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Healthy and infarcted brain tissues studied at short diffusion times: The origins of apparent restriction and the reduction in apparent diffusion coefficient
Author(s) -
Norris David G.,
Niendorf Thoralf,
Leibfritz Dieter
Publication year - 1994
Publication title -
nmr in biomedicine
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.278
H-Index - 114
eISSN - 1099-1492
pISSN - 0952-3480
DOI - 10.1002/nbm.1940070703
Subject(s) - diffusion , effective diffusion coefficient , nuclear magnetic resonance , chemistry , medicine , physics , thermodynamics , magnetic resonance imaging , radiology
The significance of NMR water diffusion measurements performed at short diffusion times (<10 ms) for brain tissue is examined. An apparent restriction to diffusion for both healthy and cytotoxically edematous tissue is shown: cytotoxic edema lengthens the diffusion time at which this phenomenon is visible. The dramatic reduction in apparent diffusion coefficient (ADC) observed in the core of cytotoxic edema is explained in terms of the enclosure of extracellular water in non‐contiguous pockets in conjunction with the shift of water from the extra‐to the intracellular space. The model presented provides an explanation for the ADC reduction without recourse to changes in the cell membrane permeability to water, or unrealistic values for the extra‐ and intracellular diffusion coefficients.