title: Diffusion tensor imaging of kidneys with respiratory triggering: optimization of parameters to demonstrate anisotropic structures on fraction anisotropy maps.
abstract: OBJECTIVE
  To demonstrate the feasibility of diffusion tensor imaging (DTI) of kidneys with respiratory triggering, and determine the optimal imaging parameters for fraction anisotropy (FA) maps.
  
  
  METHODS
  DTI of kidneys from 16 healthy volunteers was performed using a 1.5T scanner. Five different sequences with different parameters including respiration-triggered acquisition or multiple breath-holding, slice thicknesses of 3 or 5 mm, and different numbers of signal averaging and b values were compared. FA and apparent diffusion coefficients (ADCs) of the cortex and medulla were measured. Measurement error within the same and repeated examination was examined using within-individual standard deviation (Sw).
  
  
  RESULTS
  FAs of the renal cortex were lower than the medulla (mean value of a sequence ranging 0.148-0.224, 0.433-0.476) and the ADCs of the cortex were higher than the medulla (2.26-2.69x10(-3) mm2/s, 1.77-2.19x10(-3) mm2/s) in all sequences (P<0.001). The renal cortex-medulla difference was the largest, with respiratory trigger- ing including a 3-mm slice thickness, three signal averages,and a b-value=0, 200, or 400 s/mm2 (P<0.001). Sw tended to be smaller in the sequence with a b-value of 400 s/mm2.
  
  
  CONCLUSIONS
  DTI of kidneys with respiratory triggering is feasible with excellent cortex-medulla differentiation.
authors.affiliation: Department of Diagnostic Imaging and Nuclear Medicine, Graduate School of Medicine, Kyoto University, and Department of Radiology, Katsura Hospital, Kyoto, Japan. makok@kuhp.kyoto-u.ac.jp
authors.forename: Masako
authors.initials: M
authors.lastname: Kataoka
authors.forename: Aki
authors.initials: A
authors.lastname: Kido
authors.forename: Akira
authors.initials: A
authors.lastname: Yamamoto
authors.forename: Yuji
authors.initials: Y
authors.lastname: Nakamoto
authors.forename: Takashi
authors.initials: T
authors.lastname: Koyama
authors.forename: Hiroyoshi
authors.initials: H
authors.lastname: Isoda
authors.forename: Yoji
authors.initials: Y
authors.lastname: Maetani
authors.forename: Shigeaki
authors.initials: S
authors.lastname: Umeoka
authors.forename: Ken
authors.initials: K
authors.lastname: Tamai
authors.forename: Tsuneo
authors.initials: T
authors.lastname: Saga
authors.forename: Nobuko
authors.initials: N
authors.lastname: Morisawa
authors.forename: Susumu
authors.initials: S
authors.lastname: Mori
authors.forename: Kaori
authors.initials: K
authors.lastname: Togashi
mesh_terms: D000328:Adult; D016880:Anisotropy; D038524:Diffusion Magnetic Resonance Imaging / Q000379:methods*; D005240:Feasibility Studies; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods; D007668:Kidney / Q000033:anatomy & histology*; D007672:Kidney Cortex / Q000033:anatomy & histology; D007679:Kidney Medulla / Q000033:anatomy & histology; D008297:Male; D012016:Reference Values; D012119:Respiration; D055815:Young Adult