Abstract
Measurement of microvascular perfusion with Intravoxel Incoherent Motion (IVIM) MRI is gaining interest. Yet, the physiological influences on the IVIM perfusion parameters ("pseudo-diffusion" coefficient D*, perfusion fraction f, and flow related parameter fD*) remain insufficiently characterized. In this article, we hypothesize that D* and fD*, which depend on blood speed, should vary during the cardiac cycle. We extended the IVIM model to include time dependence of D* = D*(t), and demonstrate in the healthy human brain that both parameters D* and fD* are significantly larger during systole than diastole, while the diffusion coefficient D and f do not vary significantly. The results non-invasively demonstrate the pulsatility of the brain's microvasculature.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Algorithms
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Anterior Cerebral Artery / physiology
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Brain / blood supply
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Brain / physiology*
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Diastole / physiology
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Diffusion Magnetic Resonance Imaging
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Female
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Heart / physiology*
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Humans
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Male
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Motion*
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Perfusion*
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Regional Blood Flow / physiology
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Systole / physiology
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Time Factors
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Young Adult
Grants and funding
This work was supported by the Centre d'Imagerie BioMédicale (CIBM) of the UNIL, UNIGE, HUG, CHUV, EPFL and the Leenaards and Jeantet Foundations. CF was supported by the Faculté de biologie et de médecine of the University of Lausanne. PH was supported by Leenaards Foundation. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.