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Contribution Details

Type Journal Article
Scope Discipline-based scholarship
Title A comprehensive approach for correcting voxel‐wise b‐value errors in diffusion MRI
Organization Unit
  • Yoojin Lee
  • Adam O Kettinger
  • Bertram Jakob Wilm
  • Ralf Deichmann
  • Nikolaus Weiskopf
  • Christian Lambert
  • Klaas Paul Pruessmann
  • Zoltan Nagy
Item Subtype Original Work
Refereed Yes
Status Published in final form
  • English
Journal Title Magnetic Resonance in Medicine
Publisher Wiley-Blackwell Publishing, Inc.
Geographical Reach international
ISSN 0740-3194
Volume 83
Number 6
Page Range 2173 - 2184
Date 2020
Abstract Text PURPOSE: In diffusion MRI, the actual b-value played out on the scanner may deviate from the nominal value due to magnetic field imperfections. A simple image-based correction method for this problem is presented. METHODS: The apparent diffusion constant (ADC) of a water phantom was measured voxel-wise along 64 diffusion directions at b = 1000 s/mm2 . The true diffusion constant of water was estimated, considering the phantom temperature. A voxel-wise correction factor, providing an effective b-value including any magnetic field deviations, was determined for each diffusion direction by relating the measured ADC to the true diffusion constant. To test the method, the measured b-value map was used to calculate the corrected voxel-wise ADC for additionally acquired diffusion data sets on the same water phantom and data sets acquired on a small water phantom at three different positions. Diffusion tensor was estimated by applying the measured b-value map to phantom and in vivo data sets. RESULTS: The b-value-corrected ADC maps of the phantom showed the expected spatial uniformity as well as a marked improvement in consistency across diffusion directions. The b-value correction for the brain data resulted in a 5.8% and 5.5% decrease in mean diffusivity and angular differences of the primary diffusion direction of 2.71° and 0.73° inside gray and white matter, respectively. CONCLUSION: The actual b-value deviates significantly from its nominal setting, leading to a spatially variable error in the common diffusion outcome measures. The suggested method measures and corrects these artifacts.
Digital Object Identifier 10.1002/mrm.28078
PubMed ID 31840300
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Keywords Radiology Nuclear Medicine and imaging