Scott, LA;
Dickie, BR;
Rawson, SD;
Coutts, G;
Burnett, TL;
Allan, SM;
Parker, GJ;
(2020)
Characterisation of microvessel blood velocity and segment length in the brain using multi-diffusion-time diffusion-weighted MRI.
Journal of Cerebral Blood Flow and Metabolism
10.1177/0271678X20978523.
(In press).
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Abstract
Multi-diffusion-time diffusion-weighted MRI can probe tissue microstructure, but the method has not been widely applied to the microvasculature. At long diffusion-times, blood flow in capillaries is in the diffusive regime, and signal attenuation is dependent on blood velocity ( v ) and capillary segment length ( l ). It is described by the pseudo-diffusion coefficient ( D * = v l / 6 ) of intravoxel incoherent motion (IVIM). At shorter diffusion-times, blood flow is in the ballistic regime, and signal attenuation depends on v , and not l . In theory, l could be estimated using D * and v . In this study, we compare the accuracy and repeatability of three approaches to estimating v , and therefore l : the IVIM ballistic model, the velocity autocorrelation model, and the ballistic approximation to the velocity autocorrelation model. Twenty-nine rat datasets from two strains were acquired at 7 T, with b -values between 0 and 1000 smm-2 and diffusion times between 11.6 and 50 ms. Five rats were scanned twice to assess scan-rescan repeatability. Measurements of l were validated using corrosion casting and micro-CT imaging. The ballistic approximation of the velocity autocorrelation model had lowest bias relative to corrosion cast estimates of l , and had highest repeatability.
| Type: | Article |
|---|---|
| Title: | Characterisation of microvessel blood velocity and segment length in the brain using multi-diffusion-time diffusion-weighted MRI |
| Location: | United States |
| Open access status: | An open access version is available from UCL Discovery |
| DOI: | 10.1177/0271678X20978523 |
| Publisher version: | https://doi.org/10.1177/0271678X20978523 |
| Language: | English |
| Additional information: | This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. |
| Keywords: | Blood velocity, diffusion time, intravoxel incoherent motion, microvessel structure, velocity autocorrelation |
| UCL classification: | UCL UCL > Provost and Vice Provost Offices > UCL BEAMS UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Engineering Science UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Engineering Science > Dept of Med Phys and Biomedical Eng |
| URI: | https://discovery.ucl.ac.uk/id/eprint/10117998 |
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