenation level-dependent MRI at 3 T: a preliminary study.
abstract: OBJECTIVE
  The objective of our study was to investigate the feasibility and reproducibility of blood oxygenation level-dependent (BOLD) MRI using different gradient echoes at 3 T in patients with renal allografts and healthy volunteers and to evaluate whether BOLD MRI can be used to distinguish between cases of acute allograft rejection and normally functioning allografts.
  
  
  METHODS
  BOLD MRI at 3 T was performed of eight patients with normal allografts, four patients with acute allograft rejection, and 10 healthy volunteers. Multiple fast-field echo sequences were performed at gradient echoes of 8, 16, and 20 to obtain T2(*)-weighted images. The reproducibility of BOLD MRI was evaluated in patients with normal allografts.
  
  
  RESULTS
  Cortical and medullary R2(*) values were not significantly different between healthy volunteers and patients with normal allografts, but medullary R2(*) values were significantly greater than cortical R2(*) values in both groups for all three protocols (p < 0.01). Medullary R2(*) values were significantly lower in cases of acute allograft rejection than in normal allografts for all three protocols (p < 0.001). The mean difference in cortical or medullary R2(*) values was 3.8% or less in all protocols.
  
  
  CONCLUSIONS
  BOLD MRI performed using different gradient echoes at 3 T is feasible and reproducible in patients with renal allografts and can show significant changes in medullary oxygenation in patients with acute rejection.
authors.affiliation: Department of Radiology and Center for Imaging Science, Samsung Medical Center, Sungkyunkwan University School of Medicine, Kangnam-gu, Seoul, Republic of Korea.
authors.forename: Sung Yoon
authors.initials: SY
authors.lastname: Park
authors.forename: Chan Kyo
authors.initials: CK
authors.lastname: Kim
authors.forename: Byung Kwan
authors.initials: BK
authors.lastname: Park
authors.forename: Wooseong
authors.initials: W
authors.lastname: Huh
authors.forename: Sung Ju
authors.initials: SJ
authors.lastname: Kim
authors.forename: Bohyun
authors.initials: B
authors.lastname: Kim
mesh_terms: D000328:Adult; D000368:Aged; D000704:Analysis of Variance; D005240:Feasibility Studies; D005260:Female; D006084:Graft Rejection / Q000175:diagnosis* / Q000000981:diagnostic imaging; D006801:Humans; D016030:Kidney Transplantation; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D011183:Postoperative Complications / Q000175:diagnosis* / Q000000981:diagnostic imaging; D011446:Prospective Studies; D015203:Reproducibility of Results; D018709:Statistics, Nonparametric; D014184:Transplantation, Homologous; D014463:Ultrasonography