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A general model of microcirculatory blood flow effects in gradient sensitized MRI
Author(s) -
Kennan Richard P.,
Gao JiaHong,
Zhong Jianhui,
Gore John C.
Publication year - 1994
Publication title -
medical physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.473
H-Index - 180
eISSN - 2473-4209
pISSN - 0094-2405
DOI - 10.1118/1.597170
Subject(s) - autocorrelation , intravoxel incoherent motion , blood flow , diffusion , flow (mathematics) , microcirculation , amplitude , flow velocity , signal (programming language) , nuclear magnetic resonance , mathematics , biomedical engineering , mechanics , physics , statistical physics , diffusion mri , magnetic resonance imaging , statistics , optics , computer science , medicine , thermodynamics , radiology , programming language
A general expression is derived for the NMR signal from a fluid undergoing random directional flow such as encountered within the microcirculation. The dependence of the echo amplitude on flow velocity, sample morphology, and experimental parameters are described in terms of a temporal velocity autocorrelation function. The width of the correlation function determines whether the flow can properly be described as diffusive. Comparison is made between the velocity autocorrelation method outlined here and the IVIM model for tissue perfusion. Conditions for the validity of the latter approach for extracting physiologic information from apparent diffusion measurements are discussed. The approach outlined leads to a more robust measure of microcirculatory blood velocity from NMR measurements.