title: Diffusion tensor MRI of the kidney at 3.0 and 1.5 Tesla.
abstract: BACKGROUND
  Diffusion tensor imaging (DTI) at 3 T provides information on the microstructure and pathophysiology of tissues that is not available from conventional imaging with an advantage of high signal to noise ratio (SNR).
  
  
  OBJECTIVE
  To evaluate the feasibility of DTI of the normal kidney at 3.0 T compared to results obtained at 1.5 T.
  
  
  METHODS
  DTI of the normal kidney of 15 healthy volunteers obtained with 3.0 and 1.5 T scanners using respiration-triggered acquisition was examined. Fractional anisotropy (FA) and apparent diffusion coefficient (ADC) values of both the renal cortex and the medulla and SNRs were measured (b-values 0 and 400 s/mm², diffusion direction of 6). The image quality of FA and ADC maps was also compared subjectively.
  
  
  RESULTS
  The FA values of the renal cortex were 0.15 ± 0.03 at 3.0 T and 0.14± 0.03 at 1.5 T on average. This difference was not significant. The FA values of the renal medulla were 0.49 ±0.04 at 3.0 T and 0.42 ± 0.05 at 1.5 T. ADC values of the renal cortex were 2.46 x 10⁻³± 0.09 mm<²/s at 3.0 T and 2.20 x 10⁻³±0.11 mm²/s at 1.5 T. The ADC values of the renal medulla were 2.08 x 10⁻³ ± 0.08 mm²/s at 3.0 T and 1.90 x 10⁻³± 0.11 mm²/s at 1.5 T. These FA and ADC values were consistent with previous publications. The difference was significant for the FA value of the medulla (P< 0.01) and ADC values in both cortex and medulla (P < 0.01). The subjective image quality of the FA map with the 3.0 T scanner was significantly superior to that with the 1.5 T scanner (P< 0.01), but not significant for the ADC map (P = 0.18). There was a significant difference in SNR between 3.0 T (48.8 ± 6.6) and 1.5 T images (32.8 ± 5.0).
  
  
  CONCLUSIONS
  The feasibility of renal DTI with a 3.0 T magnet resulting in improved SNR was demonstrated.
authors.affiliation: Department of Diagnostic Imaging and Nuclear Medicine, Kyoto University, Shogoin, Sakyo-ku, Kyoto, Japan. akikido@kuhp.kyoto-u.ac.jp
authors.forename: Aki
authors.initials: A
authors.lastname: Kido
authors.forename: Masako
authors.initials: M
authors.lastname: Kataoka
authors.forename: Akira
authors.initials: A
authors.lastname: Yamamoto
authors.forename: Yuji
authors.initials: Y
authors.lastname: Nakamoto
authors.forename: Shigeaki
authors.initials: S
authors.lastname: Umeoka
authors.forename: Takashi
authors.initials: T
authors.lastname: Koyama
authors.forename: Yoji
authors.initials: Y
authors.lastname: Maetani
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Isoda
authors.forename: Ken
authors.initials: K
authors.lastname: Tamai
authors.forename: Nobuko
authors.initials: N
authors.lastname: Morisawa
authors.forename: Tsuneo
authors.initials: T
authors.lastname: Saga
authors.forename: Susumu
authors.initials: S
authors.lastname: Mori
authors.forename: Kaori
authors.initials: K
authors.lastname: Togashi
mesh_terms: D000328:Adult; D016880:Anisotropy; D056324:Diffusion Tensor Imaging / Q000379:methods*; D005240:Feasibility Studies; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted; D007668:Kidney / Q000033:anatomy & histology*; D008297:Male; D018709:Statistics, Nonparametric