title: Motion correction in diffusion-weighted MRI of the breast at 3T.
abstract: OBJECTIVE
  To provide a quantitative assessment of motion and distortion correction of diffusion-weighted images (DWIs) of the breast and to evaluate the effects of registration on the mean apparent diffusion coefficient (mADC).
  
  
  METHODS
  Eight datasets from four patients with breast cancer and eight datasets from six healthy controls were acquired on a 3T scanner. A 3D affine registration was used to align each set of images and principal component analysis was used to assess the results. Variance in tumor ADC measurements, tumor mADC values, and voxel-wise tumor mADC values were compared before and after registration for each patient.
  
  
  RESULTS
  Image registration significantly (P = 0.008) improved image alignment for both groups and significantly (P < 0.001) reduced the variance across individual tumor ADC measurements. While misalignment led to potential under- and overestimation of mADC values for individual voxels, average tumor mADC values did not significantly change (P > 0.09) after registration.
  
  
  CONCLUSIONS
  3D affine registration improved the alignment of DWIs of the breast and reduced the variance between ADC measurements. Although the reduced variance did not significantly change tumor region-of-interest measures of mADC, it may have a significant impact on voxel-based analyses.
authors.affiliation: Institute of Imaging Science, Vanderbilt University, Nashville, Tennessee, USA.
authors.forename: Lori R
authors.initials: LR
authors.lastname: Arlinghaus
authors.forename: E Brian
authors.initials: EB
authors.lastname: Welch
authors.forename: A Bapsi
authors.initials: AB
authors.lastname: Chakravarthy
authors.forename: Lei
authors.initials: L
authors.lastname: Xu
authors.forename: Jaime S
authors.initials: JS
authors.lastname: Farley
authors.forename: Vandana G
authors.initials: VG
authors.lastname: Abramson
authors.forename: Ana M
authors.initials: AM
authors.lastname: Grau
authors.forename: Mark C
authors.initials: MC
authors.lastname: Kelley
authors.forename: Ingrid A
authors.initials: IA
authors.lastname: Mayer
authors.forename: Julie A
authors.initials: JA
authors.lastname: Means-Powell
authors.forename: Ingrid M
authors.initials: IM
authors.lastname: Meszoely
authors.forename: John C
authors.initials: JC
authors.lastname: Gore
authors.forename: Thomas E
authors.initials: TE
authors.lastname: Yankeelov
mesh_terms: D000328:Adult; D000465:Algorithms; D016477:Artifacts; D001940:Breast / Q000473:pathology*; D001943:Breast Neoplasms / Q000175:diagnosis* / Q000473:pathology; D038524:Diffusion Magnetic Resonance Imaging / Q000379:methods*; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods; D008875:Middle Aged; D015233:Models, Statistical; D009038:Motion; D025341:Principal Component Analysis