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Yamashiro T, Takatsu Y, Morita K, Nakamura M, Yukimura Y, Nakajima K. Effect of acoustic noise reduction technology on image quality: a multivendor study. Radiol Phys Technol 2023; 16:235-243. [PMID: 36964891 DOI: 10.1007/s12194-023-00712-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2022] [Revised: 03/08/2023] [Accepted: 03/10/2023] [Indexed: 03/26/2023]
Abstract
The purpose of this study was to clarify the appropriate use of a combination of pulse sequences and acoustic noise reduction technology in general-purpose brain magnetic resonance imaging. Five pulse sequences commonly used in brain magnetic resonance imaging examinations-turbo spin-echo T2-weighted imaging, T1-weighted fluid-attenuated inversion recovery, T2-weighted fluid-attenuated inversion recovery, diffusion-weighted imaging, and magnetic resonance angiography-were performed on healthy participants at three vendors where acoustic noise reduction technology was available. The results showed that acoustic noise reduction technology reduced sound pressure levels and altered image quality in all pulse sequences across all vendors' magnetic resonance imaging scanners. Although T2-weighted imaging and T1-weighted fluid-attenuated inversion recovery resulted in little image quality degradation, T2-weighted fluid-attenuated inversion recovery, diffusion-weighted imaging, and magnetic resonance angiography had significant image degradation. Therefore, acoustic noise reduction technology should be used with caution.
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Affiliation(s)
- Takanobu Yamashiro
- Department of Radiology, Minoh City Hospital, 5-7-1 Kayano, Mino-shi, Osaka, 562-8562, Japan.
- Department of Systems and Control Engineering, Faculty of Engineering, Tokushima Bunri University, 1314-1 Shido, Sanuki-shi, Kagawa, 769-2193, Japan.
| | - Yasuo Takatsu
- School of Medical Sciences, Fujita Health University, Molecular Imaging, 1-98 Dengakugakubo, Kutsukake-cho, Toyoake, Aichi, 470-1192, Japan
- Division of Health Sciences, Graduate School of Medical Sciences, Kanazawa University, 5-11-80 Kodatsuno, Kanazawa, 920-0942, Japan
| | - Kosuke Morita
- Department of Central Radiology, Kumamoto University Hospital, 1-1-1 Honjo, , Kumamoto-shi, Kumamoto, 860-0811, Japan
| | - Masafumi Nakamura
- Division of Health Sciences, Graduate School of Medical Sciences, Kanazawa University, 5-11-80 Kodatsuno, Kanazawa, 920-0942, Japan
- Department of Radiology, Otsu City Hospital, 2-9-9 Motomiya, Otsu-shi, Shiga, 520-0804, Japan
| | - Yoshihiro Yukimura
- Department of Radiology, Ikeda City Hospital, 3-1-18 Jyonan, Ikeda-shi, Osaka, 563-8510, Japan
| | - Kazuhiro Nakajima
- Department of Radiology, Minoh City Hospital, 5-7-1 Kayano, Mino-shi, Osaka, 562-8562, Japan
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2
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Lombardi AF, Ma YJ, Jang H, Jerban S, Du J, Chang EY, Chung CB. Synthetic CT in Musculoskeletal Disorders: A Systematic Review. Invest Radiol 2023; 58:43-59. [PMID: 36070535 PMCID: PMC9742139 DOI: 10.1097/rli.0000000000000916] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
ABSTRACT Repeated computed tomography (CT) examinations increase patients' ionizing radiation exposure and health costs, making an alternative method desirable. Cortical and trabecular bone, however, have short T2 relaxation times, causing low signal intensity on conventional magnetic resonance (MR) sequences. Different techniques are available to create a "CT-like" contrast of bone, such as ultrashort echo time, zero echo time, gradient-echo, and susceptibility-weighted image MR sequences, and artificial intelligence. This systematic review summarizes the essential technical background and developments of ultrashort echo time, zero echo time, gradient-echo, susceptibility-weighted image MR imaging sequences and artificial intelligence; presents studies on research and clinical applications of "CT-like" MR imaging; and describes their main advantages and limitations. We also discuss future opportunities in research, which patients would benefit the most, the most appropriate situations for using the technique, and the potential to replace CT in the clinical workflow.
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Affiliation(s)
- Alecio F Lombardi
- From the Department of Radiology, University of California San Diego, La Jolla, and the Research Service, Veterans Affairs San Diego Healthcare System, California
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Wiesinger F, Ho ML. Zero-TE MRI: principles and applications in the head and neck. Br J Radiol 2022; 95:20220059. [PMID: 35616709 PMCID: PMC10162052 DOI: 10.1259/bjr.20220059] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Zero echo-time (ZTE) MRI is a novel imaging technique that utilizes ultrafast readouts to capture signal from short-T2 tissues. Additional sequence advantages include rapid imaging times, silent scanning, and artifact resistance. A robust application of this technology is imaging of cortical bone without the use of ionizing radiation, thus representing a viable alternative to CT for both rapid screening and "one-stop-shop" MRI. Although ZTE is increasingly used in musculoskeletal and body imaging, neuroimaging applications have historically been limited by complex anatomy and pathology. In this article, we review the imaging physics of ZTE including pulse sequence options, practical limitations, and image reconstruction. We then discuss optimization of settings for ZTE bone neuroimaging including acquisition, processing, segmentation, synthetic CT generation, and artifacts. Finally, we examine clinical utility of ZTE in the head and neck with imaging examples including malformations, trauma, tumors, and interventional procedures.
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Affiliation(s)
- Florian Wiesinger
- Department for Neuroimaging, Institute of Psychiatry & Neuroscience, King's College London, London, UK.,Principal Scientist at GE Healthcare, Munich, Germany
| | - Mai-Lan Ho
- Nationwide Children's Hospital and The Ohio State University, Columbus, USA
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Ljungberg E, Wood TC, Solana AB, Williams SCR, Barker GJ, Wiesinger F. Motion corrected silent ZTE neuroimaging. Magn Reson Med 2022; 88:195-210. [PMID: 35381110 PMCID: PMC9321117 DOI: 10.1002/mrm.29201] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2021] [Revised: 01/16/2022] [Accepted: 01/28/2022] [Indexed: 11/11/2022]
Abstract
Purpose To develop self‐navigated motion correction for 3D silent zero echo time (ZTE) based neuroimaging and characterize its performance for different types of head motion. Methods The proposed method termed MERLIN (Motion Estimation & Retrospective correction Leveraging Interleaved Navigators) achieves self‐navigation by using interleaved 3D phyllotaxis k‐space sampling. Low resolution navigator images are reconstructed continuously throughout the ZTE acquisition using a sliding window and co‐registered in image space relative to a fixed reference position. Rigid body motion corrections are then applied retrospectively to the k‐space trajectory and raw data and reconstructed into a final, high‐resolution ZTE image. Results MERLIN demonstrated successful and consistent motion correction for magnetization prepared ZTE images for a range of different instructed motion paradigms. The acoustic noise response of the self‐navigated phyllotaxis trajectory was found to be only slightly above ambient noise levels (<4 dBA). Conclusion Silent ZTE imaging combined with MERLIN addresses two major challenges intrinsic to MRI (i.e., subject motion and acoustic noise) in a synergistic and integrated manner without increase in scan time and thereby forms a versatile and powerful framework for clinical and research MR neuroimaging applications.
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Affiliation(s)
- Emil Ljungberg
- Department of Neuroimaging, Institute of Psychiatry, Psychology & Neuroscience, King's College London, London, UK.,Department of Medical Radiation Physics, Lund University, Lund, Sweden
| | - Tobias C Wood
- Department of Neuroimaging, Institute of Psychiatry, Psychology & Neuroscience, King's College London, London, UK
| | | | - Steven C R Williams
- Department of Neuroimaging, Institute of Psychiatry, Psychology & Neuroscience, King's College London, London, UK
| | - Gareth J Barker
- Department of Neuroimaging, Institute of Psychiatry, Psychology & Neuroscience, King's College London, London, UK
| | - Florian Wiesinger
- Department of Neuroimaging, Institute of Psychiatry, Psychology & Neuroscience, King's College London, London, UK.,GE Healthcare, Munich, Germany
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5
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Lee PK, Yoon D, Sandberg JK, Vasanawala SS, Hargreaves BA. Volumetric and multispectral DWI near metallic implants using a non-linear phase Carr-Purcell-Meiboom-Gill diffusion preparation. Magn Reson Med 2022; 87:2650-2666. [PMID: 35014729 DOI: 10.1002/mrm.29153] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2021] [Revised: 12/20/2021] [Accepted: 12/22/2021] [Indexed: 12/15/2022]
Abstract
PURPOSE DWI near metal implants has not been widely explored due to substantial challenges associated with through-slice and in-plane distortions, the increased encoding requirement of different spectral bins, and limited SNR. There is no widely adopted clinical protocol for DWI near metal since the commonly used EPI trajectory fails completely due to distortion from extreme off-resonance ranging from 2 to 20 kHz. We present a sequence that achieves DWI near metal with moderate b-values (400-500 s/mm2 ) and volumetric coverage in clinically feasible scan times. THEORY AND METHODS Multispectral excitation with Cartesian sampling, view angle tilting, and kz phase encoding reduce in-plane and through-plane off-resonance artifacts, and Carr-Purcell-Meiboom-Gill (CPMG) spin-echo refocusing trains counteract T2* effects. The effect of random phase on the refocusing train is eliminated using a stimulated echo diffusion preparation. Root-flipped Shinnar-Le Roux refocusing pulses permits preparation of a high spectral bandwidth, which improves imaging times by reducing the number of excitations required to cover the desired spectral range. B1 sensitivity is reduced by using an excitation that satisfies the CPMG condition in the preparation. A method for ADC quantification insensitive to background gradients is presented. RESULTS Non-linear phase refocusing pulses reduces the peak B1 by 46% which allows RF bandwidth to be doubled. Simulations and phantom experiments show that a non-linear phase CPMG pulse pair reduces B1 sensitivity. Application in vivo demonstrates complementary contrast to conventional multispectral acquisitions and improved visualization compared to DW-EPI. CONCLUSION Volumetric and multispectral DW imaging near metal can be achieved with a 3D encoded sequence.
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Affiliation(s)
- Philip K Lee
- Radiology, Stanford University, Stanford, California, USA.,Electrical Engineering, Stanford University, Stanford, California, USA
| | - Daehyun Yoon
- Radiology, Stanford University, Stanford, California, USA
| | | | | | - Brian A Hargreaves
- Radiology, Stanford University, Stanford, California, USA.,Electrical Engineering, Stanford University, Stanford, California, USA.,Bioengineering, Stanford University, Stanford, California, USA
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Sun K, Zhong Z, Dan G, Karaman M, Luo Q, Zhou XJ. Three-dimensional reduced field-of-view imaging (3D-rFOVI). Magn Reson Med 2021; 87:2372-2379. [PMID: 34894639 PMCID: PMC8847334 DOI: 10.1002/mrm.29121] [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: 07/16/2021] [Revised: 10/31/2021] [Accepted: 11/25/2021] [Indexed: 12/23/2022]
Abstract
PURPOSE This study aimed at developing a 3D reduced field-of-view imaging (3D-rFOVI) technique using a 2D radiofrequency (RF) pulse, and demonstrating its ability to achieve isotropic high spatial resolution and reduced image distortion in echo planar imaging (EPI). METHODS The proposed 3D-rFOVI technique takes advantage of a 2D RF pulse to excite a slab along the conventional slice-selection direction (i.e., z-direction) while limiting the spatial extent along the phase-encoded direction (i.e., y-direction) within the slab. The slab is phase-encoded in both through-slab and in-slab phase-encoded directions. The 3D-rFOVI technique was implemented at 3T in gradient-echo and spin-echo EPI pulse sequences for functional MRI (fMRI) and diffusion-weighted imaging (DWI), respectively. 3D-rFOVI experiments were performed on a phantom and human brain to illustrate image distortion reduction, as well as isotropic high spatial resolution, in comparison with 3D full-FOV imaging. RESULTS In both the phantom and the human brain, image voxel dislocation was substantially reduced by 3D-rFOVI when compared with full-FOV imaging. In the fMRI experiment with visual stimulation, 3D isotropic spatial resolution of (2 × 2 × 2 mm3 ) was achieved with an adequate signal-to-noise ratio (81.5) and blood oxygen level-dependent (BOLD) contrast (2.5%). In the DWI experiment, diffusion-weighted brain images with an isotropic resolution of (1 × 1 × 1 mm3 ) was obtained without appreciable image distortion. CONCLUSION This study indicates that 3D-rFOVI is a viable approach to 3D neuroimaging over a zoomed region.
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Affiliation(s)
- Kaibao Sun
- Center for Magnetic Resonance Research, University of Illinois at Chicago, Chicago, Illinois, USA
| | - Zheng Zhong
- Center for Magnetic Resonance Research, University of Illinois at Chicago, Chicago, Illinois, USA.,Department of Biomedical Engineering, University of Illinois at Chicago, Chicago, Illinois, USA
| | - Guangyu Dan
- Center for Magnetic Resonance Research, University of Illinois at Chicago, Chicago, Illinois, USA.,Department of Biomedical Engineering, University of Illinois at Chicago, Chicago, Illinois, USA
| | - Muge Karaman
- Center for Magnetic Resonance Research, University of Illinois at Chicago, Chicago, Illinois, USA.,Department of Biomedical Engineering, University of Illinois at Chicago, Chicago, Illinois, USA
| | - Qingfei Luo
- Center for Magnetic Resonance Research, University of Illinois at Chicago, Chicago, Illinois, USA
| | - Xiaohong Joe Zhou
- Center for Magnetic Resonance Research, University of Illinois at Chicago, Chicago, Illinois, USA.,Department of Biomedical Engineering, University of Illinois at Chicago, Chicago, Illinois, USA.,Departments of Radiology and Neurosurgery, University of Illinois College of Medicine at Chicago, Chicago, Illinois, USA
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Ljungberg E, Damestani NL, Wood TC, Lythgoe DJ, Zelaya F, Williams SCR, Solana AB, Barker GJ, Wiesinger F. Silent zero TE MR neuroimaging: Current state-of-the-art and future directions. PROGRESS IN NUCLEAR MAGNETIC RESONANCE SPECTROSCOPY 2021; 123:73-93. [PMID: 34078538 PMCID: PMC7616227 DOI: 10.1016/j.pnmrs.2021.03.002] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/25/2020] [Revised: 03/08/2021] [Accepted: 03/09/2021] [Indexed: 06/12/2023]
Abstract
Magnetic Resonance Imaging (MRI) scanners produce loud acoustic noise originating from vibrational Lorentz forces induced by rapidly changing currents in the magnetic field gradient coils. Using zero echo time (ZTE) MRI pulse sequences, gradient switching can be reduced to a minimum, which enables near silent operation.Besides silent MRI, ZTE offers further interesting characteristics, including a nominal echo time of TE = 0 (thus capturing short-lived signals from MR tissues which are otherwise MR-invisible), 3D radial sampling (providing motion robustness), and ultra-short repetition times (providing fast and efficient scanning).In this work we describe the main concepts behind ZTE imaging with a focus on conceptual understanding of the imaging sequences, relevant acquisition parameters, commonly observed image artefacts, and image contrasts. We will further describe a range of methods for anatomical and functional neuroimaging, together with recommendations for successful implementation.
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Affiliation(s)
- Emil Ljungberg
- Department of Neuroimaging, Institute of Psychiatry, Psychology & Neuroscience, King's College London, London, United Kingdom.
| | - Nikou L Damestani
- Department of Neuroimaging, Institute of Psychiatry, Psychology & Neuroscience, King's College London, London, United Kingdom
| | - Tobias C Wood
- Department of Neuroimaging, Institute of Psychiatry, Psychology & Neuroscience, King's College London, London, United Kingdom
| | - David J Lythgoe
- Department of Neuroimaging, Institute of Psychiatry, Psychology & Neuroscience, King's College London, London, United Kingdom
| | - Fernando Zelaya
- Department of Neuroimaging, Institute of Psychiatry, Psychology & Neuroscience, King's College London, London, United Kingdom
| | - Steven C R Williams
- Department of Neuroimaging, Institute of Psychiatry, Psychology & Neuroscience, King's College London, London, United Kingdom
| | | | - Gareth J Barker
- Department of Neuroimaging, Institute of Psychiatry, Psychology & Neuroscience, King's College London, London, United Kingdom
| | - Florian Wiesinger
- Department of Neuroimaging, Institute of Psychiatry, Psychology & Neuroscience, King's College London, London, United Kingdom; ASL Europe, GE Healthcare, Munich, Germany
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McJury MJ. Acoustic Noise and Magnetic Resonance Imaging: A Narrative/Descriptive Review. J Magn Reson Imaging 2021; 55:337-346. [PMID: 33629790 DOI: 10.1002/jmri.27525] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2020] [Revised: 01/07/2021] [Accepted: 01/08/2021] [Indexed: 12/15/2022] Open
Abstract
Magnetic resonance imaging generates unwanted acoustic noise. This review describes the work characterizing the acoustic noise, and the various solutions to control and attenuate the acoustic noise. There are also discussions about the permissible limits, and guidance regarding acoustic noise exposure for staff, patients, and volunteers. LEVEL OF EVIDENCE: 5 TECHNICAL EFFICACY STAGE: 1.
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Affiliation(s)
- Mark J McJury
- Department of Clinical Physics & Bio-Engineering, Level 2, Imaging Centre of Excellence, Queen Elizabeth University Hospital Campus, Glasgow, UK
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9
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Roccia E, Neji R, Benkert T, Kiefer B, Goh V, Dregely I. Distortion-free 3D diffusion imaging of the prostate using a multishot diffusion-prepared phase-cycled acquisition and dictionary matching. Magn Reson Med 2020; 85:1441-1454. [PMID: 32989765 DOI: 10.1002/mrm.28527] [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: 05/27/2020] [Revised: 07/27/2020] [Accepted: 08/31/2020] [Indexed: 11/06/2022]
Abstract
PURPOSE To achieve three-dimensional (3D) distortion-free apparent diffusion coefficient (ADC) maps for prostate imaging using a multishot diffusion prepared-gradient echo (msDP-GRE) sequence and ADC dictionary matching. METHODS The msDP-GRE sequence is combined with a 3D Cartesian, centric k-space trajectory with center oversampling. Oversampled k-space center averaging and phase cycling are used to address motion- and eddy current-induced magnitude corruption. Extended-phase-graph (EPG) simulations and ADC dictionary matching are used to compensate for T1 effects. To shorten the acquisition time, each volume is undersampled by a factor of two and reconstructed using iterative sensitivity encoding. The proposed approach is characterized using simulations and validated in a kiwifruit phantom, comparing the msDP-GRE ADC maps obtained using both standard monoexponential fitting and dictionary matching with the clinical standard single-shot diffusion weighted-echo planar imaging (ssDW-EPI) ADC. Initial in vivo feasibility is tested in three healthy subjects, and geometric distortion is compared with anatomical T2 -weighted-turbo spin echo. RESULTS In the kiwifruit phantom experiment, the signal magnitude could be recovered using k-space center averaging and phase cycling. No statistically significant difference was observed in the ADC values estimated using msDP-GRE with dictionary matching and clinical standard DW-EPI (P < .05). The in vivo prostate msDP-GRE scans were free of geometric distortion caused by off-resonance susceptibility, and the ADC values in the prostate were in agreement with values found in the published literature. CONCLUSION Nondistorted 3D ADC maps of the prostate can be achieved using a msDP sequence and dictionary matching.
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Affiliation(s)
- Elisa Roccia
- School of Biomedical Engineering and Imaging Sciences, King's College London, London, United Kingdom
| | - Radhouene Neji
- School of Biomedical Engineering and Imaging Sciences, King's College London, London, United Kingdom.,MR Research Collaboration, Siemens Healthcare Limited, Frimley, United Kingdom
| | - Thomas Benkert
- Oncology Application Predevelopment, Siemens Healthcare GmbH, Erlangen, Germany
| | - Berthold Kiefer
- Oncology Application Predevelopment, Siemens Healthcare GmbH, Erlangen, Germany
| | - Vicky Goh
- School of Biomedical Engineering and Imaging Sciences, King's College London, London, United Kingdom.,Department of Radiology, Guy's & St Thomas' NHS Foundation Trust, London, United Kingdom
| | - Isabel Dregely
- School of Biomedical Engineering and Imaging Sciences, King's College London, London, United Kingdom
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10
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MacKay JW, Cameron D. Editorial for "Near-Silent and Distortion-Free Diffusion MRI in Pediatric Musculoskeletal Pathology: Comparison With Echo Planar Imaging Diffusion". J Magn Reson Imaging 2020; 53:514-515. [PMID: 32869380 DOI: 10.1002/jmri.27350] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2020] [Accepted: 08/14/2020] [Indexed: 11/11/2022] Open
Affiliation(s)
- James W MacKay
- Norwich Medical School, University of East Anglia, Norwich, UK.,Department of Radiology, University of Cambridge, Cambridge, UK
| | - Donnie Cameron
- Norwich Medical School, University of East Anglia, Norwich, UK.,C. J. Gorter Center for High Field MRI, Department of Radiology, Leiden University Medical Center, Leiden, The Netherlands
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11
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Wood TC, Damestani NL, Lawrence AJ, Ljungberg E, Barker GJ, Solana AB, Wiesinger F, Williams SCR. Silent myelin-weighted magnetic resonance imaging. Wellcome Open Res 2020; 5:74. [PMID: 32832700 PMCID: PMC7431975 DOI: 10.12688/wellcomeopenres.15845.2] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/06/2020] [Indexed: 12/14/2022] Open
Abstract
Background: Inhomogeneous Magnetization Transfer (ihMT) is an emerging, uniquely myelin-specific magnetic resonance imaging (MRI) contrast. Current ihMT acquisitions utilise fast Gradient Echo sequences which are among the most acoustically noisy MRI sequences, reducing patient comfort during acquisition. We sought to address this by modifying a near silent MRI sequence to include ihMT contrast. Methods: A Magnetization Transfer preparation module was incorporated into a radial Zero Echo-Time sequence. Repeatability of the ihMT ratio and inverse ihMT ratio were assessed in a cohort of healthy subjects. We also investigated how head orientation affects ihMT across subjects, as a previous study in a single subject suggests this as a potential confound. Results: We demonstrated that ihMT ratios comparable to existing, acoustically loud, implementations could be obtained with the silent sequence. We observed a small but significant effect of head orientation on inverse ihMTR. Conclusions: Silent ihMT imaging is a comparable alternative to conventional, noisy, alternatives. For all future ihMT studies we recommend careful positioning of the subject within the scanner.
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Affiliation(s)
- Tobias C Wood
- Department of Neuroimaging, King's College London, London, UK
| | | | - Andrew J Lawrence
- Department of Psychological Medicine, King's College London, London, UK
| | - Emil Ljungberg
- Department of Neuroimaging, King's College London, London, UK
| | - Gareth J Barker
- Department of Neuroimaging, King's College London, London, UK
| | | | - Florian Wiesinger
- Department of Neuroimaging, King's College London, London, UK.,ASL Europe, GE Healthcare, Munich, Germany
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Sandberg JK, Young VA, Syed AB, Yuan J, Hu Y, Sandino C, Menini A, Hargreaves B, Vasanawala S. Near-Silent and Distortion-Free Diffusion MRI in Pediatric Musculoskeletal Disorders: Comparison With Echo Planar Imaging Diffusion. J Magn Reson Imaging 2020; 53:504-513. [PMID: 32815203 DOI: 10.1002/jmri.27330] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2020] [Revised: 07/30/2020] [Accepted: 07/31/2020] [Indexed: 12/15/2022] Open
Abstract
BACKGROUND Diffusion-weighted imaging (DWI) is common for evaluating pediatric musculoskeletal lesions, but suffers from geometric distortion and intense acoustic noise. PURPOSE To investigate the performance of a near-silent and distortion-free DWI sequence (DW-SD) relative to standard echo-planar DWI (DW-EPI) in pediatric extremity MRI. STUDY TYPE Prospective validation study. SUBJECTS Thirty-nine children referred for extremity MRI. FIELD STRENGTH/SEQUENCE DW-EPI and DW-SD, based on a rotating ultrafast sequence modified with sinusoidal diffusion preparation gradients, at 3T. ASSESSMENT DW-SD image quality (Sanat ) was assessed from 0 (nondiagnostic) to 5 (outstanding) and comparative image quality (Scomp ) (from -2 = DW-EPI more delineated to +2 = DW-SD more delineated, 0 = same). ADC measured by DW-SD and DW-EPI were compared in bone marrow, muscle, and lesions. STATISTICAL TESTS Wilcoxon rank-sum test and confidence interval of proportions (CIOP) were calculated for Scomp , Student's t-test, coefficient of variation (COV), and Bland-Altman analysis for ADC values, and intraclass correlation coefficient (ICC) for interreader agreement. RESULTS DW-SD and DW-EPI ADC values for bone marrow, muscle, and lesions were not significantly different (P = 0.3, P = 0.2, and P = 0.27, respectively) and had an overall ADC COV of 14.8% (95% confidence interval: 12.3%, 16.9%) and no significant proportional bias on Bland-Altman analysis. Sanat CIOP was rated diagnostic or better (score of 3, 4, or 5) in 72-98% of cases for bone marrow, muscle, and soft tissues. DW-SD was equivalent to or preferred over DW-EPI in muscles and soft tissues, with CIOP 86-93% and 93%, respectively. Lesions were equally visualized on DW-SD and DW-EPI in 40-51%, with DW-SD preferred in 44-56% of cases. DW-SD was rated significantly better than DW-EPI across all comparative variables that included bone marrow, muscle, soft tissue, cartilage, and lesions (P < 0.05). Readers had moderate to near-perfect (ICC range = 0.45-0.85). DATA CONCLUSION DW-SD of the extremities provided similar ADC values and improved image quality compared with conventional DW-EPI. Level of Evidence 2 Technical Efficacy Stage 2 J. MAGN. RESON. IMAGING 2021;53:504-513.
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Affiliation(s)
- Jesse K Sandberg
- Department of Radiology, Stanford University, Stanford, California, USA
| | - Victoria A Young
- Department of Radiology, Stanford University, Stanford, California, USA
| | - Ali B Syed
- Department of Radiology, Stanford University, Stanford, California, USA
| | - Jianmin Yuan
- Department of Radiology, Stanford University, Stanford, California, USA
| | - Yuxin Hu
- Department of Radiology, Stanford University, Stanford, California, USA.,Department of Electrical Engineering, Stanford University, Stanford, California, USA
| | - Christopher Sandino
- Department of Electrical Engineering, Stanford University, Stanford, California, USA
| | - Anne Menini
- Application Science Lab, GE Healthcare, Menlo Park, California, USA
| | - Brian Hargreaves
- Department of Radiology, Stanford University, Stanford, California, USA
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Wood TC, Damestani NL, Lawrence AJ, Ljungberg E, Barker GJ, Solana AB, Wiesinger F, Williams SCR. Silent myelin-weighted magnetic resonance imaging. Wellcome Open Res 2020; 5:74. [PMID: 32832700 DOI: 10.12688/wellcomeopenres.15845.1] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/16/2020] [Indexed: 02/03/2023] Open
Abstract
Background: Inhomogeneous Magnetization Transfer (ihMT) is an emerging, uniquely myelin-specific magnetic resonance imaging (MRI) contrast. Current ihMT acquisitions utilise fast Gradient Echo sequences which are among the most acoustically noisy MRI sequences, reducing patient comfort during acquisition. We sought to address this by modifying a near silent MRI sequence to include ihMT contrast. Methods: A Magnetization Transfer preparation module was incorporated into a radial Zero Echo-Time sequence. Repeatability of the ihMT ratio and inverse ihMT ratio were assessed in a cohort of healthy subjects. We also investigated how head orientation affects ihMT across subjects, as a previous study in a single subject suggests this as a potential confound. Results: We demonstrated that ihMT ratios comparable to existing, acoustically loud, implementations could be obtained with the silent sequence. We observed a small but significant effect of head orientation on inverse ihMTR. Conclusions: Silent ihMT imaging is a comparable alternative to conventional, noisy, alternatives. For all future ihMT studies we recommend careful positioning of the subject within the scanner.
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Affiliation(s)
- Tobias C Wood
- Department of Neuroimaging, King's College London, London, UK
| | | | - Andrew J Lawrence
- Department of Psychological Medicine, King's College London, London, UK
| | - Emil Ljungberg
- Department of Neuroimaging, King's College London, London, UK
| | - Gareth J Barker
- Department of Neuroimaging, King's College London, London, UK
| | | | - Florian Wiesinger
- Department of Neuroimaging, King's College London, London, UK.,ASL Europe, GE Healthcare, Munich, Germany
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