title: Diffusion tensor imaging and tractography for assessment of renal allograft dysfunction-initial results.
abstract: OBJECTIVE
  To evaluate MR diffusion tensor imaging (DTI) as non-invasive diagnostic tool for detection of acute and chronic allograft dysfunction and changes of organ microstructure.
  
  
  METHODS
  15 kidney transplanted patients with allograft dysfunction and 14 healthy volunteers were examined using a fat-saturated echo-planar DTI-sequence at 1.5 T (6 diffusion directions, b = 0, 600 s/mm²). Mean apparent diffusion coefficient (ADC) and mean fractional anisotropy (FA) were calculated separately for the cortex and for the medulla and compared between healthy and transplanted kidneys. Furthermore, the correlation between diffusion parameters and estimated GFR was determined.
  
  
  RESULTS
  The ADC in the cortex and in the medulla were lower in transplanted than in healthy kidneys (p < 0.01). Differences were more distinct for FA, especially in the renal medulla, with a significant reduction in allografts (p < 0.001). Furthermore, in transplanted patients a correlation between mean FA in the medulla and estimated GFR was observed (r = 0.72, p < 0.01). Tractography visualized changes in renal microstructure in patients with impaired allograft function.
  
  
  CONCLUSIONS
  Changes in allograft function and microstructure can be detected and quantified using DTI. However, to prove the value of DTI for standard clinical application especially correlation of imaging findings and biopsy results is necessary.
authors.affiliation: Hannover Medical School-Germany, Institute for Diagnostic and Interventional Radiology, Carl-Neuberg-Str. 1, 30625 Hannover, Germany. hueper.katja@mh-hannover.de
authors.forename: Katja
authors.initials: K
authors.lastname: Hueper
authors.forename: M
authors.initials: M
authors.lastname: Gutberlet
authors.forename: T
authors.initials: T
authors.lastname: Rodt
authors.forename: W
authors.initials: W
authors.lastname: Gwinner
authors.forename: F
authors.initials: F
authors.lastname: Lehner
authors.forename: F
authors.initials: F
authors.lastname: Wacker
authors.forename: M
authors.initials: M
authors.lastname: Galanski
authors.forename: D
authors.initials: D
authors.lastname: Hartung
mesh_terms: D000328:Adult; D000368:Aged; D016880:Anisotropy; D001706:Biopsy; D002648:Child; D003952:Diagnostic Imaging / Q000379:methods; D056324:Diffusion Tensor Imaging / Q000379:methods*; D005260:Female; D005919:Glomerular Filtration Rate; D006801:Humans; D007091:Image Processing, Computer-Assisted; D007668:Kidney / Q000473:pathology; D016030:Kidney Transplantation / Q000379:methods*; D008297:Male; D008875:Middle Aged; D014184:Transplantation, Homologous / Q000379:methods*