N.m.r. of agarose gels

Derbyshire, W.; Duff, I.D

doi:10.1039/dc9745700243

Cited by 76 publications

(41 citation statements)

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“…This is analogous to the near free rapid diffusion of water in agar gels. 71,72 Hence, the axoplasm is not as viscous, on the molecular scale, as intuition might suggest, and therefore the diffusion coefficients in pure axoplasm are not reduced to the extent that one might naively expect. Of course, as pointed out earlier, interactions of the axon water with the numerous axonal membranes in a normal neural fibre with small axons will have a marked effect in reducing the translational mobility of water relative to the free axoplasm case.…”

Section: Mgmentioning

confidence: 97%

The basis of anisotropic water diffusion in the nervous system – a technical review

2002

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Anisotropic water diffusion in neural fibres such as nerve, white matter in spinal cord, or white matter in brain forms the basis for the utilization of diffusion tensor imaging (DTI) to track fibre pathways. The fact that water diffusion is sensitive to the underlying tissue microstructure provides a unique method of assessing the orientation and integrity of these neural fibres, which may be useful in assessing a number of neurological disorders. The purpose of this review is to characterize the relationship of nuclear magnetic resonance measurements of water diffusion and its anisotropy (i.e. directional dependence) with the underlying microstructure of neural fibres. The emphasis of the review will be on model neurological systems both in vitro and in vivo. A systematic discussion of the possible sources of anisotropy and their evaluation will be presented followed by an overview of various studies of restricted diffusion and compartmentation as they relate to anisotropy. Pertinent pathological models, developmental studies and theoretical analyses provide further insight into the basis of anisotropic diffusion and its potential utility in the nervous system.

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Section: Mgmentioning

confidence: 97%

The basis of anisotropic water diffusion in the nervous system – a technical review

2002

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“…The T 1 and T 2 relaxation times represent the rate at which the longitudinal and transverse components of the magnetization vector of human tissue return to thermodynamic equilibrium. Some polymer gels that have been investigated include agarose, 2-4 agar, 5,6 polyvinyl alcohol, 7 gelatin, 8 and polysaccharide gels TX-150 9 and TX-151. 10 These studies have demonstrated that each material has potential for phantom application, but this is limited due to fragility and storage conditions.…”

Section: Introductionmentioning

confidence: 99%

Mechanical stability analysis of carrageenan-based polymer gel for magnetic resonance imaging liver phantom with lesion particles

Naguib

Haider

2014

J. Med. Imag

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Abstract. Medical imaging is an effective technique used to detect and prevent disease in cancer research. To optimize medical imaging, a calibration medium or phantom with tissue-mimicking properties is required. Although the feasibility of various polymer gel materials has previously been studied, the stability of the gels' properties has not been investigated. In this study, we fabricated carrageenan-based polymer gel to examine the stability of its properties such as density, conductivity, permittivity, elastic modulus, and T 1 and T 2 relaxation times over six weeks. We fabricated eight samples with different carrageenan and agar concentrations and found that the density, elastic modulus, and compressive strength fluctuated with no specific pattern. The elastic modulus in sample 4 with 3 wt. % carrageenan and 1.5 wt. % agar fluctuated from 0.51 to 0.64 MPa in five weeks. The T 1 and T 2 relaxation times also varied by 23% to 29%. We believe that the fluctuation of these properties is related to the change in water content of the sample due to cycles of water expulsion and absorption in their containers. The fluctuation of the properties should be minimized to achieve accurate calibration over the shelf life of the phantom and to serve as the standard for quality assurance. Furthermore, a full liver phantom with spherical lesion particles was fabricated to demonstrate the potential for phantom production.

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“…10 The long relaxation times in neonatal brain tissue compared with an adult brain are, in part, due to the very high water content (Ͼ90%) 20 in neonatal brain tissue. To our knowledge, T 1 values reported for gel phantom materials (PVA-C, 18,19 carrageenan, 21 TX-150, 22 gelatin, 23 alginate microbeads, 24 agarose, [25][26][27] and polyacrylamide 28 ) at room temperature generally do not exceed 2 seconds. One exception is 0.5% agarose by weight, which is marginally high enough in concentration to hold its shape.…”

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confidence: 87%

Development of a Composite Material Phantom Mimicking the Magnetic Resonance Parameters of the Neonatal Brain at 3.0 Tesla

Orr

Paliy²,

Winter³

et al. 2007

Investigative Radiology

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N.m.r. of agarose gels

Cited by 76 publications

References 0 publications

The basis of anisotropic water diffusion in the nervous system – a technical review

The basis of anisotropic water diffusion in the nervous system – a technical review

Mechanical stability analysis of carrageenan-based polymer gel for magnetic resonance imaging liver phantom with lesion particles

Development of a Composite Material Phantom Mimicking the Magnetic Resonance Parameters of the Neonatal Brain at 3.0 Tesla

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