1
|
Carrell T, McDougall MP. Multi-channel magnetic resonance spectroscopy graphical user interface (McMRSGUI). PLoS One 2024; 19:e0299142. [PMID: 38416774 PMCID: PMC10901321 DOI: 10.1371/journal.pone.0299142] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2023] [Accepted: 02/06/2024] [Indexed: 03/01/2024] Open
Abstract
This work introduces an open-sourced graphical user interface (GUI) software enabling the combination of multi-channel magnetic resonance spectroscopy data with different literature-based methods for the improvement of the quality and reliability of combined spectra. The multi-channel magnetic resonance spectroscopy graphical user interface (McMRSGUI) is a MATLAB-based spectroscopy processing GUI equipped to load multi-channel MRS data, pre-process, combine, and export combined data for evaluation with open-source quantification software (jMRUI). A literature-based, decision-tree process was incorporated into the combination type selection to serve as a guide to minimize spectral distortion in selecting between weighting methods. Multi-channel, simulated spectra were combined with the different combination techniques and evaluated for spectral distortion to validate the code. The incorporation of the combination methods into a single processing software enables multi-channel magnetic resonance spectroscopy (MRS) data to be combined and compared for improved spectral quality with little user knowledge of combination techniques. Through the spectral peak distortion simulation of the combination methods, combined signal-to-noise ratio (SNR) values from the literature were verified. The spectral peak distortion simulation provides a secondary tool for researchers to estimate the spectral SNR levels when spectral distortion could occur and use this knowledge to further guide the selection of their combination technique. The McMRSGUI provides a software toolkit for evaluating multi-channel MRS data and their combination. Simulations evaluating spectral distortion at different noise levels were performed for each combination method to validate the GUI and demonstrate a method for researchers to assess the combined SNR levels at which they could be introducing spectral distortion.
Collapse
Affiliation(s)
- Travis Carrell
- Department of Biomedical Engineering, Texas A&M University, College Station, Texas, United States of America
| | - Mary P McDougall
- Department of Biomedical Engineering, Texas A&M University, College Station, Texas, United States of America
| |
Collapse
|
2
|
Krimmel SR, Laumann TO, Chauvin RJ, Hershey T, Roland JL, Shimony JS, Willie JT, Norris SA, Marek S, Van AN, Monk J, Scheidter KM, Whiting F, Ramirez-Perez N, Metoki A, Wang A, Kay BP, Nahman-Averbuch H, Fair DA, Lynch CJ, Raichle ME, Gordon EM, Dosenbach NUF. The brainstem's red nucleus was evolutionarily upgraded to support goal-directed action. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2023.12.30.573730. [PMID: 38260662 PMCID: PMC10802246 DOI: 10.1101/2023.12.30.573730] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/24/2024]
Abstract
The red nucleus is a large brainstem structure that coordinates limb movement for locomotion in quadrupedal animals (Basile et al., 2021). The humans red nucleus has a different pattern of anatomical connectivity compared to quadrupeds, suggesting a unique purpose (Hatschek, 1907). Previously the function of the human red nucleus remained unclear at least partly due to methodological limitations with brainstem functional neuroimaging (Sclocco et al., 2018). Here, we used our most advanced resting-state functional connectivity (RSFC) based precision functional mapping (PFM) in highly sampled individuals (n = 5) and large group-averaged datasets (combined N ~ 45,000), to precisely examine red nucleus functional connectivity. Notably, red nucleus functional connectivity to motor-effector networks (somatomotor hand, foot, and mouth) was minimal. Instead, red nucleus functional connectivity along the central sulcus was specific to regions of the recently discovered somato-cognitive action network (SCAN; (Gordon et al., 2023)). Outside of primary motor cortex, red nucleus connectivity was strongest to the cingulo-opercular (CON) and salience networks, involved in action/cognitive control (Dosenbach et al., 2007; Newbold et al., 2021) and reward/motivated behavior (Seeley, 2019), respectively. Functional connectivity to these two networks was organized into discrete dorsal-medial and ventral-lateral zones. Red nucleus functional connectivity to the thalamus recapitulated known structural connectivity of the dento-rubral thalamic tract (DRTT) and could prove clinically useful in functionally targeting the ventral intermediate (VIM) nucleus. In total, our results indicate that far from being a 'motor' structure, the red nucleus is better understood as a brainstem nucleus for implementing goal-directed behavior, integrating behavioral valence and action plans.
Collapse
Affiliation(s)
- Samuel R Krimmel
- Department of Neurology, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Timothy O Laumann
- Department of Psychiatry, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Roselyne J Chauvin
- Department of Neurology, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Tamara Hershey
- Department of Neurology, Washington University School of Medicine, St. Louis, Missouri, USA
- Department of Psychiatry, Washington University School of Medicine, St. Louis, Missouri, USA
- Mallinckrodt Institute of Radiology, Washington University School of Medicine, St. Louis, Missouri, USA
- Department of Psychological & Brain Sciences, Washington University, St. Louis, Missouri, USA
| | - Jarod L Roland
- Department of Neurosurgery, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Joshua S Shimony
- Mallinckrodt Institute of Radiology, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Jon T Willie
- Department of Neurology, Washington University School of Medicine, St. Louis, Missouri, USA
- Department of Psychiatry, Weill Cornell Medicine, New York, New York, USA
- Department of Neuroscience, Washington University School of Medicine, St. Louis, Missouri
| | - Scott A Norris
- Department of Neurology, Washington University School of Medicine, St. Louis, Missouri, USA
- Mallinckrodt Institute of Radiology, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Scott Marek
- Mallinckrodt Institute of Radiology, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Andrew N Van
- Department of Neurology, Washington University School of Medicine, St. Louis, Missouri, USA
- Department of Biomedical Engineering, Washington University, St. Louis, Missouri
| | - Julia Monk
- Department of Neurology, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Kristen M Scheidter
- Department of Neurology, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Forrest Whiting
- Department of Neurology, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Nadeshka Ramirez-Perez
- Department of Neurology, Washington University School of Medicine, St. Louis, Missouri, USA
- Department of Neurosurgery, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Athanasia Metoki
- Department of Neurology, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Anxu Wang
- Mallinckrodt Institute of Radiology, Washington University School of Medicine, St. Louis, Missouri, USA
- Division of Computation and Data Science, Washington University, St. Louis, Missouri, USA
| | - Benjamin P Kay
- Department of Neurology, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Hadas Nahman-Averbuch
- Washington University Pain Center, Department of Anesthesiology, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Damien A Fair
- Department of Pediatrics, University of Minnesota, Minneapolis, Minnesota, USA
- Masonic Institute for the Developing Brain, University of Minnesota, Minneapolis, Minnesota, USA
- Institute of Child Development, University of Minnesota, Minneapolis, Minnesota, USA
| | - Charles J Lynch
- Department of Psychiatry, Weill Cornell Medicine, New York, New York, USA
| | - Marcus E Raichle
- Department of Neurology, Washington University School of Medicine, St. Louis, Missouri, USA
- Mallinckrodt Institute of Radiology, Washington University School of Medicine, St. Louis, Missouri, USA
- Department of Psychological & Brain Sciences, Washington University, St. Louis, Missouri, USA
- Department of Neuroscience, Washington University School of Medicine, St. Louis, Missouri
- Department of Biomedical Engineering, Washington University, St. Louis, Missouri
| | - Evan M Gordon
- Mallinckrodt Institute of Radiology, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Nico U F Dosenbach
- Department of Neurology, Washington University School of Medicine, St. Louis, Missouri, USA
- Mallinckrodt Institute of Radiology, Washington University School of Medicine, St. Louis, Missouri, USA
- Department of Psychological & Brain Sciences, Washington University, St. Louis, Missouri, USA
- Department of Biomedical Engineering, Washington University, St. Louis, Missouri
- Program in Occupational Therapy, Washington University, St. Louis, Missouri, USA
- Department of Pediatrics, Washington University School of Medicine, St. Louis, Missouri, USA
| |
Collapse
|
3
|
Hou J, Bauer CC, Sun C, Malone B, Griffin J, Wright SM. A Four-Channel Broadband MRI Receive Array Coil. ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. ANNUAL INTERNATIONAL CONFERENCE 2023; 2023:1-4. [PMID: 38082622 DOI: 10.1109/embc40787.2023.10340396] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/18/2023]
Abstract
Low-impedance preamplifier decoupling is commonly used in RF coil array construction to minimize coupling between elements through mutual impedance. The trap circuit is an essential component in preamp decoupling techniques, but becomes a limiting factor in constructing multi-tuned, multi-nuclear coil arrays. In principle, it is possible to double-tune or multi-tune the trap circuits, but will add complexity and loss. We present a broadband decoupling approach using high impedance preamplifiers. A dual-tuned prototype four-channel array using this approach which targets 2H and 23 Na at 4.7T, has been previously constructed, evaluated and reported. Without any retuning of the array, the same setup is tested at the 23Na and 31P frequencies for 3T. Initial bench measurements and Chemical Shift Imaging (CSI) results are acquired and presented in this study.Clinical Relevance- This study could reduce the complexity of multi-nuclear array coil design.
Collapse
|
4
|
Alkandari D, Bosshard JC, Huang CH, Wright SM. Multiple slot modules for high field magnetic resonance imaging array coils. Magn Reson Med 2023; 89:2485-2498. [PMID: 36763854 DOI: 10.1002/mrm.29610] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2022] [Revised: 01/15/2023] [Accepted: 01/16/2023] [Indexed: 02/12/2023]
Abstract
PURPOSE Mitigating coupling effects between coil elements represents a continuing challenge. Here, we present a 16-bowtie slot volume coil arranged in eight independent dual-slot modules without the use of any decoupling circuits. METHODS Two electrically short "bowtie" slot antennas were used to form a "module." A bowtie configuration was chosen because electromagnetic modeling results show that bowtie slots exhibit improved B 1 + P in $$ \frac{B_1^{+}}{\sqrt{P_{in}}} $$ efficiency when compared to thin rectangular slots. An eight-module volume coil was evaluated through electromagnetic modeling, bench tests, and MRI experiments at 4.7 T. RESULTS Bench tests indicate that worst-case coupling between modules did not exceed -14.5 dB. MR images demonstrate well-localized patterns about single excited modules confirming the low coupling between modules. Homogeneous MR images were acquired from a synthesized quadrature birdcage transmit mode. MRI experiments show that the RF power requirements for the proposed coil are 9.2 times more than a birdcage coil. Whereas from simulations performed to assess the proposed coil losses, the total power dissipated in the phantom was 1.1 times more for the birdcage. Simulation results at 7 T reveal an equivalent B1 + homogeneity when compared with an eight-dipole coil. CONCLUSION Although exhibiting higher RF power requirements, as a transmit coil when the power availability is not a restriction, the inherently low coupling between electrically short slots should enable the use of many slot elements around the imaging volume. The slot module described in this paper should be useful in the design of multi-channel transmit coils.
Collapse
Affiliation(s)
- Dheyaa Alkandari
- Department of Electrical Engineering, Kuwait University, Kuwait City, Kuwait
| | - John C Bosshard
- Department of Electrical and Computer Engineering, Texas A&M University, College Station, Texas, USA
| | - Chung-Huan Huang
- Department of Electrical and Computer Engineering, Texas A&M University, College Station, Texas, USA
| | - Steven M Wright
- Department of Electrical and Computer Engineering, Texas A&M University, College Station, Texas, USA.,Department of Biomedical Engineering, Texas A&M University, College Station, Texas, USA
| |
Collapse
|
5
|
Lu M, Zhang X, Chai S, Yan X. Improving Specific Absorption Rate Efficiency and Coil Robustness of Self-Decoupled Transmit/Receive Coils by Elevating Feed and Mode Conductors. SENSORS (BASEL, SWITZERLAND) 2023; 23:1800. [PMID: 36850397 PMCID: PMC9960379 DOI: 10.3390/s23041800] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/12/2023] [Revised: 02/01/2023] [Accepted: 02/03/2023] [Indexed: 06/18/2023]
Abstract
Self-decoupling technology was recently proposed for radio frequency (RF) coil array designs. Here, we propose a novel geometry to reduce the peak local specific absorption rate (SAR) and improve the robustness of the self-decoupled coil. We first demonstrate that B1 is determined by the arm conductors, while the maximum E-field and local SAR are determined by the feed conductor in a self-decoupled coil. Then, we investigate how the B1, E-field, local SAR, SAR efficiency, and coil robustness change with respect to different lift-off distances for feed and mode conductors. Next, the simulation of self-decoupled coils with optimal lift-off distances on a realistic human body is performed. Finally, self-decoupled coils with optimal lift-off distances are fabricated and tested on the workbench and MRI experiments. The peak 10 g-averaged SAR of the self-decoupled coil on the human body can be reduced by 34% by elevating the feed conductor. Less coil mismatching and less resonant frequency shift with respect to loadings were observed by elevating the mode conductor. Both the simulation and experimental results show that the coils with elevated conductors can preserve the high interelement isolation, B1+ efficiency, and SNR of the original self-decoupled coils.
Collapse
Affiliation(s)
- Ming Lu
- College of Nuclear Equipment and Nuclear Engineering, Yantai University, Yantai 264005, China
| | - Xiaoyang Zhang
- College of Nuclear Equipment and Nuclear Engineering, Yantai University, Yantai 264005, China
| | - Shuyang Chai
- Vanderbilt University Institute of Imaging Science, Vanderbilt University Medical Center, Nashville, TN 37232, USA
- Department of Radiology and Radiological Sciences, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Xinqiang Yan
- Vanderbilt University Institute of Imaging Science, Vanderbilt University Medical Center, Nashville, TN 37232, USA
- Department of Radiology and Radiological Sciences, Vanderbilt University Medical Center, Nashville, TN 37232, USA
- Department of Electrical and Computer Engineering, Vanderbilt University, Nashville, TN 37232, USA
| |
Collapse
|
6
|
Watling SE, Jagasar S, McCluskey T, Warsh J, Rhind SG, Truong P, Chavez S, Houle S, Tong J, Kish SJ, Boileau I. Imaging oxidative stress in brains of chronic methamphetamine users: A combined 1H-magnetic resonance spectroscopy and peripheral blood biomarker study. Front Psychiatry 2023; 13:1070456. [PMID: 36704729 PMCID: PMC9871559 DOI: 10.3389/fpsyt.2022.1070456] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/14/2022] [Accepted: 12/20/2022] [Indexed: 01/13/2023] Open
Abstract
Introduction Preclinical data suggest methamphetamine (MA), a widely used stimulant drug, can harm the brain by causing oxidative stress and inflammation, but only limited information is available in humans. We tested the hypothesis that levels of glutathione (GSH), a major antioxidant, would be lower in the brains of chronic human MA preferring polysubstance users. We also explored if concentrations of peripheral immunoinflammatory blood biomarkers were related with brain GSH concentrations. Methods 20 healthy controls (HC) (33 years; 11 M) and 14 MA users (40 years; 9 M) completed a magnetic resonance spectroscopy (MRS) scan, with GSH spectra obtained by the interleaved J-difference editing MEGA-PRESS method in anterior cingulate cortex (ACC) and left dorsolateral prefrontal cortex (DLPFC). Peripheral blood samples were drawn for measurements of immunoinflammatory biomarkers. Independent samples t-tests evaluated MA vs. HC differences in GSH. Results GSH levels did not differ between HC and MA users (ACC p = 0.30; DLPFC p = 0.85). A total of 17 of 25 immunoinflammatory biomarkers were significantly elevated in MA users and matrix metalloproteinase (MMP)-2 (r = 0.577, p = 0.039), myeloperoxidase (MPO) (r = -0.556, p = 0.049), and MMP-9 (r = 0.660, p = 0.038) were correlated with brain levels of GSH. Conclusion Normal brain GSH in living brain of chronic MA users is consistent with our previous postmortem brain finding and suggests that any oxidative stress caused by MA, at the doses used by our participants, might not be sufficient to cause either a compensatory increase in, or substantial overutilization of, this antioxidant. Additionally, more research is required to understand how oxidative stress and inflammatory processes are related and potentially dysregulated in MA use.
Collapse
Affiliation(s)
- Sarah E. Watling
- Institute of Medical Sciences, University of Toronto, Toronto, ON, Canada
- Brain Health Imaging Centre, Centre for Addiction and Mental Health, Toronto, ON, Canada
| | - Samantha Jagasar
- Brain Health Imaging Centre, Centre for Addiction and Mental Health, Toronto, ON, Canada
| | - Tina McCluskey
- Brain Health Imaging Centre, Centre for Addiction and Mental Health, Toronto, ON, Canada
- Campbell Mental Health Research Institute, Centre for Addiction and Mental Health, Toronto, ON, Canada
| | - Jerry Warsh
- Institute of Medical Sciences, University of Toronto, Toronto, ON, Canada
- Brain Health Imaging Centre, Centre for Addiction and Mental Health, Toronto, ON, Canada
- Campbell Mental Health Research Institute, Centre for Addiction and Mental Health, Toronto, ON, Canada
- Department of Psychiatry, University of Toronto, Toronto, ON, Canada
- Department of Pharmacology and Toxicology, University of Toronto, Toronto, ON, Canada
| | - Shawn G. Rhind
- Faculty of Kinesiology and Physical Education, University of Toronto, Toronto, ON, Canada
- Defence Research and Development Canada, Toronto Research Centre, Toronto, ON, Canada
| | - Peter Truong
- Brain Health Imaging Centre, Centre for Addiction and Mental Health, Toronto, ON, Canada
| | - Sofia Chavez
- Brain Health Imaging Centre, Centre for Addiction and Mental Health, Toronto, ON, Canada
| | - Sylvain Houle
- Brain Health Imaging Centre, Centre for Addiction and Mental Health, Toronto, ON, Canada
- Campbell Mental Health Research Institute, Centre for Addiction and Mental Health, Toronto, ON, Canada
- Department of Psychiatry, University of Toronto, Toronto, ON, Canada
| | - Junchao Tong
- Brain Health Imaging Centre, Centre for Addiction and Mental Health, Toronto, ON, Canada
- Campbell Mental Health Research Institute, Centre for Addiction and Mental Health, Toronto, ON, Canada
- Department of Psychiatry, University of Toronto, Toronto, ON, Canada
| | - Stephen J. Kish
- Institute of Medical Sciences, University of Toronto, Toronto, ON, Canada
- Brain Health Imaging Centre, Centre for Addiction and Mental Health, Toronto, ON, Canada
- Campbell Mental Health Research Institute, Centre for Addiction and Mental Health, Toronto, ON, Canada
- Department of Psychiatry, University of Toronto, Toronto, ON, Canada
- Department of Pharmacology and Toxicology, University of Toronto, Toronto, ON, Canada
| | - Isabelle Boileau
- Institute of Medical Sciences, University of Toronto, Toronto, ON, Canada
- Brain Health Imaging Centre, Centre for Addiction and Mental Health, Toronto, ON, Canada
- Campbell Mental Health Research Institute, Centre for Addiction and Mental Health, Toronto, ON, Canada
- Department of Psychiatry, University of Toronto, Toronto, ON, Canada
- Department of Pharmacology and Toxicology, University of Toronto, Toronto, ON, Canada
| |
Collapse
|
7
|
Antoniou A, Georgiou L, Evripidou N, Ioannides C, Damianou C. Challenges regarding MR compatibility of an MRgFUS robotic system. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2022; 344:107317. [PMID: 36279604 DOI: 10.1016/j.jmr.2022.107317] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/15/2022] [Revised: 10/11/2022] [Accepted: 10/13/2022] [Indexed: 06/16/2023]
Abstract
Numerous challenges are faced when employing Magnetic Resonance guided Focused Ultrasound (MRgFUS) hardware in the Magnetic Resonance Imaging (MRI) setting. The current study aimed to provide insights on this topic through a series of experiments performed in the framework of evaluating the MRI compatibility of an MRgFUS robotic device. All experiments were performed in a 1.5 T MRI scanner. The main metric for MRI compatibility assessment was the signal to noise ratio (SNR). Measurements were carried out in a tissue mimicking phantom and freshly excised pork tissue under various activation states of the system. In the effort to minimize magnetic interference and image distortion, various set-up parameters were examined. Significant SNR degradation and image distortion occurred when the FUS transducer was activated mainly owing to FUS-induced target and coil vibrations and was getting worse as the output power was increased. Proper design and stable positioning of the imaged phantom play a critical role in reducing these vibrations. Moreover, isolation of the phantom from the imaging coil was proven essential for avoiding FUS-induced vibrations from being transferred to the coil during sonication and resulted in a more than 3-fold increase in SNR. The use of a multi-channel coil increased the SNR by up to 50 % compared to a single-channel coil. Placement of the electronics outside the coil detection area increased the SNR by about 65 %. A similar SNR improvement was observed when the encoders' counting pulses were deactivated. Overall, this study raises awareness about major challenges regarding operation of an MRgFUS system in the MRI environment and proposes simple measures that could mitigate the impact of noise sources so that the monitoring value of MR imaging in FUS applications is not compromised.
Collapse
Affiliation(s)
- Anastasia Antoniou
- Department of Electrical Engineering, Computer Engineering, and Informatics, Cyprus University of Technology, Limassol, Cyprus.
| | - Leonidas Georgiou
- German Oncology Center, Department of Interventional Radiology, Limassol, Cyprus.
| | - Nikolas Evripidou
- Department of Electrical Engineering, Computer Engineering, and Informatics, Cyprus University of Technology, Limassol, Cyprus.
| | - Cleanthis Ioannides
- German Oncology Center, Department of Interventional Radiology, Limassol, Cyprus.
| | - Christakis Damianou
- Department of Electrical Engineering, Computer Engineering, and Informatics, Cyprus University of Technology, Limassol, Cyprus.
| |
Collapse
|
8
|
Nam KM, Hendriks AD, Boer VO, Klomp DWJ, Wijnen JP, Bhogal AA. Proton metabolic mapping of the brain at 7 T using a two-dimensional free induction decay-echo-planar spectroscopic imaging readout with lipid suppression. NMR IN BIOMEDICINE 2022; 35:e4771. [PMID: 35577344 PMCID: PMC9541868 DOI: 10.1002/nbm.4771] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/27/2021] [Revised: 04/14/2022] [Accepted: 05/10/2022] [Indexed: 06/15/2023]
Abstract
The increased signal-to-noise ratio (SNR) and chemical shift dispersion at high magnetic fields (≥7 T) have enabled neuro-metabolic imaging at high spatial resolutions. To avoid very long acquisition times with conventional magnetic resonance spectroscopic imaging (MRSI) phase-encoding schemes, solutions such as pulse-acquire or free induction decay (FID) sequences with short repetition time and inner volume selection methods with acceleration (echo-planar spectroscopic imaging [EPSI]), have been proposed. With the inner volume selection methods, limited spatial coverage of the brain and long echo times may still impede clinical implementation. FID-MRSI sequences benefit from a short echo time and have a high SNR per time unit; however, contamination from strong extra-cranial lipid signals remains a problem that can hinder correct metabolite quantification. L2-regularization can be applied to remove lipid signals in cases with high spatial resolution and accurate prior knowledge. In this work, we developed an accelerated two-dimensional (2D) FID-MRSI sequence using an echo-planar readout and investigated the performance of lipid suppression by L2-regularization, an external crusher coil, and the combination of these two methods to compare the resulting spectral quality in three subjects. The reduction factor of lipid suppression using the crusher coil alone varies from 2 to 7 in the lipid region of the brain boundary. For the combination of the two methods, the average lipid area inside the brain was reduced by 2% to 38% compared with that of unsuppressed lipids, depending on the subject's region of interest. 2D FID-EPSI with external lipid crushing and L2-regularization provides high in-plane coverage and is suitable for investigating brain metabolite distributions at high fields.
Collapse
Affiliation(s)
- Kyung Min Nam
- Center for Image Sciences, Department of RadiologyUniversity Medical Centre UtrechtUtrecht
| | - Arjan D. Hendriks
- Center for Image Sciences, Department of RadiologyUniversity Medical Centre UtrechtUtrecht
| | - Vincent O. Boer
- Danish Research Centre for Magnetic Resonance, Centre for Functional and Diagnostic Imaging and ResearchCopenhagen University Hospital HvidovreHvidovreDenmark
| | - Dennis W. J. Klomp
- Center for Image Sciences, Department of RadiologyUniversity Medical Centre UtrechtUtrecht
| | - Jannie P. Wijnen
- Center for Image Sciences, Department of RadiologyUniversity Medical Centre UtrechtUtrecht
| | - Alex A. Bhogal
- Center for Image Sciences, Department of RadiologyUniversity Medical Centre UtrechtUtrecht
| |
Collapse
|
9
|
Swanberg KM, Kurada AV, Prinsen H, Juchem C. Multiple sclerosis diagnosis and phenotype identification by multivariate classification of in vivo frontal cortex metabolite profiles. Sci Rep 2022; 12:13888. [PMID: 35974117 PMCID: PMC9381573 DOI: 10.1038/s41598-022-17741-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2021] [Accepted: 07/29/2022] [Indexed: 12/04/2022] Open
Abstract
Multiple sclerosis (MS) is a heterogeneous autoimmune disease for which diagnosis continues to rely on subjective clinical judgment over a battery of tests. Proton magnetic resonance spectroscopy (1H MRS) enables the noninvasive in vivo detection of multiple small-molecule metabolites and is therefore in principle a promising means of gathering information sufficient for multiple sclerosis diagnosis and subtype classification. Here we show that supervised classification using 1H-MRS-visible normal-appearing frontal cortex small-molecule metabolites alone can indeed differentiate individuals with progressive MS from control (held-out validation sensitivity 79% and specificity 68%), as well as between relapsing and progressive MS phenotypes (held-out validation sensitivity 84% and specificity 74%). Post hoc assessment demonstrated the disproportionate contributions of glutamate and glutamine to identifying MS status and phenotype, respectively. Our finding establishes 1H MRS as a viable means of characterizing progressive multiple sclerosis disease status and paves the way for continued refinement of this method as an auxiliary or mainstay of multiple sclerosis diagnostics.
Collapse
Affiliation(s)
- Kelley M. Swanberg
- grid.25879.310000 0004 1936 8972Department of Biomedical Engineering, Columbia University Fu Foundation School of Engineering and Applied Science, 351 Engineering Terrace, 1210 Amsterdam Avenue, Mail Code: 8904, New York, NY 10027 USA ,grid.47100.320000000419368710Department of Radiology and Biomedical Imaging, Yale University School of Medicine, New Haven, CT USA
| | - Abhinav V. Kurada
- grid.25879.310000 0004 1936 8972Department of Biomedical Engineering, Columbia University Fu Foundation School of Engineering and Applied Science, 351 Engineering Terrace, 1210 Amsterdam Avenue, Mail Code: 8904, New York, NY 10027 USA
| | - Hetty Prinsen
- grid.47100.320000000419368710Department of Radiology and Biomedical Imaging, Yale University School of Medicine, New Haven, CT USA
| | - Christoph Juchem
- grid.25879.310000 0004 1936 8972Department of Biomedical Engineering, Columbia University Fu Foundation School of Engineering and Applied Science, 351 Engineering Terrace, 1210 Amsterdam Avenue, Mail Code: 8904, New York, NY 10027 USA ,grid.47100.320000000419368710Department of Radiology and Biomedical Imaging, Yale University School of Medicine, New Haven, CT USA ,grid.21729.3f0000000419368729Department of Radiology, Columbia University College of Physicians and Surgeons, New York, NY USA ,grid.47100.320000000419368710Department of Neurology, Yale University School of Medicine, New Haven, CT USA
| |
Collapse
|
10
|
Fukui H, Onishi H, Nakamoto A, Wakayama T, Ota T, Tsuboyama T, Yano K, Tarewaki H, Koyama Y, Tatsumi M, Tomiyama N. Impact of Adaptive Image Receive Coil Technology for Liver MR Imaging at 3.0 Tesla: Intraindividual Comparison with use of Conventional Coil. Eur J Radiol 2022; 150:110271. [DOI: 10.1016/j.ejrad.2022.110271] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2022] [Revised: 02/22/2022] [Accepted: 03/17/2022] [Indexed: 11/03/2022]
|
11
|
Carrell T, Gu M, Bosshard JC, Sun C, McDougall MP, Wright SM. Assessing the Feasibility of Dynamic 31P Spectroscopy for Metabolic Studies with a 1.0T Extremity Scanner. IEEE Trans Biomed Eng 2021; 69:1975-1982. [PMID: 34855583 DOI: 10.1109/tbme.2021.3132252] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Objective: The feasibility of conducting in vivo non-localized 31P Magnetic Resonance Spectroscopy (MRS) with a 1.0T extremity scanner and the potential to increase accessibility of this important diagnostic tool for low cost applications is revisited. Methods: This work presents a custom transmit-only quadrature birdcage, four-element receive coil array, and spectrometer interfaced to a commercial ONI 1.0T magnet for enabling multi-channel, non-1H frequency capabilities. A custom, magnetic resonance compatible plantar flexion-extension exercise device was also developed to enable exercise protocols. The coils were assessed with bench measurements and 31P phantom studies before an in vivo demonstration. Results: In pulse and acquire spectroscopy of a phantom, the array was found to improve the signal-to-noise ratio (SNR) by a factor of 1.31 and reduce the linewidth by 13.9% when compared to a large loop coil of the same overall size. In vivo testing results show that two averages and a four second repetition time for a temporal resolution of eight seconds was sufficient to obtain phosphocreatine recovery values and baseline pH levels aligned with expected literature values. Conclusion: Initial in vivo human skeletal muscle 31P MRS allowed successful monitoring of metabolic changes during an 18-minute exercise protocol. Significance: Adding an array coil and multinuclear capability to a commercial low-cost 1.0T extremity scanner enabled the observation of characteristic 31P metabolic information, such as the phosphocreatine recovery rate and underlying baseline pH.
Collapse
|
12
|
Priovoulos N, Roos T, Ipek Ö, Meliado EF, Nkrumah RO, Klomp DWJ, van der Zwaag W. A local multi-transmit coil combined with a high-density receive array for cerebellar fMRI at 7 T. NMR IN BIOMEDICINE 2021; 34:e4586. [PMID: 34231292 PMCID: PMC8519055 DOI: 10.1002/nbm.4586] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/14/2020] [Revised: 06/09/2021] [Accepted: 06/22/2021] [Indexed: 06/13/2023]
Abstract
The human cerebellum is involved in a wide array of functions, ranging from motor control to cognitive control, and as such is of great neuroscientific interest. However, its function is underexplored in vivo, due to its small size, its dense structure and its placement at the bottom of the brain, where transmit and receive fields are suboptimal. In this study, we combined two dense coil arrays of 16 small surface receive elements each with a transmit array of three antenna elements to improve BOLD sensitivity in the human cerebellum at 7 T. Our results showed improved B1+ and SNR close to the surface as well as g-factor gains compared with a commercial coil designed for whole-head imaging. This resulted in improved signal stability and large gains in the spatial extent of the activation close to the surface (<3.5 cm), while good performance was retained deeper in the cerebellum. Modulating the phase of the transmit elements of the head coil to constructively interfere in the cerebellum improved the B1+ , resulting in a temporal SNR gain. Overall, our results show that a dedicated transmit array along with the SNR gains of surface coil arrays can improve cerebellar imaging, at the cost of a decreased field of view and increased signal inhomogeneity.
Collapse
Affiliation(s)
- Nikos Priovoulos
- Spinoza Center for NeuroimagingRoyal Netherlands Academy of Arts and Sciences (KNAW)AmsterdamThe Netherlands
| | - Thomas Roos
- Spinoza Center for NeuroimagingRoyal Netherlands Academy of Arts and Sciences (KNAW)AmsterdamThe Netherlands
| | - Özlem Ipek
- Department of Biomedical Engineering, School of Biomedical Engineering & Imaging SciencesKing's College LondonLondonUK
| | - Ettore F. Meliado
- Image Sciences InstituteUniversity Medical Center UtrechtUtrechtNetherlands
| | - Richard O. Nkrumah
- Department of Biomedical Engineering, School of Biomedical Engineering & Imaging SciencesKing's College LondonLondonUK
| | - Dennis W. J. Klomp
- Image Sciences InstituteUniversity Medical Center UtrechtUtrechtNetherlands
| | - Wietske van der Zwaag
- Spinoza Center for NeuroimagingRoyal Netherlands Academy of Arts and Sciences (KNAW)AmsterdamThe Netherlands
| |
Collapse
|
13
|
Kang Y, Chen Y, Fang J, Huang Y, Wang H, Gong Z, Zhan S, Tan W. Performance of a Flexible 12-Channel Head Coil in Comparison to Commercial 16- And 24-Channel Rigid Head Coils. Magn Reson Med Sci 2021; 21:623-631. [PMID: 34544923 PMCID: PMC9618927 DOI: 10.2463/mrms.mp.2021-0084] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Purpose: To compare the performance of a 12-channel flexible head coil (HFC12) with commercial 16-channel (HRC16) and 24-channel (HRC24) rigid coils. Methods: The phantom study was performed on a 1.5 T MR scanner with HFC12, HRC16, and HRC24. The SNR and noise correlation matrix of T1WI, T2WI, and diffusion weighted imaging (DWI) were measured. The SNR profiles were created according to the SNR. In addition, 1/g-factors were calculated in different acceleration directions. In the in vivo study, T1WI, T2WI, and DWI were performed in one healthy volunteer with three different coils. The SNR and noise correlation matrix were measured. Results: In the phantom study and in vivo study, the SNR of HFC12 in the transverse, sagittal, and coronal planes was the highest, followed by HRC24, and that of HRC16 was the lowest. The SNR profiles showed that the SNR at the edge of HFC12 was the highest. The mean value of the noise correlation matrix of HFC12 was the highest. The 1/g-factor results showed that HFC12 obtained the best acceleration ability in the head–foot acceleration direction when the reduction factor was set to two. The SNR of HFC12 in most cortices was significantly higher than that of HRC16 and HRC24, except in the occipital cortex. The SNR of HRC24 in the occipital cortex was higher than that of HFC12. Conclusion: The SNR of HFC12 in T1WI, T2WI, and DWI was better than that of the HRC24 and HFC16. The SNR of HFC12 in the cortex was significantly higher than that of the commercial rigid head coil, except in the occipital cortex.
Collapse
Affiliation(s)
- YingJie Kang
- Department of Radiology, Shuguang Hospital Affiliated with Shanghai University of Traditional Chinese Medicine
| | - YiLei Chen
- Department of Radiology, Shuguang Hospital Affiliated with Shanghai University of Traditional Chinese Medicine
| | - JieMing Fang
- Department of Diagnostic Radiology, City of Hope Medical Center
| | - YanWen Huang
- Department of Radiology, Shuguang Hospital Affiliated with Shanghai University of Traditional Chinese Medicine
| | - Hui Wang
- Department of Radiology, Shuguang Hospital Affiliated with Shanghai University of Traditional Chinese Medicine
| | - ZhiGang Gong
- Department of Radiology, Shuguang Hospital Affiliated with Shanghai University of Traditional Chinese Medicine
| | - SongHua Zhan
- Department of Radiology, Shuguang Hospital Affiliated with Shanghai University of Traditional Chinese Medicine
| | - WenLi Tan
- Department of Radiology, Shuguang Hospital Affiliated with Shanghai University of Traditional Chinese Medicine
| |
Collapse
|
14
|
Iwata Y, Nakajima S, Plitman E, Truong P, Bani-Fatemi A, Caravaggio F, Kim J, Shah P, Mar W, Chavez S, Remington G, Gerretsen P, De Luca V, Sailasuta N, Graff-Guerrero A. Glutathione Levels and Glutathione-Glutamate Correlation in Patients With Treatment-Resistant Schizophrenia. ACTA ACUST UNITED AC 2021; 2:sgab006. [PMID: 33969302 PMCID: PMC8086698 DOI: 10.1093/schizbullopen/sgab006] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Treatment-resistant schizophrenia (TRS) has been suggested to involve glutamatergic dysfunction. Glutathione (GSH), a dominant antioxidant, is known to be involved in glutamatergic neurotransmission. To date, no study has examined GSH levels in patients with TRS. The aim of this study was to examine GSH levels in the dorsal anterior cingulate cortex (dACC) of patients with TRS. Patients with schizophrenia were categorized into 3 groups with respect to their antipsychotic response: (1) clozapine (CLZ) nonresponders, (2) CLZ responders, and (3) first-line responders (FLR). GSH and glutamine + glutamate (Glx) levels were measured using 3T proton magnetic resonance spectroscopy. Firstly, dACC GSH levels were compared among the patient groups and healthy controls (HCs). Further, relationships between GSH and Glx levels were compared between the groups and GSH levels were explored stratifying the patient groups based on the glutamate-cysteine ligase catalytic (GCLC) subunit polymorphism. There was no difference in GSH levels between the groups. FLR showed a more negative relationship between GSH and Glx levels in the dACC compared to HCs. There were no effects of GCLC genotype on the GSH levels. However, CLZ responders had a higher ratio of high-risk GCLC genotype compared to CLZ nonresponders. This study demonstrated different relationships between GSH and Glx in the dACC between groups. In addition, the results suggest a potential link between CLZ response and GCLC genotype. However, it still remains unclear how these differences are related to the underlying pathophysiology of schizophrenia subtypes or the mechanisms of action of CLZ.
Collapse
Affiliation(s)
- Yusuke Iwata
- Research Imaging Centre, Centre for Addiction and Mental Health, Toronto, ON, Canada.,Department of Psychiatry, University of Toronto, Toronto, ON, Canada.,Geriatric Mental Health Division, Centre for Addiction and Mental Health, Toronto, ON, Canada.,Department of Neuropsychiatry, School of Medicine, Keio University, Tokyo, Japan
| | - Shinichiro Nakajima
- Research Imaging Centre, Centre for Addiction and Mental Health, Toronto, ON, Canada.,Department of Neuropsychiatry, School of Medicine, Keio University, Tokyo, Japan
| | - Eric Plitman
- Research Imaging Centre, Centre for Addiction and Mental Health, Toronto, ON, Canada.,Institute of Medical Science, University of Toronto, Toronto, ON, Canada
| | - Peter Truong
- Research Imaging Centre, Centre for Addiction and Mental Health, Toronto, ON, Canada
| | - Ali Bani-Fatemi
- Institute of Medical Science, University of Toronto, Toronto, ON, Canada
| | - Fernando Caravaggio
- Research Imaging Centre, Centre for Addiction and Mental Health, Toronto, ON, Canada
| | - Julia Kim
- Research Imaging Centre, Centre for Addiction and Mental Health, Toronto, ON, Canada.,Institute of Medical Science, University of Toronto, Toronto, ON, Canada
| | - Parita Shah
- Research Imaging Centre, Centre for Addiction and Mental Health, Toronto, ON, Canada.,Institute of Medical Science, University of Toronto, Toronto, ON, Canada
| | - Wanna Mar
- Research Imaging Centre, Centre for Addiction and Mental Health, Toronto, ON, Canada
| | - Sofia Chavez
- Research Imaging Centre, Centre for Addiction and Mental Health, Toronto, ON, Canada
| | - Gary Remington
- Department of Psychiatry, University of Toronto, Toronto, ON, Canada.,Institute of Medical Science, University of Toronto, Toronto, ON, Canada.,Schizophrenia Division, Centre for Addiction and Mental Health, Toronto, ON, Canada.,Campbell Institute Research Program, Centre for Addiction and Mental Health, Toronto, ON, Canada
| | - Philip Gerretsen
- Research Imaging Centre, Centre for Addiction and Mental Health, Toronto, ON, Canada.,Department of Psychiatry, University of Toronto, Toronto, ON, Canada.,Geriatric Mental Health Division, Centre for Addiction and Mental Health, Toronto, ON, Canada.,Campbell Institute Research Program, Centre for Addiction and Mental Health, Toronto, ON, Canada
| | - Vincenzo De Luca
- Department of Psychiatry, University of Toronto, Toronto, ON, Canada.,Geriatric Mental Health Division, Centre for Addiction and Mental Health, Toronto, ON, Canada.,Campbell Institute Research Program, Centre for Addiction and Mental Health, Toronto, ON, Canada
| | - Napapon Sailasuta
- Research Imaging Centre, Centre for Addiction and Mental Health, Toronto, ON, Canada.,Department of Psychiatry, University of Toronto, Toronto, ON, Canada.,Department of Tropical Medicine, University of Hawaii, Honolulu, HI, USA
| | - Ariel Graff-Guerrero
- Research Imaging Centre, Centre for Addiction and Mental Health, Toronto, ON, Canada.,Department of Psychiatry, University of Toronto, Toronto, ON, Canada.,Geriatric Mental Health Division, Centre for Addiction and Mental Health, Toronto, ON, Canada.,Campbell Institute Research Program, Centre for Addiction and Mental Health, Toronto, ON, Canada
| |
Collapse
|
15
|
Wilcox M, Ogier S, Cheshkov S, Dimitrov I, Malloy C, Wright S, McDougall M. A 16-Channel 13C Array Coil for Magnetic Resonance Spectroscopy of the Breast at 7T. IEEE Trans Biomed Eng 2021; 68:2036-2046. [PMID: 33651680 DOI: 10.1109/tbme.2021.3063061] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
OBJECTIVE Considering the reported elevation of ω-6/ω-3 fatty acid ratios in breast neoplasms, one particularly important application of 13C MRS could be in more fully understanding the breast lipidome's relationship to breast cancer incidence. However, the low natural abundance and gyromagnetic ratio of the 13C isotope lead to detection sensitivity challenges. Previous 13C MRS studies have relied on the use of small surface coils with limited field-of-view and shallow penetration depths to achieve adequate signal-to-noise ratio (SNR), and the use of receive array coils is still mostly unexplored. METHODS This work presents a unilateral breast 16-channel 13C array coil and interfacing hardware designed to retain the surface sensitivity of a single small loop coil while improving penetration depth and extending the field-of-view over the entire breast at 7T. The coil was characterized through bench measurements and phantom 13C spectroscopy experiments. RESULTS Bench measurements showed receive coil matching better than -17 dB and average preamplifier decoupling of 16.2 dB with no evident peak splitting. Phantom MRS studies show better than a three-fold increase in average SNR over the entirety of the breast region compared to volume coil reception alone as well as an ability for individual array elements to be used for coarse metabolite localization without the use of single-voxel or spectroscopic imaging methods. CONCLUSION Our current study has shown the benefits of the array. Future in vivo lipidomics studies can be pursued. SIGNIFICANCE Development of the 16-channel breast array coil opens possibilities of in vivo lipidomics studies to elucidate the link between breast cancer incidence and lipid metabolics.
Collapse
|
16
|
Lopez Kolkovsky AL, Marty B, Giacomini E, Meyerspeer M, Carlier PG. Repeatability of multinuclear interleaved acquisitions with nuclear Overhauser enhancement effect in dynamic experiments in the calf muscle at 3T. Magn Reson Med 2021; 86:115-130. [PMID: 33565187 DOI: 10.1002/mrm.28684] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2020] [Revised: 12/23/2020] [Accepted: 12/23/2020] [Indexed: 02/01/2023]
Abstract
PURPOSE To evaluate the repeatability of multinuclear interleaved 1 H/31 P NMR dynamic acquisitions in skeletal muscle and the impact of nuclear Overhauser enhancement (nOe) on the 31 P results at 3T in exercise-recovery and ischemia-hyperemia paradigms. METHODS A 1 H/31 P interleaved pulse sequence was used to measure every 2.5 s a perfusion-weighted image, a T 2 ∗ map, a 31 P spectrum and 32 1 H spectra sensitive to deoxymyoglobin. 21 subjects performed a plantar flexion exercise and after recovery underwent an 8-min lower leg ischemia. The procedure was repeated in visit 2 with 12 subjects. An additional exercise bout without 1 H excitation was appended to visit 1. Individual 1 H RF pulse nOe was measured at rest in every visit. RESULTS Repeatability scores (coefficient of variation, Bland-Altman analysis) were similar to those found in the literature using similar mono-nuclear acquisitions. |Pi]/[PCr], pH drop, creatine rephosphorylation rate (τPCr ), maximum perfusion, time to peak perfusion, and blood flow post-exercise showed high reliability (intraclass correlation coefficient > 0.7), whereas hemodynamic results from reactive hyperemia showed higher repeatability. After accounting for nOe, which increased Pi and PCr signal-to-noise ratio by 30%, no differences in 31 P results were observed between interleaved and 31 P MRS-only acquisitions. τPCr was unaffected by nOe. CONCLUSION The method shows good repeatability for both paradigms while simultaneously providing multiple dynamic data sets on a clinical scanner. The nOe effects were accounted for on a per-subject and per-visit basis using a short 31 P reference scan. This multiparametric approach has a multitude of applications for the study of oxygen utilization and ATP turnover in the muscle.
Collapse
Affiliation(s)
- Alfredo L Lopez Kolkovsky
- NMR Laboratory, Neuromuscular Investigation Center, Institute of Myology, Paris, France.,NMR Laboratory, CEA, DRF, IBFJ, MIRCen, Paris, France
| | - Benjamin Marty
- NMR Laboratory, Neuromuscular Investigation Center, Institute of Myology, Paris, France.,NMR Laboratory, CEA, DRF, IBFJ, MIRCen, Paris, France
| | - Eric Giacomini
- NMR Laboratory, Neuromuscular Investigation Center, Institute of Myology, Paris, France
| | - Martin Meyerspeer
- High Field MR Center, Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna, Austria
| | - Pierre G Carlier
- NMR Laboratory, Neuromuscular Investigation Center, Institute of Myology, Paris, France.,NMR Laboratory, CEA, DRF, IBFJ, MIRCen, Paris, France
| |
Collapse
|
17
|
Stocker D, Manoliu A, Becker AS, Barth BK, Nanz D, Klarhöfer M, Donati OF. Impact of different phased-array coils on the quality of prostate magnetic resonance images. Eur J Radiol Open 2021; 8:100327. [PMID: 33644263 PMCID: PMC7889823 DOI: 10.1016/j.ejro.2021.100327] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2021] [Revised: 01/21/2021] [Accepted: 01/21/2021] [Indexed: 11/19/2022] Open
Abstract
Image quality is similar for different body phased-array receive coil setups. An 18-channel body phased-array receive coil setup achieved good image quality. 60-channel body phased-array receive coil setup slightly improves SNR in T2W images.
Purpose To evaluate the influence of body phased-array (BPA) receive coil setups on signal-to-noise ratio (SNR) and image quality (IQ) in prostate MRI. Methods This prospective study evaluated axial T2-weighted images (T2W-TSE) and DWI of the prostate in ten healthy volunteers with 18-channel (18CH), 30-channel and 60-channel (60CH) BPA receive coil setups. SNR and ADC values were assessed in the peripheral and transition zones (TZ). Two radiologists rated IQ features. Differences in qualitative and quantitative image features between BPA receive coil setups were compared. After correction for multiple comparisons, p-values <0.004 for quantitative and p-values <0.017 for qualitative image analysis were considered statistically significant. Results Significantly higher SNR was found in T2W-TSE images in the TZ using 60CH BPA compared to 18CH BPA coil setups (15.20 ± 4.22 vs. 7.68 ± 2.37; p = 0.001). There were no significant differences between all other quantitative (T2W-TSE, p = 0.007−0.308; DWI, p = 0.024−0.574) and qualitative image features (T2W-TSE, p = 0.083–1.0; DWI, p = 0.046–1.0). Conclusion 60CH BPA receive coil setup showed marginal SNR improvement in T2W-TSE images. Good IQ could be achieved with 18CH BPA coil setups.
Collapse
Key Words
- 18CH, BPA 18-channel body array coil
- 30CH, BPA 30-channel body array coil
- 60CH, BPA 60-channel body array coil
- ANOVA, Analysis of variances
- BPA, Body phased-array
- ERC, Endorectal coil
- ICC, Intra-class correlation coefficient
- IQR, Interquartile range
- Magnetic resonance imaging
- PSTT, Post-hoc paired-sample t-tests
- Prostate imaging
- ROIs, Region of interests
- SD, Standard deviation
- SNR, Signal to noise ratio
- Signal-to-noise ratio
- T2W-TSE, T2-weighted turbo spin echo
- mpMRI, Multi-parametric magnetic resonance imaging
- ss-DWI-EPI, Single-shot diffusion-weighting spin-echo echo-planar imaging
Collapse
Affiliation(s)
- Daniel Stocker
- Institute of Diagnostic and Interventional Radiology, University Hospital Zurich and University of Zurich, Switzerland
| | - Andrei Manoliu
- Institute of Diagnostic and Interventional Radiology, University Hospital Zurich and University of Zurich, Switzerland
- Max-Planck UCL Centre for Computational Psychiatry and Ageing Research, London, UK
- Wellcome Trust Centre for Human Neuroimaging, UCL, London, UK
- Psychiatric University Hospital, University of Zurich, Switzerland
| | - Anton S. Becker
- Institute of Diagnostic and Interventional Radiology, University Hospital Zurich and University of Zurich, Switzerland
| | - Borna K. Barth
- Institute of Diagnostic and Interventional Radiology, University Hospital Zurich and University of Zurich, Switzerland
| | - Daniel Nanz
- Institute of Diagnostic and Interventional Radiology, University Hospital Zurich and University of Zurich, Switzerland
- Swiss Center for Musculoskeletal Imaging, SCMI, Balgrist Campus AG, Switzerland and Medical Faculty, University of Zurich, Zurich, Switzerland
| | | | - Olivio F. Donati
- Institute of Diagnostic and Interventional Radiology, University Hospital Zurich and University of Zurich, Switzerland
- Corresponding author at: Institute of Diagnostic and Interventional Radiology, University Hospital Zurich, Rämistrasse 100, CH-8091, Zurich, Switzerland.
| |
Collapse
|
18
|
Enomoto A, Ichikawa K. Dual channel EPR excitation coil array for Overhauser-enhanced MRI. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2021; 323:106890. [PMID: 33352434 DOI: 10.1016/j.jmr.2020.106890] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/18/2020] [Revised: 12/05/2020] [Accepted: 12/07/2020] [Indexed: 06/12/2023]
Abstract
This article describes the development of a two-channel surface coil array for Overhauser-enhanced magnetic resonance imaging (OMRI) with the aim of extending the visualization area. The surface coil array consists of two independent surface coil resonators and PIN-diode switches. We utilized the PIN-diode switch to decouple the surface coils. OMRI measurement using a surface coil array was sequentially performed by switching the channels. To evaluate the effectiveness of the surface coil array, we demonstrated OMRI measurements using a phantom filled with nitroxide solution. In addition, in vivo OMRI imaging with a mouse was performed to demonstrate the applicability of our surface coil array to in vivo measurements. As a result, the visualization area obtained with our surface coil array was extended approximately 2-fold compared to the conventional single surface coil. Furthermore, we showed that in vivo imaging with the surface coil array was possible. These results indicate that the surface coil array could enhance the applicability of OMRI imaging.
Collapse
Affiliation(s)
- Ayano Enomoto
- Department of Biophysical Chemistry, Faculty of Pharmaceutical Sciences, Nagasaki International University, 2825-7 Huis Ten Bosch, Sasebo, Nagasaki 859-3298, Japan.
| | - Kazuhiro Ichikawa
- Department of Biophysical Chemistry, Faculty of Pharmaceutical Sciences, Nagasaki International University, 2825-7 Huis Ten Bosch, Sasebo, Nagasaki 859-3298, Japan
| |
Collapse
|
19
|
Xu Z, Niedzielski JS, Sun C, Walker CM, Michel KA, Einstein SA, Martinez GV, Bankson JA. Correction and optimization of symmetric echo-planar spectroscopic imaging for hyperpolarized [1- 13C]-pyruvate. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2020; 321:106859. [PMID: 33160268 PMCID: PMC7722237 DOI: 10.1016/j.jmr.2020.106859] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/21/2020] [Revised: 10/21/2020] [Accepted: 10/23/2020] [Indexed: 06/11/2023]
Abstract
Symmetric echo-planar spectroscopic imaging (EPSI) supports higher spectral bandwidth and improves signal-to-noise efficiency compared to flyback EPSI with the same readout bandwidth, but suffers from artifacts that are associated with non-uniform temporal sampling in k-t space. Our goal is to eliminate these artifacts and enhance observation of hyperpolarized [1-13C] pyruvate and its metabolites using symmetric EPSI. We used symmetric EPSI to efficiently acquire radially encoded spectroscopic imaging projections with a spectral under-sampling scheme that was optimized for HP pyruvate and its metabolites. A simple approach called selective correction of off-resonance effects (SCORE) was developed and applied to eliminate spectral artifacts. Simulations were used to assess the relative SNR performance of this technique, and a phantom study was carried out at 3 T to evaluate this method and compare it with alternative strategies. SCORE correction eliminated spectral artifacts due to chemical shift and non-uniform sampling in time. It is also compatible with established methods to eliminate artifacts caused by eddy currents. SCORE corrected symmetric EPSI supported maximal EPSI spectral bandwidth and improved SNR efficiency. Symmetric EPSI with SCORE correction offers a straightforward, efficient, and effective framework for assessment of hyperpolarized [1-13C] pyruvate and its metabolites.
Collapse
Affiliation(s)
- Zhan Xu
- Department of Imaging Physics, The University of Texas-MD Anderson Cancer Center, Houston, TX, USA
| | - Joshua S Niedzielski
- Department of Imaging Physics, The University of Texas-MD Anderson Cancer Center, Houston, TX, USA
| | - Changyu Sun
- Department of Imaging Physics, The University of Texas-MD Anderson Cancer Center, Houston, TX, USA
| | - Christopher M Walker
- Department of Imaging Physics, The University of Texas-MD Anderson Cancer Center, Houston, TX, USA
| | - Keith A Michel
- Department of Imaging Physics, The University of Texas-MD Anderson Cancer Center, Houston, TX, USA; The University of Texas MD Anderson Cancer Center UT Health Graduate School of Biomedical Sciences, Houston, TX, USA
| | - Samuel A Einstein
- Department of Imaging Physics, The University of Texas-MD Anderson Cancer Center, Houston, TX, USA
| | - Gary V Martinez
- Department of Imaging Physics, The University of Texas-MD Anderson Cancer Center, Houston, TX, USA
| | - James A Bankson
- Department of Imaging Physics, The University of Texas-MD Anderson Cancer Center, Houston, TX, USA; The University of Texas MD Anderson Cancer Center UT Health Graduate School of Biomedical Sciences, Houston, TX, USA.
| |
Collapse
|
20
|
Mallikourti V, Cheung SM, Gagliardi T, Senn N, Masannat Y, McGoldrick T, Sharma R, Heys SD, He J. Phased-array combination of 2D MRS for lipid composition quantification in patients with breast cancer. Sci Rep 2020; 10:20041. [PMID: 33208767 PMCID: PMC7676263 DOI: 10.1038/s41598-020-74397-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2019] [Accepted: 08/24/2020] [Indexed: 12/24/2022] Open
Abstract
Lipid composition in breast cancer, a central marker of disease progression, can be non-invasively quantified using 2D MRS method of double quantum filtered correlation spectroscopy (DQF-COSY). The low signal to noise ratio (SNR), arising from signal retention of only 25% and depleted lipids within tumour, demands improvement approaches beyond signal averaging for clinically viable applications. We therefore adapted and examined combination algorithms, designed for 1D MRS, for 2D MRS with both internal and external references. Lipid composition spectra were acquired from 17 breast tumour specimens, 15 healthy female volunteers and 25 patients with breast cancer on a clinical 3 T MRI scanner. Whitened singular value decomposition (WSVD) with internal reference yielded maximal SNR with an improvement of 53.3% (40.3-106.9%) in specimens, 84.4 ± 40.6% in volunteers, 96.9 ± 54.2% in peritumoural adipose tissue and 52.4% (25.1-108.0%) in tumours in vivo. Non-uniformity, as variance of improvement across peaks, was low at 21.1% (13.7-28.1%) in specimens, 5.5% (4.2-7.2%) in volunteers, 6.1% (5.0-9.0%) in peritumoural tissue, and 20.7% (17.4-31.7%) in tumours in vivo. The bias (slope) in improvement ranged from - 1.08 to 0.21%/ppm along the diagonal directions. WSVD is therefore the optimal algorithm for lipid composition spectra with highest SNR uniformly across peaks, reducing acquisition time by up to 70% in patients, enabling clinical applications.
Collapse
Affiliation(s)
- Vasiliki Mallikourti
- Institute of Medical Sciences, School of Medicine, University of Aberdeen, Aberdeen, UK.
| | - Sai Man Cheung
- Institute of Medical Sciences, School of Medicine, University of Aberdeen, Aberdeen, UK
| | - Tanja Gagliardi
- Institute of Medical Sciences, School of Medicine, University of Aberdeen, Aberdeen, UK
- Department of Radiology, Royal Marsden Hospital, London, UK
| | - Nicholas Senn
- Institute of Medical Sciences, School of Medicine, University of Aberdeen, Aberdeen, UK
| | | | | | - Ravi Sharma
- Department of Oncology, Aberdeen Royal Infirmary, Aberdeen, UK
| | - Steven D Heys
- Institute of Medical Sciences, School of Medicine, University of Aberdeen, Aberdeen, UK
- Breast Unit, Aberdeen Royal Infirmary, Aberdeen, UK
| | - Jiabao He
- Institute of Medical Sciences, School of Medicine, University of Aberdeen, Aberdeen, UK
| |
Collapse
|
21
|
Shen S, Xu Z, Koonjoo N, Rosen MS. Optimization of a Close-Fitting Volume RF Coil for Brain Imaging at 6.5 mT Using Linear Programming. IEEE Trans Biomed Eng 2020; 68:1106-1114. [PMID: 32746026 DOI: 10.1109/tbme.2020.3002077] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
OBJECTIVE The use of a close-fitting roughly head-shaped volume coil for MRI (magnetic resonance imaging) has the merit of improving the filling factor and thus the SNR (signal-to-noise ratio) from the brain. However, the surface of the RF coil follows that of the head which makes it difficult to determine an optimal coil winding pattern. We describe here a new method to optimize a head-shaped RF coil with the objective of maximizing its SNR and RF-magnetic-field homogeneity for operation at ultra-low magnetic field (6.5 mT, 276 kHz). METHODS The approach consists of FEM (finite-element-method) simulation and linear programing based optimization. RESULTS We have implemented the optimization and further studied the relationship between the design requirements and the performance of the RF coil. Finally, we constructed an optimal RF coil and scanned both a head-shaped phantom and a human subject. CONCLUSION The method we outline here provide new insight into the conductor layout needed for magnetic optimization of structurally complex coils, especially when tradeoffs between competing attributes (SNR and homogeneity in this case) must be made.
Collapse
|
22
|
Ogier SE, Wilcox M, Cheshkov S, Dimitrov IE, Malloy CR, McDougall MP, Wright SM. A Frequency Translation System for Multi-Channel, Multi-Nuclear MR Spectroscopy. IEEE Trans Biomed Eng 2020; 68:109-118. [PMID: 32746012 DOI: 10.1109/tbme.2020.2997770] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
OBJECTIVE Most MRI scanners are equipped to receive signals from 1H array coils but few support multi-channel reception for other nuclei. Using receive arrays can provide significant SNR benefits, usually exploited to enable accelerated imaging, but the extension of these arrays to non-1H nuclei has received less attention because of the relative lack of broadband array receivers. Non-1H nuclei often have low sensitivity and stand to benefit greatly from the increase in SNR that arrays can provide. This paper presents a cost-effective approach for adapting standard 1H multi-channel array receivers for use with other nuclei - in this case, 13C. METHODS A frequency translation system has been developed that uses active mixers residing at the magnet bore to convert the received signal from a non-1H array to the 1H frequency for reception by the host system receiver. RESULTS This system has been demonstrated at 4.7T and 7T while preserving SNR and isolation. 1H decoupling, particularly important for 13C detection, can be straightforwardly accommodated. CONCLUSION Frequency translation can convert 1H-only multi-channel receivers for use with other nuclei while maintaining SNR and channel isolation while still enabling 1H decoupling. SIGNIFICANCE This work allows existing multi-channel MRI receivers to be adapted to receive signals from nuclei other than 1H, allowing for the use of receive arrays for in vivo multi-nuclear NMR.
Collapse
|
23
|
Sun C, Bauer C, Busher J, McDougall MP, Wright SM. Investigation of Low-Cost Op-Amps as Decoupling Preamplifiers for MRI Array Coils. ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. ANNUAL INTERNATIONAL CONFERENCE 2020; 2020:1473-1476. [PMID: 33018269 PMCID: PMC9377184 DOI: 10.1109/embc44109.2020.9176250] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
The benefits of array coils in MRI and MRS are well known. A key component of essentially all array coils used today is the decoupling preamplifier. Unlike conventional 50 ohm low-noise preamps, decoupling preamps present a reactive impedance to the coil, which can be used to 'block' currents from being induced in the receive coil, reducing the impact of any electromagnetic coupling between array elements. While available from a number of vendors, a lower-cost solution would be advantageous. We investigate the use of conventional operational amplifiers as low-noise decoupling preamplifiers. In this paper the performance of the op-amp preamplifier is compared to conventional 50 Ω. The op-amp preamp design shows promise for use as a decoupling preamplifier with array coils.Clinical Relevance- This work could facilitate the development of array coils for spectroscopy and imaging.
Collapse
|
24
|
Sung D, Risk BB, Owusu‐Ansah M, Zhong X, Mao H, Fleischer CC. Optimized truncation to integrate multi-channel MRS data using rank-R singular value decomposition. NMR IN BIOMEDICINE 2020; 33:e4297. [PMID: 32249522 PMCID: PMC7317403 DOI: 10.1002/nbm.4297] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/24/2019] [Revised: 02/28/2020] [Accepted: 02/29/2020] [Indexed: 06/01/2023]
Abstract
Multi-channel phased receive arrays have been widely adopted for magnetic resonance imaging (MRI) and spectroscopy (MRS). An important step in the use of receive arrays for MRS is the combination of spectra collected from individual coil channels. The goal of this work was to implement an improved strategy termed OpTIMUS (i.e., optimized truncation to integrate multi-channel MRS data using rank-R singular value decomposition) for combining data from individual channels. OpTIMUS relies on spectral windowing coupled with a rank-R decomposition to calculate the optimal coil channel weights. MRS data acquired from a brain spectroscopy phantom and 11 healthy volunteers were first processed using a whitening transformation to remove correlated noise. Whitened spectra were then iteratively windowed or truncated, followed by a rank-R singular value decomposition (SVD) to empirically determine the coil channel weights. Spectra combined using the vendor-supplied method, signal/noise2 weighting, previously reported whitened SVD (rank-1), and OpTIMUS were evaluated using the signal-to-noise ratio (SNR). Significant increases in SNR ranging from 6% to 33% (P ≤ 0.05) were observed for brain MRS data combined with OpTIMUS compared with the three other combination algorithms. The assumption that a rank-1 SVD maximizes SNR was tested empirically, and a higher rank-R decomposition, combined with spectral windowing prior to SVD, resulted in increased SNR.
Collapse
Affiliation(s)
- Dongsuk Sung
- Department of Biomedical EngineeringGeorgia Institute of Technology and Emory University School of MedicineAtlantaGeorgia
| | - Benjamin B. Risk
- Department of Biostatistics and BioinformaticsEmory UniversityAtlantaGeorgia
| | - Maame Owusu‐Ansah
- Department of Radiology and Imaging SciencesEmory University School of MedicineAtlantaGeorgia
| | - Xiaodong Zhong
- MR R&D Collaborations, Siemens HealthcareLos AngelesCalifornia
| | - Hui Mao
- Department of Radiology and Imaging SciencesEmory University School of MedicineAtlantaGeorgia
| | - Candace C. Fleischer
- Department of Biomedical EngineeringGeorgia Institute of Technology and Emory University School of MedicineAtlantaGeorgia
- Department of Radiology and Imaging SciencesEmory University School of MedicineAtlantaGeorgia
| |
Collapse
|
25
|
Chhetri A, Li X, Rispoli JV. Current and Emerging Magnetic Resonance-Based Techniques for Breast Cancer. Front Med (Lausanne) 2020; 7:175. [PMID: 32478083 PMCID: PMC7235971 DOI: 10.3389/fmed.2020.00175] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2019] [Accepted: 04/15/2020] [Indexed: 01/10/2023] Open
Abstract
Breast cancer is the most commonly diagnosed cancer among women worldwide, and early detection remains a principal factor for improved patient outcomes and reduced mortality. Clinically, magnetic resonance imaging (MRI) techniques are routinely used in determining benign and malignant tumor phenotypes and for monitoring treatment outcomes. Static MRI techniques enable superior structural contrast between adipose and fibroglandular tissues, while dynamic MRI techniques can elucidate functional characteristics of malignant tumors. The preferred clinical procedure-dynamic contrast-enhanced MRI-illuminates the hypervascularity of breast tumors through a gadolinium-based contrast agent; however, accumulation of the potentially toxic contrast agent remains a major limitation of the technique, propelling MRI research toward finding an alternative, noninvasive method. Three such techniques are magnetic resonance spectroscopy, chemical exchange saturation transfer, and non-contrast diffusion weighted imaging. These methods shed light on underlying chemical composition, provide snapshots of tissue metabolism, and more pronouncedly characterize microstructural heterogeneity. This review article outlines the present state of clinical MRI for breast cancer and examines several research techniques that demonstrate capacity for clinical translation. Ultimately, multi-parametric MRI-incorporating one or more of these emerging methods-presently holds the best potential to afford improved specificity and deliver excellent accuracy to clinics for the prediction, detection, and monitoring of breast cancer.
Collapse
Affiliation(s)
- Apekshya Chhetri
- Magnetic Resonance Biomedical Engineering Laboratory, Weldon School of Biomedical Engineering, Purdue University, West Lafayette, IN, United States
- Basic Medical Sciences, College of Veterinary Medicine, Purdue University, West Lafayette, IN, United States
| | - Xin Li
- Magnetic Resonance Biomedical Engineering Laboratory, Weldon School of Biomedical Engineering, Purdue University, West Lafayette, IN, United States
| | - Joseph V. Rispoli
- Magnetic Resonance Biomedical Engineering Laboratory, Weldon School of Biomedical Engineering, Purdue University, West Lafayette, IN, United States
- Center for Cancer Research, Purdue University, West Lafayette, IN, United States
- School of Electrical & Computer Engineering, Purdue University, West Lafayette, IN, United States
| |
Collapse
|
26
|
Dehghani M, Zhang S, Kumaragamage C, Rosa‐Neto P, Near J. Dynamic
1
H‐MRS for detection of
13
C‐labeled glucose metabolism in the human brain at 3T. Magn Reson Med 2020; 84:1140-1151. [DOI: 10.1002/mrm.28188] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2019] [Revised: 01/06/2020] [Accepted: 01/06/2020] [Indexed: 01/15/2023]
Affiliation(s)
- Masoumeh Dehghani
- Centre d’Imagerie Cérébrale Douglas Mental Health University Institute Verdun Quebec Canada
- Department of Psychiatry McGill University Montreal Quebec Canada
| | - Steven Zhang
- Department of Neuroscience McGill University Montreal Quebec Canada
| | - Chathura Kumaragamage
- Department of Radiology and Biomedical Imaging Yale University New Haven Connecticut
| | - Pedro Rosa‐Neto
- Translational Neuroimaging Laboratory The McGill University Research Center for Studies in AgiNGAlzheimer’s Diseases Research UnitDouglas Research InstituteMcGill university Montreal Quebec Canada
- Department of Neurology and Neurosurgery, Psychiatry and Pharmacology and Therapeutics McGill University Montreal Quebec Canada
| | - Jamie Near
- Centre d’Imagerie Cérébrale Douglas Mental Health University Institute Verdun Quebec Canada
- Department of Psychiatry McGill University Montreal Quebec Canada
| |
Collapse
|
27
|
De Marchi D, Flori A, Martini N, Giovannetti G. Artifacts by Misalignment of Cardiac Magnetic Resonance Phased-array Coil Elements: From Simulation to In vivo Test. Curr Med Imaging 2020; 15:301-307. [PMID: 31989881 DOI: 10.2174/1573405613666171024150250] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2017] [Revised: 10/17/2017] [Accepted: 10/18/2017] [Indexed: 11/22/2022]
Abstract
BACKGROUND Cardiac magnetic resonance evaluations generally require a radiofrequency coil setup comprising a transmit whole-body coil and a receive coil. In particular, radiofrequency phased-array coils are employed to pick up the signals emitted by the nuclei with high signal-tonoise ratio and a large region of sensitivity. METHODS Literature discussed different technical issues on how to minimize interactions between array elements and how to combine data from such elements to yield optimum Signal-to-Noise Ratio images. However, image quality strongly depends upon the correct coil position over the heart and of one array coil portion with respect to the other. RESULTS In particular, simple errors in coil positioning could cause artifacts carrying to an inaccurate interpretation of cardiac magnetic resonance images. CONCLUSION This paper describes the effect of array elements misalignment, starting from coil simulation to cardiac magnetic resonance acquisitions with a 1.5 T scanner. Phased-array coil simulation was performed using the magnetostatic approach; moreover, phantom and in vivo experiments with a commercial 8-elements cardiac phased-array receiver coil permitted to estimate signal-to-noise ratio and B1 mapping for aligned and shifted coil.
Collapse
Affiliation(s)
- Daniele De Marchi
- Fondazione G. Monasterio CNR - Regione Toscana, via G. Moruzzi 1, 56124 Pisa, Italy
| | - Alessandra Flori
- Fondazione G. Monasterio CNR - Regione Toscana, via G. Moruzzi 1, 56124 Pisa, Italy
| | - Nicola Martini
- Fondazione G. Monasterio CNR - Regione Toscana, via G. Moruzzi 1, 56124 Pisa, Italy
| | - Giulio Giovannetti
- Fondazione G. Monasterio CNR - Regione Toscana, via G. Moruzzi 1, 56124 Pisa, Italy
| |
Collapse
|
28
|
Enriquez AG, Vincent JM, Rispoli JV. Dual-Tuned Removable Common-Mode Current Trap for Magnetic Resonance Imaging and Spectroscopy .. ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. ANNUAL INTERNATIONAL CONFERENCE 2020; 2019:6802-6805. [PMID: 31947402 DOI: 10.1109/embc.2019.8857944] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Magnetic resonance imaging (MRI) and magnetic resonance spectroscopy (MRS) are preferred methods of gathering structural and metabolic information from the body due to their non-invasive approach to obtaining a diagnosis. Dual-tuned radiofrequency (RF) coils can detect signals produced by both hydrogen and a second atomic nuclei of interest. However, undesired electromagnetic coupling often confounds both the design and utilization of RF coils. Coaxial shield currents, also known as common-mode currents, can be induced during MR scans and cause image distortion and reduction in signal-to-noise ratio (SNR); furthermore, the energy dissipated from the cabling can create heat that poses a risk of patient burns if the routed too closely. Thus, common-mode currents must be suppressed in RF coils by employing non-magnetic current traps. In this paper, we present a novel dual-tuned current trap that is fully removable and does not require soldering directly to the cable. The design was manufactured with 3D printing to support rapid fabrication and distribution. Bench measurements at the 3T Larmor frequencies for hydrogen and phosphorous-31 demonstrate common-mode attenuation of -18 dB and -8.4 dB respectively.
Collapse
|
29
|
Wilcox M, Wright SM, McDougall M. A Review of Non-1H RF Receive Arrays in Magnetic Resonance Imaging and Spectroscopy. IEEE OPEN JOURNAL OF ENGINEERING IN MEDICINE AND BIOLOGY 2020; 1:290-300. [PMID: 35402958 PMCID: PMC8975242 DOI: 10.1109/ojemb.2020.3030531] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2020] [Revised: 09/15/2020] [Accepted: 09/25/2020] [Indexed: 11/16/2022] Open
Abstract
It is now common practice to use radiofrequency (RF) coils to increase the signal-to-noise ratio (SNR) in 1H magnetic resonance imaging and spectroscopy experiments. Use of array coils for non-1H experiments, however, has been historically more limited despite the fact that these nuclei suffer inherently lower sensitivity and could benefit greatly from an increased SNR. Recent advancements in receiver technology and increased support from scanner manufacturers have now opened greater options for the use of array coils for non-1H magnetic resonance experiments. This paper reviews the research in adopting array coil technology with an emphasis on studies of the most commonly studied non-1H nuclei including 31P, 13C, 23Na, and 19F. These nuclei offer complementary information to 1H imaging and spectroscopy and have proven themselves important in the study of numerous disease processes. While recent work with non-1H array coils has shown promising results, the technology is not yet widely utilized and should see substantial developments in the coming years.
Collapse
|
30
|
Mao X, Vike NL, Talavage TM, Rispoli JV, Love DJ. Multiple-Input Multiple-Output (MIMO) MRI: Combining Parallel Excitation and Parallel Reception for Enhanced Imaging. IEEE TRANSACTIONS ON COMPUTATIONAL IMAGING 2019; 5:596-605. [PMID: 31875167 PMCID: PMC6929686 DOI: 10.1109/tci.2019.2904882] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/14/2023]
Abstract
Magnetic resonance imaging (MRI) plays a critical role in visualizing the structure and functions of the human body. In order to accelerate imaging time and improve image quality, radio-frequency (RF) coil receive arrays are commonly employed to acquire the magnetic resonance (MR) signal. Similarly, multiple transmit coils have been shown to accelerate and refine RF excitation. In this work, we investigate the optimization of total imaging time and image accuracy when considering both the transmit and receive coil arrays; we term this strategy multiple-input multiple-output (MIMO) MRI. Our RF pulse design method is modeled by minimizing the excitation errors while simultaneously maximizing the signal-to-noise ratio (SNR) of the reconstructed MR image. It further allows a key tradeoff between the two optimizers. Additionally, multiple acceleration factors, varying numbers of receive coils used, maximum excitation error tolerance, and different excitation patterns are simulated and analyzed in this model. For a given excitation pattern, our method is shown to improve the SNR by 18-130% under certain acceleration schemes, as compared to conventional parallel transmission methods, while simultaneously controlling the excitation error within a desired scope (NRMSE ≤ 0.12).
Collapse
Affiliation(s)
- Xianglun Mao
- School of Electrical and Computer Engineering, Purdue University, West Lafayette, IN, 47907
| | - Nicole L Vike
- School of Veterinary Medicine/Department of Basic Medical Sciences, Purdue University, West Lafayette, IN, 47907
| | - Thomas M Talavage
- School of Electrical and Computer Engineering, and the Weldon School of Biomedical Engineering, Purdue University, West Lafayette, IN, 47907
| | - Joseph V Rispoli
- Weldon School of Biomedical Engineering, and the School of Electrical and Computer Engineering, Purdue University, West Lafayette, IN, 47907
| | - David J Love
- School of Electrical and Computer Engineering, Purdue University, West Lafayette, IN, 47907
| |
Collapse
|
31
|
Mallikourti V, Cheung SM, Gagliardi T, Masannat Y, Heys SD, He J. Optimal Phased-Array Signal Combination For Polyunsaturated Fatty Acids Measurement In Breast Cancer Using Multiple Quantum Coherence MR Spectroscopy At 3T. Sci Rep 2019; 9:9259. [PMID: 31239527 PMCID: PMC6592938 DOI: 10.1038/s41598-019-45710-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2019] [Accepted: 06/05/2019] [Indexed: 11/09/2022] Open
Abstract
Polyunsaturated fatty acid (PUFA), a key marker in breast cancer, is non-invasively quantifiable using multiple quantum coherence (MQC) magnetic resonance spectroscopy (MRS) at the expense of losing half of the signal. Signal combination for phased array coils provides potential pathways to enhance the signal to noise ratio (SNR), with current algorithms developed for conventional brain MRS. Since PUFA spectra and the biochemical environment in the breast deviate significantly from those in the brain, we set out to identify the optimal algorithm for PUFA in breast cancer. Combination algorithms were compared using PUFA spectra from 17 human breast tumour specimens, 15 healthy female volunteers, and 5 patients with breast cancer on a clinical 3 T MRI scanner. Adaptively Optimised Combination (AOC) yielded the maximum SNR improvement in specimens (median, 39.5%; interquartile range: 35.5-53.2%, p < 0.05), volunteers (82.4 ± 37.4%, p < 0.001), and patients (median, 61%; range: 34-105%, p < 0.05), while independent from voxel volume (rho = 0.125, p = 0.632), PUFA content (rho = 0.256, p = 0.320) or water/fat ratio (rho = 0.353, p = 0.165). Using AOC, acquisition in patients is 1.5 times faster compared to non-noise decorrelated algorithms. Therefore, AOC is the most suitable current algorithm to improve SNR or accelerate the acquisition of PUFA MRS from breast in a clinical setting.
Collapse
Affiliation(s)
- Vasiliki Mallikourti
- Institute of Medical Sciences, School of Medicine, University of Aberdeen, Aberdeen, UK.
| | - Sai Man Cheung
- Institute of Medical Sciences, School of Medicine, University of Aberdeen, Aberdeen, UK
| | - Tanja Gagliardi
- Department of Clinical Radiology, Aberdeen Royal Infirmary, Aberdeen, UK
- Department of Radiology, Royal Marsden Hospital, London, UK
| | | | - Steven D Heys
- Institute of Medical Sciences, School of Medicine, University of Aberdeen, Aberdeen, UK
- Breast Unit, Aberdeen Royal Infirmary, Aberdeen, UK
| | - Jiabao He
- Institute of Medical Sciences, School of Medicine, University of Aberdeen, Aberdeen, UK
| |
Collapse
|
32
|
Li Y, Lee J, Zhang L, Chen Q, Tie C, Luo C, Zhang X, Liang D, Liu X, Zheng H. Design and testing of a 24-channel head coil for MR imaging at 3 T. Magn Reson Imaging 2019; 58:162-173. [DOI: 10.1016/j.mri.2019.01.020] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2018] [Revised: 12/07/2018] [Accepted: 01/22/2019] [Indexed: 11/29/2022]
|
33
|
Da Silva T, Hafizi S, Rusjan PM, Houle S, Wilson AA, Prce I, Sailasuta N, Mizrahi R. GABA levels and TSPO expression in people at clinical high risk for psychosis and healthy volunteers: a PET-MRS study. J Psychiatry Neurosci 2019; 44:111-119. [PMID: 30255837 PMCID: PMC6397035 DOI: 10.1503/jpn.170201] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
BACKGROUND γ-Aminobutyric acidergic (GABAergic) dysfunction and immune activation have been implicated in the pathophysiology of schizophrenia. Preclinical evidence suggests that inflammation-related abnormalities may contribute to GABAergic alterations in the brain, but this has never been investigated in vivo in humans. In this multimodal imaging study, we quantified cerebral GABA plus macromolecule (GABA+) levels in antipsychotic-naive people at clinical high risk for psychosis and in healthy volunteers. We investigated for the first time the association between GABA+ levels and expression of translocator protein 18 kDa (TSPO; a marker of microglial activation) using positron emission tomography (PET). METHODS Thirty-five people at clinical high risk for psychosis and 18 healthy volunteers underwent 3 T proton magnetic resonance spectroscopy to obtain GABA+ levels in the medial prefrontal cortex (mPFC). A subset (29 people at clinical high risk for psychosis and 15 healthy volunteers) also underwent a high-resolution [18F]FEPPA PET scan to quantify TSPO expression. Each participant was genotyped for the TSPO rs6971 polymorphism. RESULTS We found that GABA+ levels were significantly associated with TSPO expression in the mPFC (F1,40 = 10.45, p = 0.002). We found no significant differences in GABA+ levels in the mPFC (F1,51 = 0.00, p > 0.99) between people at clinical high risk for psychosis and healthy volunteers. We found no significant correlations between GABA+ levels or residuals of the association with TSPO expression and the severity of prodromal symptoms or cognition. LIMITATIONS Given the cross-sectional nature of this study, we could determine no cause-and-effect relationships for GABA alterations and TSPO expression. CONCLUSION Our findings suggest that TSPO expression is negatively associated with GABA+ levels in the prefrontal cortex, independent of disease status.
Collapse
Affiliation(s)
- Tania Da Silva
- From the Research Imaging Centre, Centre for Addiction and Mental Health, Toronto, Ont., Canada (Silva, Hafizi, Rusjan, Houle, Wilson, Prce, Sailasuta, Mizrahi); the Institute of Medical Science, University of Toronto, Toronto, Ont., Canada (Silva, Rusjan, Mizrahi); the Department of Psychiatry, University of Toronto, Toronto, Ont., Canada (Rusjan, Houle, Wilson, Mizrahi); and the Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health, Toronto, Ont., Canada (Rusjan, Houle, Sailasuta, Mizrahi)
| | - Sina Hafizi
- From the Research Imaging Centre, Centre for Addiction and Mental Health, Toronto, Ont., Canada (Silva, Hafizi, Rusjan, Houle, Wilson, Prce, Sailasuta, Mizrahi); the Institute of Medical Science, University of Toronto, Toronto, Ont., Canada (Silva, Rusjan, Mizrahi); the Department of Psychiatry, University of Toronto, Toronto, Ont., Canada (Rusjan, Houle, Wilson, Mizrahi); and the Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health, Toronto, Ont., Canada (Rusjan, Houle, Sailasuta, Mizrahi)
| | - Pablo M Rusjan
- From the Research Imaging Centre, Centre for Addiction and Mental Health, Toronto, Ont., Canada (Silva, Hafizi, Rusjan, Houle, Wilson, Prce, Sailasuta, Mizrahi); the Institute of Medical Science, University of Toronto, Toronto, Ont., Canada (Silva, Rusjan, Mizrahi); the Department of Psychiatry, University of Toronto, Toronto, Ont., Canada (Rusjan, Houle, Wilson, Mizrahi); and the Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health, Toronto, Ont., Canada (Rusjan, Houle, Sailasuta, Mizrahi)
| | - Sylvain Houle
- From the Research Imaging Centre, Centre for Addiction and Mental Health, Toronto, Ont., Canada (Silva, Hafizi, Rusjan, Houle, Wilson, Prce, Sailasuta, Mizrahi); the Institute of Medical Science, University of Toronto, Toronto, Ont., Canada (Silva, Rusjan, Mizrahi); the Department of Psychiatry, University of Toronto, Toronto, Ont., Canada (Rusjan, Houle, Wilson, Mizrahi); and the Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health, Toronto, Ont., Canada (Rusjan, Houle, Sailasuta, Mizrahi)
| | - Alan A Wilson
- From the Research Imaging Centre, Centre for Addiction and Mental Health, Toronto, Ont., Canada (Silva, Hafizi, Rusjan, Houle, Wilson, Prce, Sailasuta, Mizrahi); the Institute of Medical Science, University of Toronto, Toronto, Ont., Canada (Silva, Rusjan, Mizrahi); the Department of Psychiatry, University of Toronto, Toronto, Ont., Canada (Rusjan, Houle, Wilson, Mizrahi); and the Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health, Toronto, Ont., Canada (Rusjan, Houle, Sailasuta, Mizrahi)
| | - Ivana Prce
- From the Research Imaging Centre, Centre for Addiction and Mental Health, Toronto, Ont., Canada (Silva, Hafizi, Rusjan, Houle, Wilson, Prce, Sailasuta, Mizrahi); the Institute of Medical Science, University of Toronto, Toronto, Ont., Canada (Silva, Rusjan, Mizrahi); the Department of Psychiatry, University of Toronto, Toronto, Ont., Canada (Rusjan, Houle, Wilson, Mizrahi); and the Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health, Toronto, Ont., Canada (Rusjan, Houle, Sailasuta, Mizrahi)
| | - Napapon Sailasuta
- From the Research Imaging Centre, Centre for Addiction and Mental Health, Toronto, Ont., Canada (Silva, Hafizi, Rusjan, Houle, Wilson, Prce, Sailasuta, Mizrahi); the Institute of Medical Science, University of Toronto, Toronto, Ont., Canada (Silva, Rusjan, Mizrahi); the Department of Psychiatry, University of Toronto, Toronto, Ont., Canada (Rusjan, Houle, Wilson, Mizrahi); and the Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health, Toronto, Ont., Canada (Rusjan, Houle, Sailasuta, Mizrahi)
| | - Romina Mizrahi
- From the Research Imaging Centre, Centre for Addiction and Mental Health, Toronto, Ont., Canada (Silva, Hafizi, Rusjan, Houle, Wilson, Prce, Sailasuta, Mizrahi); the Institute of Medical Science, University of Toronto, Toronto, Ont., Canada (Silva, Rusjan, Mizrahi); the Department of Psychiatry, University of Toronto, Toronto, Ont., Canada (Rusjan, Houle, Wilson, Mizrahi); and the Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health, Toronto, Ont., Canada (Rusjan, Houle, Sailasuta, Mizrahi)
| |
Collapse
|
34
|
Austin AG, Raynor WY, Reilly CC, Zadeh MZ, Werner TJ, Zhuang H, Alavi A, Rajapakse CS. Evolving Role of MR Imaging and PET in Assessing Osteoporosis. PET Clin 2019; 14:31-41. [DOI: 10.1016/j.cpet.2018.08.007] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
|
35
|
Woletz M, Hoffmann A, Tik M, Sladky R, Lanzenberger R, Robinson S, Windischberger C. Beware detrending: Optimal preprocessing pipeline for low-frequency fluctuation analysis. Hum Brain Mapp 2018; 40:1571-1582. [PMID: 30430691 PMCID: PMC6587723 DOI: 10.1002/hbm.24468] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2018] [Revised: 09/21/2018] [Accepted: 10/30/2018] [Indexed: 12/19/2022] Open
Abstract
Resting‐state functional magnetic resonance imaging (rs‐fMRI) offers the possibility to assess brain function independent of explicit tasks and individual performance. This absence of explicit stimuli in rs‐fMRI makes analyses more susceptible to nonneural signal fluctuations than task‐based fMRI. Data preprocessing is a critical procedure to minimise contamination by artefacts related to motion and physiology. We herein investigate the effects of different preprocessing strategies on the amplitude of low‐frequency fluctuations (ALFFs) and its fractional counterpart, fractional ALFF (fALFF). Sixteen artefact reduction schemes based on nuisance regression are applied to data from 82 subjects acquired at 1.5 T, 30 subjects at 3 T, and 23 subjects at 7 T, respectively. In addition, we examine test–retest variance and effects of bias correction. In total, 569 data sets are included in this study. Our results show that full artefact reduction reduced test–retest variance by up to 50%. Polynomial detrending of rs‐fMRI data has a positive effect on group‐level t‐values for ALFF but, importantly, a negative effect for fALFF. We show that the normalisation process intrinsic to fALFF calculation causes the observed reduction and introduce a novel measure for low‐frequency fluctuations denoted as high‐frequency ALFF (hfALFF). We demonstrate that hfALFF values are not affected by the negative detrending effects seen in fALFF data. Still, highest grey matter (GM) group‐level t‐values were obtained for fALFF data without detrending, even when compared to an exploratory detrending approach based on autocorrelation measures. From our results, we recommend the use of full nuisance regression including polynomial detrending in ALFF data, but to refrain from using polynomial detrending in fALFF data. Such optimised preprocessing increases GM group‐level t‐values by up to 60%.
Collapse
Affiliation(s)
- Michael Woletz
- Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna, Austria
| | - André Hoffmann
- Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna, Austria
| | - Martin Tik
- Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna, Austria
| | - Ronald Sladky
- Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna, Austria
| | - Rupert Lanzenberger
- Department of Psychiatry and Psychotherapy, Medical University of Vienna, Vienna, Austria
| | - Simon Robinson
- Department of Biomedical Imaging and Image-guided Therapy, Medical University of Vienna, Vienna, Austria
| | - Christian Windischberger
- Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna, Austria
| |
Collapse
|
36
|
Vareth M, Lupo J, Larson P, Nelson S. A comparison of coil combination strategies in 3D multi-channel MRSI reconstruction for patients with brain tumors. NMR IN BIOMEDICINE 2018; 31:e3929. [PMID: 30168205 PMCID: PMC6290901 DOI: 10.1002/nbm.3929] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/27/2017] [Revised: 03/01/2018] [Accepted: 03/07/2018] [Indexed: 05/12/2023]
Abstract
The goal of this study was to find the most robust algorithm for a phase-sensitive coil combination of 3D single-cycle and lactate-edited, multi-channel H-1 point-resolved spectroscopy (PRESS) localized echo planar spectroscopic imaging (EPSI) data for clinical applications in the brain. Data were acquired over 5-10 minutes at 3T using 8- or 32-channel array coils. Peak referencing with residual water and N-acetyl-aspartate, first-point phasing, generalized least squared (GLS) and whitened singular-value decomposition (WSVD) combination algorithms were evaluated relative to unsuppressed water with data from a phantom, six volunteers and 55 patients with brain tumors. Comparison metrics were signal-to-noise ratio, coefficient of variance and percent signal increase. Where residual water was present, using it as a reference peak for phasing and weighting factors from an imaging calibration scan gave the best overall performance. Greater improvement was seen for large selected volumes (>720 cm3 ) and for the 32-channel array (25%) compared with the 8-channel array (19%). Applying voxel-by-voxel phase corrections produced a larger increase in performance for the 32- versus 8-channel coil. We conclude that, for clinically relevant 3D H-1 PRESS localized EPSI studies, the most robust technique employed individual phase maps generated from high residual water and individual amplitude maps generated from calibration scans.
Collapse
Affiliation(s)
- Maryam Vareth
- UC Berkeley–UCSF Graduate Program in Bioengineering, University of California, Berkeley and University of California, San Francisco, California, USA
- Surbeck Laboratory of Advanced Imaging, Department of Radiology and Biomedical Imaging, University of California, San Francisco, California, USA
| | - Janine Lupo
- UC Berkeley–UCSF Graduate Program in Bioengineering, University of California, Berkeley and University of California, San Francisco, California, USA
- Surbeck Laboratory of Advanced Imaging, Department of Radiology and Biomedical Imaging, University of California, San Francisco, California, USA
| | - Peder Larson
- UC Berkeley–UCSF Graduate Program in Bioengineering, University of California, Berkeley and University of California, San Francisco, California, USA
- Surbeck Laboratory of Advanced Imaging, Department of Radiology and Biomedical Imaging, University of California, San Francisco, California, USA
| | - Sarah Nelson
- UC Berkeley–UCSF Graduate Program in Bioengineering, University of California, Berkeley and University of California, San Francisco, California, USA
- Surbeck Laboratory of Advanced Imaging, Department of Radiology and Biomedical Imaging, University of California, San Francisco, California, USA
| |
Collapse
|
37
|
Chen Q, Xie G, Luo C, Yang X, Zhu J, Lee J, Su S, Liang D, Zhang X, Liu X, Li Y, Zheng H. A Dedicated 36-Channel Receive Array for Fetal MRI at 3T. IEEE TRANSACTIONS ON MEDICAL IMAGING 2018; 37:2290-2297. [PMID: 29994303 PMCID: PMC6312740 DOI: 10.1109/tmi.2018.2839191] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Due to a lack of fetal imaging coils, the standard commercial abdominal coil is often used for fetal imaging, the performance of which is limited by its insufficient coverage, element number, and Signal-to-noise ratio (SNR). In this paper, a dedicated 36-channel coil array, of which size can best fit the body sizes of pregnancy gestation from 20 to 37+ weeks, was designed for fetal imaging at 3T. SNR with full phase encoding and G-factor denoted as noise amplification for parallel imaging were quantitatively evaluated by phantom studies. Compared with a commercial abdominal coil array, the proposed 36-channel fetal array provides not only SNR improvements in full phase encoding (with 10% in the region where the whole fetal body was located, and up to 40% in the edge region where the fetal brain and heart may appear) but also an augmented parallel imaging capability and remarkable SNR improvements at high acceleration factors.
Collapse
Affiliation(s)
- Qiaoyan Chen
- Lauterbur Imaging Research Center, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen 518055, China, and also with Shenzhen Key Laboratory for MRI, Shenzhen 518055, China
| | - Guoxi Xie
- School of Basic Science, Guangzhou Medical University, Guangzhou 511436, China
| | - Chao Luo
- Lauterbur Imaging Research Center, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen 518055, China, and also with Shenzhen Key Laboratory for MRI, Shenzhen 518055, China
| | - Xing Yang
- High-Field Magnetic Resonance Brain Imaging Key Laboratory of Sichuan Province, Chengdu 610054, China
| | - Jin Zhu
- Shenzhen People’s Hospital, Shenzhen 518020, China
| | - Jo Lee
- Lauterbur Imaging Research Center, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen 518055, China, and also with Shenzhen Key Laboratory for MRI, Shenzhen 518055, China
| | - Shi Su
- Lauterbur Imaging Research Center, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen 518055, China, and also with Shenzhen Key Laboratory for MRI, Shenzhen 518055, China
| | - Dong Liang
- Lauterbur Imaging Research Center, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen 518055, China, and also with Shenzhen Key Laboratory for MRI, Shenzhen 518055, China
| | - Xiaoliang Zhang
- Department of Radiology and Biomedical Imaging, University of California San Francisco, San Francisco, CA 94158 USA, and also with the UCSF/UC Berkeley Joint Graduate Group in Bioengineering, San Francisco, CA 94158 USA
| | - Xin Liu
- Lauterbur Imaging Research Center, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen 518055, China, and also with Shenzhen Key Laboratory for MRI, Shenzhen 518055, China
| | - Ye Li
- Corresponding authors: Ye Li, and Hairong Zheng. ; .
| | - Hairong Zheng
- Corresponding authors: Ye Li, and Hairong Zheng. ; .
| |
Collapse
|
38
|
Hendriks AD, Luijten PR, Klomp DWJ, Petridou N. Potential acceleration performance of a 256-channel whole-brain receive array at 7 T. Magn Reson Med 2018; 81:1659-1670. [PMID: 30257049 PMCID: PMC6585755 DOI: 10.1002/mrm.27519] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2018] [Revised: 08/09/2018] [Accepted: 08/11/2018] [Indexed: 11/21/2022]
Abstract
Purpose Assess the potential gain in acceleration performance of a 256‐channel versus 32‐channel receive coil array at 7 T in combination with a 2D CAIPIRINHA sequence for 3D data sets. Methods A 256‐channel receive setup was simulated by placing 2 small 16‐channel high‐density receive arrays at 2 × 8 different locations on the head of healthy participants. Multiple consecutive measurements were performed and coil sensitivity maps were combined to form a complete 256‐channel data set. This setup was compared with a standard 32‐channel head coil, in terms of SNR, noise correlation, and acceleration performance (g‐factor). Results In the periphery of the brain, the receive SNR was on average a factor 1.5 higher (ranging up to a factor 2.7 higher) than the 32‐channel coil; in the center of the brain the SNR was comparable or lower, depending on the size of the region of interest, with a factor 1.0 on average (ranging from 0.7 up to a factor of 1.6). The average noise correlation between coil elements was 3% for the 256‐channel coil, and 5% for the 32‐channel coil. At acceptable g‐factors (< 2), the achievable acceleration factor using SENSE and 2D CAIPIRINHA was 24 and 28, respectively, versus 9 and 12 for the 32‐channel coil. Conclusion The receive performance of the simulated 256 channel array was better than the 32‐channel reference. Combined with 2D CAIPIRINHA, a peak acceleration factor of 28 was assessed, showing great potential for high‐density receive arrays.
Collapse
Affiliation(s)
- Arjan D Hendriks
- Department of Radiology, Imaging Division, University Medical Center Utrecht, Utrecht, Netherlands
| | - Peter R Luijten
- Department of Radiology, Imaging Division, University Medical Center Utrecht, Utrecht, Netherlands
| | - Dennis W J Klomp
- Department of Radiology, Imaging Division, University Medical Center Utrecht, Utrecht, Netherlands
| | - Natalia Petridou
- Department of Radiology, Imaging Division, University Medical Center Utrecht, Utrecht, Netherlands
| |
Collapse
|
39
|
Chacon-Caldera J, Fischer A, Malzacher M, Vetter Y, Davids M, Flöser M, Stumpf C, Schad LR. Evaluation of stacked resonators to enhance the performance of a surface receive-only array for prostate MRI at 3 Tesla. Magn Reson Imaging 2018; 53:164-172. [PMID: 30053430 DOI: 10.1016/j.mri.2018.07.010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2018] [Revised: 06/08/2018] [Accepted: 07/21/2018] [Indexed: 10/28/2022]
Abstract
Prostate MRI is an important tool to diagnose and characterize cancer. High local sensitivity and good parallel imaging performance are of paramount importance for diagnostic quality and efficiency. The purpose of this work was to evaluate stacked resonators as part of a surface receiver array for prostate MRI at 3 Tesla. A base array of 6-channels consisting of a flexible anterior and a rigid posterior part were built each with three loop coils. A pair of stacked resonators was added concentrically to the center loops (anterior and posterior) of the base array. The evaluated stacked resonators were butterflies, composites and dipoles which yielded a total of three 8-channel arrays. The arrays were compared using noise correlations and single-channel signal-to-noise ratio maps in a phantom. Combined signal-to-noise ratio maps and parallel imaging performances were measured and compared in vivo in 6 healthy volunteers. The results were compared to the base and a commercial array. The SNR values in the prostate yielded by all the arrays were not statistically different using fully sampled k-space. However, significant differences were found in the parallel imaging performance of the arrays. More specifically, up to 88% geometric factor reduction was found compared to the commercial array and up to 83% reduction compared to the base array using butterfly coils. Thus, signal-to-noise ratio improvements were observed with stacked resonators when using parallel imaging. The use of stacked elements, in particular butterfly coils, can improve the performance of a base array consisting solely of single loops when using parallel imaging. We expect prostate MRI at 3 Tesla to benefit from using combinations of single loops and stacked resonators.
Collapse
Affiliation(s)
- Jorge Chacon-Caldera
- Computer Assisted Clinical Medicine, Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany.
| | - Alexander Fischer
- Computer Assisted Clinical Medicine, Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany
| | - Matthias Malzacher
- Computer Assisted Clinical Medicine, Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany
| | - Yannik Vetter
- Computer Assisted Clinical Medicine, Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany
| | - Mathias Davids
- Computer Assisted Clinical Medicine, Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany
| | - Martina Flöser
- Medical Physics in Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany
| | | | - Lothar R Schad
- Computer Assisted Clinical Medicine, Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany
| |
Collapse
|
40
|
Gruber B, Froeling M, Leiner T, Klomp DW. RF coils: A practical guide for nonphysicists. J Magn Reson Imaging 2018; 48:590-604. [PMID: 29897651 PMCID: PMC6175221 DOI: 10.1002/jmri.26187] [Citation(s) in RCA: 78] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2018] [Accepted: 04/23/2018] [Indexed: 11/09/2022] Open
Abstract
Radiofrequency (RF) coils are an essential MRI hardware component. They directly impact the spatial and temporal resolution, sensitivity, and uniformity in MRI. Advances in RF hardware have resulted in a variety of designs optimized for specific clinical applications. RF coils are the "antennas" of the MRI system and have two functions: first, to excite the magnetization by broadcasting the RF power (Tx-Coil) and second to receive the signal from the excited spins (Rx-Coil). Transmit RF Coils emit magnetic field pulses ( B1+) to rotate the net magnetization away from its alignment with the main magnetic field (B0 ), resulting in a transverse precessing magnetization. Due to the precession around the static main magnetic field, the magnetic flux in the receive RF Coil ( B1-) changes, which generates a current I. This signal is "picked-up" by an antenna and preamplified, usually mixed down to a lower frequency, digitized, and processed by a computer to finally reconstruct an image or a spectrum. Transmit and receive functionality can be combined in one RF Coil (Tx/Rx Coils). This review looks at the fundamental principles of an MRI RF coil from the perspective of clinicians and MR technicians and summarizes the current advances and developments in technology. LEVEL OF EVIDENCE 1 Technical Efficacy: Stage 6.
Collapse
Affiliation(s)
- Bernhard Gruber
- A.A. Martinos Center for Biomedical Imaging, Harvard‐MIT Division of Health Sciences & Technology, Massachusetts General HospitalCharlestownMassachusettsUSA
- Department of Radiology, Harvard Medical SchoolMassachusetts General HospitalBostonMassachusettsUSA
- Center for Medical Physics and Biomedical EngineeringMedical University of ViennaViennaAustria
| | - Martijn Froeling
- Department of RadiologyUniversity Medical Center UtrechtUtrechtThe Netherlands
| | - Tim Leiner
- Department of RadiologyUniversity Medical Center UtrechtUtrechtThe Netherlands
| | - Dennis W.J. Klomp
- Department of RadiologyUniversity Medical Center UtrechtUtrechtThe Netherlands
| |
Collapse
|
41
|
Gilbert KM, Schaeffer DJ, Zeman P, Diedrichsen J, Everling S, Martinez-Trujillo JC, Pruszynski JA, Menon RS. Concentric radiofrequency arrays to increase the statistical power of resting-state maps in monkeys. Neuroimage 2018; 178:287-294. [PMID: 29852280 DOI: 10.1016/j.neuroimage.2018.05.057] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2018] [Revised: 05/23/2018] [Accepted: 05/24/2018] [Indexed: 12/30/2022] Open
Abstract
The close homology of monkeys and humans has increased the prevalence of non-human-primate models in functional MRI studies of brain connectivity. To improve upon the attainable resolution in functional MRI studies, a commensurate increase in the sensitivity of the radiofrequency receiver coil is required to avoid a reduction in the statistical power of the analysis. Most receive coils are comprised of multiple loops distributed equidistantly over a surface to produce spatially independent sensitivity profiles. A larger number of smaller elements will in turn provide a higher signal-to-noise ratio (SNR) over the same field of view. As the loops become physically smaller, noise originating from the sample is reduced relative to noise originating from the coil. In this coil-noise-dominated regime, coil elements can have overlapping sensitivity profiles, yet still possess only mildly correlated noise. In this manuscript, we demonstrate that inductively decoupled, concentric coil arrays can improve temporal SNR when operating in the coil-noise-dominated regime-in contrast to what is expected for the more ubiquitous sample-noise-dominated array. A small, thin, 7-channel flexible coil is developed and operated in conjunction with an existing whole-head monkey coil. The mean and maximum noise correlation between the two arrays was 5% and 23%, respectively. When the flex coil was placed over the sensorimotor cortex, the temporal SNR improved by up to 2.3-fold in the peripheral cortex and up to 1.3-fold at a 2- to 3-cm depth within the brain. When the flex coil was placed over the frontal eye fields, resting-state maps showed substantially elevated sensitivity to correlations in the prefrontal cortex (54%), supplementary eye fields (39%), and anterior cingulate cortex (41%). The concentric-coil topology provided a pragmatic and robust means to significantly improve local temporal SNR and the statistical power of functional connectivity maps.
Collapse
Affiliation(s)
- Kyle M Gilbert
- Centre for Functional and Metabolic Mapping, The University of Western Ontario, London, Ontario, Canada.
| | - David J Schaeffer
- Centre for Functional and Metabolic Mapping, The University of Western Ontario, London, Ontario, Canada
| | - Peter Zeman
- Centre for Functional and Metabolic Mapping, The University of Western Ontario, London, Ontario, Canada
| | - Jörn Diedrichsen
- Department of Computer Science, The University of Western Ontario, London, Ontario, Canada
| | - Stefan Everling
- Centre for Functional and Metabolic Mapping, The University of Western Ontario, London, Ontario, Canada; Department of Physiology and Pharmacology, The University of Western Ontario, London, Ontario, Canada
| | - Julio C Martinez-Trujillo
- Department of Physiology and Pharmacology, The University of Western Ontario, London, Ontario, Canada
| | - J Andrew Pruszynski
- Department of Physiology and Pharmacology, The University of Western Ontario, London, Ontario, Canada
| | - Ravi S Menon
- Centre for Functional and Metabolic Mapping, The University of Western Ontario, London, Ontario, Canada
| |
Collapse
|
42
|
Cao X, Fischer E, Hennig J, Zaitsev M. Direct matching methods for coils and preamplifiers in MRI. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2018; 290:85-91. [PMID: 29597135 DOI: 10.1016/j.jmr.2018.03.009] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/17/2017] [Revised: 02/20/2018] [Accepted: 03/15/2018] [Indexed: 06/08/2023]
Abstract
In this paper, direct matching methods for coils and preamplifiers in receiver arrays are presented. Instead of compensating the reactance of the input impedance of preamplifiers, in our method, the reactance was used to resonate with the coil matching networks and thus to decouple the coils. Furthermore, coil matching networks and preamplifier input matching networks were combined, meaning the coil loop can be matched to the transistor in the preamplifier directly. These matching methods and, for comparison, the conventional matching method were implemented with custom-made preamplifiers and coils. Decoupling and noise-matching performance were compared between these three configurations. Phase shifting networks between coils and preamplifiers are not necessary in our matching methods. With fewer components, these matching networks showed lower noise factors, while similar preamplifier-decoupling performance was found for all three methods.
Collapse
Affiliation(s)
- Xueming Cao
- Dept. of Radiology, Medical Physics, University Medical Center Freiburg, Freiburg, Germany.
| | - Elmar Fischer
- Dept. of Radiology, Medical Physics, University Medical Center Freiburg, Freiburg, Germany
| | - Jürgen Hennig
- Dept. of Radiology, Medical Physics, University Medical Center Freiburg, Freiburg, Germany
| | - Maxim Zaitsev
- Dept. of Radiology, Medical Physics, University Medical Center Freiburg, Freiburg, Germany
| |
Collapse
|
43
|
Mitochondrial function in individuals at clinical high risk for psychosis. Sci Rep 2018; 8:6216. [PMID: 29670128 PMCID: PMC5906614 DOI: 10.1038/s41598-018-24355-6] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2018] [Accepted: 03/26/2018] [Indexed: 12/19/2022] Open
Abstract
Alterations in mitochondrial function have been implicated in the etiology of schizophrenia. Most studies have investigated alterations in mitochondrial function in patients in which the disorder is already established; however, whether mitochondrial dysfunction predates the onset of psychosis remains unknown. We measured peripheral mitochondrial complex (I–V) function and lactate/pyruvate levels in 27 antipsychotic-naïve individuals at clinical high risk for psychosis (CHR) and 16 healthy controls. We also explored the association between mitochondrial function and brain microglial activation and glutathione levels using a translocator protein 18 kDa [18F]FEPPA PET scan and 1H-MRS scan, respectively. There were no significant differences in mitochondrial complex function and lactate/pyruvate levels between CHR and healthy controls. In the CHR group, mitochondrial complex III function (r = −0.51, p = 0.008) and lactate levels (r = 0.61, p = 0.004) were associated with prodromal negative symptoms. As previously reported, there were no significant differences in microglial activation and glutathione levels between groups, however, mitochondrial complex IV function was inversely related to microglial activation in the hippocampus in CHR (r = −0.42, p = 0.04), but not in healthy controls. In conclusion, alterations in mitochondrial function are not yet evident in CHR, but may relate to the severity of prodromal symptoms, particularly negative symptoms.
Collapse
|
44
|
Siless V, Chang K, Fischl B, Yendiki A. AnatomiCuts: Hierarchical clustering of tractography streamlines based on anatomical similarity. Neuroimage 2018; 166:32-45. [PMID: 29100937 PMCID: PMC6152885 DOI: 10.1016/j.neuroimage.2017.10.058] [Citation(s) in RCA: 40] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2017] [Revised: 10/18/2017] [Accepted: 10/26/2017] [Indexed: 01/25/2023] Open
Abstract
Diffusion MRI tractography produces massive sets of streamlines that contain a wealth of information on brain connections. The size of these datasets creates a need for automated clustering methods to group the streamlines into meaningful bundles. Conventional clustering techniques group streamlines based on their spatial coordinates. Neuroanatomists, however, define white-matter bundles based on the anatomical structures that they go through or next to, rather than their spatial coordinates. Thus we propose a similarity measure for clustering streamlines based on their position relative to cortical and subcortical brain regions. We incorporate this measure into a hierarchical clustering algorithm and compare it to a measure that relies on Euclidean distance, using data from the Human Connectome Project. We show that the anatomical similarity measure leads to a 20% improvement in the overlap of clusters with manually labeled tracts. Importantly, this is achieved without introducing any prior information from a tract atlas into the clustering algorithm, therefore without imposing the existence of any named tracts.
Collapse
Affiliation(s)
- Viviana Siless
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA.
| | - Ken Chang
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
| | - Bruce Fischl
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA; Computer Science and Artificial Intelligence Laboratory, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Anastasia Yendiki
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
| |
Collapse
|
45
|
Kordzadeh A, De Zanche N. Optimal-permittivity Dielectric Liners for a 4.7T Transceiver Array. Magn Reson Imaging 2017; 48:89-95. [PMID: 29278763 DOI: 10.1016/j.mri.2017.12.016] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2017] [Revised: 12/14/2017] [Accepted: 12/21/2017] [Indexed: 10/18/2022]
Abstract
Placing dielectric pads adjacent to the imaging region is an effective method to increase the signal locally and also increase the radio frequency magnetic field homogeneity in magnetic resonance imaging. The use of local high permittivity pads is becoming more common, and this work focuses on the effect of larger dielectric pads on the transmit/receive performance of an array (e.g., coupling, efficiency and safety) having 8 channels, used to image a cylindrical phantom at 4.7T (200MHz). We investigate the effects of a dielectric liner surrounding the whole volume of interest both with and without an air gap. The simulations reveal that high permittivities are not recommended because they substantially degrade the longitudinal homogeneity, resulting in hot spots of specific absorption rate at the driven end of the array. Furthermore, high permittivities lead to dielectric resonances in the liner at frequencies close to the Larmor frequency, potentially degrading the performance of the array. Indeed, simulations and measurements confirm that a compromise must be made between improvements in field homogeneity and transmit performance, and that an optimal permittivity exists which is much lower than those commonly used in the literature. The optimal permittivity achieves minimal coupling (<-23dB) between array elements, exhibits an intrinsic electromagnetic impedance equal to the geometric mean of those of the coil former and phantom and can be realized with inexpensive materials. For this permittivity the performance with an air gap of thickness equal to that of the liner is equivalent to that without the air gap.
Collapse
Affiliation(s)
- Atefeh Kordzadeh
- Department of Biomedical Engineering, University of Alberta, Edmonton, Alberta, Canada; Department of Electrical and Computer Engineering, University of Alberta, Edmonton, Alberta, Canada
| | - Nicola De Zanche
- Department of Medical Physics, Cross Cancer Institute, Edmonton, Alberta, Canada; Department of Oncology, University of Alberta, Edmonton, Alberta, Canada.
| |
Collapse
|
46
|
Fleischer CC, Zhong X, Mao H. Effects of proximity and noise level of phased array coil elements on overall signal-to-noise in parallel MR spectroscopy. Magn Reson Imaging 2017; 47:125-130. [PMID: 29217493 DOI: 10.1016/j.mri.2017.12.001] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2017] [Accepted: 12/03/2017] [Indexed: 10/18/2022]
Abstract
Parallel imaging using phased array coils facilitates accelerated magnetic resonance imaging (MRI) and spectroscopy (MRS). Parallel data reconstruction requires the combination of data from individual coil elements, but limited combination algorithms currently exist for higher-order phased arrays and MRS data. Here, we present a systematic framework for identifying coil proximity-related signal inhomogeneities and noise levels in phased array coils that may affect sensitivity of parallel MRS. Single-voxel MRS was acquired in nine voxel positions in a brain spectroscopy phantom on a 3T whole-body MR scanner using commercially available 64-, 32-, and 20-channel phased array coils. Spectra produced by individual coil elements were combined using both a signal-to-noise ratio (SNR) threshold and based on the position of individual coil elements. SNR and metabolite Cramer-Rao lower bounds (CRLBs) from the final combined spectra were used as metrics to compare combination strategies and the effects of the phased array geometry and individual coil proximity. Comparisons were performed using one-way repeated measures ANOVA and post-hoc Tukey's range test (p<0.05). The 32-channel phased array coil produced the highest overall SNR compared to the 64-channel (p=0.0009) or 20-channel coils (p=0.003). Low SNR spectra from individual coil elements in the 64-channel coil can reduce the overall SNR when simply combining spectra from all elements. SNR varied significantly as a function of voxel position (F=58.3, p<0.0001) and SNR threshold for all phased arrays (p<0.05 for 64-, 32-, and 20-channel coils). Metabolite CRLBs were dependent on the combination strategy. We demonstrate the importance of the sampling voxel position and coil proximity on overall SNR in parallel MRS data acquisition, with significant SNR improvements after selectively filtering individual spectra based on pre-determined SNR thresholds which must be optimized for each phased array coil element and volume of interest.
Collapse
Affiliation(s)
- Candace C Fleischer
- Department of Radiology and Imaging Sciences, Emory University School of Medicine, Atlanta, GA, United States
| | - Xiaodong Zhong
- MR R&D Collaborations, Siemens Healthcare, Atlanta, GA, United States; Department of Radiology and Imaging Sciences, Emory University School of Medicine, Atlanta, GA, United States
| | - Hui Mao
- Department of Radiology and Imaging Sciences, Emory University School of Medicine, Atlanta, GA, United States.
| |
Collapse
|
47
|
Lemdiasov R, Venkatasubramanian A. Transmit coil design for Wireless Power Transfer for medical implants. ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. ANNUAL INTERNATIONAL CONFERENCE 2017; 2017:2158-2161. [PMID: 29060324 DOI: 10.1109/embc.2017.8037282] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
A new design approach for the design of transmit coils for Wireless Power Transfer (WPT) is presented. The theoretical formulation involves a figure of merit that has to be maximized to solve for the surface current. Numerical predictions and comparisons with practical measurements for the coil parameters (inductance. resistance) underscore the success of this approach in terms of achieving strong coupling with a receive coil while maintaining low resistance.
Collapse
|
48
|
Da Silva T, Hafizi S, Andreazza AC, Kiang M, Bagby RM, Navas E, Laksono I, Truong P, Gerritsen C, Prce I, Sailasuta N, Mizrahi R. Glutathione, the Major Redox Regulator, in the Prefrontal Cortex of Individuals at Clinical High Risk for Psychosis. Int J Neuropsychopharmacol 2017; 21:311-318. [PMID: 29618014 PMCID: PMC5888512 DOI: 10.1093/ijnp/pyx094] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/03/2017] [Accepted: 10/06/2017] [Indexed: 12/12/2022] Open
Abstract
INTRODUCTION Oxidative stress and glutathione dysregulation have been implicated in the etiology of schizophrenia. To date, most in vivo studies have investigated alterations in cerebral glutathione levels in patients in which the disorder is already established; however, whether oxidative stress actually predates the onset of psychosis remains unknown. In the current study, we investigated cerebral glutathione levels of antipsychotic-naïve individuals at clinical high risk for psychosis. As exploratory analyses, we also investigated the associations between cerebral glutathione levels and peripheral glutathione peroxidase activity and clinical and neuropsychological measures. METHODS Glutathione levels were measured in the medial prefrontal cortex of 30 clinical high risk (n=26 antipsychotic naïve) and 26 healthy volunteers using 3T proton magnetic resonance spectroscopy. Each participant was assessed for glutathione peroxidase activity in plasma and genotyped for the glutamate cysteine ligase catalytic subunit polymorphism. RESULTS No significant differences were observed in glutathione levels between clinical high risk and healthy volunteers in the medial prefrontal cortex (F(1,54)=0.001, P =0.98). There were no significant correlations between cerebral glutathione levels and clinical and neuropsychological measures. Similarly, no significant differences were found in peripheral glutathione peroxidase activity between clinical high risk and healthy volunteers (F(1,37)=0.15, P =0.70). However, in clinical high risk, we observed a significant effect of lifetime history of cannabis use on glutathione peroxidase activity (F(1,23)=7.41, P =0.01). DISCUSSION The lack of significant differences between antipsychotic naïve clinical high risk and healthy volunteers suggests that alterations in glutathione levels in medial prefrontal cortex are not present in the clinical high risk state.
Collapse
Affiliation(s)
- Tania Da Silva
- Research Imaging Centre, Centre for Addiction and Mental Health, Toronto, Ontario, Canada
| | - Sina Hafizi
- Research Imaging Centre, Centre for Addiction and Mental Health, Toronto, Ontario, Canada
| | - Ana C Andreazza
- Department of Pharmacology and Toxicology, University of Toronto, Toronto, Ontario, Canada,Institute of Medical Science, University of Toronto, Toronto, Ontario, Canada
| | - Michael Kiang
- Research Imaging Centre, Centre for Addiction and Mental Health, Toronto, Ontario, Canada,Institute of Medical Science, University of Toronto, Toronto, Ontario, Canada,Department of Psychiatry, University of Toronto, Toronto, Ontario, Canada
| | - R Michael Bagby
- Department of Psychiatry, University of Toronto, Toronto, Ontario, Canada
| | - Efren Navas
- Research Imaging Centre, Centre for Addiction and Mental Health, Toronto, Ontario, Canada
| | - Isabelle Laksono
- Department of Pharmacology and Toxicology, University of Toronto, Toronto, Ontario, Canada
| | - Peter Truong
- Research Imaging Centre, Centre for Addiction and Mental Health, Toronto, Ontario, Canada
| | - Cory Gerritsen
- Research Imaging Centre, Centre for Addiction and Mental Health, Toronto, Ontario, Canada
| | - Ivana Prce
- Research Imaging Centre, Centre for Addiction and Mental Health, Toronto, Ontario, Canada
| | - Napapon Sailasuta
- Research Imaging Centre, Centre for Addiction and Mental Health, Toronto, Ontario, Canada,Department of Psychiatry, University of Toronto, Toronto, Ontario, Canada,Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health, Toronto, Ontario, Canada
| | - Romina Mizrahi
- Research Imaging Centre, Centre for Addiction and Mental Health, Toronto, Ontario, Canada,Department of Pharmacology and Toxicology, University of Toronto, Toronto, Ontario, Canada,Institute of Medical Science, University of Toronto, Toronto, Ontario, Canada,Department of Psychiatry, University of Toronto, Toronto, Ontario, Canada,Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health, Toronto, Ontario, Canada,Correspondence: Romina Mizrahi, MD, PhD, PET Centre, Research Imaging Centre, Centre for Addiction and Mental Health, 250 College Street, Toronto, Ontario, Canada M5T 1R8 ()
| |
Collapse
|
49
|
Ding SL, Royall JJ, Sunkin SM, Ng L, Facer BAC, Lesnar P, Guillozet-Bongaarts A, McMurray B, Szafer A, Dolbeare TA, Stevens A, Tirrell L, Benner T, Caldejon S, Dalley RA, Dee N, Lau C, Nyhus J, Reding M, Riley ZL, Sandman D, Shen E, van der Kouwe A, Varjabedian A, Wright M, Zöllei L, Dang C, Knowles JA, Koch C, Phillips JW, Sestan N, Wohnoutka P, Zielke HR, Hohmann JG, Jones AR, Bernard A, Hawrylycz MJ, Hof PR, Fischl B, Lein ES. Comprehensive cellular-resolution atlas of the adult human brain. J Comp Neurol 2017; 524:3127-481. [PMID: 27418273 PMCID: PMC5054943 DOI: 10.1002/cne.24080] [Citation(s) in RCA: 209] [Impact Index Per Article: 29.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2016] [Revised: 07/11/2016] [Accepted: 07/13/2016] [Indexed: 12/12/2022]
Abstract
Detailed anatomical understanding of the human brain is essential for unraveling its functional architecture, yet current reference atlases have major limitations such as lack of whole‐brain coverage, relatively low image resolution, and sparse structural annotation. We present the first digital human brain atlas to incorporate neuroimaging, high‐resolution histology, and chemoarchitecture across a complete adult female brain, consisting of magnetic resonance imaging (MRI), diffusion‐weighted imaging (DWI), and 1,356 large‐format cellular resolution (1 µm/pixel) Nissl and immunohistochemistry anatomical plates. The atlas is comprehensively annotated for 862 structures, including 117 white matter tracts and several novel cyto‐ and chemoarchitecturally defined structures, and these annotations were transferred onto the matching MRI dataset. Neocortical delineations were done for sulci, gyri, and modified Brodmann areas to link macroscopic anatomical and microscopic cytoarchitectural parcellations. Correlated neuroimaging and histological structural delineation allowed fine feature identification in MRI data and subsequent structural identification in MRI data from other brains. This interactive online digital atlas is integrated with existing Allen Institute for Brain Science gene expression atlases and is publicly accessible as a resource for the neuroscience community. J. Comp. Neurol. 524:3127–3481, 2016. © 2016 The Authors The Journal of Comparative Neurology Published by Wiley Periodicals, Inc.
Collapse
Affiliation(s)
- Song-Lin Ding
- Allen Institute for Brain Science, Seattle, Washington, 98109.
| | - Joshua J Royall
- Allen Institute for Brain Science, Seattle, Washington, 98109
| | - Susan M Sunkin
- Allen Institute for Brain Science, Seattle, Washington, 98109
| | - Lydia Ng
- Allen Institute for Brain Science, Seattle, Washington, 98109
| | | | - Phil Lesnar
- Allen Institute for Brain Science, Seattle, Washington, 98109
| | | | - Bergen McMurray
- Allen Institute for Brain Science, Seattle, Washington, 98109
| | - Aaron Szafer
- Allen Institute for Brain Science, Seattle, Washington, 98109
| | - Tim A Dolbeare
- Allen Institute for Brain Science, Seattle, Washington, 98109
| | - Allison Stevens
- Department of Radiology, Harvard Medical School, Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Charlestown, Massachusetts, 02129
| | - Lee Tirrell
- Department of Radiology, Harvard Medical School, Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Charlestown, Massachusetts, 02129
| | - Thomas Benner
- Department of Radiology, Harvard Medical School, Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Charlestown, Massachusetts, 02129
| | | | - Rachel A Dalley
- Allen Institute for Brain Science, Seattle, Washington, 98109
| | - Nick Dee
- Allen Institute for Brain Science, Seattle, Washington, 98109
| | - Christopher Lau
- Allen Institute for Brain Science, Seattle, Washington, 98109
| | - Julie Nyhus
- Allen Institute for Brain Science, Seattle, Washington, 98109
| | - Melissa Reding
- Allen Institute for Brain Science, Seattle, Washington, 98109
| | - Zackery L Riley
- Allen Institute for Brain Science, Seattle, Washington, 98109
| | - David Sandman
- Allen Institute for Brain Science, Seattle, Washington, 98109
| | - Elaine Shen
- Allen Institute for Brain Science, Seattle, Washington, 98109
| | - Andre van der Kouwe
- Department of Radiology, Harvard Medical School, Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Charlestown, Massachusetts, 02129
| | - Ani Varjabedian
- Department of Radiology, Harvard Medical School, Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Charlestown, Massachusetts, 02129
| | - Michelle Wright
- Department of Radiology, Harvard Medical School, Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Charlestown, Massachusetts, 02129
| | - Lilla Zöllei
- Department of Radiology, Harvard Medical School, Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Charlestown, Massachusetts, 02129
| | - Chinh Dang
- Allen Institute for Brain Science, Seattle, Washington, 98109
| | - James A Knowles
- Zilkha Neurogenetic Institute, and Department of Psychiatry, University of Southern California, Los Angeles, California, 90033
| | - Christof Koch
- Allen Institute for Brain Science, Seattle, Washington, 98109
| | - John W Phillips
- Allen Institute for Brain Science, Seattle, Washington, 98109
| | - Nenad Sestan
- Department of Neurobiology and Kavli Institute for Neuroscience, Yale University School of Medicine, New Haven, Connecticut, 06510
| | - Paul Wohnoutka
- Allen Institute for Brain Science, Seattle, Washington, 98109
| | - H Ronald Zielke
- Department of Pediatrics, University of Maryland School of Medicine, Baltimore, Maryland, 21201
| | - John G Hohmann
- Allen Institute for Brain Science, Seattle, Washington, 98109
| | - Allan R Jones
- Allen Institute for Brain Science, Seattle, Washington, 98109
| | - Amy Bernard
- Allen Institute for Brain Science, Seattle, Washington, 98109
| | | | - Patrick R Hof
- Fishberg Department of Neuroscience and Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, New York, 11029
| | - Bruce Fischl
- Department of Radiology, Harvard Medical School, Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Charlestown, Massachusetts, 02129
| | - Ed S Lein
- Allen Institute for Brain Science, Seattle, Washington, 98109.
| |
Collapse
|
50
|
Chang G, Boone S, Martel D, Rajapakse CS, Hallyburton RS, Valko M, Honig S, Regatte RR. MRI assessment of bone structure and microarchitecture. J Magn Reson Imaging 2017; 46:323-337. [PMID: 28165650 PMCID: PMC5690546 DOI: 10.1002/jmri.25647] [Citation(s) in RCA: 74] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2016] [Accepted: 12/21/2016] [Indexed: 12/12/2022] Open
Abstract
Osteoporosis is a disease of weak bone and increased fracture risk caused by low bone mass and microarchitectural deterioration of bone tissue. The standard-of-care test used to diagnose osteoporosis, dual-energy x-ray absorptiometry (DXA) estimation of areal bone mineral density (BMD), has limitations as a tool to identify patients at risk for fracture and as a tool to monitor therapy response. Magnetic resonance imaging (MRI) assessment of bone structure and microarchitecture has been proposed as another method to assess bone quality and fracture risk in vivo. MRI is advantageous because it is noninvasive, does not require ionizing radiation, and can evaluate both cortical and trabecular bone. In this review article, we summarize and discuss research progress on MRI of bone structure and microarchitecture over the last decade, focusing on in vivo translational studies. Single-center, in vivo studies have provided some evidence for the added value of MRI as a biomarker of fracture risk or treatment response. Larger, prospective, multicenter studies are needed in the future to validate the results of these initial translational studies. LEVEL OF EVIDENCE 5 Technical Efficacy: Stage 5 J. MAGN. RESON. IMAGING 2017;46:323-337.
Collapse
Affiliation(s)
- Gregory Chang
- Department of Radiology, Center for Biomedical Imaging, NYU Langone Medical Center, New York, New York, USA
| | - Sean Boone
- Department of Radiology, Center for Biomedical Imaging, NYU Langone Medical Center, New York, New York, USA
| | - Dimitri Martel
- Department of Radiology, Center for Biomedical Imaging, NYU Langone Medical Center, New York, New York, USA
| | - Chamith S Rajapakse
- Department of Radiology, Hospital of the University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Robert S Hallyburton
- Department of Radiology, Center for Biomedical Imaging, NYU Langone Medical Center, New York, New York, USA
| | - Mitch Valko
- Department of Radiology, Center for Biomedical Imaging, NYU Langone Medical Center, New York, New York, USA
| | - Stephen Honig
- Osteoporosis Center, Hospital for Joint Diseases, NYU Langone Medical Center, New York, New York, USA
| | - Ravinder R Regatte
- Department of Radiology, Center for Biomedical Imaging, NYU Langone Medical Center, New York, New York, USA
| |
Collapse
|