Abstract:
:Clinical diffusion MRI (dMRI) is sensitive to micrometer scale spin displacements, but the image resolution is ∼mm, so the biophysical interpretation of the signal relies on establishing appropriate subvoxel tissue models. A class of two-compartment exchange models originally proposed by Kärger have been used successfully in neural tissue dMRI. Their use to interpret the signal in skeletal muscle dMRI is challenging because myocyte diameters are comparable to the root-mean-square of spin displacement and their membrane permeability is high. A continuum tissue model consisting of the Bloch-Torrey equation integrated by a hybrid lattice Boltzmann scheme is used for comparison. The validity domain of a classical two-compartment tissue model is probed by comparing it with the prediction of the continuum model for a 2D unidirectional composite continuum model of myocytes embedded in a uniform matrix. This domain is described in terms of two dimensionless parameters inspired by mass transfer phenomena, the Fourier (F) and Biot (B) numbers. The two-compartment model is valid when [Formula: see text] and [Formula: see text], or when [Formula: see text] and [Formula: see text]. The model becomes less appropriate for muscle dMRI as the cell diameter and volume fraction increase, with the primary source of error associated with modeling diffusion in the extracellular matrix.
journal_name
Phys Med Bioljournal_title
Physics in medicine and biologyauthors
Naughton NM,Georgiadis JGdoi
10.1088/1361-6560/ab2aa6subject
Has Abstractpub_date
2019-08-01 00:00:00pages
155004issue
15eissn
0031-9155issn
1361-6560journal_volume
64pub_type
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