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In vivo demonstration of microscopic anisotropy in the human kidney using multidimensional diffusion MRI

Nery, Fabio ; Szczepankiewicz, Filip LU ; Kerkelä, Leevi ; Hall, Matt G. ; Kaden, Enrico ; Gordon, Isky ; Thomas, David L. and Clark, Chris A. (2019) In Magnetic Resonance in Medicine 82(6). p.2160-2168
Abstract

Purpose: To demonstrate the feasibility of multidimensional diffusion MRI to probe and quantify microscopic fractional anisotropy (µFA) in human kidneys in vivo. Methods: Linear tensor encoded (LTE) and spherical tensor encoded (STE) renal diffusion MRI scans were performed in 10 healthy volunteers. Respiratory triggering and image registration were used to minimize motion artefacts during the acquisition. Kidney cortex–medulla were semi-automatically segmented based on fractional anisotropy (FA) values. A model-free analysis of LTE and STE signal dependence on b-value in the renal cortex and medulla was performed. Subsequently, µFA was estimated using a single-shell approach. Finally, a comparison of conventional FA and µFA is shown.... (More)

Purpose: To demonstrate the feasibility of multidimensional diffusion MRI to probe and quantify microscopic fractional anisotropy (µFA) in human kidneys in vivo. Methods: Linear tensor encoded (LTE) and spherical tensor encoded (STE) renal diffusion MRI scans were performed in 10 healthy volunteers. Respiratory triggering and image registration were used to minimize motion artefacts during the acquisition. Kidney cortex–medulla were semi-automatically segmented based on fractional anisotropy (FA) values. A model-free analysis of LTE and STE signal dependence on b-value in the renal cortex and medulla was performed. Subsequently, µFA was estimated using a single-shell approach. Finally, a comparison of conventional FA and µFA is shown. Results: The hallmark effect of µFA (divergence of LTE and STE signal with increasing b-value) was observed in all subjects. A statistically significant difference between LTE and STE signal was found in the cortex and medulla, starting from b = 750 s/mm2 and b = 500 s/mm2, respectively. This difference was maximal at the highest b-value sampled (b = 1000 s/mm2) which suggests that relatively high b-values are required for µFA mapping in the kidney compared to conventional FA. Cortical and medullary µFA were, respectively, 0.53 ± 0.09 and 0.65 ± 0.05, both respectively higher than conventional FA (0.19 ± 0.02 and 0.40 ± 0.02). Conclusion: The feasibility of combining LTE and STE diffusion MRI to probe and quantify µFA in human kidneys is demonstrated for the first time. By doing so, we show that novel microstructure information—not accessible by conventional diffusion encoding—can be probed by multidimensional diffusion MRI. We also identify relevant technical limitations that warrant further development of the technique for body MRI.

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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
diffusion, fractional anisotropy, kidney, microscopic anisotropy, spherical tensor encoding, tensor-valued diffusion encoding
in
Magnetic Resonance in Medicine
volume
82
issue
6
pages
2160 - 2168
publisher
Wiley Online Library
external identifiers
  • scopus:85068368866
  • pmid:31243814
ISSN
0740-3194
DOI
10.1002/mrm.27869
language
English
LU publication?
yes
id
68af28de-3ecf-4606-966c-6a8583c115e5
date added to LUP
2019-07-19 14:11:10
date last changed
2020-01-22 07:43:59
@article{68af28de-3ecf-4606-966c-6a8583c115e5,
  abstract     = {<p>Purpose: To demonstrate the feasibility of multidimensional diffusion MRI to probe and quantify microscopic fractional anisotropy (µFA) in human kidneys in vivo. Methods: Linear tensor encoded (LTE) and spherical tensor encoded (STE) renal diffusion MRI scans were performed in 10 healthy volunteers. Respiratory triggering and image registration were used to minimize motion artefacts during the acquisition. Kidney cortex–medulla were semi-automatically segmented based on fractional anisotropy (FA) values. A model-free analysis of LTE and STE signal dependence on b-value in the renal cortex and medulla was performed. Subsequently, µFA was estimated using a single-shell approach. Finally, a comparison of conventional FA and µFA is shown. Results: The hallmark effect of µFA (divergence of LTE and STE signal with increasing b-value) was observed in all subjects. A statistically significant difference between LTE and STE signal was found in the cortex and medulla, starting from b = 750 s/mm<sup>2</sup> and b = 500 s/mm<sup>2</sup>, respectively. This difference was maximal at the highest b-value sampled (b = 1000 s/mm<sup>2</sup>) which suggests that relatively high b-values are required for µFA mapping in the kidney compared to conventional FA. Cortical and medullary µFA were, respectively, 0.53 ± 0.09 and 0.65 ± 0.05, both respectively higher than conventional FA (0.19 ± 0.02 and 0.40 ± 0.02). Conclusion: The feasibility of combining LTE and STE diffusion MRI to probe and quantify µFA in human kidneys is demonstrated for the first time. By doing so, we show that novel microstructure information—not accessible by conventional diffusion encoding—can be probed by multidimensional diffusion MRI. We also identify relevant technical limitations that warrant further development of the technique for body MRI.</p>},
  author       = {Nery, Fabio and Szczepankiewicz, Filip and Kerkelä, Leevi and Hall, Matt G. and Kaden, Enrico and Gordon, Isky and Thomas, David L. and Clark, Chris A.},
  issn         = {0740-3194},
  language     = {eng},
  month        = {06},
  number       = {6},
  pages        = {2160--2168},
  publisher    = {Wiley Online Library},
  series       = {Magnetic Resonance in Medicine},
  title        = {In vivo demonstration of microscopic anisotropy in the human kidney using multidimensional diffusion MRI},
  url          = {http://dx.doi.org/10.1002/mrm.27869},
  doi          = {10.1002/mrm.27869},
  volume       = {82},
  year         = {2019},
}