A volume birdcage coil with an adjustable sliding tuner ring for neuroimaging in high field vertical magnets: Ex and in vivo applications at 21.1 T

Cui, Qian; Masad, Ihssan S.; Rosenberg, Jens T.; Elumalai, Malathy; Brey, Wallace S.; Grant, Samuel C.; Gor’kov, Peter L.

doi:10.1016/j.jmr.2012.05.016

Cited by 31 publications

(29 citation statements)

References 31 publications

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“…Independent tuning and matching trimmer capacitors were implemented for in-phase and quadrature ports. The chlorine coil was designed for use with a vertical in vivo probe frame developed at the NHMFL [22] which provides support for gas anesthesia and respiratory monitoring. The tuning and matching capacitors can be adjusted from the base of the probe.…”

Section: Methodsmentioning

confidence: 99%

In vivo chlorine and sodium MRI of rat brain at 21.1 T

Schepkin

Elumalai

Kitchen

et al. 2013

Magn Reson Mater Phy

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Object MR imaging of low-gamma nuclei at the ultrahigh magnetic field of 21.1 T provides a new opportunity for understanding a variety of biological processes. Among these, chlorine and sodium are attracting attention for their involvement in brain function and cancer development. Materials and methods MRI of 35Cl and 23Na were performed and relaxation times were measured in vivo in normal rat (n = 3) and in rat with glioma (n = 3) at 21.1 T. The concentrations of both nuclei were evaluated using the center-out back-projection method. Results T1 relaxation curve of chlorine in normal rat head was fitted by bi-exponential function (T1a = 4.8 ms (0.7) T1b = 24.4 ± 7 ms (0.3) and compared with sodium (T1 = 41.4 ms). Free induction decays (FID) of chlorine and sodium in vivo were bi-exponential with similar rapidly decaying components of T2normala∗=0.4 ms and T2normala∗=0.53 ms, respectively. Effects of small acquisition matrix and bi-exponential FIDs were assessed for quantification of chlorine (33.2 mM) and sodium (44.4 mM) in rat brain. Conclusion The study modeled a dramatic effect of the bi-exponential decay on MRI results. The revealed increased chlorine concentration in glioma (~1.5 times) relative to a normal brain correlates with the hypothesis asserting the importance of chlorine for tumor progression.

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Section: Methodsmentioning

confidence: 99%

In vivo chlorine and sodium MRI of rat brain at 21.1 T

Schepkin

Elumalai

Kitchen

et al. 2013

Magn Reson Mater Phy

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“…Furthermore, volume RF coil used here has excellent spatial RF homogeneity [18]. Therefore, no RF, i.e.…”

Section: Discussionmentioning

confidence: 99%

“…The dual-tuned 1 H/ 23 Na RF probe-head combines sliding-ring birdcage coil [18] in 900 MHz proton channel with the second, orthogonal birdcage in sodium channel (238 MHz). Sodium images were acquired by ZTE Bruker RF pulse sequence based on the detection of free induction decays (FID) in the presence of gradient to minimize the acquisition dead time.…”

Section: Methodsmentioning

confidence: 99%

Sodium 3D COncentration MApping (COMA 3D) using 23Na and proton MRI

Truong

Harrington

Schepkin

et al. 2014

Journal of Magnetic Resonance

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Functional changes of sodium 3D MRI signals were converted into millimolar concentration changes using an open-source fully automated MATLAB toolbox. These concentration changes are visualized via 3D sodium concentration maps, and they are overlaid over conventional 3D proton images to provide high-resolution co-registration for easy correlation of functional changes to anatomical regions. Nearly 5000/hour concentration maps were generated on a personal computer (ca. 2012) using 21.1 T 3D sodium MRI brain images of live rats with spatial resolution of 0.8×0.8×0.8 mm3 and imaging matrices of 60×60×60. The produced concentration maps allowed for non-invasive quantitative measurement of in vivo sodium concentration in the normal rat brain as a functional response to migraine-like conditions. The presented work can also be applied to sodium-associated changes in migraine, cancer, and other metabolic abnormalities that can be sensed by molecular imaging. The MATLAB toolbox allows for automated image analysis of the 3D images acquired on the Bruker platform and can be extended to other imaging platforms. The resulting images are presented in a form of series of 2D slices in all three dimensions in native MATLAB and PDF formats. The following is provided: (a) MATLAB source code for image processing, (b) the detailed processing procedures, (c) description of the code and all sub-routines, (d) example data sets of initial and processed data. The toolbox can be downloaded at: http://www.vuiis.vanderbilt.edu/~truongm/COMA3D/

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“…However, systems achieving densities of 9.4 T or even 21.1 T have also been developed. 9,10 Strong penetration by the magnetic field is accompanied by high EM field strength, inducing radio frequency impulses. Conventional measuring equipment was not designed to work in such an environment.…”

Section: Introductionmentioning

confidence: 99%

Fiber-optic sensors for monitoring patient physiological parameters: a review of applicable technologies and relevance to use during magnetic resonance imaging procedures

Dziuda

2015

J. Biomed. Opt.

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Abstract. The issues involved with recording vital functions in the magnetic resonance imaging (MRI) environment using fiber-optic sensors are considered in this paper. Basic physiological parameters, such as respiration and heart rate, are fundamental for predicting the risk of anxiety, panic, and claustrophobic episodes in patients undergoing MRI examinations. Electronic transducers are generally hazardous to the patient and are prone to erroneous operation in heavily electromagnetically penetrated MRI environments; however, nonmetallic fiberoptic sensors are inherently immune to electromagnetic effects and will be crucial for acquiring the abovementioned physiological parameters. Forty-seven MRI-tested or potentially MRI-compatible sensors have appeared in the literature over the last 20 years. The author classifies these sensors into several categories and subcategories, depending on the sensing element placement, method of application, and measurand type. The author includes five in-house-designed fiber Bragg grating based sensors and shares experience in acquiring physiological measurements during MRI scans. This paper aims to systematize the knowledge of fiber-optic techniques for recording life functions and to indicate the current directions of development in this area.

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A volume birdcage coil with an adjustable sliding tuner ring for neuroimaging in high field vertical magnets: Ex and in vivo applications at 21.1 T

Cited by 31 publications

References 31 publications

In vivo chlorine and sodium MRI of rat brain at 21.1 T

In vivo chlorine and sodium MRI of rat brain at 21.1 T

Sodium 3D COncentration MApping (COMA 3D) using 23Na and proton MRI

Fiber-optic sensors for monitoring patient physiological parameters: a review of applicable technologies and relevance to use during magnetic resonance imaging procedures

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