scholarly journals Magnetic-Resonance-Based Electrical Property Mapping Using Global Maxwell Tomography With an 8-Channel Head Coil at 7 Tesla: A Simulation Study

2021 ◽  
Vol 68 (1) ◽  
pp. 236-246
Author(s):  
Ilias I. Giannakopoulos ◽  
Jose E. C. Serralles ◽  
Luca Daniel ◽  
Daniel K. Sodickson ◽  
Athanasios G. Polimeridis ◽  
...  
Keyword(s):  
Electrical Property ◽  
Magnetic Resonance ◽  
Simulation Study ◽  
7 Tesla ◽  
Head Coil

A new magnetic resonance head coil and head immobilization device for gamma knife radiosurgery: an analysis of geometric distortion and signal/noise characteristics

2002 ◽  
Vol 97 ◽  
pp. 563-568 ◽  
Author(s):  
Paul Jursinic ◽  
Robert Prost ◽  
Christopher Schultz
Keyword(s):  
Magnetic Resonance ◽  
Gamma Knife Radiosurgery ◽  
Geometric Distortion ◽  
Gradient Field ◽  
Main Magnetic Field ◽  
Content Type ◽  
Signal Noise ◽  
Noise Characteristics ◽  
Head Coil ◽  
Fine Print

Object. The authors report on a new head coil into which the Leksell aluminum localization frame can be easily and securely mounted. Mechanically, the head coil interferes little with the patient. Methods. The head coil, which is for magnetic resonance (MR) imaging, is a 12-element quadrature transmitand-receive high-pass birdcage coil with a nominal operation frequency (63.86 MHz). The coil was built into a plastic housing. This new head coil minimizes patient motion and provides a 20% increase in signal/noise ratios compared with standard head coils. An MR image test phantom was mounted in the coil and this allowed quantification of image distortion due to inhomogeneities in the main magnetic field, nonlinearity in the gradient field, and paramagnetism of the aluminum headframe. There were no significant differences in geometric distortion between the new head coil and the standard coil. Conclusions. The new head coil has advantages for reducing patient movement artifacts and has a better signal/noise ratio with no reduction in geometric accuracy.

scholarly journals Alteration within the Hippocampal Volume in Patients with LHON Disease—7 Tesla MRI Study

2020 ◽  
Vol 10 (1) ◽  
pp. 14
Author(s):  
Cezary Grochowski ◽  
Kamil Jonak ◽  
Marcin Maciejewski ◽  
Andrzej Stępniewski ◽  
Mansur Rahnama-Hezavah
Keyword(s):  
Magnetic Resonance Imaging ◽  
Magnetic Resonance ◽  
Molecular Layer ◽  
Three Dimensional ◽  
Hippocampal Volume ◽  
7 Tesla ◽  
Diagnostic Process ◽  
Resonance Imaging ◽  
The Right

Purpose: The aim of this study was to assess the volumetry of the hippocampus in the Leber’s hereditary optic neuropathy (LHON) of blind patients. Methods: A total of 25 patients with LHON were randomly included into the study from the national health database. A total of 15 patients were selected according to the inclusion criteria. The submillimeter segmentation of the hippocampus was based on three-dimensional spoiled gradient recalled acquisition in steady state (3D-SPGR) BRAVO 7T magnetic resonance imaging (MRI) protocol. Results: Statistical analysis revealed that compared to healthy controls (HC), LHON subjects had multiple significant differences only in the right hippocampus, including a significantly higher volume of hippocampal tail (p = 0.009), subiculum body (p = 0.018), CA1 body (p = 0.002), hippocampal fissure (p = 0.046), molecular layer hippocampus (HP) body (p = 0.014), CA3 body (p = 0.006), Granule Cell (GC) and Molecular Layer (ML) of the Dentate Gyrus (DG)–GC ML DG body (p = 0.003), CA4 body (p = 0.001), whole hippocampal body (p = 0.018), and the whole hippocampus volume (p = 0.023). Discussion: The ultra-high-field magnetic resonance imaging allowed hippocampus quality visualization and analysis, serving as a powerful in vivo diagnostic tool in the diagnostic process and LHON disease course assessment. The study confirmed previous reports regarding volumetry of hippocampus in blind individuals.

scholarly journals Prefrontal and hippocampal atrophy using 7-tesla magnetic resonance imaging in patients with Parkinson’s disease

2021 ◽  
Vol 10 (2) ◽  
pp. 205846012098809
Author(s):  
Byeong H Oh ◽  
Hyeong C Moon ◽  
Aryun Kim ◽  
Hyeon J Kim ◽  
Chae J Cheong ◽  
...  
Keyword(s):  
Magnetic Resonance Imaging ◽  
Parkinson’S Disease ◽  
Parkinson's Disease ◽  
Magnetic Resonance ◽  
7 Tesla ◽  
Cortical Atrophy ◽  
Automated Segmentation ◽  
Healthy Controls ◽  
Segmentation Method ◽  
Resonance Imaging

Background The pathology of Parkinson’s disease leads to morphological changes in brain structure. Currently, the progressive changes in gray matter volume that occur with time and are specific to patients with Parkinson’s disease, compared to healthy controls, remain unclear. High-tesla magnetic resonance imaging might be useful in differentiating neurological disorders by brain cortical changes. Purpose We aimed to investigate patterns in gray matter changes in patients with Parkinson’s disease by using an automated segmentation method with 7-tesla magnetic resonance imaging. Material and Methods High-resolution T1-weighted 7 tesla magnetic resonance imaging volumes of 24 hemispheres were acquired from 12 Parkinson’s disease patients and 12 age- and sex-matched healthy controls with median ages of 64.5 (range, 41–82) years and 60.5 (range, 25–74) years, respectively. Subgroup analysis was performed according to whether axial motor symptoms were present in the Parkinson’s disease patients. Cortical volume, cortical thickness, and subcortical volume were measured using a high-resolution image processing technique based on the Desikan-Killiany-Tourville atlas and an automated segmentation method (FreeSurfer version 6.0). Results After cortical reconstruction, in 7 tesla magnetic resonance imaging volume segmental analysis, compared with the healthy controls, the Parkinson’s disease patients showed global cortical atrophy, mostly in the prefrontal area (rostral middle frontal, superior frontal, inferior parietal lobule, medial orbitofrontal, rostral anterior cingulate area), and subcortical volume atrophy in limbic/paralimbic areas (fusiform, hippocampus, amygdala). Conclusion We first demonstrated that 7 tesla magnetic resonance imaging detects structural abnormalities in Parkinson’s disease patients compared to healthy controls using an automated segmentation method. Compared with the healthy controls, the Parkinson’s disease patients showed global prefrontal cortical atrophy and hippocampal area atrophy.

scholarly journals Implantable NMR Microcoils in Rats: A New Tool for Exploring Tumor Metabolism at Sub-Microliter Scale?

Metabolites ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 176
Author(s):  
Justine Deborne ◽  
Noël Pinaud ◽  
Yannick Crémillieux
Keyword(s):  
Magnetic Resonance ◽  
Tumor Model ◽  
Surface Coil ◽  
Regions Of Interest ◽  
7 Tesla ◽  
Resonance Spectroscopy ◽  
Volume Coil ◽  
Detection Volume ◽  
The Right

The aim of this study was to evaluate the potential of a miniaturized implantable nuclear magnetic resonance (NMR) coil to acquire in vivo proton NMR spectra in sub-microliter regions of interest and to obtain metabolic information using magnetic resonance spectroscopy (MRS) in these small volumes. For this purpose, the NMR microcoils were implanted in the right cortex of healthy rats and in C6 glioma-bearing rats. The dimensions of the microcoil were 450 micrometers wide and 3 mm long. The MRS acquisitions were performed at 7 Tesla using volume coil for RF excitation and microcoil for signal reception. The detection volume of the microcoil was measured equal to 450 nL. A gain in sensitivity equal to 76 was found in favor of implanted microcoil as compared to external surface coil. Nine resonances from metabolites were assigned in the spectra acquired in healthy rats (n = 5) and in glioma-bearing rat (n = 1). The differences in relative amplitude of choline, lactate and creatine resonances observed in glioma-bearing animal were in agreement with published findings on this tumor model. In conclusion, the designed implantable microcoil is suitable for in vivo MRS and can be used for probing the metabolism in localized and very small regions of interest in a tumor.

scholarly journals Tissue Electrical Property Mapping From Zero Echo-Time Magnetic Resonance Imaging

2015 ◽  
Vol 34 (2) ◽  
pp. 541-550 ◽  
Author(s):  
Seung-Kyun Lee ◽  
Selaka Bulumulla ◽  
Florian Wiesinger ◽  
Laura Sacolick ◽  
Wei Sun ◽  
...  
Keyword(s):  
Magnetic Resonance Imaging ◽  
Electrical Property ◽  
Magnetic Resonance ◽  
Resonance Imaging ◽  
Echo Time
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