TY - JOUR
T1 - Edge enhancement by diffusion in microscopic magnetic resonance imaging
AU - Pütz, B.
AU - Barsky, D.
AU - Schulten, K.
N1 - Funding Information:
ACKNOWLEDGMENTS We thank Paul Iauterbur for calling our attention to the issue of diffusion effects in MRI microscopy and for his insights and suggestions. In numerous discussions Richard Magin gave us valuable insight into the experimental aspects involved in microscopic MRI. Lino Becerra helped us understand FFI techniques used in magnetic resonance experiments. We also thank Robert Bitt1 for a program for calculating lineshape functions and Clint Potter and Patrick Moran for their visualization programs VIEWIT and VT, respectively. The simulations have been computed on a Transputer-based parallel computer at the Center for Parallel Computation for Molecular Dynamics at the University of Illinois, supported by the National Institute of Health (Grant 1 P4 1 RR05969 *0 1)
Copyright:
Copyright 2018 Elsevier B.V., All rights reserved.
PY - 1992/3
Y1 - 1992/3
N2 - In microscopic MRI (≈ 10 Am resolution), diffusion boundaries impermeable to water on a millisecond time scale distort the lineshape function of the observed frequency spectra from the transverse magnetization in a manner similar to motional narrowing in MR spectroscopy. Reconstruction techniques developed for macroscopic imaging interpret these distortions as spatial deformations of objects. This distortion of frequency spectra is demonstrated for geometrically simple objects, and it is shown how in such cases the reconstructed images should be interpreted and how diffusion-induced distortions in frequency space may actually be exploited to enhance image contrast around compartmental boundaries. The distortions are properly described by Kubo's lineshape function, for which suitable numerical algorithms are provided. A parameter is introduced that provides an estimation of the extent of diffusion-induced distortions which can vary from an enhancement of image intensity near boundaries to, for extreme motional narrowing, a focusing of image intensity around compartment centers.
AB - In microscopic MRI (≈ 10 Am resolution), diffusion boundaries impermeable to water on a millisecond time scale distort the lineshape function of the observed frequency spectra from the transverse magnetization in a manner similar to motional narrowing in MR spectroscopy. Reconstruction techniques developed for macroscopic imaging interpret these distortions as spatial deformations of objects. This distortion of frequency spectra is demonstrated for geometrically simple objects, and it is shown how in such cases the reconstructed images should be interpreted and how diffusion-induced distortions in frequency space may actually be exploited to enhance image contrast around compartmental boundaries. The distortions are properly described by Kubo's lineshape function, for which suitable numerical algorithms are provided. A parameter is introduced that provides an estimation of the extent of diffusion-induced distortions which can vary from an enhancement of image intensity near boundaries to, for extreme motional narrowing, a focusing of image intensity around compartment centers.
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U2 - 10.1016/0022-2364(92)90235-Y
DO - 10.1016/0022-2364(92)90235-Y
M3 - Article
AN - SCOPUS:30244535047
VL - 97
SP - 27
EP - 53
JO - Journal of Magnetic Resonance (1969)
JF - Journal of Magnetic Resonance (1969)
SN - 0022-2364
IS - 1
ER -