title: Diffusion kurtosis imaging of the human kidney: a feasibility study.
abstract: OBJECTIVE
  To assess the feasibility and to optimize imaging parameters of diffusion kurtosis imaging (DKI) in human kidneys.
  
  
  METHODS
  The kidneys of ten healthy volunteers were examined on a clinical 3T MR scanner. For DKI, respiratory triggered EPI sequences were acquired in the coronal plane (3 b-values: 0, 300, 600s/mm(2), 30 diffusion directions). A goodness of fit analysis was performed and the influence of the signal-to-noise ratio (SNR) on the DKI results was evaluated. Region-of-interest (ROI) measurements were performed to determine apparent diffusion coefficient (ADC), fractional anisotropy (FA) and mean kurtosis (MK) of the cortex and the medulla of the kidneys. Intra-observer and inter-observer reproducibility using Bland-Altman plots as well as subjective image quality of DKI were examined and ADC, FA, and MK parameters were compared.
  
  
  RESULTS
  The DKI model fitted better to the experimental data (r=0.99) with p<0.05 than the common mono-exponential ADC model (r=0.96). Calculation of reliable kurtosis parameters in human kidneys requires a minimum SNR of 8.31 on b=0s/mm(2) images. Corticomedullary differentiation was possible on FA and MK maps. ADC, FA and MK revealed significant differences in medulla (ADC=2.82 × 10(-3)mm(2)/s±0.25, FA=0.42±0. 05, MK=0.78±0.07) and cortex (ADC=3.60 × 10(-3)mm(2)/s±0.28, FA=0.18±0.04, MK=0.94±0.07) with p<0.001.
  
  
  CONCLUSIONS
  Our initial results indicate the feasibility of DKI in the human kidney presuming an adequate SNR. Future studies in patients with kidney diseases are required to determine the value of DKI for functional kidney imaging.
authors.affiliation: University Dusseldorf, Medical Faculty, Department of Diagnostic and Interventional Radiology, Moorenstrasse 5, D-40225 Düsseldorf, Germany.
authors.forename: Gael
authors.initials: G
authors.lastname: Pentang
authors.affiliation: University Dusseldorf, Medical Faculty, Department of Diagnostic and Interventional Radiology, Moorenstrasse 5, D-40225 Düsseldorf, Germany.
authors.forename: Rotem Shlomo
authors.initials: RS
authors.lastname: Lanzman
authors.affiliation: University Dusseldorf, Medical Faculty, Department of Diagnostic and Interventional Radiology, Moorenstrasse 5, D-40225 Düsseldorf, Germany. Electronic address: Philipp.Heusch@med.uni-duesseldorf.de.
authors.forename: Philpp
authors.initials: P
authors.lastname: Heusch
authors.affiliation: University Dusseldorf, Medical Faculty, Department of Diagnostic and Interventional Radiology, Moorenstrasse 5, D-40225 Düsseldorf, Germany.
authors.forename: Anja
authors.initials: A
authors.lastname: Müller-Lutz
authors.affiliation: University Dusseldorf, Medical Faculty, Department of Diagnostic and Interventional Radiology, Moorenstrasse 5, D-40225 Düsseldorf, Germany.
authors.forename: Dirk
authors.initials: D
authors.lastname: Blondin
authors.affiliation: University Dusseldorf, Medical Faculty, Department of Diagnostic and Interventional Radiology, Moorenstrasse 5, D-40225 Düsseldorf, Germany.
authors.forename: Gerald
authors.initials: G
authors.lastname: Antoch
authors.affiliation: University Dusseldorf, Medical Faculty, Department of Diagnostic and Interventional Radiology, Moorenstrasse 5, D-40225 Düsseldorf, Germany.
authors.forename: Hans-Jörg
authors.initials: HJ
authors.lastname: Wittsack
mesh_terms: D000328:Adult; D000465:Algorithms; D001834:Body Water / Q000378:metabolism*; D003198:Computer Simulation; D038524:Diffusion Magnetic Resonance Imaging / Q000379:methods*; D005240:Feasibility Studies; D005260:Female; D006801:Humans; D007089:Image Enhancement / Q000379:methods*; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D007668:Kidney / Q000033:anatomy & histology* / Q000378:metabolism*; D008297:Male; D008954:Models, Biological; D015588:Observer Variation; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity
keywords: Anisotropy; DKI; DTI; DWI; Diffusion; Kidney; Kurtosis