Diffusion‐time dependence of diffusional kurtosis in the mouse brain

Purpose To investigate diffusion‐time dependency of diffusional kurtosis in the mouse brain using pulsed‐gradient spin‐echo (PGSE) and oscillating‐gradient spin‐echo (OGSE) sequences. Methods 3D PGSE and OGSE kurtosis tensor data were acquired from ex vivo brains of adult, cuprizone‐treated, and age...

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Published in:Magnetic resonance in medicine Vol. 84; no. 3; pp. 1564 - 1578
Main Authors: Aggarwal, Manisha, Smith, Matthew D., Calabresi, Peter A.
Format: Journal Article
Language:English
Published: United States Wiley Subscription Services, Inc 01.09.2020
Subjects:
Animals
Brain
Brain - diagnostic imaging
Cerebellum
Cerebral cortex
Computer simulation
Corpus Callosum
Cuprizone
Data acquisition
Demyelination
Diffusion
Diffusion Magnetic Resonance Imaging
diffusion time
Heterogeneity
Kurtosis
Mathematical analysis
Mice
non‐Gaussian diffusion
oscillating gradient
Permeability
pulsed gradient
Sensitivity
Simulation
Substantia alba
Substantia grisea
Tensors
Time dependence
Waveforms
White Matter
pulsed gradient
permeability
oscillating gradient
diffusion time
brain
kurtosis
non-Gaussian diffusion
ISSN:0740-3194, 1522-2594, 1522-2594
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Summary:Purpose To investigate diffusion‐time dependency of diffusional kurtosis in the mouse brain using pulsed‐gradient spin‐echo (PGSE) and oscillating‐gradient spin‐echo (OGSE) sequences. Methods 3D PGSE and OGSE kurtosis tensor data were acquired from ex vivo brains of adult, cuprizone‐treated, and age‐matched control mice with diffusion‐time (tD) ~ 20 ms and frequency (f) = 70 Hz, respectively. Further, 2D acquisitions were performed at multiple times/frequencies ranging from f = 140 Hz to tD = 30 ms with b‐values up to 4000 s/mm2. Monte Carlo simulations were used to investigate the coupled effects of varying restriction size and permeability on time/frequency‐dependence of kurtosis with both diffusion‐encoding schemes. Simulations and experiments were further performed to investigate the effect of varying number of cycles in OGSE waveforms. Results Kurtosis and diffusivity maps exhibited significant region‐specific changes with diffusion time/frequency across both gray and white matter areas. PGSE‐ and OGSE‐based kurtosis maps showed reversed contrast between gray matter regions in the cerebellar and cerebral cortex. Localized time/frequency‐dependent changes in kurtosis tensor metrics were found in the splenium of the corpus callosum in cuprizone‐treated mouse brains, corresponding to regional demyelination seen with histological assessment. Monte Carlo simulations showed that kurtosis estimates with pulsed‐ and oscillating‐gradient waveforms differ in their sensitivity to exchange. Both simulations and experiments showed dependence of kurtosis on number of cycles in OGSE waveforms for non‐zero permeability. Conclusion The results show significant time/frequency‐dependency of diffusional kurtosis in the mouse brain, which can provide sensitivity to probe intrinsic cellular heterogeneity and pathological alterations in gray and white matter.
Bibliography:Funding information
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This study was supported by the National Institutes of Health (NIH) grants R21NS096249 (to M.A.) and R01AG057991 (to M.A.)
Correction added after online publication 18 February, 2020. Due to publisher's error, the authors have corrected the permeablity values from “P” to
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ISSN:0740-3194
1522-2594
1522-2594
DOI:10.1002/mrm.28189