title: A systematically designed study to investigate the effects of contrast medium on diffusion tensor MRI.
abstract: OBJECTIVE
  This study investigated whether or not the effect of contrast medium on diffusion tensor magnetic resonance imaging (DTI) is time-related in patients with malignant brain tumours.
  
  
  METHODS
  Twelve patients who only had malignant brain tumours were included in the study. DTI acquisitions were performed five times consecutively: twice before, once during, then twice after contrast injection. Diffusion indices were mapped and regions of interest (ROIs) were placed in the tumour, peritumoral edema and contralateral normal brain tissue. Repeated-measures ANOVA was used to investigate the effects of time on contrast medium in relation to diffusion indices.
  
  
  RESULTS
  Precontrast DTI was redefined as "pre" by averaging the two before-contrast scans, as there were no statistically significant differences between them. There were statistically significant differences at four time points for only the edema ROI for fractional anisotropy and the first-largest eigenvalue, but not for trace and the second-largest eigenvalue.
  
  
  CONCLUSIONS
  The effects of contrast medium on DTI were time-dependent for diffusion anisotropic indices. DTI obtained at>6 min after contrast injection does not cause significant changes in diffusion isotropic and anisotropic values.
authors.affiliation: Department of Radiology, Graduate School of Medicine, Kyung Hee University, #1, Whogi-dong, Dongdaemoon-gu, Seoul, 130-702, Republic of Korea.
authors.forename: Min Sun
authors.initials: MS
authors.lastname: Bae
authors.forename: Geon-Ho
authors.initials: GH
authors.lastname: Jahng
authors.forename: Chang Woo
authors.initials: CW
authors.lastname: Ryu
authors.forename: Eui Jong
authors.initials: EJ
authors.lastname: Kim
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D001921:Brain / Q000473:pathology*; D001932:Brain Neoplasms / Q000473:pathology*; D003287:Contrast Media; D056324:Diffusion Tensor Imaging / Q000379:methods*; D005260:Female; D005910:Glioma / Q000473:pathology*; D006801:Humans; D008297:Male; D008875:Middle Aged
chemical_list: D003287:Contrast Media