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Jacobs PS, Wilson N, Brink W, Swain A, Armbruster R, Hanumapur A, Tisdall MD, Detre J, Nanga RPR, Elliott MA, Reddy R. In vivo B 1 + enhancement of calf MRI at 7 T via optimized flexible metasurfaces. Magn Reson Med 2024; 92:1277-1289. [PMID: 38469893 PMCID: PMC11209820 DOI: 10.1002/mrm.30060] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2023] [Revised: 01/18/2024] [Accepted: 02/05/2024] [Indexed: 03/13/2024]
Abstract
PURPOSE Ultrahigh field (≥7 T) MRI is at the cutting edge of medical imaging, enabling enhanced spatial and spectral resolution as well as enhanced susceptibility contrast. However, transmit (B 1 + $$ {\mathrm{B}}_1^{+} $$ ) field inhomogeneity due to standing wave effects caused by the shortened RF wavelengths at 7 T is still a challenge to overcome. Novel hardware methods such as dielectric pads have been shown to improve theB 1 + $$ {\mathrm{B}}_1^{+} $$ field inhomogeneity but are currently limited in their corrective effect by the range of high-permittivity materials available and have a fixed shelf life. In this work, an optimized metasurface design is presented that demonstrates in vivo enhancement of theB 1 + $$ {\mathrm{B}}_1^{+} $$ field. METHODS A prototype metasurface was optimized by an empirical capacitor sweep and by varying the period size. Phantom temperature experiments were performed to evaluate potential metasurface heating effects during scanning. Lastly, in vivo gradient echo images andB 1 + $$ {\mathrm{B}}_1^{+} $$ maps were acquired on five healthy subjects on a 7 T system. Dielectric pads were also used as a comparison throughout the work as a standard comparison. RESULTS The metasurfaces presented here enhanced the average relative SNR of the gradient echo images by a factor of 2.26 compared to the dielectric pads factor of 1.61. AverageB 1 + $$ {\mathrm{B}}_1^{+} $$ values reflected a similar enhancement of 27.6% with the metasurfaces present versus 8.9% with the dielectric pads. CONCLUSION The results demonstrate that metasurfaces provide superior performance to dielectric padding as shown byB 1 + $$ {\mathrm{B}}_1^{+} $$ maps reflecting their direct effects and resulting enhancements in image SNR at 7 T.
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Affiliation(s)
- Paul S Jacobs
- Center for Advanced Metabolic Imaging in Precision Medicine, Department of Radiology, University of Pennsylvania, Philadelphia, PA, United States
| | - Neil Wilson
- Center for Advanced Metabolic Imaging in Precision Medicine, Department of Radiology, University of Pennsylvania, Philadelphia, PA, United States
| | - Wyger Brink
- Magnetic Detection and Imaging group, TechMed Centre, University of Twente, Enschede, The Netherlands
| | - Anshuman Swain
- Center for Advanced Metabolic Imaging in Precision Medicine, Department of Radiology, University of Pennsylvania, Philadelphia, PA, United States
| | - Ryan Armbruster
- Center for Advanced Metabolic Imaging in Precision Medicine, Department of Radiology, University of Pennsylvania, Philadelphia, PA, United States
| | - Aniketh Hanumapur
- Center for Advanced Metabolic Imaging in Precision Medicine, Department of Radiology, University of Pennsylvania, Philadelphia, PA, United States
| | - M. Dylan Tisdall
- Department of Radiology, University of Pennsylvania, Philadelphia, PA, United States
| | - John Detre
- Center for Advanced Metabolic Imaging in Precision Medicine, Department of Radiology, University of Pennsylvania, Philadelphia, PA, United States
- Department of Neurology, University of Pennsylvania, Philadelphia, PA, United States
| | - Ravi Prakash Reddy Nanga
- Center for Advanced Metabolic Imaging in Precision Medicine, Department of Radiology, University of Pennsylvania, Philadelphia, PA, United States
| | - Mark A. Elliott
- Center for Advanced Metabolic Imaging in Precision Medicine, Department of Radiology, University of Pennsylvania, Philadelphia, PA, United States
| | - Ravinder Reddy
- Center for Advanced Metabolic Imaging in Precision Medicine, Department of Radiology, University of Pennsylvania, Philadelphia, PA, United States
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Seginer A, Niry D, Furman-Haran E, Kolb H, Schmidt R. Reducing blood flow pulsation artifacts in 3D time-of-flight angiography by locally scrambling the order of the acquisition at 3 T and 7 T. Magn Reson Med 2024. [PMID: 38923628 DOI: 10.1002/mrm.30196] [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: 02/27/2024] [Revised: 05/01/2024] [Accepted: 06/03/2024] [Indexed: 06/28/2024]
Abstract
PURPOSE Non-contrast-enhanced time of flight (TOF) is a standard method for magnetic resonance angiography used to depict vessel morphology. TOF is commonly performed with a 3D steady-state acquisition, employing a short repetition time to support high resolution imaging. At 7 T, TOF exhibits substantial increase in SNR and contrast, improving its clinical value. However, one of the remaining challenges, exacerbated at 7 T, is the presence of artifacts due to pulsatile blood flow, especially near major blood vessels. In this study we examine a method to significantly reduce these artifacts. METHODS We recently introduced a new "local-scrambling" approach that semi-randomizes the acquisition order of the phase encodes, to achieve a controllable cutoff frequency above which the artifacts are drastically reduced. With this approach, artifacts resulting from fast local fluctuations such as cardiac pulsation are significantly reduced. In this study, we explore the ability of this local-scrambling approach to reduce pulsatile blood flow artifacts in a 3D TOF acquisition. Cartesian line-by-line and center-out ordering, with and without local-scrambling, were compared in simulations and in human brain imaging at 3 and 7 T scanners. RESULTS In the simulations the artifact intensity showed a 10-fold reduction using local-scrambling compared to line-by-line and 4-fold compared to center-out ordering. In vivo results show that artifacts are much more pronounced at 7 T compared to 3 T, and in both cases they are effectively reduced by local-scrambling. CONCLUSION Local-scrambling improves image quality for both line-by-line and center-out ordering. This approach can easily be implemented in the scanner without any changes to the reconstruction.
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Affiliation(s)
- Amir Seginer
- Weizmann Institute of Science, Life Sciences Core Facilities, Rehovot, Israel
- The Azrieli National Institute for Human Brain Imaging and Research, Weizmann Institute of Science, Rehovot, Israel
| | - Dana Niry
- Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
- Department of Radiology, Tel Aviv Sourasky Medical Center, Tel Aviv, Israel
| | - Edna Furman-Haran
- Weizmann Institute of Science, Life Sciences Core Facilities, Rehovot, Israel
- The Azrieli National Institute for Human Brain Imaging and Research, Weizmann Institute of Science, Rehovot, Israel
| | - Hadar Kolb
- Neuroimmunology service, Division of Neurology, Tel Aviv Sourasky Medical Center, Tel-Aviv, Israel
| | - Rita Schmidt
- The Azrieli National Institute for Human Brain Imaging and Research, Weizmann Institute of Science, Rehovot, Israel
- Weizmann Institute of Science, Department of Brain Sciences, Rehovot, Israel
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Li C, Buch S, Sun Z, Muccio M, Jiang L, Chen Y, Haacke EM, Zhang J, Wisniewski TM, Ge Y. In vivo mapping of hippocampal venous vasculature and oxygenation using susceptibility imaging at 7T. Neuroimage 2024; 291:120597. [PMID: 38554779 PMCID: PMC11115460 DOI: 10.1016/j.neuroimage.2024.120597] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2023] [Revised: 03/19/2024] [Accepted: 03/28/2024] [Indexed: 04/02/2024] Open
Abstract
Mapping the small venous vasculature of the hippocampus in vivo is crucial for understanding how functional changes of hippocampus evolve with age. Oxygen utilization in the hippocampus could serve as a sensitive biomarker for early degenerative changes, surpassing hippocampal tissue atrophy as the main source of information regarding tissue degeneration. Using an ultrahigh field (7T) susceptibility-weighted imaging (SWI) sequence, it is possible to capture oxygen-level dependent contrast of submillimeter-sized vessels. Moreover, the quantitative susceptibility mapping (QSM) results derived from SWI data allow for the simultaneous estimation of venous oxygenation levels, thereby enhancing the understanding of hippocampal function. In this study, we proposed two potential imaging markers in a cohort of 19 healthy volunteers aged between 20 and 74 years. These markers were: 1) hippocampal venous density on SWI images and 2) venous susceptibility (Δχvein) in the hippocampus-associated draining veins (the inferior ventricular veins (IVV) and the basal veins of Rosenthal (BVR) using QSM images). They were chosen specifically to help characterize the oxygen utilization of the human hippocampus and medial temporal lobe (MTL). As part of the analysis, we demonstrated the feasibility of measuring hippocampal venous density and Δχvein in the IVV and BVR at 7T with high spatial resolution (0.25 × 0.25 × 1 mm3). Our results demonstrated the in vivo reconstruction of the hippocampal venous system, providing initial evidence regarding the presence of the venous arch structure within the hippocampus. Furthermore, we evaluated the age effect of the two quantitative estimates and observed a significant increase in Δχvein for the IVV with age (p=0.006, r2 = 0.369). This may suggest the potential application of Δχvein in IVV as a marker for assessing changes in atrophy-related hippocampal oxygen utilization in normal aging and neurodegenerative diseases such as AD and dementia.
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Affiliation(s)
- Chenyang Li
- Department of Radiology, Center for Biomedical Imaging, NYU Grossman School of Medicine, New York, NY, USA; Vilcek Institute of Graduate Biomedical Sciences, NYU Grossman School of Medicine, New York, NY, USA
| | - Sagar Buch
- Department of Neurology, Wayne State University School of Medicine, Detroit, MI, USA
| | - Zhe Sun
- Department of Radiology, Center for Biomedical Imaging, NYU Grossman School of Medicine, New York, NY, USA; Vilcek Institute of Graduate Biomedical Sciences, NYU Grossman School of Medicine, New York, NY, USA
| | - Marco Muccio
- Department of Radiology, Center for Biomedical Imaging, NYU Grossman School of Medicine, New York, NY, USA
| | - Li Jiang
- Department of Radiology, Center for Biomedical Imaging, NYU Grossman School of Medicine, New York, NY, USA
| | - Yongsheng Chen
- Department of Neurology, Wayne State University School of Medicine, Detroit, MI, USA
| | - E Mark Haacke
- Department of Neurology, Wayne State University School of Medicine, Detroit, MI, USA; Department of Radiology, Wayne State University School of Medicine, Detroit, MI, USA
| | - Jiangyang Zhang
- Department of Radiology, Center for Biomedical Imaging, NYU Grossman School of Medicine, New York, NY, USA
| | | | - Yulin Ge
- Department of Radiology, Center for Biomedical Imaging, NYU Grossman School of Medicine, New York, NY, USA.
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Duan C, Bian X, Cheng K, Lyu J, Xiong Y, Xiao S, Wang X, Duan Q, Li C, Huang J, Hu J, Wang ZJ, Zhou X, Lou X. Synthesized 7T MPRAGE From 3T MPRAGE Using Generative Adversarial Network and Validation in Clinical Brain Imaging: A Feasibility Study. J Magn Reson Imaging 2024; 59:1620-1629. [PMID: 37559435 DOI: 10.1002/jmri.28944] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2022] [Revised: 07/24/2023] [Accepted: 07/26/2023] [Indexed: 08/11/2023] Open
Abstract
BACKGROUND Ultra-high field 7T MRI can provide excellent tissue contrast and anatomical details, but is often cost prohibitive, and is not widely accessible in clinical practice. PURPOSE To generate synthetic 7T images from widely acquired 3T images with deep learning and to evaluate the feasibility of this approach for brain imaging. STUDY TYPE Prospective. POPULATION 33 healthy volunteers and 89 patients with brain diseases, divided into training, and evaluation datasets in the ratio 4:1. SEQUENCE AND FIELD STRENGTH T1-weighted nonenhanced or contrast-enhanced magnetization-prepared rapid acquisition gradient-echo sequence at both 3T and 7T. ASSESSMENT A generative adversarial network (SynGAN) was developed to produce synthetic 7T images from 3T images as input. SynGAN training and evaluation were performed separately for nonenhanced and contrast-enhanced paired acquisitions. Qualitative image quality of acquired 3T and 7T images and of synthesized 7T images was evaluated by three radiologists in terms of overall image quality, artifacts, sharpness, contrast, and visualization of vessel using 5-point Likert scales. STATISTICAL TESTS Wilcoxon signed rank tests to compare synthetic 7T images with acquired 7T and 3T images and intraclass correlation coefficients to evaluate interobserver variability. P < 0.05 was considered significant. RESULTS Of the 122 paired 3T and 7T MRI scans, 66 were acquired without contrast agent and 56 with contrast agent. The average time to generate synthetic images was ~11.4 msec per slice (2.95 sec per participant). The synthetic 7T images achieved significantly improved tissue contrast and sharpness in comparison to 3T images in both nonenhanced and contrast-enhanced subgroups. Meanwhile, there was no significant difference between acquired 7T and synthetic 7T images in terms of all the evaluation criteria for both nonenhanced and contrast-enhanced subgroups (P ≥ 0.180). DATA CONCLUSION The deep learning model has potential to generate synthetic 7T images with similar image quality to acquired 7T images. LEVEL OF EVIDENCE 2 TECHNICAL EFFICACY: Stage 1.
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Affiliation(s)
- Caohui Duan
- Department of Radiology, Chinese PLA General Hospital, Beijing, China
| | - Xiangbing Bian
- Department of Radiology, Chinese PLA General Hospital, Beijing, China
| | - Kun Cheng
- Department of Radiology, Chinese PLA General Hospital, Beijing, China
| | - Jinhao Lyu
- Department of Radiology, Chinese PLA General Hospital, Beijing, China
| | - Yongqin Xiong
- Department of Radiology, Chinese PLA General Hospital, Beijing, China
| | - Sa Xiao
- Key Laboratory of Magnetic Resonance in Biological Systems, State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, National Center for Magnetic Resonance in Wuhan, Wuhan Institute of Physics and Mathematics, Innovation Academy for Precision Measurement Science and Technology, Chinese Academy of Sciences-Wuhan National Laboratory for Optoelectronics, Wuhan, China
| | - Xueyang Wang
- Department of Radiology, Chinese PLA General Hospital, Beijing, China
| | - Qi Duan
- Department of Radiology, Chinese PLA General Hospital, Beijing, China
| | - Chenxi Li
- Department of Radiology, Chinese PLA General Hospital, Beijing, China
| | - Jiayu Huang
- Department of Radiology, Chinese PLA General Hospital, Beijing, China
| | - Jianxing Hu
- Department of Radiology, Chinese PLA General Hospital, Beijing, China
| | - Z Jane Wang
- Department of Electrical and Computer Engineering, The University of British Columbia, Vancouver, British Columbia, Canada
| | - Xin Zhou
- Key Laboratory of Magnetic Resonance in Biological Systems, State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, National Center for Magnetic Resonance in Wuhan, Wuhan Institute of Physics and Mathematics, Innovation Academy for Precision Measurement Science and Technology, Chinese Academy of Sciences-Wuhan National Laboratory for Optoelectronics, Wuhan, China
| | - Xin Lou
- Department of Radiology, Chinese PLA General Hospital, Beijing, China
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Jacobs PS, Brink W, Reddy R. A review of recent developments and applications of high-permittivity dielectric shimming in magnetic resonance. NMR IN BIOMEDICINE 2024; 37:e5094. [PMID: 38214202 DOI: 10.1002/nbm.5094] [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: 08/16/2023] [Revised: 10/20/2023] [Accepted: 11/29/2023] [Indexed: 01/13/2024]
Abstract
We present a review outlining the basic mechanism, background, recent technical developments, and clinical applications of aqueous dielectric padding in the field of MRI. Originally meant to be a temporary solution, it has gained traction as an effective method for correcting B1 + inhomogeneities due to the unique properties of the calcium titanate and barium titanate perovskites used. Aqueous dielectric pads have used a variety of high-permittivity materials over the years to improve the quality of MRI acquisitions at 1.5 and 3 T and more recently for 7 T neuroimaging applications. The technical development and assessment of these pads have been advanced by an increased use of mathematical modeling and electromagnetic simulations. These tools have allowed for a more complete understanding of the physical interactions between dielectric pads and the RF coil, making testing and safety assessments more accurate. The ease of use and effectiveness that dielectric pads offer have allowed them to become more commonplace in tackling imaging challenges in more clinically focused environments. More recently, they have seen usage not only in anatomical imaging methods but also in specialized metabolic imaging sequences such as GluCEST and NOEMTR . New colossally high-permittivity materials have been proposed; however, practical utilization has been a continued challenge due to unfavorable frequency dependences as well as safety limitations. A new class of metasurfaces has been under development to address the shortcomings of conventional dielectric padding while also providing increased performance in enhancing MRI images.
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Affiliation(s)
- Paul S Jacobs
- Center for Advanced Metabolic Imaging in Precision Medicine, Department of Radiology, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Wyger Brink
- Magnetic Detection and Imaging group, TechMed Centre, University of Twente, Enschede, The Netherlands
| | - Ravinder Reddy
- Center for Advanced Metabolic Imaging in Precision Medicine, Department of Radiology, University of Pennsylvania, Philadelphia, Pennsylvania, USA
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Perera Molligoda Arachchige AS, Garner AK. Seven Tesla MRI in Alzheimer's disease research: State of the art and future directions: A narrative review. AIMS Neurosci 2023; 10:401-422. [PMID: 38188012 PMCID: PMC10767068 DOI: 10.3934/neuroscience.2023030] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2023] [Revised: 11/29/2023] [Accepted: 12/04/2023] [Indexed: 01/09/2024] Open
Abstract
Seven tesla magnetic resonance imaging (7T MRI) is known to offer a superior spatial resolution and a signal-to-noise ratio relative to any other non-invasive imaging technique and provides the possibility for neuroimaging researchers to observe disease-related structural changes, which were previously only apparent on post-mortem tissue analyses. Alzheimer's disease is a natural and widely used subject for this technology since the 7T MRI allows for the anticipation of disease progression, the evaluation of secondary prevention measures thought to modify the disease trajectory, and the identification of surrogate markers for treatment outcome. In this editorial, we discuss the various neuroimaging biomarkers for Alzheimer's disease that have been studied using 7T MRI, which include morphological alterations, molecular characterization of cerebral T2*-weighted hypointensities, the evaluation of cerebral microbleeds and microinfarcts, biochemical changes studied with MR spectroscopy, as well as some other approaches. Finally, we discuss the limitations of the 7T MRI regarding imaging Alzheimer's disease and we provide our outlook for the future.
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Jacobs PS, Benyard B, Cao Q, Swain A, Wilson N, Nanga RPR, Tisdall MD, Detre J, Elliott MA, Haris M, Reddy R. B 1 + $$ {\mathrm{B}}_1^{+} $$ inhomogeneity correction of volumetric brain NOE MTR via high permittivity dielectric padding at 7 T. Magn Reson Med 2023; 90:1537-1546. [PMID: 37279010 PMCID: PMC10425166 DOI: 10.1002/mrm.29739] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2023] [Revised: 04/23/2023] [Accepted: 05/16/2023] [Indexed: 06/07/2023]
Abstract
PURPOSE Nuclear Overhauser effect magnetization transfer ratio (NOEMTR ) is a technique used to investigate brain lipids and macromolecules in greater detail than other techniques and benefits from increased contrast at 7 T. However, this contrast can become degraded because ofB 1 + $$ {\mathrm{B}}_1^{+} $$ inhomogeneities present at ultra-high field strengths. High-permittivity dielectric pads (DP) have been used to correct for these inhomogeneities via displacement currents generating secondary magnetic fields. The purpose of this work is to demonstrate that dielectric pads can be used to mitigateB 1 + $$ {\mathrm{B}}_1^{+} $$ inhomogeneities and improve NOEMTR contrast in the temporal lobes at 7 T. METHODS Partial 3D NOEMTR contrast images and whole brainB 1 + $$ {\mathrm{B}}_1^{+} $$ field maps were acquired on a 7 T MRI across six healthy subjects. Calcium titanate DP, having a relative permittivity of 110, was placed next to the subject's head near the temporal lobes. Pad corrected NOEMTR images had a separate postprocessing linear correction applied. RESULTS DP provided supplementalB 1 + $$ {\mathrm{B}}_1^{+} $$ to the temporal lobes while also reducing theB 1 + $$ {\mathrm{B}}_1^{+} $$ magnitude across the posterior and superior regions of the brain. This resulted in a statistically significant increase in NOEMTR contrast in substructures of the temporal lobes both with and without linear correction. The padding also produced a convergence in NOEMTR contrast toward approximately equal mean values. CONCLUSION NOEMTR images showed significant improvement in temporal lobe contrast when DP were used, which resulted from an increase inB 1 + $$ {\mathrm{B}}_1^{+} $$ homogeneity across the entire brain slab. DP-derived improvements in NOEMTR are expected to increase the robustness of the brain substructural measures both in healthy and pathological conditions.
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Affiliation(s)
- Paul S Jacobs
- Center for Advanced Metabolic Imaging in Precision Medicine, Department of Radiology, University of Pennsylvania, Philadelphia, PA, United States
| | - Blake Benyard
- Center for Advanced Metabolic Imaging in Precision Medicine, Department of Radiology, University of Pennsylvania, Philadelphia, PA, United States
| | - Quy Cao
- Penn Statistics in Imaging and Visualization Center, Department of Biostatistics, Epidemiology, and Informatics, University of Pennsylvania, Philadelphia, PA, United States
| | - Anshuman Swain
- Center for Advanced Metabolic Imaging in Precision Medicine, Department of Radiology, University of Pennsylvania, Philadelphia, PA, United States
| | - Neil Wilson
- Center for Advanced Metabolic Imaging in Precision Medicine, Department of Radiology, University of Pennsylvania, Philadelphia, PA, United States
| | - Ravi Prakash Reddy Nanga
- Center for Advanced Metabolic Imaging in Precision Medicine, Department of Radiology, University of Pennsylvania, Philadelphia, PA, United States
| | - M. Dylan Tisdall
- Department of Radiology, University of Pennsylvania, Philadelphia, PA, United States
| | - John Detre
- Center for Advanced Metabolic Imaging in Precision Medicine, Department of Radiology, University of Pennsylvania, Philadelphia, PA, United States
- Department of Neurology, University of Pennsylvania, Philadelphia, PA, United States
| | - Mark A Elliott
- Center for Advanced Metabolic Imaging in Precision Medicine, Department of Radiology, University of Pennsylvania, Philadelphia, PA, United States
| | - Mohammad Haris
- Center for Advanced Metabolic Imaging in Precision Medicine, Department of Radiology, University of Pennsylvania, Philadelphia, PA, United States
| | - Ravinder Reddy
- Center for Advanced Metabolic Imaging in Precision Medicine, Department of Radiology, University of Pennsylvania, Philadelphia, PA, United States
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Jia K, Goebel R, Kourtzi Z. Ultra-High Field Imaging of Human Visual Cognition. Annu Rev Vis Sci 2023; 9:479-500. [PMID: 37137282 DOI: 10.1146/annurev-vision-111022-123830] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
Functional magnetic resonance imaging (fMRI), the key methodology for mapping the functions of the human brain in a noninvasive manner, is limited by low temporal and spatial resolution. Recent advances in ultra-high field (UHF) fMRI provide a mesoscopic (i.e., submillimeter resolution) tool that allows us to probe laminar and columnar circuits, distinguish bottom-up versus top-down pathways, and map small subcortical areas. We review recent work demonstrating that UHF fMRI provides a robust methodology for imaging the brain across cortical depths and columns that provides insights into the brain's organization and functions at unprecedented spatial resolution, advancing our understanding of the fine-scale computations and interareal communication that support visual cognition.
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Affiliation(s)
- Ke Jia
- Department of Neurobiology, Affiliated Mental Health Center & Hangzhou Seventh People's Hospital, Zhejiang University School of Medicine, Hangzhou, China
- Liangzhu Laboratory, MOE Frontier Science Center for Brain Science and Brain-machine Integration, State Key Laboratory of Brain-machine Intelligence, Zhejiang University, Hangzhou, China
- NHC and CAMS Key Laboratory of Medical Neurobiology, Zhejiang University, Hangzhou, China
- Department of Psychology, University of Cambridge, Cambridge, United Kingdom;
| | - Rainer Goebel
- Department of Cognitive Neuroscience, Faculty of Psychology and Neuroscience, Maastricht University, Maastricht, The Netherlands
| | - Zoe Kourtzi
- Department of Psychology, University of Cambridge, Cambridge, United Kingdom;
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Lin CJ, Chung CP, Liao NC, Chen PL, Chi NF, Lai YJ, Tang CW, Wu CH, Chang FC, Luo CB, Fay LY, Lin CF, Chou CH, Lee TH, Lee JT, Jeng JS, Lee IH. The 2023 Taiwan Stroke Society Guidelines for the management of patients with intracranial atherosclerotic disease. J Chin Med Assoc 2023; 86:697-714. [PMID: 37341526 DOI: 10.1097/jcma.0000000000000952] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 06/22/2023] Open
Abstract
Intracranial atherosclerotic disease (ICAD) is a major cause of ischemic stroke, especially in Asian populations, which has a high risk of recurrent stroke and cardiovascular comorbidities. The present guidelines aim to provide updated evidence-based recommendations for diagnosis and management of patients with ICAD. Taiwan Stroke Society guideline consensus group developed recommendations for management of patients with ICAD via consensus meetings based on updated evidences. Each proposed class of recommendation and level of evidence was approved by all members of the group. The guidelines cover six topics, including (1) epidemiology and diagnostic evaluation of ICAD, (2) nonpharmacological management of ICAD, (3) medical therapy for symptomatic ICAD, (4) endovascular thrombectomy and rescue therapy for acute ischemic stroke with underlying ICAD, (5) endovascular interventional therapy for postacute symptomatic intracranial arterial stenosis, and (6) surgical treatment of chronic symptomatic intracranial arterial stenosis. Intensive medical treatment including antiplatelet therapy, risk factor control, and life style modification are essential for patients with ICAD.
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Affiliation(s)
- Chun-Jen Lin
- Department of Neurology, Taipei Veterans General Hospital, Taipei, Taiwan, ROC
| | - Chih-Ping Chung
- Department of Neurology, Taipei Veterans General Hospital, Taipei, Taiwan, ROC
| | - Nien-Chen Liao
- Department of Neurology, Taichung Veterans General Hospital, Taichung, Taiwan, ROC
| | - Po-Lin Chen
- Department of Neurology, Taichung Veterans General Hospital, Taichung, Taiwan, ROC
| | - Nai-Fang Chi
- Department of Neurology, Taipei Veterans General Hospital, Taipei, Taiwan, ROC
| | - Yen-Jun Lai
- Radiology Department, Far-Eastern Memorial Hospital, New Taipei City, Taiwan, ROC
| | - Chih-Wei Tang
- Neurology Department and Stroke Center, Far-Eastern Memorial Hospital, New Taipei City, Taiwan, ROC
| | - Chia-Hung Wu
- Department of Radiology, Taipei Veterans General Hospital, Taipei, Taiwan, ROC
| | - Feng-Chi Chang
- Department of Radiology, Taipei Veterans General Hospital, Taipei, Taiwan, ROC
| | - Chao-Bao Luo
- Department of Radiology, Taipei Veterans General Hospital, Taipei, Taiwan, ROC
| | - Li-Yu Fay
- Department of Neurosurgery, Taipei Veterans General Hospital, Taipei, Taiwan, ROC
| | - Chun-Fu Lin
- Department of Neurosurgery, Taipei Veterans General Hospital, Taipei, Taiwan, ROC
| | - Chung-Hsing Chou
- Neurology Department, Tri-Service General Hospital, Taipei, Taiwan, ROC
| | - Tsong-Hai Lee
- Department of Neurology, Linkou Chang Gung Memorial Hospital, Taoyuan, Taiwan, ROC
| | - Jiunn-Tay Lee
- Neurology Department, Tri-Service General Hospital, Taipei, Taiwan, ROC
| | - Jiann-Shing Jeng
- Department of Neurology and Stroke Center, National Taiwan University Hospital, Taipei, Taiwan, ROC
| | - I-Hui Lee
- Department of Neurology, Taipei Veterans General Hospital, Taipei, Taiwan, ROC
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Rizvi QM, Singh S. Assessment of the low-field magnetic resonance imaging for the brain scan imaging of the infant hydrocephalus. Int J Health Sci (Qassim) 2023; 17:44-53. [PMID: 37416843 PMCID: PMC10321462] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/08/2023] Open
Abstract
Objective In today's global clinical settings, low-field magnetic resonance imaging (MRI) technology is becoming increasingly prevalent. Ensuring high-quality image acquisition is crucial for accurate disease diagnosis and treatment and for evaluating the impact of poor-quality images. In this study, we explored the potential of deep learning as a diagnostic tool for improving image quality in hydrocephalus analysis planning. This could include discussions on the diagnostic accuracy, cost-effectiveness, and practicality of using low-field MRI as an alternative. Methods There are many reasons which are going to affect infant computed tomography images. These are spatial resolution, noise, and contrast between the brain and cerebrospinal fluid (CSF). Now, we can enhance using the application of deep learning algorithms. Both improved and down quality were situated to the three qualified pediatric neurosurgeons comfortable with working in poor- to middle-level income countries for the analysis of clinical tools in the planning of the treatment of hydrocephalus. Results The results predict that a picture will be classified as beneficial for hydrocephalus treatment planning, according to image resolution and the contrast-to-noise ratio (CNR) between the brain and CSF. The CNR is significantly improved by deep learning enhancement, which also improves the apparent likelihood of the image. Conclusion However, poor-quality images might be desirable to image improved by deep learning, since those images will not offer the risk of confusing facts which could misguide the decision of the analysis of patients. Such findings support the newly introduced measurement standards in estimating the acceptable quality of images for clinical use.
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Affiliation(s)
- Qaim Mehdi Rizvi
- Department of Computer Applications, Shri Ramswaroop Memorial College of Engineering and Management, Lucknow, Uttar Pradesh, India
| | - Sarika Singh
- Department of Computer Applications, Shri Ramswaroop Memorial College of Engineering and Management, Lucknow, Uttar Pradesh, India
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Shaffer A, Nigh N, Weisbaum D, Anderson A, Wszalek T, Sutton BP, Webb A, Damon B, Moussa I, Arnold PM. Cardiothoracic and Vascular Surgery Implant Compatibility With Ultrahigh Field Magnetic Resonance Imaging (4.7 Tesla and 7 Tesla). Am J Cardiol 2023; 201:239-246. [PMID: 37392607 DOI: 10.1016/j.amjcard.2023.05.062] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/16/2023] [Revised: 05/23/2023] [Accepted: 05/31/2023] [Indexed: 07/03/2023]
Abstract
The use of 7 Tesla (T) magnetic resonance imaging (MRI) is expanding across medical specialties, particularly, clinical neurosciences and orthopedics. Investigational 7 T MRI has also been performed in cardiology. A limiting factor for expansion of the role of 7 T, irrespective of the body part being imaged, is the sparse testing of biomedical implant compatibility at field strengths >3 T. Implant compatibility can be tested following the American Society for Testing and Materials International guidelines. To assess the current state of cardiovascular implant safety at field strengths >3 T, a systematic search was performed using PubMed, Web of Science, and citation matching. Studies written in English that included at least 1 cardiovascular-related implant and at least 1 safety outcome (deflection angle, torque, or temperature change) were included. Data were extracted for the implant studied, implant composition, deflection angle, torque, and temperature change, and the American Society for Testing and Materials International standards were followed. The Preferred Reporting Items for Systematic Reviews and Meta-Analyses reporting guidelines for scoping reviews were followed. A total of 9 studies were included. A total of 34 cardiovascular-related implants tested ex vivo at 7 T and 91 implants tested ex vivo at 4.7 T were included. The implants included vascular grafts and conduits, vascular access ports, peripheral and coronary stents, caval filters, and artificial valves. A total of 2 grafts, 1 vascular access port, 2 vena cava filters, and 5 stents were identified as incompatible with the 7 T MRI. All incompatible stents were 40 mm in length. Based on the safety outcomes reported, we identify several implants that may be compatible with >3 T MRI. This scoping review seeks to concisely summarize all the cardiovascular-related implants tested for ultrahigh field MRI compatibility to date.
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Affiliation(s)
- Annabelle Shaffer
- Carle Illinois College of Medicine, University of Illinois Urbana Champaign, Urbana, Illinois
| | - Noah Nigh
- Carle Illinois College of Medicine, University of Illinois Urbana Champaign, Urbana, Illinois
| | - David Weisbaum
- Department of Neurosurgery, Carle Foundation Hospital, Urbana, Illinois
| | - Aaron Anderson
- Carle Illinois Advanced Imaging Center, Carle Foundation Hospital, Urbana, Illinois; Department of Radiology, Leiden University Medical Center, Leiden, The Netherlands
| | - Tracey Wszalek
- Carle Illinois Advanced Imaging Center, Carle Foundation Hospital, Urbana, Illinois; Department of Radiology, Leiden University Medical Center, Leiden, The Netherlands
| | - Bradley P Sutton
- Carle Illinois College of Medicine, University of Illinois Urbana Champaign, Urbana, Illinois; Carle Illinois Advanced Imaging Center, Carle Foundation Hospital, Urbana, Illinois; Department of Radiology, Leiden University Medical Center, Leiden, The Netherlands
| | - Andrew Webb
- Carle Illinois Advanced Imaging Center, Carle Foundation Hospital, Urbana, Illinois; Department of Radiology, Leiden University Medical Center, Leiden, The Netherlands; Leiden University Medical Center, Leiden, The Netherlands
| | - Bruce Damon
- Carle Illinois Advanced Imaging Center, Carle Foundation Hospital, Urbana, Illinois; Department of Radiology, Leiden University Medical Center, Leiden, The Netherlands
| | - Issam Moussa
- Carle Illinois College of Medicine, University of Illinois Urbana Champaign, Urbana, Illinois; Heart and Vascular Institute, Carle Foundation Hospital, Urbana, Illinois
| | - Paul M Arnold
- Carle Illinois College of Medicine, University of Illinois Urbana Champaign, Urbana, Illinois; Department of Neurosurgery, Carle Foundation Hospital, Urbana, Illinois.
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12
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Sprenger F, Demartini Junior Z, Teixeira BCDA. Enhancement of the parent vessel in a giant thrombosed aneurysm. ARQUIVOS DE NEURO-PSIQUIATRIA 2023; 81:510-512. [PMID: 37257472 DOI: 10.1055/s-0043-1767820] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Affiliation(s)
- Flávia Sprenger
- Universidade Federal do Paraná, Hospital de Clínicas, Departamento de Radiologia, Curitiba PR, Brazil
| | - Zeferino Demartini Junior
- Universidade Federal do Paraná, Hospital de Clínicas, Departamento de Hemodinâmica, Curitiba PR, Brazil
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13
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Wiesmueller M, Meixner CR, Weber M, Kesting M, Nagel AM, Wuest W, May MS, Roemer FW, Uder M, Heiss R. Time-of-Flight Angiography in Ultra-High-Field 7 T MRI for the Evaluation of Peroneal Perforator Arteries Before Osseomyocutaneous Flap Surgery. Invest Radiol 2023; 58:216-222. [PMID: 36165876 PMCID: PMC9914154 DOI: 10.1097/rli.0000000000000926] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2022] [Accepted: 08/11/2022] [Indexed: 10/14/2022]
Abstract
OBJECTIVES Presurgical identification and morphologic characterization of the peroneal perforator arteries (PPAs) are essential for osseomyocutaneous flap surgery. The aim of this study was to evaluate PPAs using time-of-flight (TOF) angiography in 7 T magnetic resonance imaging in comparison with dual-energy computed tomographic angiography (CTA). MATERIALS AND METHODS In this prospective study, TOF angiography and CTA of both lower legs were acquired before flap surgery from 07/2019 to 02/2020. Magnetic resonance imaging was performed using a dedicated 28-channel knee coil with an acquisition time of 9:55 minutes (voxel size: 0.4 × 0.4 × 0.8 mm). Computed tomographic angiography was acquired with a third-generation dual-source computed tomography on the same day. Virtual monoenergetic reconstructions at 40 keV photon energy served as the standard of reference for PPA identification and subtyping. Two independent readers assessed the image quality, quantity, length assessment, and classification according to surgical considerations of PPAs for TOF angiography and CTA. Both TOF angiography and CTA were used for presurgical flap design and were evaluated by an orofacial surgeon. RESULTS Ten patients (mean age, 59.9 ± 14.9 years; 7 men) were included. Time-of-flight angiography and CTA identified 53 and 51 PPAs in total, respectively. Time-of-flight angiography showed superior image quality (both readers, P < 0.05). Time-of-flight angiography enabled specific classification of PPA subtypes more often (53 vs 39; P < 0.05), and both readers reported higher diagnostic confidence for TOF angiography than CTA in all patients (interrater agreement κ = 0.8; P < 0.05). Regarding length assessment, PPAs were significantly more conspicuous with TOF angiography (TOF mean , 50 ± 11 mm; CTA mean , 40 ± 9 mm; P = 0.001). In comparison with CTA, TOF angiography prospectively changed the orofacial surgeon's final decision on the presurgical selected PPAs in 60% of cases. CONCLUSIONS Presurgical assessment of PPAs is feasible using TOF in 7 T magnetic resonance imaging. Moreover, TOF angiography was superior to CTA for classifying and identifying PPAs, which may facilitate the planning of reconstructive surgery.
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Affiliation(s)
| | | | - Manuel Weber
- Department of Oral and Maxillofacial Surgery, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Erlangen, Germany
| | - Marco Kesting
- Department of Oral and Maxillofacial Surgery, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Erlangen, Germany
| | - Armin M. Nagel
- From the Institute of Radiology, University Hospital Erlangen
- Division of Medical Physics in Radiology, German Cancer Research Centre (DKFZ), Heidelberg, Germany
| | - Wolfgang Wuest
- From the Institute of Radiology, University Hospital Erlangen
| | - Matthias S. May
- From the Institute of Radiology, University Hospital Erlangen
| | - Frank W. Roemer
- From the Institute of Radiology, University Hospital Erlangen
- Quantitative Imaging Center (QIC), Department of Radiology, Boston University School of Medicine, Massachusetts
| | - Michael Uder
- From the Institute of Radiology, University Hospital Erlangen
| | - Rafael Heiss
- From the Institute of Radiology, University Hospital Erlangen
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14
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Jacobs PS, Benyard B, Cember A, Nanga RPR, Cao Q, Tisdall MD, Wilson N, Das S, Davis KA, Detre J, Roalf D, Reddy R. Repeatability of B 1 + inhomogeneity correction of volumetric (3D) glutamate CEST via High-permittivity dielectric padding at 7T. Magn Reson Med 2022; 88:2475-2484. [PMID: 36178233 PMCID: PMC9529237 DOI: 10.1002/mrm.29409] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2022] [Revised: 07/18/2022] [Accepted: 07/19/2022] [Indexed: 12/03/2023]
Abstract
PURPOSE Ultra-high field MR imaging lacks B1 + inhomogeneity due to shorter RF wavelengths used at higher field strengths compared to human anatomy. CEST techniques tend to be highly susceptible to B1 + inhomogeneities due to a high and uniform B1 + field being necessary to create the endogenous contrast. High-permittivity dielectric pads have seen increasing usage in MR imaging due to their ability to tailor the spatial distribution of the B1 + field produced. The purpose of this work is to demonstrate that dielectric materials can be used to improve glutamate weighted CEST (gluCEST) at 7T. THEORY AND METHODS GluCEST images were acquired on a 7T system on six healthy volunteers. Aqueous calcium titanate pads, with a permittivity of approximately 110, were placed on either side in the subject's head near the temporal lobes. A post-processing correction algorithm was implemented in combination with dielectric padding to compare contrast improvement. Tissue segmentation was performed to assess the effect of dielectric pads on gray and white matter separately. RESULTS GluCEST images demonstrated contrast enhancement in the lateral temporal lobe regions with dielectric pad placement. Tissue segmentation analysis showed an increase in correction effectiveness within the gray matter tissue compared to white matter tissue. Statistical testing suggested a significant difference in gluCEST contrast when pads were used and showed a difference in the gray matter tissue segment. CONCLUSION The use of dielectric pads improved the B1 + field homogeneity and enhanced gluCEST contrast for all subjects when compared to data that did not incorporate padding.
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Affiliation(s)
- Paul S Jacobs
- Center for Advanced Metabolic Imaging in Precision Medicine, Department of Radiology, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Blake Benyard
- Center for Advanced Metabolic Imaging in Precision Medicine, Department of Radiology, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Abigail Cember
- Center for Advanced Metabolic Imaging in Precision Medicine, Department of Radiology, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Ravi Prakash Reddy Nanga
- Center for Advanced Metabolic Imaging in Precision Medicine, Department of Radiology, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Quy Cao
- Penn Statistics in Imaging and Visualization Center, Department of Biostatistics, Epidemiology, and Informatics, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - M Dylan Tisdall
- Department of Radiology, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Neil Wilson
- Center for Advanced Metabolic Imaging in Precision Medicine, Department of Radiology, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Sandhitsu Das
- Department of Neurology, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Kathryn A Davis
- Department of Neurology, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - John Detre
- Center for Advanced Metabolic Imaging in Precision Medicine, Department of Radiology, University of Pennsylvania, Philadelphia, Pennsylvania, USA
- Department of Neurology, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - David Roalf
- Department of Psychiatry, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Ravinder Reddy
- Center for Advanced Metabolic Imaging in Precision Medicine, Department of Radiology, University of Pennsylvania, Philadelphia, Pennsylvania, USA
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15
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Zhu C, Tanter M, Fan Z, Hu S, Sadat U, Wang DJJ. Editorial: Cerebrovascular imaging-From micro- to macroscopic scales. Front Neurosci 2022; 16:1086022. [PMID: 36483181 PMCID: PMC9723370 DOI: 10.3389/fnins.2022.1086022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2022] [Accepted: 11/14/2022] [Indexed: 01/25/2023] Open
Affiliation(s)
- Chengcheng Zhu
- Department of Radiology, University of Washington, Seattle, WA, United States,*Correspondence: Chengcheng Zhu
| | - Mickael Tanter
- INSERM U1273 Physics for Medicine Paris (ESPCI), Paris, France
| | - Zhaoyang Fan
- Department of Radiology, University of Southern California, Los Angeles, CA, United States
| | - Song Hu
- McKelvey School of Engineering, Washington University in St. Louis, St. Louis, MO, United States
| | - Umar Sadat
- Department of Surgery, University of Cambridge, Cambridge, United Kingdom
| | - Danny J. J. Wang
- Department of Neurology, University of Southern California, Los Angeles, CA, United States
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16
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Rusheen AE, Goyal A, Owen RL, Berning EM, Bothun DT, Giblon RE, Blaha CD, Welker KM, Huston J, Bennet KE, Oh Y, Fagan AJ, Lee KH. The development of ultra-high field MRI guidance technology for neuronavigation. J Neurosurg 2022; 137:1265-1277. [PMID: 35334465 PMCID: PMC10193481 DOI: 10.3171/2021.11.jns211078] [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: 04/30/2021] [Accepted: 11/19/2021] [Indexed: 11/06/2022]
Abstract
OBJECTIVE Magnetic resonance imaging at 7T offers improved image spatial and contrast resolution for visualization of small brain nuclei targeted in neuromodulation. However, greater image geometric distortion and a lack of compatible instrumentation preclude implementation. In this report, the authors detail the development of a stereotactic image localizer and accompanying imaging sequences designed to mitigate geometric distortion, enabling accurate image registration and surgical planning of basal ganglia nuclei. METHODS Magnetization-prepared rapid acquisition with gradient echo (MPRAGE), fast gray matter acquisition T1 inversion recovery (FGATIR), T2-weighted, and T2*-weighted sequences were optimized for 7T in 9 human subjects to visualize basal ganglia nuclei, minimize image distortion, and maximize target contrast-to-noise and signal-to-noise ratios. Extracranial spatial distortions were mapped to develop a skull-contoured image localizer embedded with spherical silicone fiducials for improved MR image registration and target guidance. Surgical plan accuracy testing was initially performed in a custom-developed MRI phantom (n = 5 phantom studies) and finally in a human trial. RESULTS MPRAGE and T2*-weighted sequences had the best measures among global measures of image quality (3.8/4, p < 0.0001; and 3.7/4, p = 0.0002, respectively). Among basal ganglia nuclei, FGATIR outperformed MPRAGE for globus pallidus externus (GPe) visualization (2.67/4 vs 1.78/4, p = 0.008), and FGATIR, T2-weighted imaging, and T2*-weighted imaging outperformed MPRAGE for substantia nigra visualization (1.44/4 vs 2.56/4, p = 0.04; vs 2.56/4, p = 0.04; vs 2.67/4, p = 0.003). Extracranial distortion was lower in the head's midregion compared with the base and apex ( 1.17-1.33 mm; MPRAGE and FGATIR, p < 0.0001; T2-weighted imaging, p > 0.05; and T2*-weighted imaging, p = 0.013). Fiducial placement on the localizer in low distortion areas improved image registration (fiducial registration error, 0.79-1.19 mm; p < 0.0001) and targeting accuracy (target registration error, 0.60-1.09 mm; p = 0.04). Custom surgical software and the refined image localizer enabled successful surgical planning in a human trial (fiducial registration error = 1.0 mm). CONCLUSIONS A skull-contoured image localizer that accounts for image distortion is necessary to enable high-accuracy 7T imaging-guided targeting for surgical neuromodulation. These results may enable improved clinical efficacy for the treatment of neurological disease.
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Affiliation(s)
- Aaron E. Rusheen
- Department of Neurologic Surgery, Mayo Clinic, Rochester
- Medical Scientist Training Program, Mayo Clinic, Rochester
| | - Abhinav Goyal
- Department of Neurologic Surgery, Mayo Clinic, Rochester
- Medical Scientist Training Program, Mayo Clinic, Rochester
| | - Robert L. Owen
- Mayo Clinic Alix School of Medicine, Mayo Clinic, Rochester
| | | | - Dane T. Bothun
- Department of Neurologic Surgery, Mayo Clinic, Rochester
| | - Rachel E. Giblon
- Kern Center for the Science of Health Care Delivery, Mayo Clinic, Rochester
| | | | | | - John Huston
- Department of Radiology, Mayo Clinic, Rochester; and
| | | | - Yoonbae Oh
- Department of Neurologic Surgery, Mayo Clinic, Rochester
| | - Andrew J. Fagan
- Department of Radiology, Mayo Clinic, Rochester; and
- Department of Physiology and Biomedical Engineering, Mayo Clinic, Rochester, Minnesota
| | - Kendall H. Lee
- Department of Neurologic Surgery, Mayo Clinic, Rochester
- Department of Physiology and Biomedical Engineering, Mayo Clinic, Rochester, Minnesota
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17
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McCarthy L, Verma G, Hangel G, Neal A, Moffat BA, Stockmann JP, Andronesi OC, Balchandani P, Hadjipanayis CG. Application of 7T MRS to High-Grade Gliomas. AJNR Am J Neuroradiol 2022; 43:1378-1395. [PMID: 35618424 PMCID: PMC9575545 DOI: 10.3174/ajnr.a7502] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2021] [Accepted: 02/11/2022] [Indexed: 01/26/2023]
Abstract
MRS, including single-voxel spectroscopy and MR spectroscopic imaging, captures metabolites in high-grade gliomas. Emerging evidence indicates that 7T MRS may be more sensitive to aberrant metabolic activity than lower-field strength MRS. However, the literature on the use of 7T MRS to visualize high-grade gliomas has not been summarized. We aimed to identify metabolic information provided by 7T MRS, optimal spectroscopic sequences, and areas for improvement in and new applications for 7T MRS. Literature was found on PubMed using "high-grade glioma," "malignant glioma," "glioblastoma," "anaplastic astrocytoma," "7T," "MR spectroscopy," and "MR spectroscopic imaging." 7T MRS offers higher SNR, modestly improved spatial resolution, and better resolution of overlapping resonances. 7T MRS also yields reduced Cramér-Rao lower bound values. These features help to quantify D-2-hydroxyglutarate in isocitrate dehydrogenase 1 and 2 gliomas and to isolate variable glutamate, increased glutamine, and increased glycine with higher sensitivity and specificity. 7T MRS may better characterize tumor infiltration and treatment effect in high-grade gliomas, though further study is necessary. 7T MRS will benefit from increased sample size; reductions in field inhomogeneity, specific absorption rate, and acquisition time; and advanced editing techniques. These findings suggest that 7T MRS may advance understanding of high-grade glioma metabolism, with reduced Cramér-Rao lower bound values and better measurement of smaller metabolite signals. Nevertheless, 7T is not widely used clinically, and technical improvements are necessary. 7T MRS isolates metabolites that may be valuable therapeutic targets in high-grade gliomas, potentially resulting in wider ranging neuro-oncologic applications.
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Affiliation(s)
- L McCarthy
- From the Department of Neurosurgery (L.M., C.G.H.), Icahn School of Medicine at Mount Sinai, Mount Sinai Health System, New York, New York
| | - G Verma
- BioMedical Engineering and Imaging Institute (G.V., P.B.), Icahn School of Medicine at Mount Sinai, New York, New York
| | - G Hangel
- Department of Neurosurgery (G.H.)
- High-field MR Center (G.H.), Department of Biomedical Imaging and Image-Guided Therapy, Medical University of Vienna, Vienna, Austria
| | - A Neal
- Department of Medicine (A.N.), Royal Melbourne Hospital, University of Melbourne, Melbourne, Australia
- Department of Neurology (A.N.), Royal Melbourne Hospital, Melbourne, Australia
| | - B A Moffat
- The Melbourne Brain Centre Imaging Unit (B.A.M.), Department of Radiology, The University of Melbourne, Melbourne, Australia
| | - J P Stockmann
- A. A. Martinos Center for Biomedical Imaging (J.P.S., O.C.A.), Massachusetts General Hospital, Charlestown, Massachusetts
- Harvard Medical School (J.P.S., O.C.A.), Boston, Massachusetts
| | - O C Andronesi
- A. A. Martinos Center for Biomedical Imaging (J.P.S., O.C.A.), Massachusetts General Hospital, Charlestown, Massachusetts
- Harvard Medical School (J.P.S., O.C.A.), Boston, Massachusetts
| | - P Balchandani
- BioMedical Engineering and Imaging Institute (G.V., P.B.), Icahn School of Medicine at Mount Sinai, New York, New York
| | - C G Hadjipanayis
- From the Department of Neurosurgery (L.M., C.G.H.), Icahn School of Medicine at Mount Sinai, Mount Sinai Health System, New York, New York
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18
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Renal imaging at 5 T versus 3 T: a comparison study. Insights Imaging 2022; 13:155. [PMID: 36153471 PMCID: PMC9509503 DOI: 10.1186/s13244-022-01290-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2022] [Accepted: 08/24/2022] [Indexed: 11/10/2022] Open
Abstract
Background Recently, a whole-body 5 T MRI scanner was developed to open the door of abdominal imaging at high-field strength. This prospective study aimed to evaluate the feasibility of renal imaging at 5 T and compare the image quality, potential artifacts, and contrast ratios with 3 T. Methods Forty healthy volunteers underwent MRI examination both at 3 T and 5 T. MRI sequences included T1-weighted gradient-echo (GRE), T2-weighted fast spin echo, diffusion-weighted imaging, and multi-echo GRE T2* mapping. Image quality and presence of artifacts were assessed for all sequences using four-point scales. For anatomical imaging, the signal-to-noise ratio (SNR) and contrast ratio (CR) of abdomen organ tissues were calculated. Besides, for functional imaging, the contrast-to-noise ratio of cortex/medulla was calculated. Wilcoxon signed rank-sum test was used to compare the visual evaluation scores and quantitative measurements between 3 and 5 T images. Results Compared to 3 T examination, T1-weighted sequence at 5 T showed significantly better image quality with higher conspicuity of the renal veins and arteries, and comparable artifacts. Image quality was comparable between both field strengths on T2-weighted images, whereas a significantly higher level of artifacts was observed at 5 T. Besides, 5 T MRI contributed to higher SNR and CR for abdomen organ tissues. For functional imaging, 5 T MRI showed improved corticomedullar discrimination. There was no significant difference between apparent diffusion coefficient of renal at 3 T and 5 T, while 5 T MRI resulted in significantly shorter T2* values in both cortex and medulla. Conclusions 5 T MRI provides anatomical and functional images of the kidney with sufficient image quality.
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19
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Klontzas ME, Karantanas AH. Research in Musculoskeletal Radiology: Setting Goals and Strategic Directions. Semin Musculoskelet Radiol 2022; 26:354-358. [PMID: 35654100 DOI: 10.1055/s-0042-1748319] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
The future of musculoskeletal (MSK) radiology is being built on research developments in the field. Over the past decade, MSK imaging research has been dominated by advancements in molecular imaging biomarkers, artificial intelligence, radiomics, and novel high-resolution equipment. Adequate preparation of trainees and specialists will ensure that current and future leaders will be prepared to embrace and critically appraise technological developments, will be up to date on clinical developments, such as the use of artificial tissues, will define research directions, and will actively participate and lead multidisciplinary research. This review presents an overview of the current MSK research landscape and proposes tangible future goals and strategic directions that will fortify the future of MSK radiology.
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Affiliation(s)
- Michail E Klontzas
- Department of Medical Imaging, University Hospital of Heraklion, Crete, Greece.,Advanced Hybrid Imaging Systems, Institute of Computer Science, Foundation for Research and Technology (FORTH), Heraklion, Crete, Greece.,Department of Radiology, School of Medicine, University of Crete, Heraklion, Greece
| | - Apostolos H Karantanas
- Department of Medical Imaging, University Hospital of Heraklion, Crete, Greece.,Advanced Hybrid Imaging Systems, Institute of Computer Science, Foundation for Research and Technology (FORTH), Heraklion, Crete, Greece.,Department of Radiology, School of Medicine, University of Crete, Heraklion, Greece
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20
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Varela C, Valdés R, Rojas A, Soffia P. Principles of magnetic resonance imaging (MRI). Nucl Med Mol Imaging 2022. [DOI: 10.1016/b978-0-12-822960-6.00101-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022] Open
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21
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Harper JR, Cherukuri V, O'Reilly T, Yu M, Mbabazi-Kabachelor E, Mulando R, Sheth KN, Webb AG, Warf BC, Kulkarni AV, Monga V, Schiff SJ. Assessing the utility of low resolution brain imaging: treatment of infant hydrocephalus. Neuroimage Clin 2021; 32:102896. [PMID: 34911199 PMCID: PMC8646178 DOI: 10.1016/j.nicl.2021.102896] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2021] [Revised: 10/27/2021] [Accepted: 11/22/2021] [Indexed: 11/21/2022]
Abstract
As low-field MRI technology is being disseminated into clinical settings around the world, it is important to assess the image quality required to properly diagnose and treat a given disease and evaluate the role of machine learning algorithms, such as deep learning, in the enhancement of lower quality images. In this post hoc analysis of an ongoing randomized clinical trial, we assessed the diagnostic utility of reduced-quality and deep learning enhanced images for hydrocephalus treatment planning. CT images of post-infectious infant hydrocephalus were degraded in terms of spatial resolution, noise, and contrast between brain and CSF and enhanced using deep learning algorithms. Both degraded and enhanced images were presented to three experienced pediatric neurosurgeons accustomed to working in low- to middle-income countries (LMIC) for assessment of clinical utility in treatment planning for hydrocephalus. In addition, enhanced images were presented alongside their ground-truth CT counterparts in order to assess whether reconstruction errors caused by the deep learning enhancement routine were acceptable to the evaluators. Results indicate that image resolution and contrast-to-noise ratio between brain and CSF predict the likelihood of an image being characterized as useful for hydrocephalus treatment planning. Deep learning enhancement substantially increases contrast-to-noise ratio improving the apparent likelihood of the image being useful; however, deep learning enhancement introduces structural errors which create a substantial risk of misleading clinical interpretation. We find that images with lower quality than is customarily acceptable can be useful for hydrocephalus treatment planning. Moreover, low quality images may be preferable to images enhanced with deep learning, since they do not introduce the risk of misleading information which could misguide treatment decisions. These findings advocate for new standards in assessing acceptable image quality for clinical use.
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Affiliation(s)
- Joshua R Harper
- Center for Neural Engineering, Department of Engineering Science and Mechanics, The Pennsylvania State University, University Park, PA, USA
| | - Venkateswararao Cherukuri
- School of Electrical Engineering and Computer Science, The Pennsylvania State University, University Park, PA, USA
| | - Tom O'Reilly
- Gorter Center for High Field MRI, Leiden University Medical Center, Leiden, NL, the Netherlands
| | - Mingzhao Yu
- School of Electrical Engineering and Computer Science, The Pennsylvania State University, University Park, PA, USA
| | | | | | - Kevin N Sheth
- Department of Neurology, Yale University School of Medicine, New Haven, CT, USA
| | - Andrew G Webb
- Gorter Center for High Field MRI, Leiden University Medical Center, Leiden, NL, the Netherlands
| | - Benjamin C Warf
- Department of Neurosurgery, Boston Children's Hospital, Harvard Medical School, Boston, USA
| | - Abhaya V Kulkarni
- Department of Surgery, Hospital for Sick Children, University of Toronto, CA, USA
| | - Vishal Monga
- School of Electrical Engineering and Computer Science, The Pennsylvania State University, University Park, PA, USA
| | - Steven J Schiff
- Center for Neural Engineering, Department of Engineering Science and Mechanics, The Pennsylvania State University, University Park, PA, USA; Departments of Neurosurgery, and Physics, The Pennsylvania State University, University Park, PA, USA.
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22
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Klontzas ME, Protonotarios A. High-Resolution Imaging for the Analysis and Reconstruction of 3D Microenvironments for Regenerative Medicine: An Application-Focused Review. Bioengineering (Basel) 2021; 8:182. [PMID: 34821748 PMCID: PMC8614770 DOI: 10.3390/bioengineering8110182] [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: 10/28/2021] [Revised: 11/07/2021] [Accepted: 11/08/2021] [Indexed: 11/29/2022] Open
Abstract
The rapid evolution of regenerative medicine and its associated scientific fields, such as tissue engineering, has provided great promise for multiple applications where replacement and regeneration of damaged or lost tissue is required. In order to evaluate and optimise the tissue engineering techniques, visualisation of the material of interest is crucial. This includes monitoring of the cellular behaviour, extracellular matrix composition, scaffold structure, and other crucial elements of biomaterials. Non-invasive visualisation of artificial tissues is important at all stages of development and clinical translation. A variety of preclinical and clinical imaging methods-including confocal multiphoton microscopy, optical coherence tomography, magnetic resonance imaging (MRI), and computed tomography (CT)-have been used for the evaluation of artificial tissues. This review attempts to present the imaging methods available to assess the composition and quality of 3D microenvironments, as well as their integration with human tissues once implanted in the human body. The review provides tissue-specific application examples to demonstrate the applicability of such methods on cardiovascular, musculoskeletal, and neural tissue engineering.
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Affiliation(s)
- Michail E. Klontzas
- Department of Medical Imaging, University Hospital of Heraklion, 71110, Heraklion, Crete, Greece
- Computational Biomedicine Laboratory, Institute of Computer Science, Foundation for Research and Technology (FORTH), 70013 Heraklion, Crete, Greece
- Department of Radiology, School of Medicine, Voutes Campus, University of Crete, 71003 Heraklion, Crete, Greece
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Deelchand DK, Ho ML, Nestrasil I. Ultra-High-Field Imaging of the Pediatric Brain and Spinal Cord. Magn Reson Imaging Clin N Am 2021; 29:643-653. [PMID: 34717851 DOI: 10.1016/j.mric.2021.06.013] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
Neuroimaging with ultra-high field magnets (≥7T) provides superior signal-to-noise, spatial resolution and tissue contrast; but also greater safety concerns, longer scanning times, and increased distortion and field inhomogeneity. Brain and spinal cord anatomic microstructure and function imaged in greater detail offers improved lesion detection, delineation, and characterization. The ongoing development of novel imaging contrasts and translation of cutting-edge sequences will aid more accurate, sensitive, and precise diagnosis, interventional planning, and follow-up for a variety of pathologic conditions.
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Affiliation(s)
- Dinesh Kumar Deelchand
- Department of Radiology, Center for Magnetic Resonance Research, University of Minnesota, 2021 6th Street Southeast, Minneapolis, MN 55455, USA
| | - Mai-Lan Ho
- Department of Radiology, Nationwide Children's Hospital, 700 Children's Drive, Columbus, OH 43205, USA
| | - Igor Nestrasil
- Masonic Institute for the Developing Brain, Division of Clinical Behavioral Neuroscience, Department of Pediatrics, University of Minnesota, 2025 East River Parkway, Minneapolis, MN 55414, USA.
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24
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Feng J, Liu X, Zhang Z, Wu Y, Li Z, Zhang Q, Jiang Y, You W, Liu P, Wang Y, Mossa-Basha M, Saloner D, Li Y, Zhu C. Comparison of 7 T and 3 T vessel wall MRI for the evaluation of intracranial aneurysm wall. Eur Radiol 2021; 32:2384-2392. [PMID: 34643780 DOI: 10.1007/s00330-021-08331-9] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2021] [Revised: 08/28/2021] [Accepted: 09/15/2021] [Indexed: 12/31/2022]
Abstract
OBJECTIVES To compare the visibility of intracranial aneurysm wall and thickness quantification between 7 and 3 T vessel wall imaging and evaluate the association between aneurysm size and wall thickness. METHODS Twenty-nine patients with 29 unruptured intracranial aneurysms were prospectively recruited for 3D T1-weighted vessel wall MRI at both 3 T and 7 T with 0.53 mm (3 T) and 0.4 mm (7 T) isotropic resolution, respectively. Two neuroradiologists independently evaluated wall visibility (0-5 Likert scale), quantified the apparent wall thickness (AWT) using a semi-automated full-width-half-maximum method, calculated wall sharpness, and measured the wall-to-lumen contrast ratio (CRwall/lumen). RESULTS Twenty-four patients with 24 aneurysms were included in this study. 7 T achieved significantly better aneurysm wall visibility than 3 T (3.6 ± 1.1 vs 2.7 ± 0.8, p = 0.003). AWT measured on 3 T and 7 T had a good correlation (averaged r = 0.63 ± 0.19). However, AWT on 3 T was 15% thicker than that on 7 T (0.52 ± 0.07 mm vs 0.45 ± 0.05 mm, p < 0.001). Wall sharpness on 7 T was 57% higher than that on 3 T (1.95 ± 0.32 mm-1 vs 1.24 ± 0.15 mm-1, p < 0.001). CRwall/lumen on 3 T and 7 T was comparable (p = 0.424). AWT on 7 T was positively correlated with aneurysm size (saccular: r = 0.58, q = 0.046; fusiform: r = 0.67, q = 0.049). CONCLUSIONS 7 T provides better visualization of intracranial aneurysm wall with higher sharpness than 3 T. 3 T overestimates the wall thickness relative to 7 T. Aneurysm wall thickness is positively correlated with aneurysm size. 7 T MRI is a promising tool to evaluate aneurysm wall in vivo. KEY POINTS • 7 T provides better visualization of intracranial aneurysm wall with higher sharpness than 3 T. • 3 T overestimates the wall thickness comparing with 7 T. • Aneurysm wall thickness is positively correlated with aneurysm size.
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Affiliation(s)
- Junqiang Feng
- Department of Interventional Neuroradiology, Beijing Neurosurgical Institute and Beijing Tiantan Hospital, Capital Medical University, Beijing, China
| | - Xinke Liu
- Department of Interventional Neuroradiology, Beijing Neurosurgical Institute and Beijing Tiantan Hospital, Capital Medical University, Beijing, China
| | - Zihao Zhang
- State Key Laboratory of Brain and Cognitive Science, Institute of Biophysics, Chinese Academy of Sciences, 15 Datun Road, Beijing, 100101, China. .,University of Chinese Academy of Sciences, 19A Yuquan Road, Beijing, 100049, China. .,CAS Center for Excellence in Brain Science and Intelligence Technology, Beijing, 100049, China.
| | - Yue Wu
- State Key Laboratory of Brain and Cognitive Science, Institute of Biophysics, Chinese Academy of Sciences, 15 Datun Road, Beijing, 100101, China.,University of Chinese Academy of Sciences, 19A Yuquan Road, Beijing, 100049, China.,CAS Center for Excellence in Brain Science and Intelligence Technology, Beijing, 100049, China
| | - Zhixin Li
- State Key Laboratory of Brain and Cognitive Science, Institute of Biophysics, Chinese Academy of Sciences, 15 Datun Road, Beijing, 100101, China.,University of Chinese Academy of Sciences, 19A Yuquan Road, Beijing, 100049, China.,CAS Center for Excellence in Brain Science and Intelligence Technology, Beijing, 100049, China
| | - Qiang Zhang
- Center for Biomedical Imaging Research, Department of Biomedical Engineering, School of Medicine, Tsinghua University, Beijing, China
| | - Yuhua Jiang
- Department of Interventional Neuroradiology, Beijing Neurosurgical Institute and Beijing Tiantan Hospital, Capital Medical University, Beijing, China
| | - Wei You
- Department of Interventional Neuroradiology, Beijing Neurosurgical Institute and Beijing Tiantan Hospital, Capital Medical University, Beijing, China
| | - Peng Liu
- Department of Interventional Neuroradiology, Beijing Neurosurgical Institute and Beijing Tiantan Hospital, Capital Medical University, Beijing, China
| | - Yan Wang
- Department of Radiology and Biomedical Imaging, University of California San Francisco, San Francisco, USA
| | | | - David Saloner
- Department of Radiology and Biomedical Imaging, University of California San Francisco, San Francisco, USA
| | - Youxiang Li
- Department of Interventional Neuroradiology, Beijing Neurosurgical Institute and Beijing Tiantan Hospital, Capital Medical University, Beijing, China.
| | - Chengcheng Zhu
- Department of Radiology, University of Washington, Seattle, WA, USA
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Morrison MA, Lupo JM. 7-T Magnetic Resonance Imaging in the Management of Brain Tumors. Magn Reson Imaging Clin N Am 2021; 29:83-102. [PMID: 33237018 DOI: 10.1016/j.mric.2020.09.007] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
This article provides an overview of the current status of ultrahigh-field 7-T magnetic resonance (MR) imaging in neuro-oncology, specifically for the management of patients with brain tumors. It includes a discussion of areas across the pretherapeutic, peritherapeutic, and posttherapeutic stages of patient care where 7-T MR imaging is currently being exploited and holds promise. This discussion includes existing technical challenges, barriers to clinical integration, as well as our impression of the future role of 7-T MR imaging as a clinical tool in neuro-oncology.
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Affiliation(s)
- Melanie A Morrison
- Department of Radiology and Biomedical Imaging, University of California, San Francisco, 505 Parnassus Avenue, San Francisco, CA 94143, USA
| | - Janine M Lupo
- Department of Radiology and Biomedical Imaging, University of California, San Francisco, 505 Parnassus Avenue, San Francisco, CA 94143, USA.
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Vachha B, Huang SY. MRI with ultrahigh field strength and high-performance gradients: challenges and opportunities for clinical neuroimaging at 7 T and beyond. Eur Radiol Exp 2021; 5:35. [PMID: 34435246 PMCID: PMC8387544 DOI: 10.1186/s41747-021-00216-2] [Citation(s) in RCA: 27] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2020] [Accepted: 03/30/2021] [Indexed: 12/12/2022] Open
Abstract
Research in ultrahigh magnetic field strength combined with ultrahigh and ultrafast gradient technology has provided enormous gains in sensitivity, resolution, and contrast for neuroimaging. This article provides an overview of the technical advantages and challenges of performing clinical neuroimaging studies at ultrahigh magnetic field strength combined with ultrahigh and ultrafast gradient technology. Emerging clinical applications of 7-T MRI and state-of-the-art gradient systems equipped with up to 300 mT/m gradient strength are reviewed, and the impact and benefits of such advances to anatomical, structural and functional MRI are discussed in a variety of neurological conditions. Finally, an outlook and future directions for ultrahigh field MRI combined with ultrahigh and ultrafast gradient technology in neuroimaging are examined.
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Affiliation(s)
- Behroze Vachha
- Department of Radiology, Memorial Sloan Kettering Cancer Center, 1275 York Ave, New York, NY, 10065, USA
| | - Susie Y Huang
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, 149 13th Street, Room 2301, Charlestown, MA, 02129, USA.
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27
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Cosottini M, Roccatagliata L. Neuroimaging at 7 T: are we ready for clinical transition? Eur Radiol Exp 2021; 5:37. [PMID: 34435257 PMCID: PMC8387509 DOI: 10.1186/s41747-021-00234-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2021] [Accepted: 07/19/2021] [Indexed: 12/23/2022] Open
Abstract
In the last 20 years, ultra-high field (UHF) magnetic resonance imaging (MRI) has become an outstanding research tool for the study of the human brain, with 90 of these scanners installed today, worldwide. The recent clearances from regulatory bodies in the USA and Europe to 7-T clinical systems have set the ground for a transition from pure research applications to research and clinical use of these systems. As today, UFH neuroimaging is demonstrating clinical value and, given the importance of this topic for both preclinical scientists and clinical neuroradiologists, European Radiology Experimental is launching a thematic series entitled "7-T neuro MRI: from research to clinic", consisting of peer-reviewed articles, invited or spontaneously submitted, on topics selected by the guest editors, describing the state of the art of UHF MRI neuroimaging across different pathologies, as well as related clinical applications. In this editorial, we discuss some of the challenges related to the clinical use of 7-T scanners and the strengths and weaknesses of clinical imaging at UHF.
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Affiliation(s)
- Mirco Cosottini
- Department of Translational Research On New Technologies in Medicine and Surgery, University of Pisa, Pisa, Italy
| | - Luca Roccatagliata
- Department of Health Sciences (DISSAL), University of Genoa, Via Pastore 1, 16132, Genoa, Italy.
- Department of Neuroradiology, Ospedale Policlinico San Martino IRCCS, Genoa, Italy.
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28
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Eckstein K, Bachrata B, Hangel G, Widhalm G, Enzinger C, Barth M, Trattnig S, Robinson SD. Improved susceptibility weighted imaging at ultra-high field using bipolar multi-echo acquisition and optimized image processing: CLEAR-SWI. Neuroimage 2021; 237:118175. [PMID: 34000407 PMCID: PMC7612087 DOI: 10.1016/j.neuroimage.2021.118175] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2021] [Revised: 04/28/2021] [Accepted: 05/13/2021] [Indexed: 02/07/2023] Open
Abstract
Purpose Susceptibility Weighted Imaging (SWI) has become established in the clinical investigation of stroke, microbleeds, tumor vascularization, calcification and iron deposition, but suffers from a number of shortcomings and artefacts. The goal of this study was to reduce the sensitivity of SWI to strong B1 and B0 inhomogeneities at ultra-high field to generate homogeneous images with increased contrast and free of common artefacts. All steps in SWI processing have been addressed −coil combination, phase unwrapping, image combination over echoes, phase filtering and homogeneity correction −and applied to an efficient bipolar multi-echo acquisition to substantially improve the quality of SWI. Principal results Our findings regarding the optimal individual processing steps lead us to propose a Contrast-weighted, Laplace-unwrapped, bipolar multi-Echo, ASPIRE-combined, homogeneous, improved Resolution SWI, or CLEAR-SWI. CLEAR-SWI was compared to two other multi-echo SWI methods and standard, single-echo SWI with the same acquisition time at 7 T in 10 healthy volunteers and with single-echo SWI in 13 patients with brain tumors. CLEAR-SWI had improved contrast-to-noise and homogeneity, reduced signal dropout and was not compromised by the artefacts which affected standard SWI in 10 out of 13 cases close to tumors (as assessed by expert raters), as well as generating T2* maps and phase images which can be used for Quantitative Susceptibility Mapping. In a comparison with other multi-echo SWI methods, CLEAR-SWI had the fewest artefacts, highest SNR and generally higher contrast-to-noise. Major conclusions CLEAR-SWI eliminates the artefacts common in standard, single-echo SWI, reduces signal dropouts and improves image homogeneity and contrast-to-noise. Applied clinically, in a study of brain tumor patients, CLEAR-SWI was free of the artefacts which affected standard, single-echo SWI.
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Affiliation(s)
- Korbinian Eckstein
- High Field MR Centre, Department of Biomedical Imaging and Image-guided Therapy, Medical University of Vienna, Vienna, Austria
| | - Beata Bachrata
- High Field MR Centre, Department of Biomedical Imaging and Image-guided Therapy, Medical University of Vienna, Vienna, Austria; Karl Landsteiner Institute for Clinical Molecular MR in Musculoskeletal Imaging, Vienna, Austria
| | - Gilbert Hangel
- High Field MR Centre, Department of Biomedical Imaging and Image-guided Therapy, Medical University of Vienna, Vienna, Austria; Department of Neurosurgery, Medical University of Vienna, Vienna, Austria
| | - Georg Widhalm
- Department of Neurosurgery, Medical University of Vienna, Vienna, Austria
| | | | - Markus Barth
- School of Information Technology and Electrical Engineering, Faculty of Engineering, Architecture and Information Technology, The University of Queensland, Brisbane, Australia
| | - Siegfried Trattnig
- High Field MR Centre, Department of Biomedical Imaging and Image-guided Therapy, Medical University of Vienna, Vienna, Austria; Karl Landsteiner Institute for Clinical Molecular MR in Musculoskeletal Imaging, Vienna, Austria
| | - Simon Daniel Robinson
- High Field MR Centre, Department of Biomedical Imaging and Image-guided Therapy, Medical University of Vienna, Vienna, Austria; Karl Landsteiner Institute for Clinical Molecular MR in Musculoskeletal Imaging, Vienna, Austria; Department of Neurology, Medical University of Graz, Graz, Austria; Centre for Advanced Imaging, The University of Queensland, Brisbane, Australia
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29
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Klontzas ME, Kakkos GA, Papadakis GZ, Marias K, Karantanas AH. Advanced clinical imaging for the evaluation of stem cell based therapies. Expert Opin Biol Ther 2021; 21:1253-1264. [PMID: 33576278 DOI: 10.1080/14712598.2021.1890711] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Introduction: As stem cell treatments reach closer to the clinic, the need for appropriate noninvasive imaging for accurate disease diagnosis, treatment planning, follow-up, and early detection of complications, is constantly rising. Clinical radiology affords an extensive arsenal of advanced imaging techniques, to provide anatomical and functional information on the whole spectrum of stem cell treatments from diagnosis to follow-up.Areas covered: This manuscript aims at providing a critical review of major published studies on the utilization of advanced imaging for stem cell treatments. Uses of magnetic resonance imaging (MRI), computed tomography (CT), ultrasound, and positron emission tomography (PET) are reviewed and interrogated for their applicability to stem cell imaging.Expert opinion: A wide spectrum of imaging methods have been utilized for the evaluation of stem cell therapies. The majority of published techniques are not clinically applicable, using methods exclusively applicable to animals or technology irrelevant to current clinical practice. Harmonization of preclinical methods with clinical reality is necessary for the timely translation of stem cell therapies to the clinic. Methods such as diffusion weighted MRI, hybrid imaging, and contrast-enhanced ultrasound hold great promise and should be routinely incorporated in the evaluation of patients receiving stem cell treatments.
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Affiliation(s)
- Michail E Klontzas
- Department of Medical Imaging, University Hospital of Heraklion, Crete, Greece.,Advanced Hybrid Imaging Systems, Institute of Computer Science, Foundation for Research and Technology (FORTH), Heraklion, Crete, Greece
| | - George A Kakkos
- Department of Medical Imaging, University Hospital of Heraklion, Crete, Greece
| | - Georgios Z Papadakis
- Advanced Hybrid Imaging Systems, Institute of Computer Science, Foundation for Research and Technology (FORTH), Heraklion, Crete, Greece.,Computational Biomedicine Laboratory (CBML), Foundation for Research and Technology Hellas (FORTH), Heraklion, Crete, Greece.,Department of Radiology, School of Medicine, University of Crete, Heraklion, Crete, Greece
| | - Kostas Marias
- Computational Biomedicine Laboratory (CBML), Foundation for Research and Technology Hellas (FORTH), Heraklion, Crete, Greece.,Department of Electrical and Computer Engineering, Hellenic Mediterranean University, Heraklion, Crete, Greece
| | - Apostolos H Karantanas
- Department of Medical Imaging, University Hospital of Heraklion, Crete, Greece.,Advanced Hybrid Imaging Systems, Institute of Computer Science, Foundation for Research and Technology (FORTH), Heraklion, Crete, Greece.,Computational Biomedicine Laboratory (CBML), Foundation for Research and Technology Hellas (FORTH), Heraklion, Crete, Greece.,Department of Radiology, School of Medicine, University of Crete, Heraklion, Crete, Greece
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30
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Shao X, Yan L, Ma SJ, Wang K, Wang DJJ. High-Resolution Neurovascular Imaging at 7T: Arterial Spin Labeling Perfusion, 4-Dimensional MR Angiography, and Black Blood MR Imaging. Magn Reson Imaging Clin N Am 2021; 29:53-65. [PMID: 33237015 PMCID: PMC7694883 DOI: 10.1016/j.mric.2020.09.003] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
Ultrahigh field offers increased resolution and contrast for neurovascular imaging. Arterial spin labeling methods benefit from an increased intrinsic signal-to-noise ratio of MR imaging signal and a prolonged tracer half-life at ultrahigh field, allowing the visualization of layer-dependent microvascular perfusion. Arterial spin labeling-based time-resolved 4-dimensional MR angiography at 7T provides a detailed depiction of the vascular architecture and dynamic blood flow pattern with high spatial and temporal resolutions. High-resolution black blood MR imaging at 7T allows detailed characterization of small perforating arteries such as lenticulostriate arteries. All techniques benefit from advances in parallel radiofrequency transmission technologies at ultrahigh field.
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Affiliation(s)
- Xingfeng Shao
- Laboratory of FMRI Technology (LOFT), USC Mark & Mary Stevens Neuroimaging and Informatics Institute, Keck School of Medicine, University of Southern California, 2025 Zonal Avenue, Los Angeles, CA 90033, USA
| | - Lirong Yan
- Laboratory of FMRI Technology (LOFT), USC Mark & Mary Stevens Neuroimaging and Informatics Institute, Keck School of Medicine, University of Southern California, 2025 Zonal Avenue, Los Angeles, CA 90033, USA; Department of Neurology, Keck School of Medicine, University of Southern California, 2025 Zonal Avenue, Los Angeles, CA 90033, USA
| | - Samantha J Ma
- Laboratory of FMRI Technology (LOFT), USC Mark & Mary Stevens Neuroimaging and Informatics Institute, Keck School of Medicine, University of Southern California, 2025 Zonal Avenue, Los Angeles, CA 90033, USA; Siemens Healthcare, Los Angeles, CA, USA
| | - Kai Wang
- Laboratory of FMRI Technology (LOFT), USC Mark & Mary Stevens Neuroimaging and Informatics Institute, Keck School of Medicine, University of Southern California, 2025 Zonal Avenue, Los Angeles, CA 90033, USA
| | - Danny J J Wang
- Laboratory of FMRI Technology (LOFT), USC Mark & Mary Stevens Neuroimaging and Informatics Institute, Keck School of Medicine, University of Southern California, 2025 Zonal Avenue, Los Angeles, CA 90033, USA; Department of Neurology, Keck School of Medicine, University of Southern California, 2025 Zonal Avenue, Los Angeles, CA 90033, USA.
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Harper JR, Zárate C, Krauch F, Muhumuza I, Molina J, Obungoloch J, Schiff SJ. An Unmatched Radio Frequency Chain for Low-Field Magnetic Resonance Imaging. FRONTIERS IN PHYSICS 2021; 9:727536. [PMID: 36213526 PMCID: PMC9536774 DOI: 10.3389/fphy.2021.727536] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
Magnetic Resonance Imaging (MRI) is a safe and versatile diagnostic tool for intracranial imaging, however it is also one of the most expensive and specialized making it scarce in low- to middle-income countries (LMIC). The affordability and portability of low-field MRI offers the potential for increased access to brain imaging for diseases like Hydrocephalus in LMIC. In this tutorial style work, we show the design of a low powered and low cost radio frequency chain of electronics to be paired with a previously reported prepolarized low-field MRI for childhood hydrocephalus imaging in sub-Saharan Africa where the incidence of this condition is high. Since the Larmor frequency for this system is as low as 180 kHz, we are able to minimize the impedance of the transmit coil to 5 ohms rather than match to 50 ohms as is traditionally the case. This reduces transmit power consumption by a factor of 10. We also show the use of inexpensive and commonly available animal enclosure fencing ("chicken wire") as a shield material at this frequency and compare to more traditional shield designs. These preliminary results show that highly portable and affordable low-field MRI systems could provide image resolution and signal-to-noise sufficient for planning hydrocephalus treatment in areas of the world with substantial resource limitations. Employment of these technologies in sub-Saharan Africa offers a cost-effective, sustainable approach to neurological diagnosis and treatment planning in this disease burdened region.
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Affiliation(s)
- Joshua R. Harper
- Center for Neural Engineering, Department of Engineering Science and Mechanics, The Pennsylvania State University, University Park, PA, United States
| | - Cristhian Zárate
- Laboratory of Mechanics and Energy, Department of Engineering, National University of Asunción, Asunción, Paraguay
| | - Federico Krauch
- Laboratory of Mechanics and Energy, Department of Engineering, National University of Asunción, Asunción, Paraguay
| | - Ivan Muhumuza
- Low Field MRI Lab, Department of Biomedical Engineering, Mbarara University of Science and Technology, Mbarara, Uganda
| | - Jorge Molina
- Laboratory of Mechanics and Energy, Department of Engineering, National University of Asunción, Asunción, Paraguay
| | - Johnes Obungoloch
- Low Field MRI Lab, Department of Biomedical Engineering, Mbarara University of Science and Technology, Mbarara, Uganda
| | - Steven J. Schiff
- Center for Neural Engineering, Department of Engineering Science and Mechanics, The Pennsylvania State University, University Park, PA, United States
- Department of Neurosurgery, The Pennsylvania State University, University Park, PA, United States
- Department of Physics, The Pennsylvania State University, University Park, PA, United States
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32
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Qiao R, Huang X, Qin Y, Li Y, Davis TP, Hagemeyer CE, Gao M. Recent advances in molecular imaging of atherosclerotic plaques and thrombosis. NANOSCALE 2020; 12:8040-8064. [PMID: 32239038 DOI: 10.1039/d0nr00599a] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
As the complications of atherosclerosis such as myocardial infarction and stroke are still one of the leading causes of mortality worldwide, the development of new diagnostic tools for the early detection of plaque instability and thrombosis is urgently needed. Advanced molecular imaging probes based on functional nanomaterials in combination with cutting edge imaging techniques are now paving the way for novel and unique approaches to monitor the inflammatory progress in atherosclerosis. This review focuses on the development of various molecular probes for the diagnosis of plaques and thrombosis in atherosclerosis, along with perspectives of their diagnostic applications in cardiovascular diseases. Specifically, we summarize the biological targets that can be used for atherosclerosis and thrombosis imaging. Then we describe the emerging molecular imaging techniques based on the utilization of engineered nanoprobes together with their challenges in clinical translation.
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Affiliation(s)
- Ruirui Qiao
- State Key Laboratory of Radiation Medicine and Protection, School for Radiological and Interdisciplinary Sciences (RAD-X), Collaborative Innovation Center of Radiation Medicine of Jiangsu Higher Education Institutions, Soochow University, Suzhou 215123, China
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