title: Intra-Individual, Inter-Vendor Comparison of Diffusion-Weighted MR Imaging of Upper Abdominal Organs at 3.0 Tesla with an Emphasis on the Value of Normalization with the Spleen.
abstract: OBJECTIVE
  To compare the apparent diffusion coefficient (ADC) values of upper abdominal organs with 2 different 3.0 tesla MR systems and to investigate the usefulness of normalization using the spleen.
  
  
  METHODS
  Forty-one patients were enrolled in this prospective study, of which, 35 patients (M:F, 27:8; mean age ± standard deviation, 62.3 ± 12.3 years) were finally analyzed. In addition to the routine liver MR protocol, single-shot spin-echo echo-planar diffusion-weighted imaging using b values of 0, 50, 400, and 800 s/mm(2) in 2 different MR systems was performed. ADC values of the liver, spleen, pancreas, kidney and liver lesion (if present) were measured and analyzed. ADC values of the spleen were used for normalization. The Pearson correlation, Spearman correlation, paired sample t test, Wilcoxon signed rank test and Bland-Altman method were used for statistical analysis.
  
  
  RESULTS
  For all anatomical regions and liver lesions, both non-normalized and normalized ADC values from 2 different MR systems showed significant correlations (r = 0.5196-0.8488). Non-normalized ADC values of both MR systems differed significantly in all anatomical regions and liver lesions (p < 0.001). However, the normalized ADC of all anatomical regions and liver lesions did not differ significantly (p = 0.065-0.661), with significantly lower coefficient of variance than that of non-normalized ADC (p < 0.009).
  
  
  CONCLUSIONS
  Normalization of the abdominal ADC values using the spleen as a reference organ reduces differences between different MR systems, and could facilitate consistent use of ADC as an imaging biomarker for multi-center or longitudinal studies.
authors.affiliation: Department of Radiology, Chonbuk National University Medical School and Hospital, Jeonju 54907, Korea.; Research Institute of Clinical Medicine of Chonbuk National University-Biomedical Research Institute of Chonbuk National University Hospital, Jeonju 54907, Korea.
authors.forename: Ji Soo
authors.initials: JS
authors.lastname: Song
authors.affiliation: Department of Radiology, Chonbuk National University Medical School and Hospital, Jeonju 54907, Korea.; Research Institute of Clinical Medicine of Chonbuk National University-Biomedical Research Institute of Chonbuk National University Hospital, Jeonju 54907, Korea.
authors.forename: Seung Bae
authors.initials: SB
authors.lastname: Hwang
authors.affiliation: Department of Radiology, Chonbuk National University Medical School and Hospital, Jeonju 54907, Korea.; Research Institute of Clinical Medicine of Chonbuk National University-Biomedical Research Institute of Chonbuk National University Hospital, Jeonju 54907, Korea.
authors.forename: Gyung Ho
authors.initials: GH
authors.lastname: Chung
authors.affiliation: Department of Radiology, Chonbuk National University Medical School and Hospital, Jeonju 54907, Korea.; Research Institute of Clinical Medicine of Chonbuk National University-Biomedical Research Institute of Chonbuk National University Hospital, Jeonju 54907, Korea.
authors.forename: Gong Yong
authors.initials: GY
authors.lastname: Jin
mesh_terms: D000368:Aged; D038524:Diffusion Magnetic Resonance Imaging; D017352:Echo-Planar Imaging; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted; D007668:Kidney / Q000000981:diagnostic imaging*; D008099:Liver / Q000000981:diagnostic imaging*; D008297:Male; D008875:Middle Aged; D010179:Pancreas / Q000000981:diagnostic imaging*; D011446:Prospective Studies; D013154:Spleen / Q000000981:diagnostic imaging*
keywords: 3.0 T; Apparent diffusion coefficient; Diffusion-weighted imaging; Inter-vendor differences