Objective
To evaluate the relationship between fiber bundle direction and changes in diffusion
kurtosis, we evaluated the apparent diffusion kurtosis coefficients (AKCs) that were
perpendicular to and parallel to the principal diffusion tensor eigenvector.
Materials and Methods
Adult male Wistar rats were subjected to 30 or 60 minutes of middle cerebral artery
occlusion and imaged with a 7T Magnetic Resonance Imager System (Varian MRI System
7T/210: Agilent Technologies, CA). Diffusion kurtosis images were obtained before
middle cerebral artery (MCA) reperfusion and 3, 6, and 24 hours after reperfusion
to generate the apparent diffusion coefficient (ADC), fractional anisotropy (FA),
mean apparent diffusion kurtosis coefficient (mAKC), AKC axial to the eigenvector
(axAKC), and AKC radial to the eigenvector (radAKC) images. The time course of the
region/normal ratio was evaluated for the above parameters in the caudoputamen and
white matter.
Results
Relative FA and relative ADC values decreased 3 hours after MCA reperfusion and remained
decreased until 24 hours. Relative mAKC, axAKC, and radAKC values were increased 3
hours after MCA reperfusion, peaked after 6 hours, and slightly decreased after 24
hours. In the white matter, axAKC showed larger changes than radAKC.
Conclusion
The time course of the diffusion kurtosis value showed earlier pseudonormalization
than the ADC value of the lesions. For white matter lesions, the increase in axAKC
was larger than that in radAKC, suggesting that the tissue changes after infarction
mainly produce reduced diffusivity along the fibers and lead to increased inhomogeneity
of the diffusion.
Key Words
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Article info
Publication history
Published online: December 24, 2015
Accepted:
November 22,
2015
Received in revised form:
November 10,
2015
Received:
August 31,
2015
Identification
DOI: https://doi.org/10.1016/j.jstrokecerebrovasdis.2015.11.028
Copyright
© 2016 National Stroke Association. Published by Elsevier Inc. All rights reserved.
