title: The effect of a gadolinium-based contrast agent on diffusion tensor imaging.
abstract: OBJECTIVE
  The aim of this study was to investigate in detail the effect of gadolinium contrast on diffusion tensor imaging scans. As the present literature offers conflicting results, we have included a large selection of indices in the analysis.
  
  
  METHODS
  Sixteen patients harboring an intra-axial contrast enhancing brain tumor were included in this study. Two diffusion tensor imaging scans were performed-one natively, and the second following a gadolinium contrast agent application. Maps of the invariant indices fractional anisotropy (FA), linear, planar, and spherical indices, trace, eigenvalues λ(1), λ(2), λ(3) as well as of the components of the diffusion tensor matrix Dxx, Dyy, Dzz, Dxy, Dxz and Dyz were co-registered and compared statistically with matching ROI pairs in the contrast enhancing areas, peritumoral edema and the normal appearing white matter.
  
  
  RESULTS
  We have observed a significant increase in the FA and disproportional decrease of the eigenvalues in the post-contrast scans. In accordance with these findings, the spherical index was decreased and the linear and planar indices were increased. There was a significant decrease of all diagonal components of the diffusion tensor matrix. These changes have been strongest in the contrast enhancing areas, but there were also significant changes in the peritumoral edema and the normal appearing white matter.
  
  
  CONCLUSIONS
  Diffusion tensor imaging scans performed after gadolinium contrast agent administration may display artificially increased FA values due to disproportional changes of the measured eigenvalues. The distortion of the diffusion measurement is strongest in, but not limited to the contrasting areas.
authors.affiliation: Department of Neurosurgery, JE Purkynje University and Masaryk Hospital, Usti nad Labem, Czech Republic. amirzolal@gmail.com
authors.forename: Amir
authors.initials: A
authors.lastname: Zolal
authors.forename: Martin
authors.initials: M
authors.lastname: Sameš
authors.forename: Martin
authors.initials: M
authors.lastname: Burian
authors.forename: Martina
authors.initials: M
authors.lastname: Nováková
authors.forename: Alberto
authors.initials: A
authors.lastname: Malucelli
authors.forename: Aleš
authors.initials: A
authors.lastname: Hejčl
authors.forename: Robert
authors.initials: R
authors.lastname: Bartoš
authors.forename: Petr
authors.initials: P
authors.lastname: Vachata
authors.forename: Milouš
authors.initials: M
authors.lastname: Derner
mesh_terms: D000328:Adult; D000368:Aged; D001932:Brain Neoplasms / Q000473:pathology*; D003287:Contrast Media; D038524:Diffusion Magnetic Resonance Imaging / Q000379:methods*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009942:Organometallic Compounds; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity
chemical_list: D003287:Contrast Media; D009942:Organometallic Compounds; C090600:gadobutrol