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Inferring diameters of spheres and cylinders using interstitial water

Inferring diameters of spheres and cylinders using interstitial water Object Most early methods to infer axon diameter distributions using magnetic resonance imaging (MRI) used single dif- fusion encoding sequences such as pulsed gradient spin echo (SE) and are thus sensitive to axons of diameters > 5 μm. We previously simulated oscillating gradient (OG) SE sequences for diffusion spectroscopy to study smaller axons including the majority constituting cortical connections. That study suggested the model of constant extra-axonal diffusion breaks down at OG accessible frequencies. In this study we present data from phantoms to test a time-varying interstitial apparent diffusion coefficient. Materials and Methods Diffusion spectra were measured in four samples from water packed around beads of diameters 3, 6 and 10 μm; and 151 μm diameter tubes. Surface-to-volume ratios, and diameters were inferred. Results The bead pore radii estimates were 0.60±0.08 μm, 0.54±0.06 μm and 1.0±0.1 μm corresponding to bead diameters ranging from 2.9±0.4 μm to 5.3±0.7 μm, 2.6±0.3 μm to 4.8±0.6 μm, and 4.9±0.7 μm to 9±1 μm. The tube surface-to-volume −1 ratio estimate was 0.06±0.02 μm corresponding to a tube diameter of 180±70 μm. Conclusion Interstitial models with OG inferred 3-10 μm bead diameters from 0.54±0.06 μm to 1.0±0.1 μm pore radii and −1 151 μm tube http://www.deepdyve.com/assets/images/DeepDyve-Logo-lg.png Magnetic Resonance Materials in Physics, Biology and Medicine Springer Journals

Inferring diameters of spheres and cylinders using interstitial water

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Publisher
Springer Journals
Copyright
Copyright © 2018 by ESMRMB
Subject
Medicine & Public Health; Imaging / Radiology; Computer Appl. in Life Sciences; Solid State Physics; Biomedical Engineering; Health Informatics
ISSN
0968-5243
eISSN
1352-8661
DOI
10.1007/s10334-018-0685-9
Publisher site
See Article on Publisher Site

Abstract

Object Most early methods to infer axon diameter distributions using magnetic resonance imaging (MRI) used single dif- fusion encoding sequences such as pulsed gradient spin echo (SE) and are thus sensitive to axons of diameters > 5 μm. We previously simulated oscillating gradient (OG) SE sequences for diffusion spectroscopy to study smaller axons including the majority constituting cortical connections. That study suggested the model of constant extra-axonal diffusion breaks down at OG accessible frequencies. In this study we present data from phantoms to test a time-varying interstitial apparent diffusion coefficient. Materials and Methods Diffusion spectra were measured in four samples from water packed around beads of diameters 3, 6 and 10 μm; and 151 μm diameter tubes. Surface-to-volume ratios, and diameters were inferred. Results The bead pore radii estimates were 0.60±0.08 μm, 0.54±0.06 μm and 1.0±0.1 μm corresponding to bead diameters ranging from 2.9±0.4 μm to 5.3±0.7 μm, 2.6±0.3 μm to 4.8±0.6 μm, and 4.9±0.7 μm to 9±1 μm. The tube surface-to-volume −1 ratio estimate was 0.06±0.02 μm corresponding to a tube diameter of 180±70 μm. Conclusion Interstitial models with OG inferred 3-10 μm bead diameters from 0.54±0.06 μm to 1.0±0.1 μm pore radii and −1 151 μm tube

Journal

Magnetic Resonance Materials in Physics, Biology and MedicineSpringer Journals

Published: Jun 4, 2018

References