Magnetic susceptibility measurement of insoluble solids by NMR: Magnetic susceptibility of bone.

Hopkins, Jeffrey A.; Wehrli, Félix W.

doi:10.1002/mrm.1910370404

Cited by 142 publications

(144 citation statements)

References 38 publications

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“…Computed and experimental field maps were found to be in excellent agreement with one another. Lastly, from the slopes of regression between the experimental and computed fields, the absolute volume susceptibility of bone was nondestructively determined as À11.0 Â 10 À6 (SI), which is in close agreement with a reported value of À11.3 Â 10 À6 obtained with the previously discussed spectroscopic susceptibility matching technique (34).…”

Section: Nature Of the Susceptibility-induced Fieldsupporting

confidence: 84%

Quantitative MRI for the assessment of bone structure and function

et al. 2006

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Osteoporosis is the most common degenerative disease in the elderly. It is characterized by low bone mass and structural deterioration of bone tissue, leading to morbidity and increased fracture risk in the hip, spine and wrist-all sites of predominantly trabecular bone. Bone densitometry, currently the standard methodology for diagnosis and treatment monitoring, has significant limitations in that it cannot provide information on the structural manifestations of the disease. Recent advances in imaging, in particular MRI, can now provide detailed insight into the architectural consequences of disease progression and regression in response to treatment. The focus of this review is on the emerging methodology of quantitative MRI for the assessment of structure and function of trabecular bone. During the past 10 years, various approaches have been explored for obtaining image-based quantitative information on trabecular architecture. Indirect methods that do not require resolution on the scale of individual trabeculae and therefore can be practiced at any skeletal location, make use of the induced magnetic fields in the intertrabecular space. These fields, which have their origin in the greater diamagnetism of bone relative to surrounding marrow, can be measured in various ways, most typically in the form of R 0 2 , the recoverable component of the total transverse relaxation rate. Alternatively, the trabecular network can be quantified by high-resolution MRI (m-MRI), which requires resolution adequate to at least partially resolve individual trabeculae. Micro-MRI-based structure analysis is therefore technically demanding in terms of image acquisition and algorithms needed to extract the structural information under conditions of limited signal-to-noise ratio and resolution. Other requirements that must be met include motion correction and image registration, both critical for achieving the reproducibility needed in repeat studies. Key clinical applications targeted involve fracture risk prediction and evaluation of the effect of therapeutic intervention.

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Section: Nature Of the Susceptibility-induced Fieldsupporting

confidence: 84%

Quantitative MRI for the assessment of bone structure and function

et al. 2006

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“…The values are, however, in agreement with the reported susceptibility value of animal fat (−7.79 × 10 −6 ) [10].…”

Section: Resultssupporting

confidence: 91%

Temperature dependence of the magnetic volume susceptibility of human breast fat tissue: an NMR study

Sprinkhuizen

Bakker

Ippel

et al. 2011

Magn Reson Mater Phy

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Object Proton resonance frequency shift (PRFS)-based MR thermometry (MRT) is hampered by heat-induced susceptibility changes when applied in tissues containing fat, e.g., the human breast. In order to assess the impact of fat susceptibility changes on PRFS-based MRT during thermal therapy in the human breast, reliable knowledge of the temperature dependence of the magnetic volume susceptibility of fat, dχ fat /dT , is a prerequisite. In this work we have measured dχ fat /dT of human breast fat tissue, using a double-reference method to ensure invariance to temperature-induced changes in the proton electron screening constant. Materials and methods Ex vivo measurements were taken on a 14.1 T five mm narrow bore NMR spectrometer. Breast fat tissue samples were collected from six subjects, directly postmortem. The susceptibility was measured over a temperature range from 24 • C to 65 • C. Results A linear behavior of the susceptibility over temperature was observed for all samples. The resulting dχ fat /dT of human breast fat ranged between 0.0039 and 0.0076 ppm/ • C. Conclusion It is concluded that the impact of heat-induced susceptibility changes of fat during thermal therapy in the breast may not be neglected.

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“…It is expected that the resonances for these environments are predominantly broadened by the microscopic magnetic field inhomogeneities at the interface between the surface of the carbon particles that are embedded in the electrode film, and the liquid-filled voids between them (the electrode films also contain a small amount of PTFE binder, which will have a slight influence on the effects discussed here but with no charge dependence). Importantly, the magnitude of the broadening is directly proportional to the difference between the susceptibilities of the solid and liquid media 36 , in this case between the carbon particles and the electrolyte solution inside the electrodes. On charging, electrons are added or removed from the electronic structure of the carbon, thereby changing its susceptibility, and therefore the linewidths of the SA and WA peaks.…”

Section: Nmrmentioning

confidence: 99%

Multinuclear in situ magnetic resonance imaging of electrochemical double-layer capacitors

et al. 2014

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The last decade has seen an intensified interest in the development and use of electrochemical double-layer capacitors, fuelled by the availability of new electrode materials. The use of nanoporous carbons, in particular, with extremely high surface areas for ion adsorption has enabled the development of working devices with significantly increased capacitances that have become viable alternatives to lithium-ion batteries in certain applications. An understanding of the charge storage mechanism and the ion dynamics inside the nanopores is only just emerging, with the most compelling evidence coming from simulation. Here we present the first in situ magnetic resonance imaging experiments of electrochemical double-layer capacitors. These experiments overcome the limitations of other techniques and give spatially resolved chemical information about the electrolyte ions in real time for a working capacitor of standard geometry. The results provide insight into the predominant capacitive processes occurring at different states of charge and discharge.

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Magnetic susceptibility measurement of insoluble solids by NMR: Magnetic susceptibility of bone.

Cited by 142 publications

References 38 publications

Quantitative MRI for the assessment of bone structure and function

Quantitative MRI for the assessment of bone structure and function

Temperature dependence of the magnetic volume susceptibility of human breast fat tissue: an NMR study

Multinuclear in situ magnetic resonance imaging of electrochemical double-layer capacitors

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