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Li G, Ma X, Li S, Ye X, Börnert P, Zhou XJ, Guo H. Comparison of uniform-density, variable-density, and dual-density spiral samplings for multi-shot DWI. Magn Reson Med 2023; 90:133-149. [PMID: 36883748 DOI: 10.1002/mrm.29633] [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: 09/03/2022] [Revised: 02/17/2023] [Accepted: 02/21/2023] [Indexed: 03/09/2023]
Abstract
PURPOSE To compare the performances of uniform-density spiral (UDS), variable-density spiral (VDS), and dual-density spiral (DDS) samplings in multi-shot diffusion imaging, and determine a sampling strategy that balances reliability of shot navigator and overall DWI image quality. THEORY AND METHODS UDS, VDS, and DDS trajectories were implemented to achieve four-shot diffusion-weighted spiral imaging. First, the static B0 off-resonance effects in UDS, VDS, and DDS acquisitions were analyzed based on a signal model. Then, in vivo experiments were performed to verify the theoretical analyses, and fractional anisotropy (FA) fitting residuals were used to quantitatively assess the quality of spiral diffusion data for tensor estimation. Finally, the SNR performances and g-factor behavior of the three spiral samplings were evaluated using a Monte Carlo-based pseudo multiple replica method. RESULTS Among the three spiral trajectories with the same readout duration, UDS sampling exhibited the least off-resonance artifacts. This was most evident when the static B0 off-resonance effect was severe. The UDS diffusion images had higher anatomical fidelity and lower FA fitting residuals than the other two counterparts. Furthermore, the four-shot UDS acquisition achieved the best SNR performance in diffusion imaging with 12.11% and 40.85% improvements over the VDS and DDS acquisitions with the same readout duration, respectively. CONCLUSION UDS sampling is an efficient spiral acquisition scheme for high-resolution diffusion imaging with reliable navigator information. It provides superior off-resonance performance and SNR efficiency over the VDS and DDS samplings for the tested scenarios.
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Affiliation(s)
- Guangqi Li
- Center for Biomedical Imaging Research, Department of Biomedical Engineering, Tsinghua University, Beijing, China
| | - Xiaodong Ma
- Department of Radiology and Imaging Sciences, University of Utah, Salt Lake City, Utah, USA
| | - Sisi Li
- Center for Biomedical Imaging Research, Department of Biomedical Engineering, Tsinghua University, Beijing, China
| | - Xinyu Ye
- Center for Biomedical Imaging Research, Department of Biomedical Engineering, Tsinghua University, Beijing, China
| | - Peter Börnert
- Radiology, C.J. Gorter Center for High-Field MRI, Leiden University Medical Center, Leiden, The Netherlands.,Philips Research, Hamburg, Germany
| | - Xiaohong Joe Zhou
- Center for MR Research and Departments of Radiology, Neurosurgery, and Biomedical Engineering, University of Illinois College of Medicine at Chicago, Chicago, Illinois, USA
| | - Hua Guo
- Center for Biomedical Imaging Research, Department of Biomedical Engineering, Tsinghua University, Beijing, China
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2
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Kodama N, Setoi A, Kose K. Spiral MRI on a 9.4T Vertical-bore Superconducting Magnet Using Unshielded and Self-shielded Gradient Coils. Magn Reson Med Sci 2018; 17:174-183. [PMID: 28367906 PMCID: PMC5891344 DOI: 10.2463/mrms.tn.2016-0049] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022] Open
Abstract
Spiral MRI sequences were developed for a 9.4T vertical standard bore (54 mm) superconducting magnet using unshielded and self-shielded gradient coils. Clear spiral images with 64-shot scan were obtained with the self-shielded gradient coil, but severe shading artifacts were observed for the spiral-scan images acquired with the unshielded gradient coil. This shading artifact was successfully corrected with a phase-correction technique using reference scans that we developed based on eddy current field measurements. We therefore concluded that spiral imaging sequences can be installed even for unshielded gradient coils if phase corrections are performed using the reference scans.
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Affiliation(s)
- Nao Kodama
- Institute of Applied Physics, University of Tsukuba
| | - Ayana Setoi
- Institute of Applied Physics, University of Tsukuba
| | - Katsumi Kose
- Institute of Applied Physics, University of Tsukuba
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3
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Engel M, Kasper L, Barmet C, Schmid T, Vionnet L, Wilm B, Pruessmann KP. Single‐shot spiral imaging at 7
T. Magn Reson Med 2018; 80:1836-1846. [DOI: 10.1002/mrm.27176] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2017] [Revised: 02/15/2018] [Accepted: 02/18/2018] [Indexed: 01/18/2023]
Affiliation(s)
- Maria Engel
- Institute for Biomedical EngineeringETH Zurich and University of ZurichZurich Switzerland
| | - Lars Kasper
- Institute for Biomedical EngineeringETH Zurich and University of ZurichZurich Switzerland
- Translational Neuromodeling Unit, Institute for Biomedical EngineeringUniversity of Zurich and ETH ZurichZurich Switzerland
| | - Christoph Barmet
- Institute for Biomedical EngineeringETH Zurich and University of ZurichZurich Switzerland
- Skope Magnetic Resonance Technologies AGZurich Switzerland
| | - Thomas Schmid
- Institute for Biomedical EngineeringETH Zurich and University of ZurichZurich Switzerland
| | - Laetitia Vionnet
- Institute for Biomedical EngineeringETH Zurich and University of ZurichZurich Switzerland
| | - Bertram Wilm
- Institute for Biomedical EngineeringETH Zurich and University of ZurichZurich Switzerland
- Skope Magnetic Resonance Technologies AGZurich Switzerland
| | - Klaas P. Pruessmann
- Institute for Biomedical EngineeringETH Zurich and University of ZurichZurich Switzerland
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4
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Thulborn KR. Quantitative sodium MR imaging: A review of its evolving role in medicine. Neuroimage 2018; 168:250-268. [PMID: 27890804 PMCID: PMC5443706 DOI: 10.1016/j.neuroimage.2016.11.056] [Citation(s) in RCA: 70] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2016] [Revised: 10/23/2016] [Accepted: 11/22/2016] [Indexed: 12/26/2022] Open
Abstract
Sodium magnetic resonance (MR) imaging in humans has promised metabolic information that can improve medical management in important diseases. This technology has yet to find a role in clinical practice, lagging proton MR imaging by decades. This review covers the literature that demonstrates that this delay is explained by initial challenges of low sensitivity at low magnetic fields and the limited performance of gradients and electronics available in the 1980s. These constraints were removed by the introduction of 3T and now ultrahigh (≥7T) magnetic field scanners with superior gradients and electronics for proton MR imaging. New projection pulse sequence designs have greatly improved sodium acquisition efficiency. The increased field strength has provided the expected increased sensitivity to achieve resolutions acceptable for metabolic interpretation even in small target tissues. Consistency of quantification of the sodium MR image to provide metabolic parametric maps has been demonstrated by several different pulse sequences and calibration procedures. The vital roles of sodium ion in membrane transport and the extracellular matrix will be reviewed to indicate the broad opportunities that now exist for clinical sodium MR imaging. The final challenge is for the technology to be supplied on clinical ≥3T scanners.
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Affiliation(s)
- Keith R Thulborn
- Center for Magnetic Resonance Research, University of Illinois at Chicago, 1801 West Taylor Street, Chicago, IL 60612, United States.
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5
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Kasper L, Engel M, Barmet C, Haeberlin M, Wilm BJ, Dietrich BE, Schmid T, Gross S, Brunner DO, Stephan KE, Pruessmann KP. Rapid anatomical brain imaging using spiral acquisition and an expanded signal model. Neuroimage 2017; 168:88-100. [PMID: 28774650 DOI: 10.1016/j.neuroimage.2017.07.062] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2016] [Revised: 06/22/2017] [Accepted: 07/29/2017] [Indexed: 11/30/2022] Open
Abstract
We report the deployment of spiral acquisition for high-resolution structural imaging at 7T. Long spiral readouts are rendered manageable by an expanded signal model including static off-resonance and B0 dynamics along with k-space trajectories and coil sensitivity maps. Image reconstruction is accomplished by inversion of the signal model using an extension of the iterative non-Cartesian SENSE algorithm. Spiral readouts up to 25 ms are shown to permit whole-brain 2D imaging at 0.5 mm in-plane resolution in less than a minute. A range of options is explored, including proton-density and T2* contrast, acceleration by parallel imaging, different readout orientations, and the extraction of phase images. Results are shown to exhibit competitive image quality along with high geometric consistency.
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Affiliation(s)
- Lars Kasper
- Institute for Biomedical Engineering, ETH Zurich and University of Zurich, Zurich, Switzerland; Translational Neuromodeling Unit, IBT, University of Zurich and ETH Zurich, Zurich, Switzerland.
| | - Maria Engel
- Institute for Biomedical Engineering, ETH Zurich and University of Zurich, Zurich, Switzerland
| | - Christoph Barmet
- Institute for Biomedical Engineering, ETH Zurich and University of Zurich, Zurich, Switzerland; Skope Magnetic Resonance Technologies AG, Zurich, Switzerland
| | - Maximilian Haeberlin
- Institute for Biomedical Engineering, ETH Zurich and University of Zurich, Zurich, Switzerland
| | - Bertram J Wilm
- Institute for Biomedical Engineering, ETH Zurich and University of Zurich, Zurich, Switzerland
| | - Benjamin E Dietrich
- Institute for Biomedical Engineering, ETH Zurich and University of Zurich, Zurich, Switzerland
| | - Thomas Schmid
- Institute for Biomedical Engineering, ETH Zurich and University of Zurich, Zurich, Switzerland
| | - Simon Gross
- Institute for Biomedical Engineering, ETH Zurich and University of Zurich, Zurich, Switzerland
| | - David O Brunner
- Institute for Biomedical Engineering, ETH Zurich and University of Zurich, Zurich, Switzerland
| | - Klaas E Stephan
- Translational Neuromodeling Unit, IBT, University of Zurich and ETH Zurich, Zurich, Switzerland; Wellcome Trust Centre for Neuroimaging, University College London, London, United Kingdom; Max Planck Institute for Metabolism Research, Cologne, Germany
| | - Klaas P Pruessmann
- Institute for Biomedical Engineering, ETH Zurich and University of Zurich, Zurich, Switzerland
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6
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Zaric O, Pinker K, Zbyn S, Strasser B, Robinson S, Minarikova L, Gruber S, Farr A, Singer C, Helbich TH, Trattnig S, Bogner W. Quantitative Sodium MR Imaging at 7 T: Initial Results and Comparison with Diffusion-weighted Imaging in Patients with Breast Tumors. Radiology 2016; 280:39-48. [PMID: 27007803 DOI: 10.1148/radiol.2016151304] [Citation(s) in RCA: 58] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Purpose To investigate the clinical feasibility of a quantitative sodium 23 ((23)Na) magnetic resonance (MR) imaging protocol developed for breast tumor assessment and to compare it with 7-T diffusion-weighted imaging (DWI). Materials and Methods Written informed consent in this institutional review board-approved study was obtained from eight healthy volunteers and 17 patients with 20 breast tumors (five benign, 15 malignant). To achieve the best image quality and reproducibility, the (23)Na sequence was optimized and tested on phantoms and healthy volunteers. For in vivo quantification of absolute tissue sodium concentration (TSC), an external phantom was used. Static magnetic field, or B0, and combined transmit and receive radiofrequency field, or B1, maps were acquired, and image quality, measurement reproducibility, and accuracy testing were performed. Bilateral (23)Na and DWI sequences were performed before contrast material-enhanced MR imaging in patients with breast tumors. TSC and apparent diffusion coefficient (ADC) were calculated and correlated for healthy glandular tissue and benign and malignant lesions. Results The (23)Na MR imaging protocol is feasible, with 1.5-mm in-plane resolution and 16-minute imaging time. Good image quality was achieved, with high reproducibility (mean TSC values ± standard deviation for the test, 36 mmol per kilogram of wet weight ± 2 [range, 34-37 mmol/kg]; for the retest, 37 mmol/kg ± 1 [range, 35-39 mmol/kg]; P = .610) and accuracy (r = 0.998, P < .001). TSC values in normal glandular and adipose breast tissue were 35 mmol/kg ± 3 and 18 mmol/kg ± 3, respectively. In malignant lesions (mean size, 31 mm ± 24; range, 6-92 mm), the TSC of 69 mmol/kg ± 10 was, on average, 49% higher than that in benign lesions (mean size, 14 mm ± 12; range, 6-35 mm), with a TSC of 47 mmol/kg ± 8 (P = .002). There were similar ADC differences between benign ([1.78 ± 0.23] × 10(-3) mm(2)/sec) and malignant ([1.03 ± 0.23] × 10(-3) mm(2)/sec) tumors (P = .002). ADC and TSC were inversely correlated (r = -0.881, P < .001). Conclusion Quantitative (23)Na MR imaging is clinically feasible, may provide good differentiation between malignant and benign breast lesions, and demonstrates an inverse correlation with ADC. (©) RSNA, 2016 Online supplemental material is available for this article.
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Affiliation(s)
- Olgica Zaric
- From the MR Center of Excellence (MRCE), Department of Biomedical Imaging and Image-guided Therapy (O.Z., S.Z., B.S., S.R., L.M., S.G., S.T., W.B.), Division of Molecular and Gender Imaging, Department of Biomedical Imaging and Image-guided Therapy (K.P., T.H.H.), and Department of Obstetrics and Gynecology (A.F., C.S.), Medical University of Vienna, Lazarettgasse 14, A-1090, Vienna, Austria; and Christian Doppler Laboratory for Clinical Molecular MRI, Christian Doppler Forschungsgesellschaft, Vienna, Austria (S.T.)
| | - Katja Pinker
- From the MR Center of Excellence (MRCE), Department of Biomedical Imaging and Image-guided Therapy (O.Z., S.Z., B.S., S.R., L.M., S.G., S.T., W.B.), Division of Molecular and Gender Imaging, Department of Biomedical Imaging and Image-guided Therapy (K.P., T.H.H.), and Department of Obstetrics and Gynecology (A.F., C.S.), Medical University of Vienna, Lazarettgasse 14, A-1090, Vienna, Austria; and Christian Doppler Laboratory for Clinical Molecular MRI, Christian Doppler Forschungsgesellschaft, Vienna, Austria (S.T.)
| | - Stefan Zbyn
- From the MR Center of Excellence (MRCE), Department of Biomedical Imaging and Image-guided Therapy (O.Z., S.Z., B.S., S.R., L.M., S.G., S.T., W.B.), Division of Molecular and Gender Imaging, Department of Biomedical Imaging and Image-guided Therapy (K.P., T.H.H.), and Department of Obstetrics and Gynecology (A.F., C.S.), Medical University of Vienna, Lazarettgasse 14, A-1090, Vienna, Austria; and Christian Doppler Laboratory for Clinical Molecular MRI, Christian Doppler Forschungsgesellschaft, Vienna, Austria (S.T.)
| | - Bernhard Strasser
- From the MR Center of Excellence (MRCE), Department of Biomedical Imaging and Image-guided Therapy (O.Z., S.Z., B.S., S.R., L.M., S.G., S.T., W.B.), Division of Molecular and Gender Imaging, Department of Biomedical Imaging and Image-guided Therapy (K.P., T.H.H.), and Department of Obstetrics and Gynecology (A.F., C.S.), Medical University of Vienna, Lazarettgasse 14, A-1090, Vienna, Austria; and Christian Doppler Laboratory for Clinical Molecular MRI, Christian Doppler Forschungsgesellschaft, Vienna, Austria (S.T.)
| | - Simon Robinson
- From the MR Center of Excellence (MRCE), Department of Biomedical Imaging and Image-guided Therapy (O.Z., S.Z., B.S., S.R., L.M., S.G., S.T., W.B.), Division of Molecular and Gender Imaging, Department of Biomedical Imaging and Image-guided Therapy (K.P., T.H.H.), and Department of Obstetrics and Gynecology (A.F., C.S.), Medical University of Vienna, Lazarettgasse 14, A-1090, Vienna, Austria; and Christian Doppler Laboratory for Clinical Molecular MRI, Christian Doppler Forschungsgesellschaft, Vienna, Austria (S.T.)
| | - Lenka Minarikova
- From the MR Center of Excellence (MRCE), Department of Biomedical Imaging and Image-guided Therapy (O.Z., S.Z., B.S., S.R., L.M., S.G., S.T., W.B.), Division of Molecular and Gender Imaging, Department of Biomedical Imaging and Image-guided Therapy (K.P., T.H.H.), and Department of Obstetrics and Gynecology (A.F., C.S.), Medical University of Vienna, Lazarettgasse 14, A-1090, Vienna, Austria; and Christian Doppler Laboratory for Clinical Molecular MRI, Christian Doppler Forschungsgesellschaft, Vienna, Austria (S.T.)
| | - Stephan Gruber
- From the MR Center of Excellence (MRCE), Department of Biomedical Imaging and Image-guided Therapy (O.Z., S.Z., B.S., S.R., L.M., S.G., S.T., W.B.), Division of Molecular and Gender Imaging, Department of Biomedical Imaging and Image-guided Therapy (K.P., T.H.H.), and Department of Obstetrics and Gynecology (A.F., C.S.), Medical University of Vienna, Lazarettgasse 14, A-1090, Vienna, Austria; and Christian Doppler Laboratory for Clinical Molecular MRI, Christian Doppler Forschungsgesellschaft, Vienna, Austria (S.T.)
| | - Alex Farr
- From the MR Center of Excellence (MRCE), Department of Biomedical Imaging and Image-guided Therapy (O.Z., S.Z., B.S., S.R., L.M., S.G., S.T., W.B.), Division of Molecular and Gender Imaging, Department of Biomedical Imaging and Image-guided Therapy (K.P., T.H.H.), and Department of Obstetrics and Gynecology (A.F., C.S.), Medical University of Vienna, Lazarettgasse 14, A-1090, Vienna, Austria; and Christian Doppler Laboratory for Clinical Molecular MRI, Christian Doppler Forschungsgesellschaft, Vienna, Austria (S.T.)
| | - Christian Singer
- From the MR Center of Excellence (MRCE), Department of Biomedical Imaging and Image-guided Therapy (O.Z., S.Z., B.S., S.R., L.M., S.G., S.T., W.B.), Division of Molecular and Gender Imaging, Department of Biomedical Imaging and Image-guided Therapy (K.P., T.H.H.), and Department of Obstetrics and Gynecology (A.F., C.S.), Medical University of Vienna, Lazarettgasse 14, A-1090, Vienna, Austria; and Christian Doppler Laboratory for Clinical Molecular MRI, Christian Doppler Forschungsgesellschaft, Vienna, Austria (S.T.)
| | - Thomas H Helbich
- From the MR Center of Excellence (MRCE), Department of Biomedical Imaging and Image-guided Therapy (O.Z., S.Z., B.S., S.R., L.M., S.G., S.T., W.B.), Division of Molecular and Gender Imaging, Department of Biomedical Imaging and Image-guided Therapy (K.P., T.H.H.), and Department of Obstetrics and Gynecology (A.F., C.S.), Medical University of Vienna, Lazarettgasse 14, A-1090, Vienna, Austria; and Christian Doppler Laboratory for Clinical Molecular MRI, Christian Doppler Forschungsgesellschaft, Vienna, Austria (S.T.)
| | - Siegfried Trattnig
- From the MR Center of Excellence (MRCE), Department of Biomedical Imaging and Image-guided Therapy (O.Z., S.Z., B.S., S.R., L.M., S.G., S.T., W.B.), Division of Molecular and Gender Imaging, Department of Biomedical Imaging and Image-guided Therapy (K.P., T.H.H.), and Department of Obstetrics and Gynecology (A.F., C.S.), Medical University of Vienna, Lazarettgasse 14, A-1090, Vienna, Austria; and Christian Doppler Laboratory for Clinical Molecular MRI, Christian Doppler Forschungsgesellschaft, Vienna, Austria (S.T.)
| | - Wolfgang Bogner
- From the MR Center of Excellence (MRCE), Department of Biomedical Imaging and Image-guided Therapy (O.Z., S.Z., B.S., S.R., L.M., S.G., S.T., W.B.), Division of Molecular and Gender Imaging, Department of Biomedical Imaging and Image-guided Therapy (K.P., T.H.H.), and Department of Obstetrics and Gynecology (A.F., C.S.), Medical University of Vienna, Lazarettgasse 14, A-1090, Vienna, Austria; and Christian Doppler Laboratory for Clinical Molecular MRI, Christian Doppler Forschungsgesellschaft, Vienna, Austria (S.T.)
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CHENG K. What We Have Learned about Human Primary Visual Cortex from High Resolution Functional Magnetic Resonance Imaging. Magn Reson Med Sci 2016; 15:1-10. [DOI: 10.2463/mrms.2015-0008] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Affiliation(s)
- Kang CHENG
- Laboratory for Cognitive Brain Mapping and Support Unit for Functional Magnetic Resonance Imaging, RIKEN Brain Science Institute
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8
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Brown R, Lakshmanan K, Madelin G, Alon L, Chang G, Sodickson DK, Regatte RR, Wiggins GC. A flexible nested sodium and proton coil array with wideband matching for knee cartilage MRI at 3T. Magn Reson Med 2015; 76:1325-34. [PMID: 26502310 DOI: 10.1002/mrm.26017] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2015] [Revised: 08/27/2015] [Accepted: 09/25/2015] [Indexed: 12/11/2022]
Abstract
PURPOSE We describe a 2 × 6 channel sodium/proton array for knee MRI at 3T. Multielement coil arrays are desirable because of well-known signal-to-noise ratio advantages over volume and single-element coils. However, low tissue-coil coupling that is characteristic of coils operating at low frequency can make the potential gains from a phased array difficult to realize. METHODS The issue of low tissue-coil coupling in the developed six-channel sodium receive array was addressed by implementing 1) a mechanically flexible former to minimize the coil-to-tissue distance and reduce the overall diameter of the array and 2) a wideband matching scheme that counteracts preamplifier noise degradation caused by coil coupling and a high-quality factor. The sodium array was complemented with a nested proton array to enable standard MRI. RESULTS The wideband matching scheme and tight-fitting mechanical design contributed to >30% central signal-to-noise ratio gain on the sodium module over a mononuclear sodium birdcage coil, and the performance of the proton module was sufficient for clinical imaging. CONCLUSION We expect the strategies presented in this study to be generally relevant in high-density receive arrays, particularly in x-nuclei or small animal applications. Magn Reson Med 76:1325-1334, 2016. © 2015 Wiley Periodicals, Inc.
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Affiliation(s)
- Ryan Brown
- Bernard and Irene Schwartz Center for Biomedical Imaging, Department of Radiology, New York University School of Medicine, New York, New York, USA. .,Center for Advanced Imaging Innovation and Research, Department of Radiology, New York University School of Medicine, New York, New York, USA. .,NYU WIRELESS, Polytechnic Institute of New York University, Brooklyn, New York, USA.
| | - Karthik Lakshmanan
- Bernard and Irene Schwartz Center for Biomedical Imaging, Department of Radiology, New York University School of Medicine, New York, New York, USA.,Center for Advanced Imaging Innovation and Research, Department of Radiology, New York University School of Medicine, New York, New York, USA
| | - Guillaume Madelin
- Bernard and Irene Schwartz Center for Biomedical Imaging, Department of Radiology, New York University School of Medicine, New York, New York, USA.,Center for Advanced Imaging Innovation and Research, Department of Radiology, New York University School of Medicine, New York, New York, USA
| | - Leeor Alon
- Bernard and Irene Schwartz Center for Biomedical Imaging, Department of Radiology, New York University School of Medicine, New York, New York, USA.,Center for Advanced Imaging Innovation and Research, Department of Radiology, New York University School of Medicine, New York, New York, USA.,NYU WIRELESS, Polytechnic Institute of New York University, Brooklyn, New York, USA
| | - Gregory Chang
- Bernard and Irene Schwartz Center for Biomedical Imaging, Department of Radiology, New York University School of Medicine, New York, New York, USA.,Center for Advanced Imaging Innovation and Research, Department of Radiology, New York University School of Medicine, New York, New York, USA
| | - Daniel K Sodickson
- Bernard and Irene Schwartz Center for Biomedical Imaging, Department of Radiology, New York University School of Medicine, New York, New York, USA.,Center for Advanced Imaging Innovation and Research, Department of Radiology, New York University School of Medicine, New York, New York, USA.,NYU WIRELESS, Polytechnic Institute of New York University, Brooklyn, New York, USA
| | - Ravinder R Regatte
- Bernard and Irene Schwartz Center for Biomedical Imaging, Department of Radiology, New York University School of Medicine, New York, New York, USA.,Center for Advanced Imaging Innovation and Research, Department of Radiology, New York University School of Medicine, New York, New York, USA
| | - Graham C Wiggins
- Bernard and Irene Schwartz Center for Biomedical Imaging, Department of Radiology, New York University School of Medicine, New York, New York, USA.,Center for Advanced Imaging Innovation and Research, Department of Radiology, New York University School of Medicine, New York, New York, USA
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9
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Deng W, Zahneisen B, Stenger VA. Rotated stack-of-spirals partial acquisition for rapid volumetric parallel MRI. Magn Reson Med 2015; 76:127-35. [PMID: 26268139 DOI: 10.1002/mrm.25863] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2015] [Revised: 06/30/2015] [Accepted: 07/10/2015] [Indexed: 11/10/2022]
Abstract
PURPOSE We present a volumetric sampling method that rotates the spiral interleaves of a stack of spirals (SOSP) trajectory for reduced aliasing artifacts using parallel imaging with undersampling. METHODS The aliasing pattern in an undersampled SOSP acquisition was modified by consecutively rotating spiral interleaves in each phase-encoding plane. This allows a sampling scheme with a high reduction factor when using a volumetric multireceiver array. Phantom and in vivo brain images at a resolution of 1 × 1 × 2 mm(3) were acquired at 3T using a 32-channel coil. Images reconstructed with a reduction factor of 16 were compared for aliasing artifacts and geometry factor (g-factor). RESULTS Phantom and in vivo brain image results revealed that the rotated SOSP acquisition with a reduction factor of 16 produces images with reduced aliasing and lower g-factors than images acquired without rotation. CONCLUSION The proposed rotated SOSP sampling method is a highly efficient way to maximize the encoding power of volumetric receiver arrays in parallel imaging and is applicable to rapid volumetric scanning, including susceptibility-weighted imaging and functional MRI. Magn Reson Med 76:127-135, 2016. © 2015 Wiley Periodicals, Inc.
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Affiliation(s)
- Weiran Deng
- University of Hawaii John A. Burns School of Medicine, Honolulu, Hawaii, USA
| | - Benjamin Zahneisen
- University of Hawaii John A. Burns School of Medicine, Honolulu, Hawaii, USA
| | - V Andrew Stenger
- University of Hawaii John A. Burns School of Medicine, Honolulu, Hawaii, USA
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10
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Reynaud O, Gallichan D, Schaller B, Gruetter R. Fast low-specific absorption rate B0
-mapping along projections at high field using two-dimensional radiofrequency pulses. Magn Reson Med 2014; 73:901-8. [DOI: 10.1002/mrm.25217] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2013] [Revised: 02/13/2014] [Accepted: 02/13/2014] [Indexed: 12/24/2022]
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11
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Mirkes CC, Hoffmann J, Shajan G, Pohmann R, Scheffler K. High-resolution quantitative sodium imaging at 9.4 Tesla. Magn Reson Med 2014; 73:342-51. [PMID: 24435910 DOI: 10.1002/mrm.25096] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2013] [Revised: 12/04/2013] [Accepted: 12/05/2013] [Indexed: 11/10/2022]
Abstract
PURPOSE Investigation of the feasibility to perform high-resolution quantitative sodium imaging at 9.4 Tesla (T). METHODS A proton patch antenna was combined with a sodium birdcage coil to provide a proton signal without compromising the efficiency of the X-nucleus coil. Sodium density weighted images with a nominal resolution of 1 × 1 × 5 mm(3) were acquired within 30 min with an ultrashort echo time sequence. The methods used for signal calibration as well as for B0, B1, and off-resonance correction were verified on a phantom and five healthy volunteers. RESULTS An actual voxel volume of roughly 40 μL could be achieved at 9.4T, while maintaining an acceptable signal-to-noise ratio (8 for brain tissue and 35 for cerebrospinal fluid). The measured mean sodium concentrations for gray and white matter were 36 ± 2 and 31 ± 1 mmol/L of wet tissue, which are comparable to values previously reported in the literature. CONCLUSION The reduction of partial volume effects is essential for accurate measurement of the sodium concentration in the human brain. Ultrahigh field imaging is a viable tool to achieve this goal due to its increased sensitivity.
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Affiliation(s)
- Christian C Mirkes
- Department for Biomedical Magnetic Resonance, University of Tübingen, Tübingen, Germany.,High-Field MR Center, Max Planck Institute for Biological Cybernetics, Tübingen, Germany
| | - Jens Hoffmann
- High-Field MR Center, Max Planck Institute for Biological Cybernetics, Tübingen, Germany
| | - G Shajan
- High-Field MR Center, Max Planck Institute for Biological Cybernetics, Tübingen, Germany
| | - Rolf Pohmann
- High-Field MR Center, Max Planck Institute for Biological Cybernetics, Tübingen, Germany
| | - Klaus Scheffler
- Department for Biomedical Magnetic Resonance, University of Tübingen, Tübingen, Germany.,High-Field MR Center, Max Planck Institute for Biological Cybernetics, Tübingen, Germany
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Pang Y, Yu B, Zhang X. Hepatic fat assessment using advanced Magnetic Resonance Imaging. Quant Imaging Med Surg 2012; 2:213-8. [PMID: 23256082 DOI: 10.3978/j.issn.2223-4292.2012.08.05] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2012] [Accepted: 08/31/2012] [Indexed: 01/12/2023]
Affiliation(s)
- Yong Pang
- Department of Radiology and Biomedical Imaging, University of California San Francisco, San Francisco, CA, United States
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Qian Y, Zhao T, Zheng H, Weimer J, Boada FE. High-resolution sodium imaging of human brain at 7 T. Magn Reson Med 2011; 68:227-33. [PMID: 22144258 DOI: 10.1002/mrm.23225] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2011] [Revised: 08/29/2011] [Accepted: 08/30/2011] [Indexed: 01/17/2023]
Abstract
The feasibility of high-resolution sodium magnetic resonance imaging on human brain at 7 T was demonstrated in this study. A three-dimensional anisotropic resolution data acquisition was used to address the challenge of low signal-to-noise ratio associated with high resolution. Ultrashort echo-time sequence was used for the anisotropic data acquisition. Phantoms and healthy human brains were studied on a whole-body 7-T magnetic resonance imaging scanner. Sodium images were obtained at two high nominal in-plane resolutions (1.72 and 0.86 mm) at a slice thickness of 4 mm. Signal-to-noise ratio in the brain image (cerebrospinal fluid) was measured as 14.4 and 6.8 at the two high resolutions, respectively. The actual in-plane resolution was measured as 2.9 and 1.6 mm, 69-86% larger than their nominal values. The quantification of sodium concentration on the phantom and brain images enabled better accuracy at the high nominal resolutions than at the low nominal resolution of 3.44 mm (measured resolution 5.5 mm) due to the improvement of in-plane resolution.
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Affiliation(s)
- Yongxian Qian
- MR Research Center, Department of Radiology, University of Pittsburgh, Pittsburgh, Pennsylvania, USA.
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Abstract
PURPOSE OF REVIEW For functional MRI (fMRI), as for any imaging technique, the higher the spatial resolution, the more the details it can reveal. This review will discuss the factors restricting the spatial resolution of fMRI, describe high-resolution fMRI (HR-fMRI) applications in neuroscience and outline a few research areas for future HR-fMRI studies. RECENT FINDINGS HR-fMRI has been successfully used to map fine cortical architectures and reveal cortical laminar structures and subcortical structures. HR-fMRI has also played important roles in resolving controversies regarding modular representations in the ventral visual pathway and interpretations of multivariate pattern analysis results. SUMMARY Real-time HR-fMRI as well as high-resolution anatomical MRI may emerge as indispensable tools for surgical planning, diagnosis of neurological diseases and targeting of deep brain stimulation.
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Qian Y, Williams AA, Chu CR, Boada FE. High-resolution ultrashort echo time (UTE) imaging on human knee with AWSOS sequence at 3.0 T. J Magn Reson Imaging 2011; 35:204-10. [PMID: 22002811 DOI: 10.1002/jmri.22639] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2010] [Accepted: 04/06/2011] [Indexed: 11/09/2022] Open
Abstract
PURPOSE To demonstrate the technical feasibility of high-resolution (0.28-0.14 mm) ultrashort echo time (UTE) imaging on human knee at 3T with the acquisition-weighted stack of spirals (AWSOS) sequence. MATERIALS AND METHODS Nine human subjects were scanned on a 3T MRI scanner with an 8-channel knee coil using the AWSOS sequence and isocenter positioning plus manual shimming. RESULTS High-resolution UTE images were obtained on the subject knees at TE = 0.6 msec with total acquisition time of 5.12 minutes for 60 slices at an in-plane resolution of 0.28 mm and 10.24 minutes for 40 slices at an in-plane resolution of 0.14 mm. Isocenter positioning, manual shimming, and the 8-channel array coil helped minimize image distortion and achieve high signal-to-noise ratio (SNR). CONCLUSION It is technically feasible on a clinical 3T MRI scanner to perform UTE imaging on human knee at very high spatial resolutions (0.28-0.14 mm) within reasonable scan time (5-10 min) using the AWSOS sequence.
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Affiliation(s)
- Yongxian Qian
- MR Research Center, Department of Radiology, University of Pittsburgh, Pittsburgh, Pennsylvania 15213, USA.
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Pang Y, Wu B, Wang C, Vigneron DB, Zhang X. Numerical Analysis of Human Sample Effect on RF Penetration and Liver MR Imaging at Ultrahigh Field. CONCEPTS IN MAGNETIC RESONANCE. PART B, MAGNETIC RESONANCE ENGINEERING 2011; 39B:206-216. [PMID: 22337345 PMCID: PMC3277816 DOI: 10.1002/cmr.b.20209] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/14/2023]
Abstract
Magnetic resonance imaging (MRI) can provide clinically-valuable images for hepatic diseases and has become one of the most promising noninvasive methods in evaluating liver lesions. To facilitate the ultrahigh field human liver MRI, in this work, the RF penetration behavior in the conductive and high dielectric human body at the ultrahigh field of 7 Tesla (7T) is investigated and evaluated using the finite-difference time-domain numerical analysis. The study shows that in brain imaging at the ultrahigh field of 7T, the "dielectric resonance" effect dominates among other factors, resulting in improved B(1) penetration; while in liver imaging, due to its irregular geometry of the liver, the "dielectric resonance" effect is not readily to be established, leading to a reduced B(1) penetration or limited image coverage comparing to that in the brain. Therefore, it is necessary to build a large size coil to have deeper penetration to image human liver although the coil design may become more challenging due to the required high frequency. Based on this study, a bisected microstrip coil operating at 300 MHz range is designed and constructed. Three-dimensional in vivo liver images in axial, sagittal and coronal orientations are then acquired from healthy volunteers using this dedicated RF coil on a 7T whole body MR scanner.
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Affiliation(s)
- Yong Pang
- Department of Radiology & Biomedical Imaging, University of California San Francisco, San Francisco, CA
| | - Bing Wu
- Department of Radiology & Biomedical Imaging, University of California San Francisco, San Francisco, CA
| | - Chunsheng Wang
- Department of Radiology & Biomedical Imaging, University of California San Francisco, San Francisco, CA
| | - Daniel B. Vigneron
- Department of Radiology & Biomedical Imaging, University of California San Francisco, San Francisco, CA
- UCSF/UC Berkeley Joint Graduate Group in Bioengineering, San Francisco & Berkeley, CA
| | - Xiaoliang Zhang
- Department of Radiology & Biomedical Imaging, University of California San Francisco, San Francisco, CA
- UCSF/UC Berkeley Joint Graduate Group in Bioengineering, San Francisco & Berkeley, CA
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