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Zhang Y, Zu T, Liu R, Zhou J. Acquisition sequences and reconstruction methods for fast chemical exchange saturation transfer imaging. NMR IN BIOMEDICINE 2023; 36:e4699. [PMID: 35067987 DOI: 10.1002/nbm.4699] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/09/2021] [Revised: 01/02/2022] [Accepted: 01/17/2022] [Indexed: 05/23/2023]
Abstract
Chemical exchange saturation transfer (CEST) imaging is an emerging molecular magnetic resonance imaging (MRI) technique that has been developed and employed in numerous diseases. Based on the unique saturation transfer principle, a family of CEST-detectable biomolecules in vivo have been found capable of providing valuable diagnostic information. However, CEST MRI needs a relatively long scan time due to the common long saturation labeling module and typical acquisition of multiple frequency offsets and signal averages, limiting its widespread clinical applications. So far, a plethora of imaging schemes and techniques has been developed to accelerate CEST MRI. In this review, the key acquisition and reconstruction methods for fast CEST imaging are summarized from a practical and systematic point of view. The first acquisition sequence section describes the major development of saturation schemes, readout patterns, ultrafast z-spectroscopy, and saturation-editing techniques for rapid CEST imaging. The second reconstruction method section lists the important advances of parallel imaging, compressed sensing, sparsity in the z-spectrum, and algorithms beyond the Fourier transform for speeding up CEST MRI.
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Affiliation(s)
- Yi Zhang
- Key Laboratory for Biomedical Engineering of Ministry of Education, Department of Biomedical Engineering, College of Biomedical Engineering & Instrument Science, Zhejiang University, Hangzhou, Zhejiang, China
- Cancer Center, Zhejiang University, Hangzhou, Zhejiang, China
| | - Tao Zu
- Key Laboratory for Biomedical Engineering of Ministry of Education, Department of Biomedical Engineering, College of Biomedical Engineering & Instrument Science, Zhejiang University, Hangzhou, Zhejiang, China
| | - Ruibin Liu
- Key Laboratory for Biomedical Engineering of Ministry of Education, Department of Biomedical Engineering, College of Biomedical Engineering & Instrument Science, Zhejiang University, Hangzhou, Zhejiang, China
| | - Jinyuan Zhou
- Department of Radiology, Johns Hopkins University, Baltimore, Maryland, USA
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Igarashi T, Kim H, Sun PZ. Detection of tissue pH with quantitative chemical exchange saturation transfer magnetic resonance imaging. NMR IN BIOMEDICINE 2023; 36:e4711. [PMID: 35141979 PMCID: PMC10249910 DOI: 10.1002/nbm.4711] [Citation(s) in RCA: 12] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/08/2021] [Revised: 02/03/2022] [Accepted: 02/05/2022] [Indexed: 05/12/2023]
Abstract
Chemical exchange saturation transfer (CEST) magnetic resonance imaging (MRI) has emerged as a novel means for sensitive detection of dilute labile protons and chemical exchange rates. By sensitizing to pH-dependent chemical exchange, CEST MRI has shown promising results in monitoring tissue statuses such as pH changes in disorders like acute stroke, tumor, and acute kidney injury. This article briefly reviews the basic principles for CEST imaging and quantitative measures, from the simplistic asymmetry analysis to multipool Lorentzian decoupling and quasi-steady-state reconstruction. In particular, the advantages and limitations of commonly used quantitative approaches for CEST applications are discussed.
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Affiliation(s)
- Takahiro Igarashi
- Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Harvard Medical School, Charlestown, MA
| | - Hahnsung Kim
- Department of Radiology and Imaging Sciences, Emory University School of Medicine, Atlanta, GA
- Yerkes Imaging Center, Yerkes National Primate Research Center, Emory University, Atlanta, GA
| | - Phillip Zhe Sun
- Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Harvard Medical School, Charlestown, MA
- Department of Radiology and Imaging Sciences, Emory University School of Medicine, Atlanta, GA
- Yerkes Imaging Center, Yerkes National Primate Research Center, Emory University, Atlanta, GA
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Wittsack HJ, Radke KL, Stabinska J, Ljimani A, Müller-Lutz A. calf - Software for CEST Analysis with Lorentzian Fitting. J Med Syst 2023; 47:39. [PMID: 36961580 PMCID: PMC10038975 DOI: 10.1007/s10916-023-01931-6] [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: 09/14/2022] [Accepted: 02/27/2023] [Indexed: 03/25/2023]
Abstract
Analysis of chemical exchange saturation transfer (CEST) MRI data requires sophisticated methods to obtain reliable results about metabolites in the tissue under study. CEST generates z-spectra with multiple components, each originating from individual molecular groups. The individual lines with Lorentzian line shape are mostly overlapping and disturbed by various effects. We present an elaborate method based on an adaptive nonlinear least squares algorithm that provides robust quantification of z-spectra and incorporates prior knowledge in the fitting process. To disseminate CEST to the research community, we developed software as part of this study that runs on the Microsoft Windows operating system and will be made freely available to the community. Special attention has been paid to establish a low entrance threshold and high usability, so that even less experienced users can successfully analyze CEST data.
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Affiliation(s)
- Hans-Jörg Wittsack
- Medical Faculty, Department of Diagnostic and Interventional Radiology, University Dusseldorf, D-40225, Dusseldorf, Germany.
| | - Karl Ludger Radke
- Medical Faculty, Department of Diagnostic and Interventional Radiology, University Dusseldorf, D-40225, Dusseldorf, Germany
| | - Julia Stabinska
- F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, MD, 21205, USA
- Division of MR Research, The Russell H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltimore, MD, 21205, USA
| | - Alexandra Ljimani
- Medical Faculty, Department of Diagnostic and Interventional Radiology, University Dusseldorf, D-40225, Dusseldorf, Germany
| | - Anja Müller-Lutz
- Medical Faculty, Department of Diagnostic and Interventional Radiology, University Dusseldorf, D-40225, Dusseldorf, Germany
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Barbieri M, Chaudhari AS, Moran CJ, Gold GE, Hargreaves BA, Kogan F. A method for measuring B 0 field inhomogeneity using quantitative double-echo in steady-state. Magn Reson Med 2023; 89:577-593. [PMID: 36161727 PMCID: PMC9712261 DOI: 10.1002/mrm.29465] [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: 03/29/2022] [Revised: 08/31/2022] [Accepted: 09/01/2022] [Indexed: 12/13/2022]
Abstract
PURPOSE To develop and validate a method forB 0 $$ {B}_0 $$ mapping for knee imaging using the quantitative Double-Echo in Steady-State (qDESS) exploiting the phase difference (Δ θ $$ \Delta \theta $$ ) between the two echoes acquired. Contrary to a two-gradient-echo (2-GRE) method,Δ θ $$ \Delta \theta $$ depends only on the first echo time. METHODS Bloch simulations were applied to investigate robustness to noise of the proposed methodology and all imaging studies were validated with phantoms and in vivo simultaneous bilateral knee acquisitions. Two phantoms and five healthy subjects were scanned using qDESS, water saturation shift referencing (WASSR), and multi-GRE sequences.Δ B 0 $$ \Delta {B}_0 $$ maps were calculated with the qDESS and the 2-GRE methods and compared against those obtained with WASSR. The comparison was quantitatively assessed exploiting pixel-wise difference maps, Bland-Altman (BA) analysis, and Lin's concordance coefficient (ρ c $$ {\rho}_c $$ ). For in vivo subjects, the comparison was assessed in cartilage using average values in six subregions. RESULTS The proposed method for measuringΔ B 0 $$ \Delta {B}_0 $$ inhomogeneities from a qDESS acquisition providedΔ B 0 $$ \Delta {B}_0 $$ maps that were in good agreement with those obtained using WASSR.Δ B 0 $$ \Delta {B}_0 $$ ρ c $$ {\rho}_c $$ values were≥ $$ \ge $$ 0.98 and 0.90 in phantoms and in vivo, respectively. The agreement between qDESS and WASSR was comparable to that of a 2-GRE method. CONCLUSION The proposed method may allow B0 correction for qDESST 2 $$ {T}_2 $$ mapping using an inherently co-registeredΔ B 0 $$ \Delta {B}_0 $$ map without requiring an additional B0 measurement sequence. More generally, the method may help shorten knee imaging protocols that require an auxiliaryΔ B 0 $$ \Delta {B}_0 $$ map by exploiting a qDESS acquisition that also providesT 2 $$ {T}_2 $$ measurements and high-quality morphological imaging.
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Affiliation(s)
- Marco Barbieri
- Department of Radiology, Stanford University, Stanford, CA, U.S.A
| | - Akshay S. Chaudhari
- Department of Radiology, Stanford University, Stanford, CA, U.S.A
- Department of Biomedical Data Science, Stanford University, Stanford, CA, U.S.A
| | | | - Garry E. Gold
- Department of Radiology, Stanford University, Stanford, CA, U.S.A
- Department of Bioengineering, Stanford University, Stanford, CA, U.S.A
| | - Brian A. Hargreaves
- Department of Radiology, Stanford University, Stanford, CA, U.S.A
- Department of Bioengineering, Stanford University, Stanford, CA, U.S.A
- Department of Electrical Engineering, Stanford University, Stanford, CA, U.S.A
| | - Feliks Kogan
- Department of Radiology, Stanford University, Stanford, CA, U.S.A
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Lorentzian-Corrected Apparent Exchange-Dependent Relaxation (LAREX) Ω-Plot Analysis-An Adaptation for qCEST in a Multi-Pool System: Comprehensive In Silico, In Situ, and In Vivo Studies. Int J Mol Sci 2022; 23:ijms23136920. [PMID: 35805925 PMCID: PMC9266897 DOI: 10.3390/ijms23136920] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2022] [Revised: 06/05/2022] [Accepted: 06/20/2022] [Indexed: 12/14/2022] Open
Abstract
Based on in silico, in situ, and in vivo studies, this study aims to develop a new method for the quantitative chemical exchange saturation transfer (qCEST) technique considering multi-pool systems. To this end, we extended the state-of-the-art apparent exchange-dependent relaxation (AREX) method with a Lorentzian correction (LAREX). We then validated this new method with in situ and in vivo experiments on human intervertebral discs (IVDs) using the Kendall-Tau correlation coefficient. In the in silico experiments, we observed significant deviations of the AREX method as a function of the underlying exchange rate (kba) and fractional concentration (fb) compared to the ground truth due to the influence of other exchange pools. In comparison to AREX, the LAREX-based Ω-plot approach yielded a substantial improvement. In the subsequent in situ and in vivo experiments on human IVDs, no correlation to the histological reference standard or Pfirrmann classification could be found for the fb (in situ: τ = −0.17 p = 0.51; in vivo: τ = 0.13 p = 0.30) and kba (in situ: τ = 0.042 p = 0.87; in vivo: τ = −0.26 p = 0.04) of Glycosaminoglycan (GAG) with AREX. In contrast, the influence of interfering pools could be corrected by LAREX, and a moderate to strong correlation was observed for the fractional concentration of GAG for both in situ (τ = −0.71 p = 0.005) and in vivo (τ = −0.49 p < 0.001) experiments. The study presented here is the first to introduce a new qCEST method that enables qCEST imaging in systems with multiple proton pools.
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Zhou J, Zaiss M, Knutsson L, Sun PZ, Ahn SS, Aime S, Bachert P, Blakeley JO, Cai K, Chappell MA, Chen M, Gochberg DF, Goerke S, Heo HY, Jiang S, Jin T, Kim SG, Laterra J, Paech D, Pagel MD, Park JE, Reddy R, Sakata A, Sartoretti-Schefer S, Sherry AD, Smith SA, Stanisz GJ, Sundgren PC, Togao O, Vandsburger M, Wen Z, Wu Y, Zhang Y, Zhu W, Zu Z, van Zijl PCM. Review and consensus recommendations on clinical APT-weighted imaging approaches at 3T: Application to brain tumors. Magn Reson Med 2022; 88:546-574. [PMID: 35452155 PMCID: PMC9321891 DOI: 10.1002/mrm.29241] [Citation(s) in RCA: 81] [Impact Index Per Article: 40.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2021] [Revised: 02/26/2022] [Accepted: 03/02/2022] [Indexed: 12/16/2022]
Abstract
Amide proton transfer-weighted (APTw) MR imaging shows promise as a biomarker of brain tumor status. Currently used APTw MRI pulse sequences and protocols vary substantially among different institutes, and there are no agreed-on standards in the imaging community. Therefore, the results acquired from different research centers are difficult to compare, which hampers uniform clinical application and interpretation. This paper reviews current clinical APTw imaging approaches and provides a rationale for optimized APTw brain tumor imaging at 3 T, including specific recommendations for pulse sequences, acquisition protocols, and data processing methods. We expect that these consensus recommendations will become the first broadly accepted guidelines for APTw imaging of brain tumors on 3 T MRI systems from different vendors. This will allow more medical centers to use the same or comparable APTw MRI techniques for the detection, characterization, and monitoring of brain tumors, enabling multi-center trials in larger patient cohorts and, ultimately, routine clinical use.
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Affiliation(s)
- Jinyuan Zhou
- Division of MR Research, Department of Radiology, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Moritz Zaiss
- Magnetic Resonance Center, Max Planck Institute for Biological Cybernetics, Tübingen, Germany.,Institute of Neuroradiology, University Hospital Erlangen, Friedrich-Alexander Universität Erlangen-Nürnberg, Erlangen, Germany
| | - Linda Knutsson
- Division of MR Research, Department of Radiology, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA.,Department of Medical Radiation Physics, Lund University, Lund, Sweden.,F.M. Kirby Research Center for Functional Brain Imaging, Hugo W. Moser Research Institute at Kennedy Krieger, Baltimore, Maryland, USA
| | - Phillip Zhe Sun
- Yerkes Imaging Center, Yerkes National Primate Research Center, Emory University, Atlanta, Georgia, USA
| | - Sung Soo Ahn
- Department of Radiology and Research Institute of Radiological Science, Yonsei University College of Medicine, Seoul, South Korea
| | - Silvio Aime
- Molecular Imaging Center, Department of Molecular Biotechnology and Health Sciences, University of Torino, Torino, Italy
| | - Peter Bachert
- Department of Medical Physics in Radiology, German Cancer Research Center, Heidelberg, Germany.,Faculty of Physics and Astronomy, University of Heidelberg, Heidelberg, Germany
| | - Jaishri O Blakeley
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Kejia Cai
- Department of Radiology, University of Illinois at Chicago, Chicago, Illinois, USA
| | - Michael A Chappell
- Mental Health and Clinical Neurosciences and Sir Peter Mansfield Imaging Centre, School of Medicine, University of Nottingham, Nottingham, UK.,Nottingham Biomedical Research Centre, Queen's Medical Centre, University of Nottingham, Nottingham, UK
| | - Min Chen
- Department of Radiology, Beijing Hospital, National Center of Gerontology, Beijing, China
| | - Daniel F Gochberg
- Vanderbilt University Institute of Imaging Science (VUIIS), Vanderbilt University Medical Center, Nashville, Tennessee, USA.,Department of Radiology and Radiological Sciences, Vanderbilt University Medical Center, Nashville, Tennessee, USA.,Department of Physics, Vanderbilt University, Nashville, Tennessee, USA
| | - Steffen Goerke
- Department of Medical Physics in Radiology, German Cancer Research Center, Heidelberg, Germany
| | - Hye-Young Heo
- Division of MR Research, Department of Radiology, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Shanshan Jiang
- Division of MR Research, Department of Radiology, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Tao Jin
- Department of Radiology, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Seong-Gi Kim
- Center for Neuroscience Imaging Research, Institute for Basic Science and Department of Biomedical Engineering, Sungkyunkwan University, Suwon, South Korea
| | - John Laterra
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA.,Hugo W. Moser Research Institute at Kennedy Krieger, Baltimore, Maryland, USA
| | - Daniel Paech
- Department of Radiology, German Cancer Research Center, Heidelberg, Germany.,Clinic for Neuroradiology, University Hospital Bonn, Bonn, Germany
| | - Mark D Pagel
- Department of Cancer Systems Imaging, The University of Texas MD Anderson Cancer Center, Houston, Texas, USA
| | - Ji Eun Park
- Department of Radiology and Research Institute of Radiology, University of Ulsan College of Medicine, Asan Medical Center, Seoul, South Korea
| | - Ravinder Reddy
- Center for Advance Metabolic Imaging in Precision Medicine, Department of Radiology, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Akihiko Sakata
- Department of Diagnostic Imaging and Nuclear Medicine, Kyoto University Graduate School of Medicine, Kyoto, Japan
| | | | - A Dean Sherry
- Advanced Imaging Research Center and Department of Radiology, University of Texas Southwestern Medical Center, Dallas, Texas, USA.,Department of Chemistry and Biochemistry, University of Texas at Dallas, Richardson, Texas, USA
| | - Seth A Smith
- Vanderbilt University Institute of Imaging Science (VUIIS), Vanderbilt University Medical Center, Nashville, Tennessee, USA.,Department of Radiology and Radiological Sciences, Vanderbilt University Medical Center, Nashville, Tennessee, USA.,Department of Biomedical Engineering, Vanderbilt University, Nashville, Tennessee, USA
| | - Greg J Stanisz
- Department of Medical Biophysics, University of Toronto, Toronto, Ontario, Canada
| | - Pia C Sundgren
- Department of Diagnostic Radiology/Clinical Sciences Lund, Lund University, Lund, Sweden.,Lund University Bioimaging Center, Lund University, Lund, Sweden.,Department of Medical Imaging and Physiology, Skåne University Hospital, Lund University, Lund, Sweden
| | - Osamu Togao
- Department of Molecular Imaging and Diagnosis, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan
| | | | - Zhibo Wen
- Department of Radiology, Zhujiang Hospital, Southern Medical University, Guangzhou, Guangdong, China
| | - Yin Wu
- Paul C. Lauterbur Research Center for Biomedical Imaging, Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, Shenzhen, Guangdong, China
| | - Yi Zhang
- Key Laboratory for Biomedical Engineering of Ministry of Education, Department of Biomedical Engineering, College of Biomedical Engineering and Instrument Science, Zhejiang University, Hangzhou, Zhejiang, China
| | - Wenzhen Zhu
- Department of Radiology, Tongji Hospital of Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, China
| | - Zhongliang Zu
- Vanderbilt University Institute of Imaging Science (VUIIS), Vanderbilt University Medical Center, Nashville, Tennessee, USA.,Department of Radiology and Radiological Sciences, Vanderbilt University Medical Center, Nashville, Tennessee, USA
| | - Peter C M van Zijl
- Division of MR Research, Department of Radiology, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA.,F.M. Kirby Research Center for Functional Brain Imaging, Hugo W. Moser Research Institute at Kennedy Krieger, Baltimore, Maryland, USA
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Soellner ST, Welsch GH, Gelse K, Goldmann A, Kleyer A, Schett G, Pachowsky ML. gagCEST imaging at 3 T MRI in patients with articular cartilage lesions of the knee and intraoperative validation. Osteoarthritis Cartilage 2021; 29:1163-1172. [PMID: 33933584 DOI: 10.1016/j.joca.2021.04.012] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/02/2020] [Revised: 03/22/2021] [Accepted: 04/05/2021] [Indexed: 02/02/2023]
Abstract
OBJECTIVE The aim of this study was to compare glycosaminoglycan chemical exchange saturation transfer (gagCEST) of knee cartilage with intraoperative results for the assessment of early osteoarthritis (OA) and to define gagCEST values for the differentiation between healthy and degenerated cartilage. DESIGN Twenty-one patients with cartilage lesions or moderate OA were examined using 3 T Magnetic Resonance Imaging (MRI). In this prospective study, regions of interest (ROIs) were examined by a sagittal gagCEST analysis and a morphological high-resolution three-dimensional, fat-saturated proton-density space sequence. Cartilage lesions were identified arthroscopically, graded by the International Cartilage Repair Society (ICRS) score in 42 defined ROIs per patient and consecutively compared with mean gagCEST values using analysis of variance and Spearman's rank correlation test. Receiver operating characteristics (ROC) curves were applied to identify gagCEST threshold values to differentiate between the ICRS grades. RESULTS A total of 882 ROIs were examined and graduated in ICRS score 0 (67.3%), 1 (25.2%), 2 (6.2%) and the merged ICRS 3 and 4 (1.0%). gagCEST values decreased with increasing grade of cartilage damage with a negative correlation between gagCEST values and ICRS scores. A gagCEST value threshold of 3.55% was identified to differentiate between ICRS score 0 (normal) and all other grades. CONCLUSIONS gagCEST reflects the content of glycosaminoglycan and might provide a diagnostic tool for the detection of early knee-joint cartilage damage and for the non-invasive subtle differentiation between ICRS grades by MRI even at early stages in clinical practice.
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Affiliation(s)
- S T Soellner
- Department of Trauma and Orthopaedic Surgery, University Hospital of Erlangen, Friedrich-Alexander-University Erlangen-Nürnberg (FAU), Germany.
| | - G H Welsch
- UKE Athleticum, and Department of Trauma and Orthopaedic Surgery, University Medical Center Hamburg-Eppendorf, Hamburg, Germany.
| | - K Gelse
- Klinikum Traunstein, Traunstein, Germany; Department of Trauma and Orthopaedic Surgery, University Hospital of Erlangen, Friedrich-Alexander-University Erlangen-Nürnberg (FAU), Germany; University Hospital of Erlangen, Friedrich-Alexander-University Erlangen-Nürnberg (FAU), Germany.
| | - A Goldmann
- OCE Orthopaedie Centrum Erlangen, Erlangen, Germany.
| | - A Kleyer
- Department of Internal Medicine 3 - Rheumatology and Immunology, University Hospital of Erlangen, Friedrich-Alexander-University Erlangen-Nürnberg (FAU), Germany.
| | - G Schett
- Department of Internal Medicine 3 - Rheumatology and Immunology, University Hospital of Erlangen, Friedrich-Alexander-University Erlangen-Nürnberg (FAU), Germany.
| | - M L Pachowsky
- Department of Trauma and Orthopaedic Surgery and Department of Internal Medicine 3 - Rheumatology and Immunology, University Hospital of Erlangen, Friedrich-Alexander-University Erlangen-Nürnberg (FAU), Ulmenweg 18, 91054 Erlangen, Germany.
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Poblador Rodriguez E, Moser P, Auno S, Eckstein K, Dymerska B, van der Kouwe A, Gruber S, Trattnig S, Bogner W. Real-time motion and retrospective coil sensitivity correction for CEST using volumetric navigators (vNavs) at 7T. Magn Reson Med 2021; 85:1909-1923. [PMID: 33165952 PMCID: PMC7839562 DOI: 10.1002/mrm.28555] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2020] [Revised: 09/22/2020] [Accepted: 09/22/2020] [Indexed: 12/12/2022]
Abstract
PURPOSE To explore the impact of temporal motion-induced coil sensitivity changes on CEST-MRI at 7T and its correction using interleaved volumetric EPI navigators, which are applied for real-time motion correction. METHODS Five healthy volunteers were scanned via CEST. A 4-fold correction pipeline allowed the mitigation of (1) motion, (2) motion-induced coil sensitivity variations, ΔB1- , (3) motion-induced static magnetic field inhomogeneities, ΔB0 , and (4) spatially varying transmit RF field fluctuations, ΔB1+ . Four CEST measurements were performed per session. For the first 2, motion correction was turned OFF and then ON in absence of voluntary motion, whereas in the other 2 controlled head rotations were performed. During post-processing ΔB1- was removed additionally for the motion-corrected cases, resulting in a total of 6 scenarios to be compared. In all cases, retrospective ∆B0 and - ΔB1+ corrections were performed to compute artifact-free magnetization transfer ratio maps with asymmetric analysis (MTRasym ). RESULTS Dynamic ΔB1- correction successfully mitigated signal deviations caused by head motion. In 2 frontal lobe regions of volunteer 4, induced relative signal errors of 10.9% and 3.9% were reduced to 1.1% and 1.0% after correction. In the right frontal lobe, the motion-corrected MTRasym contrast deviated 0.92%, 1.21%, and 2.97% relative to the static case for Δω = 1, 2, 3 ± 0.25 ppm. The additional application of ΔB1- correction reduced these deviations to 0.10%, 0.14%, and 0.42%. The fully corrected MTRasym values were highly consistent between measurements with and without intended head rotations. CONCLUSION Temporal ΔB1- cause significant CEST quantification bias. The presented correction pipeline including the proposed retrospective ΔB1- correction significantly reduced motion-related artifacts on CEST-MRI.
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Affiliation(s)
- Esau Poblador Rodriguez
- High Field MR Center, Department of Biomedical Imaging and Image-guided Therapy, Medical University Vienna, Vienna, Austria
| | - Philipp Moser
- High Field MR Center, Department of Biomedical Imaging and Image-guided Therapy, Medical University Vienna, Vienna, Austria
| | - Sami Auno
- Neuroscience Center, University of Helsinki, Helsinki, Finland
| | - Korbinian Eckstein
- High Field MR Center, Department of Biomedical Imaging and Image-guided Therapy, Medical University Vienna, Vienna, Austria
| | - Barbara Dymerska
- Medical Physics and Bioengineering, University College London, London, United Kingdom
| | - Andre van der Kouwe
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts, USA
| | - Stephan Gruber
- High Field MR Center, Department of Biomedical Imaging and Image-guided Therapy, Medical University Vienna, Vienna, Austria
| | - Siegfried Trattnig
- High Field MR Center, Department of Biomedical Imaging and Image-guided Therapy, Medical University Vienna, Vienna, Austria.,Christian Doppler Laboratory for Clinical Molecular MR Imaging, Vienna, Austria
| | - Wolfgang Bogner
- High Field MR Center, Department of Biomedical Imaging and Image-guided Therapy, Medical University Vienna, Vienna, Austria
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9
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Kim H, Wu Y, Villano D, Longo DL, McMahon MT, Sun PZ. Analysis Protocol for the Quantification of Renal pH Using Chemical Exchange Saturation Transfer (CEST) MRI. Methods Mol Biol 2021; 2216:667-688. [PMID: 33476030 DOI: 10.1007/978-1-0716-0978-1_40] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/21/2023]
Abstract
The kidney plays a major role in maintaining body pH homeostasis. Renal pH, in particular, changes immediately following injuries such as intoxication and ischemia, making pH an early biomarker for kidney injury before the symptom onset and complementary to well-established laboratory tests. Because of this, it is imperative to develop minimally invasive renal pH imaging exams and test pH as a new diagnostic biomarker in animal models of kidney injury before clinical translation. Briefly, iodinated contrast agents approved by the US Food and Drug Administration (FDA) for computed tomography (CT) have demonstrated promise as novel chemical exchange saturation transfer (CEST) MRI agents for pH-sensitive imaging. The generalized ratiometric iopamidol CEST MRI analysis enables concentration-independent pH measurement, which simplifies in vivo renal pH mapping. This chapter describes quantitative CEST MRI analysis for preclinical renal pH mapping, and their application in rodents, including normal conditions and acute kidney injury.This publication is based upon work from the COST Action PARENCHIMA, a community-driven network funded by the European Cooperation in Science and Technology (COST) program of the European Union, which aims to improve the reproducibility and standardization of renal MRI biomarkers. This analysis protocol chapter is complemented by two separate chapters describing the basic concepts and experimental procedure.
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Affiliation(s)
- Hahnsung Kim
- Yerkes Imaging Center, Yerkes National Primate Research Center, Emory University, Atlanta, GA, USA.,Department of Radiology and Imaging Sciences, Emory University School of Medicine, Atlanta, GA, USA
| | - Yin Wu
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital and Harvard Medical School, Charlestown, MA, USA.,Paul C. Lauterbur Research Center for Biomedical Imaging, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, Guangdong, China
| | - Daisy Villano
- Department of Molecular Biotechnology and Health Sciences, University of Torino, Torino, Italy
| | - Dario Livio Longo
- Institute of Biostructures and Bioimaging (IBB), Italian National Research Council (CNR), Torino, Italy
| | - Michael T McMahon
- F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, MD, USA.,The Russell H. Morgan Department of Radiology and Radiological Science, Division of MR Research, The Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Phillip Zhe Sun
- Yerkes Imaging Center, Yerkes National Primate Research Center, Emory University, Atlanta, GA, USA. .,Department of Radiology and Imaging Sciences, Emory University School of Medicine, Atlanta, GA, USA. .,Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital and Harvard Medical School, Charlestown, MA, USA.
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Frenken M, Nebelung S, Schleich C, Müller-Lutz A, Radke KL, Kamp B, Boschheidgen M, Wollschläger L, Bittersohl B, Antoch G, Konieczny MR, Abrar DB. Non-Specific Low Back Pain and Lumbar Radiculopathy: Comparison of Morphologic and Compositional MRI as Assessed by gagCEST Imaging at 3T. Diagnostics (Basel) 2021; 11:diagnostics11030402. [PMID: 33652924 PMCID: PMC7996864 DOI: 10.3390/diagnostics11030402] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2021] [Revised: 02/16/2021] [Accepted: 02/23/2021] [Indexed: 12/15/2022] Open
Abstract
Using glycosaminoglycan Chemical Exchange Saturation Transfer (gagCEST) magnetic resonance imaging (MRI), this study comparatively evaluated the GAG contents of lumbar intervertebral disks (IVDs) of patients with non-specific low back pain (nsLBP), radiculopathy, and asymptomatic volunteers to elucidate the association of clinical manifestation and compositional correlate. A total of 18 patients (mean age 57.5 ± 22.5 years) with radiculopathy, 16 age-matched patients with chronic nsLBP and 20 age-matched volunteers underwent standard morphologic and compositional gagCEST MRI on a 3T scanner. In all cohorts, GAG contents of lumbar IVDs were determined using gagCEST MRI. An assessment of morphologic IVD degeneration based on the Pfirrmann classification and T2-weighted sequences served as a reference. A linear mixed model adjusted for multiple confounders was used for statistical evaluation. IVDs of patients with nsLBP showed lower gagCEST values than those of volunteers (nsLBP: 1.3% [99% confidence intervals (CI): 1.0; 1.6] vs. volunteers: 1.9% [99% CI: 1.6; 2.2]). Yet, IVDs of patients with radiculopathy (1.8% [99% CI: 1.4; 2.1]) were not different from patients with nsLBP or volunteers. In patients with radiculopathy, IVDs directly adjacent to IVD extrusions demonstrated lower gagCEST values than distant IVDs (adjacent: 0.9% [99% CI: 0.3; 1.5], distant: 2.1% [99% CI: 1.7; 2.5]). Advanced GAG depletion in nsLBP and directly adjacent to IVD extrusions in radiculopathy indicates close interrelatedness of clinical pathology and compositional degeneration.
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Affiliation(s)
- Miriam Frenken
- Department of Diagnostic and Interventional Radiology, Medical Faculty, University Dusseldorf, D-40225 Dusseldorf, Germany; (M.F.); (S.N.); (C.S.); (A.M.-L.); (K.L.R.); (B.K.); (M.B.); (G.A.)
| | - Sven Nebelung
- Department of Diagnostic and Interventional Radiology, Medical Faculty, University Dusseldorf, D-40225 Dusseldorf, Germany; (M.F.); (S.N.); (C.S.); (A.M.-L.); (K.L.R.); (B.K.); (M.B.); (G.A.)
| | - Christoph Schleich
- Department of Diagnostic and Interventional Radiology, Medical Faculty, University Dusseldorf, D-40225 Dusseldorf, Germany; (M.F.); (S.N.); (C.S.); (A.M.-L.); (K.L.R.); (B.K.); (M.B.); (G.A.)
| | - Anja Müller-Lutz
- Department of Diagnostic and Interventional Radiology, Medical Faculty, University Dusseldorf, D-40225 Dusseldorf, Germany; (M.F.); (S.N.); (C.S.); (A.M.-L.); (K.L.R.); (B.K.); (M.B.); (G.A.)
| | - Karl Ludger Radke
- Department of Diagnostic and Interventional Radiology, Medical Faculty, University Dusseldorf, D-40225 Dusseldorf, Germany; (M.F.); (S.N.); (C.S.); (A.M.-L.); (K.L.R.); (B.K.); (M.B.); (G.A.)
| | - Benedikt Kamp
- Department of Diagnostic and Interventional Radiology, Medical Faculty, University Dusseldorf, D-40225 Dusseldorf, Germany; (M.F.); (S.N.); (C.S.); (A.M.-L.); (K.L.R.); (B.K.); (M.B.); (G.A.)
| | - Matthias Boschheidgen
- Department of Diagnostic and Interventional Radiology, Medical Faculty, University Dusseldorf, D-40225 Dusseldorf, Germany; (M.F.); (S.N.); (C.S.); (A.M.-L.); (K.L.R.); (B.K.); (M.B.); (G.A.)
| | - Lena Wollschläger
- Department of Orthopedic and Trauma Surgery, University Hospital of Duesseldorf, D-40225 Duesseldorf, Germany; (L.W.); (B.B.); (M.R.K.)
| | - Bernd Bittersohl
- Department of Orthopedic and Trauma Surgery, University Hospital of Duesseldorf, D-40225 Duesseldorf, Germany; (L.W.); (B.B.); (M.R.K.)
| | - Gerald Antoch
- Department of Diagnostic and Interventional Radiology, Medical Faculty, University Dusseldorf, D-40225 Dusseldorf, Germany; (M.F.); (S.N.); (C.S.); (A.M.-L.); (K.L.R.); (B.K.); (M.B.); (G.A.)
| | - Markus R. Konieczny
- Department of Orthopedic and Trauma Surgery, University Hospital of Duesseldorf, D-40225 Duesseldorf, Germany; (L.W.); (B.B.); (M.R.K.)
| | - Daniel B. Abrar
- Department of Diagnostic and Interventional Radiology, Medical Faculty, University Dusseldorf, D-40225 Dusseldorf, Germany; (M.F.); (S.N.); (C.S.); (A.M.-L.); (K.L.R.); (B.K.); (M.B.); (G.A.)
- Correspondence:
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11
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Liu R, Zhang H, Qian Y, Hsu YC, Fu C, Sun Y, Wu D, Zhang Y. Frequency-stabilized chemical exchange saturation transfer imaging with real-time free-induction-decay readout. Magn Reson Med 2020; 85:1322-1334. [PMID: 32970882 DOI: 10.1002/mrm.28513] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2020] [Revised: 08/17/2020] [Accepted: 08/17/2020] [Indexed: 01/19/2023]
Abstract
PURPOSE To correct the temporal B0 drift in chemical exchange saturation transfer (CEST) imaging in real-time with extra free-induction-decay (FID) readout. THEORY AND METHODS The frequency stabilization module of the recently proposed frequency-stabilized CEST (FS-CEST) sequence was further simplified by replacing the original three k-space lines of gradient-echo (GRE) readout with a single k-space line of FID readout. The B0 drift was quantified using the phase difference between the odd and even parts of the FID signal in the frequency stabilization module and then used to update the B0 frequency in the succeeding modules. The proposed FS-CEST sequence with FID readout (FID FS-CEST) was validated in phantoms and 16 human subjects on cross-vendor scanners. RESULTS In the Siemens experiments, the FID FS-CEST sequence successfully corrected the user-induced B0 drift, generating consistent amide proton transfer-weighted (APTw) images and magnetization transfer ratio asymmetry (MTRasym ) spectra with those from the non-frequency-stabilized CEST (NFS-CEST) sequence without B0 drift. In the Philips experiments, the FID FS-CEST sequence produced more stable APTw images and MTRasym spectra than the NFS-CEST sequence in the presence of practical B0 drift. Quantitatively, the SD of the APTw signal values in the deep gray matter from 15 subjects was 0.26% for the FID FS-CEST sequence compared to 1.03% for the NFS-CEST sequences, with the fluctuations reduced by nearly three-quarters. CONCLUSIONS The proposed FS-CEST sequence with FID readout can effectively correct the temporal B0 drift on cross-vendor scanners.
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Affiliation(s)
- Ruibin Liu
- Key Laboratory for Biomedical Engineering of Ministry of Education, Department of Biomedical Engineering, College of Biomedical Engineering & Instrument Science, Zhejiang University, Hangzhou, Zhejiang, China
| | - Hongxi Zhang
- Department of Radiology, Children's Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China
| | - Yue Qian
- Department of Radiology, Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China
| | - Yi-Cheng Hsu
- MR Collaboration, Siemens Healthcare Ltd., Shanghai, China
| | - Caixia Fu
- Siemens Shenzhen Magnetic Resonance Ltd., Shenzhen, China
| | - Yi Sun
- MR Collaboration, Siemens Healthcare Ltd., Shanghai, China
| | - Dan Wu
- Key Laboratory for Biomedical Engineering of Ministry of Education, Department of Biomedical Engineering, College of Biomedical Engineering & Instrument Science, Zhejiang University, Hangzhou, Zhejiang, China
| | - Yi Zhang
- Key Laboratory for Biomedical Engineering of Ministry of Education, Department of Biomedical Engineering, College of Biomedical Engineering & Instrument Science, Zhejiang University, Hangzhou, Zhejiang, China
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12
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Liver MRI with amide proton transfer imaging: feasibility and accuracy for the characterization of focal liver lesions. Eur Radiol 2020; 31:222-231. [PMID: 32785767 DOI: 10.1007/s00330-020-07122-y] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2020] [Revised: 05/28/2020] [Accepted: 07/29/2020] [Indexed: 12/21/2022]
Abstract
OBJECTIVE To investigate the feasibility of using amide proton transfer (APT) magnetic resonance imaging (MRI) in the liver and to evaluate its ability to characterize focal liver lesions (FLLs). METHODS A total of 203 patients with suspected FLLs who underwent APT imaging at 3T were included. APT imaging was obtained using a single-slice turbo spin-echo sequence to include FLLs through five breath-holds, and its acquisition time was approximately 1 min. APT signals in the background liver and FLL were measured with magnetization transfer ratio asymmetry (MTRasym) at 3.5 ppm. The technical success rate of APT imaging and the reasons for failure to obtain meaningful MTRasym values were assessed. The Mann Whitney U test was used to compare MTRasym values between different FLLs. RESULTS The technical success rate of APT imaging in the liver was 62.1% (126/203). The reasons for failure were a too large B0 inhomogeneity (n = 43), significant respiratory motion (n = 12), and these two factors together (n = 22), respectively. Among 59 FLLs with analyzable APT images, MTRasym values were compared between 27 patients with liver metastases and 23 patients with hepatocellular carcinomas (HCCs). The MTRasym values of metastases were significantly higher than those of HCC (0.13 ± 2.15% vs. - 1.41 ± 3.68%, p = 0.027). CONCLUSIONS APT imaging could be an imaging biomarker for the differentiation of FLLs. However, further technical improvement is required before APT imaging can be clinically applied to liver MRI. KEY POINTS • Liver APT imaging was technically feasible, but with a relatively low success rate (62.1%). • Liver metastases showed higher APT values than hepatocellular carcinomas.
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13
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Sun PZ. Fast correction of B 0 field inhomogeneity for pH-specific magnetization transfer and relaxation normalized amide proton transfer imaging of acute ischemic stroke without Z-spectrum. Magn Reson Med 2019; 83:1688-1697. [PMID: 31631414 DOI: 10.1002/mrm.28040] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2019] [Revised: 09/17/2019] [Accepted: 09/23/2019] [Indexed: 01/04/2023]
Abstract
PURPOSE The magnetization transfer and relaxation normalized amide proton transfer (MRAPT) analysis is promising to provide a highly pH-specific mapping of tissue acidosis, complementing commonly used CEST asymmetry analysis. We aimed to develop a fast B0 inhomogeneity correction algorithm for acute stroke magnetization transfer and relaxation normalized amide proton transfer imaging without Z-spectral interpolation. METHODS The proposed fast field inhomogeneity correction describes B0 artifacts with linear regression. We compared the new algorithm with the routine interpolation correction approach in CEST imaging of a dual-pH phantom. The fast B0 correction was further evaluated in amide proton transfer imaging of normal and acute stroke rats. RESULTS Our phantom data showed that the proposed fast B0 inhomogeneity correction significantly improved pH MRI contrast, recovering over 80% of the pH MRI contrast-to-noise-ratio difference between the raw magnetization transfer ratio asymmetry and that using the routine interpolation-based B0 correction approach. In normal rat brains, the proposed fast B0 correction improved pH-specific MRI uniformity across the intact tissue, with the ratio of magnetization transfer and relaxation normalized amide proton transfer ratio being 10% of that without B0 inhomogeneity correction. In acute stroke rats, fast B0 inhomogeneity-corrected pH MRI reveals substantially improved pH lesion conspicuity, particularly in regions with nonnegligible B0 inhomogeneity. The pH MRI contrast-to-noise ratio between the ipsilateral diffusion lesion and contralateral normal tissue improved significantly with fast B0 correction (from 1.88 ± 0.48 to 2.20 ± 0.44, P < .01). CONCLUSIONS Our study established an expedient B0 inhomogeneity correction algorithm for fast pH imaging of acute ischemia.
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Affiliation(s)
- Phillip Zhe Sun
- Department of Radiology, Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts.,Yerkes Imaging Center, Yerkes National Primate Research Center, Emory University, Atlanta, Georgia.,Department of Radiology and Imaging Sciences, Emory University School of Medicine, Atlanta, Georgia
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14
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Sun PZ. Development of intravoxel inhomogeneity correction for chemical exchange saturation transfer spectral imaging: a high-resolution field map-based deconvolution algorithm for magnetic field inhomogeneity correction. Magn Reson Med 2019; 83:1348-1355. [PMID: 31628765 DOI: 10.1002/mrm.28015] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2019] [Revised: 09/04/2019] [Accepted: 09/05/2019] [Indexed: 12/12/2022]
Abstract
PURPOSE CEST MRI is sensitive to dilute proteins/peptides and microenvironmental properties yet susceptible to magnetic field inhomogeneity. We aimed to develop a high-resolution field map-based CEST intravoxel inhomogeneity correction (CIVIC) algorithm for CEST Z-spectral imaging. METHODS The proposed CIVIC approach treats the intravoxel inhomogeneity as a point spread function and applies the deconvolution algorithm to reconstruct the original Z-spectrum. We simulated the effect of B0 field inhomogeneity on CEST measurement and tested the efficacy of the proposed CIVIC algorithm. We also performed CEST MRI on a dual-pH Creatine-gel phantom under varied field homogeneity conditions and compared the CEST MRI contrast-to-noise ratio from the raw Z-spectrum, water saturation shift referencing, and the proposed CIVIC methods. RESULTS The numerical simulation showed that the CIVIC algorithm remains effective even in the case of symmetric field dispersion with a 0 mean shift. The experimental results confirmed that the proposed CIVIC method substantially improves the CEST MRI contrast-to-noise ratio under different field homogeneity conditions. CONCLUSION Our study established a new intravoxel B0 inhomogeneity correction algorithm, promising to facilitate CEST spectral imaging in challenging experimental conditions.
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Affiliation(s)
- Phillip Zhe Sun
- Yerkes Imaging Center, Yerkes National Primate Research Center, Emory University, Atlanta, Georgia.,Department of Radiology and Imaging Sciences, Emory University School of Medicine, Atlanta, Georgia
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15
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Martín Noguerol T, Raya JG, Wessell DE, Vilanova JC, Rossi I, Luna A. Functional MRI for evaluation of hyaline cartilage extracelullar matrix, a physiopathological-based approach. Br J Radiol 2019; 92:20190443. [PMID: 31433668 DOI: 10.1259/bjr.20190443] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
MRI of articular cartilage (AC) integrity has potential to become a biomarker for osteoarthritis progression. Traditional MRI sequences evaluate AC morphology, allowing for the measurement of thickness and its change over time. In the last two decades, more advanced, dedicated MRI cartilage sequences have been developed aiming to assess AC matrix composition non-invasively and detect early changes in cartilage not captured on morphological sequences. T2-mapping and T1ρ sequences can be used to estimate the relaxation times of water inside the AC. These sequences have been introduced into clinical protocols and show promising results for cartilage assessment. Extracelullar matrix can also be assessed using diffusion-weighted imaging and diffusion tensor imaging as the movement of water is limited by the presence of extracellular matrix in AC. Specific techniques for glycosaminoglycans (GAG) evaluation, such as delayed gadolinium enhanced MRI of cartilage or Chemical Exchange Saturation Transfer imaging of GAG, as well as sodium imaging have also shown utility in the detection of AC damage. This manuscript provides an educational update on the physical principles behind advanced AC MRI techniques as well as a comprehensive review of the strengths and weaknesses of each approach. Current clinical applications and potential future applications of these techniques are also discussed.
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Affiliation(s)
| | - Jose G Raya
- Department of Radiology, NYU School of Medicine, NY, USA
| | | | - Joan C Vilanova
- Department of Radiology, Clínica Girona. Institute Diagnostic Imaging (IDI), University of Girona, Girona, Spain
| | | | - Antonio Luna
- MRI unit, Radiology department, Health Time, Jaén, Spain
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16
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Poblador Rodriguez E, Moser P, Dymerska B, Robinson S, Schmitt B, van der Kouwe A, Gruber S, Trattnig S, Bogner W. A comparison of static and dynamic ∆B 0 mapping methods for correction of CEST MRI in the presence of temporal B 0 field variations. Magn Reson Med 2019; 82:633-646. [PMID: 30924210 PMCID: PMC6563466 DOI: 10.1002/mrm.27750] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2019] [Revised: 03/02/2019] [Accepted: 03/04/2019] [Indexed: 12/18/2022]
Abstract
PURPOSE To assess the performance, in the presence of scanner instabilities, of three dynamic correction methods which integrate ∆B0 mapping into the chemical exchange saturation transfer (CEST) measurement and three established static ∆B0 -correction approaches. METHODS A homogeneous phantom and five healthy volunteers were scanned with a CEST sequence at 7 T. The in vivo measurements were performed twice: first with unaltered system frequency and again applying frequency shifts during the CEST acquisition. In all cases, retrospective voxel-wise ∆B0 -correction was performed using one intrinsic and two extrinsic [prescans with dual-echo gradient-echo and water saturation shift referencing (WASSR)] static approaches. These were compared with two intrinsic [using phase data directly generated by single-echo or double-echo GRE (gradient-echo) CEST readout (CEST-GRE-2TE)] and one extrinsic [phase from interleaved dual-echo EPI (echo planar imaging) navigator (NAV-EPI-2TE)] dynamic ∆B0 -correction approaches [allowing correction of each Z-spectral point before magnetization transfer ratio asymmetry (MTRasym) analysis]. RESULTS All three dynamic methods successfully mapped the induced drift. The intrinsic approaches were affected by the CEST labeling near water (∆ω < |0.3| ppm). The MTRasym contrast was distorted by the frequency drift in the brain by up to 0.21%/Hz when static ∆B0 -corrections were applied, whereas the dynamic ∆B0 corrections reduced this to <0.01%/Hz without the need of external scans. The CEST-GRE-2TE and NAV-EPI-2TE resulted in highly consistent MTRasym values with/without drift for all subjects. CONCLUSION Reliable correction of scanner instabilities is essential to establish clinical CEST MRI. The three dynamic approaches presented improved the ∆B0 -correction performance significantly in the presence of frequency drift compared to established static methods. Among them, the self-corrected CEST-GRE-2TE was the most accurate and straightforward to implement.
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Affiliation(s)
- Esau Poblador Rodriguez
- High Field MR Center, Department of Biomedical Imaging and Image-Guided Therapy, Medical University Vienna, Vienna, Austria
| | - Philipp Moser
- High Field MR Center, Department of Biomedical Imaging and Image-Guided Therapy, Medical University Vienna, Vienna, Austria
| | - Barbara Dymerska
- Medical Physics and Bioengineering, University College London, London, United Kingdom
| | - Simon Robinson
- High Field MR Center, Department of Biomedical Imaging and Image-Guided Therapy, Medical University Vienna, Vienna, Austria
| | | | - Andre van der Kouwe
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts
| | - Stephan Gruber
- High Field MR Center, Department of Biomedical Imaging and Image-Guided Therapy, Medical University Vienna, Vienna, Austria
| | - Siegfried Trattnig
- High Field MR Center, Department of Biomedical Imaging and Image-Guided Therapy, Medical University Vienna, Vienna, Austria.,Christian Doppler Laboratory for Clinical Molecular MR Imaging, Vienna, Austria
| | - Wolfgang Bogner
- High Field MR Center, Department of Biomedical Imaging and Image-Guided Therapy, Medical University Vienna, Vienna, Austria
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17
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Zhou J, Heo HY, Knutsson L, van Zijl PCM, Jiang S. APT-weighted MRI: Techniques, current neuro applications, and challenging issues. J Magn Reson Imaging 2019; 50:347-364. [PMID: 30663162 DOI: 10.1002/jmri.26645] [Citation(s) in RCA: 217] [Impact Index Per Article: 43.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2018] [Revised: 12/26/2018] [Accepted: 12/27/2018] [Indexed: 02/06/2023] Open
Abstract
Amide proton transfer-weighted (APTw) imaging is a molecular MRI technique that generates image contrast based predominantly on the amide protons in mobile cellular proteins and peptides that are endogenous in tissue. This technique, the most studied type of chemical exchange saturation transfer imaging, has been used successfully for imaging of protein content and pH, the latter being possible due to the strong dependence of the amide proton exchange rate on pH. In this article we briefly review the basic principles and recent technical advances of APTw imaging, which is showing promise clinically, especially for characterizing brain tumors and distinguishing recurrent tumor from treatment effects. Early applications of this approach to stroke, Alzheimer's disease, Parkinson's disease, multiple sclerosis, and traumatic brain injury are also illustrated. Finally, we outline the technical challenges for clinical APT-based imaging and discuss several controversies regarding the origin of APTw imaging signals in vivo. Level of Evidence: 3 Technical Efficacy Stage: 3 J. Magn. Reson. Imaging 2019;50:347-364.
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Affiliation(s)
- Jinyuan Zhou
- Division of MR Research, Department of Radiology, Johns Hopkins University, Baltimore, Maryland, USA.,F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, Maryland, USA
| | - Hye-Young Heo
- Division of MR Research, Department of Radiology, Johns Hopkins University, Baltimore, Maryland, USA.,F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, Maryland, USA
| | - Linda Knutsson
- Division of MR Research, Department of Radiology, Johns Hopkins University, Baltimore, Maryland, USA.,Department of Medical Radiation Physics, Lund University, Lund, Sweden
| | - Peter C M van Zijl
- Division of MR Research, Department of Radiology, Johns Hopkins University, Baltimore, Maryland, USA.,F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, Maryland, USA
| | - Shanshan Jiang
- Division of MR Research, Department of Radiology, Johns Hopkins University, Baltimore, Maryland, USA.,F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, Maryland, USA
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18
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Windschuh J, Zaiss M, Ehses P, Lee JS, Jerschow A, Regatte RR. Assessment of frequency drift on CEST MRI and dynamic correction: application to gagCEST at 7 T. Magn Reson Med 2019; 81:573-582. [PMID: 29851141 PMCID: PMC6258338 DOI: 10.1002/mrm.27367] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2018] [Revised: 04/26/2018] [Accepted: 04/26/2018] [Indexed: 02/02/2023]
Abstract
PURPOSE To investigate the effect of a frequency drift of the static magnetic field on 3D CEST MRI based on glycosaminoglycans (GAGs) of articular cartilage at 7 T and to introduce a retrospective correction method that uses the phase images of the gradient-echo readout. METHODS Repeated gagCEST and B0 measurements were performed in a glucose model solution and in vivo in the knee joint of 3 healthy volunteers at 7 T. Phase images of the modified 3D rectangular spiral centric-reordered gradient-echo CEST sequence were used to quantify and compensate the apparent frequency drift in repeated gagCEST measurements. RESULTS The frequency drift of the MRI scanner strongly influences the gagCEST signal in the articular cartilage of the human knee joint. The gagCEST signal in the articular cartilage is changed by 0.18%/Hz while an average drift of 0.7 ± 0.2 Hz/minute was observed. The proposed correction method can be applied retrospectively without the need of additional measurements and provides improved comparability and reproducibility for gagCEST studies. This correction method may also be of interest for other applications of CEST MRI. CONCLUSION Prospective or retrospective correction of the frequency drift of the MRI scanner is essential for reproducible gagCEST measurements. The proposed retrospective correction method fulfills this requirement without the need of additional measurements.
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Affiliation(s)
- Johannes Windschuh
- New York University Langone Medical Center, Department of Radiology, Center for Biomedical Imaging, 660 First Avenue, New York, NY 10013, USA
| | - Moritz Zaiss
- Max Planck Institute for Biological Cybernetics, High-field Magnetic Resonance Center, Spemannstr. 41, 72076 Tübingen, Germany
| | - Philipp Ehses
- German Center for Neurodegenerative Diseases, Department of MR Physics, Sigmund-Freud-Str. 27, 53127 Bonn, Germany
| | - Jae-Seung Lee
- New York University Langone Medical Center, Department of Radiology, Center for Biomedical Imaging, 660 First Avenue, New York, NY 10013, USA
- New York University, Department of Chemistry, 100 Washington Square East, New York, NY 10003, USA
| | - Alexej Jerschow
- New York University, Department of Chemistry, 100 Washington Square East, New York, NY 10003, USA
| | - Ravinder R Regatte
- New York University Langone Medical Center, Department of Radiology, Center for Biomedical Imaging, 660 First Avenue, New York, NY 10013, USA
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19
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Ladd ME, Bachert P, Meyerspeer M, Moser E, Nagel AM, Norris DG, Schmitter S, Speck O, Straub S, Zaiss M. Pros and cons of ultra-high-field MRI/MRS for human application. PROGRESS IN NUCLEAR MAGNETIC RESONANCE SPECTROSCOPY 2018; 109:1-50. [PMID: 30527132 DOI: 10.1016/j.pnmrs.2018.06.001] [Citation(s) in RCA: 267] [Impact Index Per Article: 44.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/06/2018] [Revised: 06/06/2018] [Accepted: 06/07/2018] [Indexed: 05/08/2023]
Abstract
Magnetic resonance imaging and spectroscopic techniques are widely used in humans both for clinical diagnostic applications and in basic research areas such as cognitive neuroimaging. In recent years, new human MR systems have become available operating at static magnetic fields of 7 T or higher (≥300 MHz proton frequency). Imaging human-sized objects at such high frequencies presents several challenges including non-uniform radiofrequency fields, enhanced susceptibility artifacts, and higher radiofrequency energy deposition in the tissue. On the other side of the scale are gains in signal-to-noise or contrast-to-noise ratio that allow finer structures to be visualized and smaller physiological effects to be detected. This review presents an overview of some of the latest methodological developments in human ultra-high field MRI/MRS as well as associated clinical and scientific applications. Emphasis is given to techniques that particularly benefit from the changing physical characteristics at high magnetic fields, including susceptibility-weighted imaging and phase-contrast techniques, imaging with X-nuclei, MR spectroscopy, CEST imaging, as well as functional MRI. In addition, more general methodological developments such as parallel transmission and motion correction will be discussed that are required to leverage the full potential of higher magnetic fields, and an overview of relevant physiological considerations of human high magnetic field exposure is provided.
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Affiliation(s)
- Mark E Ladd
- Medical Physics in Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany; Faculty of Medicine, University of Heidelberg, Heidelberg, Germany; Faculty of Physics and Astronomy, University of Heidelberg, Heidelberg, Germany; Erwin L. Hahn Institute for MRI, University of Duisburg-Essen, Essen, Germany.
| | - Peter Bachert
- Medical Physics in Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany; Faculty of Physics and Astronomy, University of Heidelberg, Heidelberg, Germany.
| | - Martin Meyerspeer
- Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna, Austria; MR Center of Excellence, Medical University of Vienna, Vienna, Austria.
| | - Ewald Moser
- Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna, Austria; MR Center of Excellence, Medical University of Vienna, Vienna, Austria.
| | - Armin M Nagel
- Medical Physics in Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany; Institute of Radiology, University Hospital Erlangen, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Erlangen, Germany.
| | - David G Norris
- Donders Institute for Brain, Cognition and Behaviour, Radboud University Nijmegen, Nijmegen, Netherlands; Erwin L. Hahn Institute for MRI, University of Duisburg-Essen, Essen, Germany.
| | - Sebastian Schmitter
- Medical Physics in Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany; Physikalisch-Technische Bundesanstalt (PTB), Braunschweig and Berlin, Germany.
| | - Oliver Speck
- Department of Biomedical Magnetic Resonance, Otto-von-Guericke-University Magdeburg, Magdeburg, Germany; German Center for Neurodegenerative Diseases, Magdeburg, Germany; Center for Behavioural Brain Sciences, Magdeburg, Germany; Leibniz Institute for Neurobiology, Magdeburg, Germany.
| | - Sina Straub
- Medical Physics in Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany.
| | - Moritz Zaiss
- High-Field Magnetic Resonance Center, Max-Planck-Institute for Biological Cybernetics, Tübingen, Germany.
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Comparison of B0 versus B0 and B1 field inhomogeneity correction for glycosaminoglycan chemical exchange saturation transfer imaging. MAGNETIC RESONANCE MATERIALS IN PHYSICS BIOLOGY AND MEDICINE 2018; 31:645-651. [DOI: 10.1007/s10334-018-0689-5] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/05/2018] [Revised: 04/26/2018] [Accepted: 05/03/2018] [Indexed: 10/16/2022]
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Togao O, Hiwatashi A, Wada T, Yamashita K, Kikuchi K, Tokunaga C, Keupp J, Yoneyama M, Honda H. A Qualitative and Quantitative Correlation Study of Lumbar Intervertebral Disc Degeneration Using Glycosaminoglycan Chemical Exchange Saturation Transfer, Pfirrmann Grade, and T1-ρ. AJNR Am J Neuroradiol 2018; 39:1369-1375. [PMID: 29748204 DOI: 10.3174/ajnr.a5657] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/01/2018] [Accepted: 03/09/2018] [Indexed: 11/07/2022]
Abstract
BACKGROUND AND PURPOSE Glycosaminoglycan chemical exchange saturation transfer (gagCEST) imaging allows the direct measurement and mapping of glycosaminoglycans. In this study, we aimed to evaluate the usefulness of gagCEST imaging in the quantitative assessment of intervertebral disc degeneration in a comparison with Pfirrmann grade and T1-ρ measurements. MATERIALS AND METHODS Ninety-six lumbar intervertebral discs in 24 volunteers (36.0 ± 8.5 years of age, 21 men and 3 women) were examined with both gagCEST imaging and T1-ρ measurements. The gagCEST imaging was performed at 3T with a saturation pulse with 1.0-second duration and the B1 amplitude of 0.8 μT followed by imaging by a 2D fast spin-echo sequence. The Z-spectra were obtained at 25 frequency offsets from -3 to +3 ppm (step, 0.25 ppm). A point-by-point B0 correction was performed with a B0 map. The gagCEST signal and T1-ρ values were measured in the nucleus pulposus in each intervertebral disc. The Pfirrmann grades were assessed on T2-weighted images. RESULTS The gagCEST signal at grade I (5.36% ± 2.79%) was significantly higher than those at Pfirrmann grade II (3.15% ± 1.40%, P = .0006), grade III (0.14% ± 1.03%, P < .0001), grade IV (-1.75% ± 2.82%, P < .0001), and grade V (-1.47% ± 0.36%, P < .0001). The gagCEST signal at grade II was significantly higher than those of grade III (P < .0001), grade IV (P < .0001), and grade V (P < .0001). The gagCEST signal was significantly correlated negatively with Pfirrmann grade (P < .0001) and positively correlated with T1-ρ (P < .0001). CONCLUSIONS GagCEST imaging could be a reliable and quantitative technique for assessing intervertebral disc degeneration.
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Affiliation(s)
- O Togao
- From the Department of Clinical Radiology (O.T., A.H., K.Y., K.K., H.H.), Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan
| | - A Hiwatashi
- From the Department of Clinical Radiology (O.T., A.H., K.Y., K.K., H.H.), Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan
| | - T Wada
- Division of Radiology (T.W., C.T.), Department of Medical Technology, Kyushu University Hospital, Fukuoka, Japan
| | - K Yamashita
- From the Department of Clinical Radiology (O.T., A.H., K.Y., K.K., H.H.), Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan
| | - K Kikuchi
- From the Department of Clinical Radiology (O.T., A.H., K.Y., K.K., H.H.), Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan
| | - C Tokunaga
- Division of Radiology (T.W., C.T.), Department of Medical Technology, Kyushu University Hospital, Fukuoka, Japan
| | - J Keupp
- Philips Research (J.K.), Hamburg, Germany
| | | | - H Honda
- From the Department of Clinical Radiology (O.T., A.H., K.Y., K.K., H.H.), Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan
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22
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Wei W, Lambach B, Jia G, Kaeding C, Flanigan D, Knopp MV. A Phase I clinical trial of the knee to assess the correlation of gagCEST MRI, delayed gadolinium-enhanced MRI of cartilage and T2 mapping. Eur J Radiol 2017; 90:220-224. [PMID: 28583638 DOI: 10.1016/j.ejrad.2017.02.030] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2016] [Revised: 02/14/2017] [Accepted: 02/18/2017] [Indexed: 01/08/2023]
Abstract
PURPOSE Osteoarthritis (OA) is associated with the loss of glycosaminoglycan (GAG) during disease progression, which can be detected by glycosaminoglycan chemical exchange-dependent saturation transfer (gagCEST) MRI. Delayed gadolinium-enhanced MRI of cartilage (dGEMRIC) is considered one of the standard methods for GAG quantification in vivo. This Phase I study assessed the correlation between gagCEST MRI and dGEMRIC in determining cartilage GAG concentration. Standard T2 mapping was used as a comparator with the two other methods. MATERIALS AND METHODS Eight athletic volunteers with no known knee diseases were recruited in this study. The sagittal images of both knees in each volunteer were obtained by a 3T MRI system. GAG concentration was calculated based on fixed charge density (FCD) within articular cartilage as calculated by T1 values obtained from dGEMRIC sequences. Magnetization transfer ratio asymmetry (MTRasym) of the CEST spectrum at 1ppm was determined with gagCEST MRI. T2 values were calculated using a multi-echo turbo spin echo (TSE) sequence. The Pearson correlations among MTRasym were calculated from gagCEST analysis. RESULTS There was moderate correlation (correlation coefficient r=0.55) between dGEMRIC and gagCEST MRI results. T2 had a low correlation (r=-0.30) with gagCEST and no correlation with dGEMRIC (r=0.003). Both gagCEST and dGEMRIC were able to distinguish between high GAG concentration cartilage compartments (higher than 210mM) and low GAG cartilage compartments (lower than 210mM). CONCLUSION dGEMRIC was shown to be a more accurate and sensitive clinical imaging tool in evaluating cartilage GAG levels in vivo. While GagCEST showed less sensitivity to GAG concentration variations than dGEMRIC, further improvements may yet enable gagCEST to be a clinically robust methodology.
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Affiliation(s)
- Wenbo Wei
- Wright Center of Innovation in Biomedical Imaging and Department of Radiology, The Ohio State University, Columbus, OH, United States
| | - Becky Lambach
- Department of Mechanical and Aerospace Engineering, The Ohio State University, Columbus, OH, United States
| | - Guang Jia
- Department of Physics and Astronomy, Louisiana State University, Baton Rouge, LA, United States
| | - Christopher Kaeding
- Department of Orthopedics, The Ohio State University, Columbus, OH, United States
| | - David Flanigan
- Department of Orthopedics, The Ohio State University, Columbus, OH, United States
| | - Michael V Knopp
- Wright Center of Innovation in Biomedical Imaging and Department of Radiology, The Ohio State University, Columbus, OH, United States.
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Russell C, Pedoia V, Majumdar S. Composite metric R 2 - R 1ρ (1/T 2 - 1/T 1ρ ) as a potential MR imaging biomarker associated with changes in pain after ACL reconstruction: A six-month follow-up. J Orthop Res 2017; 35:718-729. [PMID: 27563836 PMCID: PMC7021321 DOI: 10.1002/jor.23400] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/04/2016] [Accepted: 08/25/2016] [Indexed: 02/04/2023]
Abstract
This study looked to investigate a new quantitative metric, R2 - R1ρ (1/T2 - 1/T1ρ ), using magnetic resonance (MR) images and voxel-based relaxometry (VBR) for detecting early cartilage degeneration and explore the association with patient-reported outcomes measures (PROMs) in patients 6 months after ACL reconstruction. Sixty-four patients from three sites were bilaterally scanned on a 3T MR with a combined T1ρ /T2 protocol to calculate R1ρ (1/T1ρ ) and R2 (1/T2 ) values at baseline and 6 months after reconstructive surgery. Non-rigid registration was applied to align images onto a template, allowing VBR to determine VBR rate differences and explore cross-sectional and longitudinal differences between injured and uninjured knees, generating Statistical Parametric Maps (SPMs). Baseline R2 - R1ρ differences were further correlated with change in PROMs from the Knee Injury and Osteoarthritis Outcome Score (KOOS) from baseline to 6 months. Cross-sectional results demonstrated low relaxation rate differences in the injured patella (baseline: 21%, p = 0.01; 6-months: 18%, p = 0.02), lateral tibia (baseline: 25%, p = 0.01; 6-months: 24%, p = 0.01), and weight-bearing regions of the tibia and femur. The uninjured patella showed significant longitudinal changes (17%, p = 0.02). R2 - R1ρ differences showed significant correlations with KOOS PROMs, particularly in the lateral tibia, patella, and trochlea. R2 - R1ρ difference VBR analyses provide new and highly sensitive parameters for assessing early cartilage degeneration in patients after ACL injury by integrating findings from both T1ρ and T2 , commonly used relaxation time parameters, into a single metric. © 2016 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 35:718-729, 2017.
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Affiliation(s)
- Colin Russell
- Musculoskeletal Quantitative Imaging Research Group, Department of Radiology and Biomedical Imaging; University of California; San Francisco California
| | - Valentina Pedoia
- Musculoskeletal Quantitative Imaging Research Group, Department of Radiology and Biomedical Imaging; University of California; San Francisco California
| | - Sharmila Majumdar
- Musculoskeletal Quantitative Imaging Research Group, Department of Radiology and Biomedical Imaging; University of California; San Francisco California
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A narrative overview of the current status of MRI of the hip and its relevance for osteoarthritis research - what we know, what has changed and where are we going? Osteoarthritis Cartilage 2017; 25:1-13. [PMID: 27621214 DOI: 10.1016/j.joca.2016.08.015] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/24/2016] [Revised: 08/24/2016] [Accepted: 08/28/2016] [Indexed: 02/02/2023]
Abstract
OBJECTIVE To review and discuss the role of magnetic resonance imaging (MRI) in the context of hip osteoarthritis (OA) research. DESIGN The content of this narrative review, based on an extensive PubMed database research including English literature only, describes the advances in MRI of the hip joint and its potential usefulness in hip OA research, reviews the relevance of different MRI features in regard to symptomatic and structural progression in hip OA, and gives an outlook regarding future use of MRI in hip OA research endeavors. RESULTS Recent technical advances have helped to overcome many of the past difficulties related to MRI assessment of hip OA. MRI-based morphologic scoring systems allow for detailed assessment of several hip joint tissues and, in combination with the recent advances in MRI, may increase reproducibility and sensitivity to change. Compositional MRI techniques may add to our understanding of disease onset and progression. Knowledge about imaging pitfalls and anatomical variants is crucial to avoid misinterpretation. In comparison to research on knee OA, the associations between MRI features and the incidence and progression of disease as well as with clinical symptoms have been little explored. Anatomic alterations of the hip joint as seen in femoro-acetabular impingement (FAI) seem to play a role in the onset and progression of structural damage. CONCLUSIONS With the technical advances occurring in recent years, MRI may play a major role in investigating the natural history of hip OA and provide an improved method for assessment of the efficacy of new therapeutic approaches.
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Investigation of the performance of variable-density Z-spectrum acquisition scheme in MR chemical exchange saturation transfer effect quantification. ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. ANNUAL INTERNATIONAL CONFERENCE 2016; 2015:7929-32. [PMID: 26738131 DOI: 10.1109/embc.2015.7320231] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Chemical exchange saturation transfer (CEST) MRI emerges as a powerful imaging method to probe chemical exchange between bulk water and labile protons. Conventional CEST imaging needs detailed Z-spectrum acquisition, even at frequencies with limited information for CEST parameter quantification, which harms imaging efficiency and is not favorable in practical applications. In this study, a variable-density Z-spectrum acquisition scheme was proposed. Data with saturation frequencies close to water, labile protons and their negative frequency offset was densely sampled, while the remaining part was sparsely acquired. The accuracy of the proposed method in CEST ratio measurement was investigated with numerical simulation. Compared to the conventionally evenly distributed Z-spectrum acquisition method, the proposed scheme showed significant improvement of CEST ratio characterization with existence of noise and static magnetic field inhomogeneity. With the additional advantage of easy implementation, the developed Z-spectrum acquisition scheme provides a useful framework for accurate CEST parameter quantification without compromising the imaging time.
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Wada T, Togao O, Tokunaga C, Funatsu R, Yamashita Y, Kobayashi K, Nakamura Y, Honda H. Glycosaminoglycan chemical exchange saturation transfer in human lumbar intervertebral discs: Effect of saturation pulse and relationship with low back pain. J Magn Reson Imaging 2016; 45:863-871. [PMID: 27439061 DOI: 10.1002/jmri.25397] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2015] [Accepted: 07/05/2016] [Indexed: 12/27/2022] Open
Abstract
PURPOSE To evaluate the dependence of saturation pulse power and duration on glycosaminoglycan chemical exchange saturation transfer (gagCEST) imaging and assess the degeneration of human lumbar intervertebral discs (IVDs) using this method. MATERIALS AND METHODS All images were acquired on a 3T magnetic resonance imaging (MRI) scanner. The CEST effects were measured in the glycosaminoglycan (GAG) phantoms with different concentrations. In the human study, CEST effects were measured in the nucleus pulposus of IVD. We compared the CEST effects among the different saturation pulse powers (0.4, 0.8, and 1.6 μT) or durations (0.5, 1.0, and 2.0 sec) at each Pfirrmann grade (I-V). The relationship between the CEST effects and low back pain was also evaluated. RESULTS The phantom study showed high correlations between the CEST effects and GAG concentration (R2 = 0.863, P < 0.0001, linear regression). In the human study, the CEST effect obtained with the 0.8 μT power was significantly greater than those obtained with 0.4 (P < 0.01) and 1.6 μT power (P < 0.05) at Pfirrmann grade I. The CEST effect obtained with a 1.0-sec duration was significantly greater than those derived with 0.5 and 2.0 sec (P < 0.01) durations at Pfirrmann grades I and II. The CEST effects in the group with moderate low back pain were significantly lower than those in the groups without pain (P < 0.001) and with mild pain (P = 0.0216). CONCLUSION The contrast of gagCEST imaging in the lumbar IVDs varied with saturation pulse power and duration. GagCEST imaging may serve as a tool for evaluating IVD degeneration in the lumbar spine. LEVEL OF EVIDENCE 2 J. Magn. Reson. Imaging 2017;45:863-871.
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Affiliation(s)
- Tatsuhiro Wada
- Division of Radiology, Department of Medical Technology, Kyushu University Hospital, Fukuoka, Japan
| | - Osamu Togao
- Department of Clinical Radiology, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan
| | - Chiaki Tokunaga
- Division of Radiology, Department of Medical Technology, Kyushu University Hospital, Fukuoka, Japan
| | - Ryohei Funatsu
- Division of Radiology, Department of Medical Technology, Kyushu University Hospital, Fukuoka, Japan
| | - Yasuo Yamashita
- Division of Radiology, Department of Medical Technology, Kyushu University Hospital, Fukuoka, Japan
| | - Kouji Kobayashi
- Division of Radiology, Department of Medical Technology, Kyushu University Hospital, Fukuoka, Japan
| | - Yasuhiko Nakamura
- Division of Radiology, Department of Medical Technology, Kyushu University Hospital, Fukuoka, Japan
| | - Hiroshi Honda
- Department of Clinical Radiology, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan
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Togao O, Keupp J, Hiwatashi A, Yamashita K, Kikuchi K, Yoneyama M, Honda H. Amide proton transfer imaging of brain tumors using a self-corrected 3D fast spin-echo dixon method: Comparison With separate B 0 correction. Magn Reson Med 2016; 77:2272-2279. [PMID: 27385636 DOI: 10.1002/mrm.26322] [Citation(s) in RCA: 61] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2016] [Revised: 05/19/2016] [Accepted: 06/02/2016] [Indexed: 12/30/2022]
Abstract
PURPOSE To assess the quantitative performance of three-dimensional (3D) fast spin-echo (FSE) Dixon amide proton transfer (APT) imaging of brain tumors compared with B0 correction with separate mapping methods. METHODS Twenty-two patients with brain tumors (54.2 ± 18.7 years old, 12 males and 10 females) were scanned at 3 Tesla (T). Z-spectra were obtained at seven different frequency offsets at ±3.1 ppm, ± 3.5 ppm, ± 3.9 ppm, and -1560 ppm. The scan was repeated three times at +3.5 ppm with echo shifts for Dixon B0 mapping. The APT image corrected by a three-point Dixon-type B0 map from the same scan (3D-Dixon) or a separate B0 map (2D-separate and 3D-separate), and an uncorrected APT image (3D-uncorrected) were generated. We compared the APT-weighted signals within a tumor obtained with each 3D method with those obtained with 2D-separate as a reference standard. RESULTS Excellent agreements and correlations with the 2D-separate were obtained by the 3D-Dixon method for both mean (ICC = 0.964, r = 0.93, P < 0.0001) and 90th-percentile (ICC = 0.972, r = 0.95, P < 0.0001) APT-weighted signals. These agreements and correlations for 3D-Dixon were better than those obtained by the 3D-uncorrected and 3D-separate methods. CONCLUSION The 3D FSE Dixon APT method with intrinsic B0 correction offers a quantitative performance that is similar to that of established two-dimensional (2D) methods. Magn Reson Med 77:2272-2279, 2017. © 2016 International Society for Magnetic Resonance in Medicine.
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Affiliation(s)
- Osamu Togao
- Department of Clinical Radiology, Graduate School of Medical Sciences, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka, 812-8582, Japan
| | - Jochen Keupp
- Philips Research Europe, Röntgenstrasse 24-26, Hamburg, 22335, Germany
| | - Akio Hiwatashi
- Department of Clinical Radiology, Graduate School of Medical Sciences, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka, 812-8582, Japan
| | - Koji Yamashita
- Department of Clinical Radiology, Graduate School of Medical Sciences, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka, 812-8582, Japan
| | - Kazufumi Kikuchi
- Department of Clinical Radiology, Graduate School of Medical Sciences, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka, 812-8582, Japan
| | - Masami Yoneyama
- Philips Electronics Japan, 2-13-37 Konan, Minato-ku, Tokyo, 108-8507, Japan
| | - Hiroshi Honda
- Department of Clinical Radiology, Graduate School of Medical Sciences, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka, 812-8582, Japan
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Schleich C, Bittersohl B, Miese F, Schmitt B, Müller-Lutz A, Sondern M, Antoch G, Krauspe R, Zilkens C. Glycosaminoglycan chemical exchange saturation transfer at 3T MRI in asymptomatic knee joints. Acta Radiol 2016; 57:627-32. [PMID: 26253931 DOI: 10.1177/0284185115598811] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2015] [Accepted: 07/12/2015] [Indexed: 12/27/2022]
Abstract
BACKGROUND Biochemical alterations such as glycosaminoglycan (GAG) depletion occur early in the course of osteoarthritis, but cannot be detected with standard magnetic resonance techniques. With glycosaminoglycan chemical exchange saturation transfer (gagCEST), a biochemical imaging technique, it is feasible to detect biochemical components in knee joint cartilage. PURPOSE To establish baseline values for gagCEST magnetic resonance imaging (MRI) in knee joint cartilage at 3 Tesla (T). MATERIAL AND METHODS Twenty volunteers (8 women, 12 men; mean age, 24.55 ± 2.35 years;age range, 21-29 years) with no history or clinical findings indicative of knee joint pathologies underwent MRI at 3T. The imaging protocol included three-dimensional (3D) double-echo steady-state sequence for morphological cartilage assessment and a prototype 3D CEST pulse sequence to evaluate the CEST effects in six cartilage regions of the knee joint: (i) lateral femoral condyle; (ii) medial femoral condyle; (iii) lateral tibial plateau; (iv) medial tibial plateau; (v) patella; and (vi) trochlea. We used the asymmetry of the magnetization transfer ratio (MTRasym) parameter to quantify the gagCEST effects in these regions. RESULTS Regional differences revealed high MTRasym values in the patellar (1.62% ± 1.19%) and the trochlear (1.17% ± 1.29%) cartilages, and low MTRasym values in the medial femoral condyle (0.41% ± 0.58%) and the lateral tibial plateau (0.52% ± 0.53%) cartilages. CONCLUSION Regional differences in the gagCEST values must be considered when conducting gagCEST imaging of knee joint cartilage. In the future gagCEST imaging may be an additional feature in the evaluation of the biochemical composition of knee joint cartilage.
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Affiliation(s)
- Christoph Schleich
- University Düsseldorf, Medical Faculty, Department of Diagnostic and Interventional Radiology, Düsseldorf, Germany
| | - Bernd Bittersohl
- University Düsseldorf, Medical Faculty, Department of Orthopedics, Düsseldorf, Germany
| | - Falk Miese
- University Düsseldorf, Medical Faculty, Department of Diagnostic and Interventional Radiology, Düsseldorf, Germany
| | - Benjamin Schmitt
- Siemens Ltd. Australia, Healthcare Sector, Macquarie Park, NSW, Australia
| | - Anja Müller-Lutz
- University Düsseldorf, Medical Faculty, Department of Diagnostic and Interventional Radiology, Düsseldorf, Germany
| | - Malte Sondern
- University Düsseldorf, Medical Faculty, Department of Orthopedics, Düsseldorf, Germany
| | - Gerald Antoch
- University Düsseldorf, Medical Faculty, Department of Diagnostic and Interventional Radiology, Düsseldorf, Germany
| | - Rüdiger Krauspe
- University Düsseldorf, Medical Faculty, Department of Orthopedics, Düsseldorf, Germany
| | - Christoph Zilkens
- University Düsseldorf, Medical Faculty, Department of Orthopedics, Düsseldorf, Germany
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Liu Z, Dimitrov IE, Lenkinski RE, Hajibeigi A, Vinogradov E. UCEPR: Ultrafast localized CEST-spectroscopy with PRESS in phantoms and in vivo. Magn Reson Med 2016; 75:1875-85. [PMID: 26033357 PMCID: PMC4663188 DOI: 10.1002/mrm.25780] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2015] [Revised: 04/02/2015] [Accepted: 04/27/2015] [Indexed: 11/10/2022]
Abstract
PURPOSE Chemical exchange saturation transfer (CEST) is a contrast mechanism enhancing low-concentration molecules through saturation transfer from their exchangeable protons to bulk water. Often many scans are acquired to form a Z-spectrum, making the CEST method time-consuming. Here, an ultrafast localized CEST-spectroscopy with PRESS (UCEPR) is proposed to obtain the entire Z-spectrum of a voxel using only two scans, significantly accelerating CEST. THEORY AND METHODS The approach combines ultrafast nonlocalized CEST spectroscopy with localization using PRESS. A field gradient is applied concurrently with the saturation pulse producing simultaneous saturation of all Z-spectrum frequencies that are also spatially encoded. A readout gradient during data acquisition resolves the spatial dependence of the CEST responses into frequency. UCEPR was tested on a 3T scanner both in phantoms and in vivo. RESULTS In phantoms, a fast Z-spectroscopy acquisition of multiple pH-variant iopamidol samples was achieved with four- to seven-fold acceleration as compared to the conventional CEST methods. In vivo, amide proton transfer (APT) in white matter of healthy human brain was measured rapidly in 48 s and with high frequency resolution (≤ 0.2 ppm). CONCLUSION Compared with conventional CEST methods, UCEPR has the advantage of rapidly acquiring high-resolution Z-spectra. Potential in vivo applications include ultrafast localized Z-spectroscopy, quantitative, or dynamic CEST studies.
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Affiliation(s)
- Zheng Liu
- Radiology, University of Texas Southwestern Medical Center, Dallas, Texas, USA
- Division of Neuroscience, Oregon National Primate Research Center, Oregon Health & Science University, Beaverton, Oregon, USA
| | - Ivan E. Dimitrov
- Advanced Imaging Research Center, University of Texas Southwestern Medical Center, Dallas, Texas, USA
- Philips Medical Systems, Highland Heights, Ohio, USA
| | - Robert E. Lenkinski
- Radiology, University of Texas Southwestern Medical Center, Dallas, Texas, USA
- Advanced Imaging Research Center, University of Texas Southwestern Medical Center, Dallas, Texas, USA
| | - Asghar Hajibeigi
- Radiology, University of Texas Southwestern Medical Center, Dallas, Texas, USA
| | - Elena Vinogradov
- Radiology, University of Texas Southwestern Medical Center, Dallas, Texas, USA
- Advanced Imaging Research Center, University of Texas Southwestern Medical Center, Dallas, Texas, USA
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Improvement of water saturation shift referencing by sequence and analysis optimization to enhance chemical exchange saturation transfer imaging. Magn Reson Imaging 2016; 34:771-778. [PMID: 26988704 DOI: 10.1016/j.mri.2016.03.013] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2015] [Revised: 02/18/2016] [Accepted: 03/03/2016] [Indexed: 02/05/2023]
Abstract
PURPOSE To optimize B0-field inhomogeneity correction for chemical exchange saturation transfer (CEST) imaging by investigating different water saturation shift referencing (WASSR) Z-spectrum shapes and different frequency correction techniques. METHODS WASSR Z-spectra were simulated for different B1-fields and pulse durations (PD). Two parameter settings were used for further simulations and experiments (WASSR1: B1=0.1 μT, PD=50ms; WASSR2: B1=0.3 μT, PD=40ms). Four frequency correction techniques were investigated: 1) MinW: Minimum of the spline-interpolated WASSR-spectrum; 2) MSCF: maximum symmetry center frequency algorithm; 3) PMSCF: further development of MSCF algorithm; 4) BFit: fit with Bloch equations. Performance of frequency correction was assessed with Monte-Carlo simulations and in-vivo MR examinations in the brain and intervertebral disks. RESULTS Different shapes of WASSR-Z-spectra were obtained by changing B1 and PD including spectra with one (1-Peak) or two (2-Peak) minima. WASSR1 resulted in 1-Peak WASSR-spectrum, whereas WASSR2 resulted in 2-Peak WASSR-spectrum. Both Monte-Carlo simulations and in-vivo MR examinations revealed highest accuracy of field-inhomogeneity correction with WASSR1 combined with PMSCF or BFit. CONCLUSION Using a WASSR sequence, which results in a Z-spectrum with a single absorption peak, in combination with advanced postprocessing algorithms enables improved B0-field inhomogeneity correction for CEST imaging.
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Schreiner MM, Zbýň Š, Schmitt B, Weber M, Domayer S, Windhager R, Trattnig S, Mlynárik V. Reproducibility and regional variations of an improved gagCEST protocol for the in vivo evaluation of knee cartilage at 7 T. MAGNETIC RESONANCE MATERIALS IN PHYSICS BIOLOGY AND MEDICINE 2016; 29:513-21. [PMID: 26965509 DOI: 10.1007/s10334-016-0544-5] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/27/2015] [Revised: 02/25/2016] [Accepted: 02/29/2016] [Indexed: 12/31/2022]
Abstract
OBJECTIVE The objective was to establish a gagCEST protocol that would enable robust and reproducible assessment of the glycosaminoglycan (GAG) content in knee cartilage at 7 T within a clinically feasible measurement time. MATERIALS AND METHODS Ten young healthy volunteers (mean age 26 years, range 24-28, five males, five females) were examined on a 7 T MR system. Informed consent was obtained from all individual participants prior to enrollment into the study. Each volunteer was measured twice for reproducibility assessment. The examined knee was immobilized using a custom-made fixation device. For the gagCEST measurement, a prototype segmented 3-D RF-spoiled gradient-echo sequence with an improved saturation scheme employing adiabatic pulses was used in a scan time of 19 min. The asymmetry of the Z-spectra (MTRasym) in selected regions of interest in knee cartilage was calculated. Differences in MTRasym between different regions were evaluated using ANOVA and the Bonferroni corrected post hoc test. RESULTS The improvement of the saturation scheme reduced the influence of field inhomogeneities, resulted in more uniform saturation, and allowed for good reproducibility in a reasonable measurement time (19 min), as demonstrated by an intraclass correlation coefficient of 0.77. Improved fixation helped to reduce motion artifacts. Whereas similar MTRasym values were found for weight-bearing and non-weight-bearing femoral cartilage, lower values were observed in the trochlear groove (p = 0.028), patellar (p = 0.015) and tibial cartilage (p < 0.001) when compared to non-weight-bearing femoral cartilage. CONCLUSION Reasonable reproducibility and sensitivity to regional differences in GAG content suggests that the improved gagCEST protocol might be useful for assessing the biochemical changes in articular cartilage that are associated with early stages of cartilage degeneration.
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Affiliation(s)
- Markus M Schreiner
- Department of Orthopaedic Surgery, Medical University of Vienna, Waehringer Guertel 18-20, 1090, Vienna, Austria.,Department of Biomedical Imaging and Image-Guided Therapy, High Field MR Centre, Medical University of Vienna, Waehringer Guertel 18-20, 1090, Vienna, Austria
| | - Štefan Zbýň
- Department of Biomedical Imaging and Image-Guided Therapy, High Field MR Centre, Medical University of Vienna, Waehringer Guertel 18-20, 1090, Vienna, Austria
| | - Benjamin Schmitt
- Healthcare Sector, Siemens Ltd. Australia, Macquarie Park, NSW, Australia
| | - Michael Weber
- Department of Biomedical Imaging and Image-Guided Therapy, Medical University of Vienna, Waehringer Guertel 18-20, 1090, Vienna, Austria
| | - Stephan Domayer
- Department of Orthopaedic Surgery, Medical University of Vienna, Waehringer Guertel 18-20, 1090, Vienna, Austria
| | - Reinhard Windhager
- Department of Orthopaedic Surgery, Medical University of Vienna, Waehringer Guertel 18-20, 1090, Vienna, Austria
| | - Siegfried Trattnig
- Department of Biomedical Imaging and Image-Guided Therapy, High Field MR Centre, Medical University of Vienna, Waehringer Guertel 18-20, 1090, Vienna, Austria.
| | - Vladimir Mlynárik
- Department of Biomedical Imaging and Image-Guided Therapy, High Field MR Centre, Medical University of Vienna, Waehringer Guertel 18-20, 1090, Vienna, Austria
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Müller-Lutz A, Schleich C, Schmitt B, Topgöz M, Pentang G, Antoch G, Wittsack HJ, Miese F. Improvement of gagCEST imaging in the human lumbar intervertebral disc by motion correction. Skeletal Radiol 2015; 44:505-11. [PMID: 25339437 DOI: 10.1007/s00256-014-2034-z] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/14/2014] [Revised: 09/08/2014] [Accepted: 10/08/2014] [Indexed: 02/02/2023]
Abstract
OBJECTIVE To investigate whether motion correction improves glycosaminoglycan chemical exchange saturation transfer imaging (gagCEST imaging) of intervertebral discs (IVDs). MATERIALS AND METHODS Magnetic resonance gagCEST imaging of 12 volunteers was obtained in lumbar IVDs at 3 T using a prototype pulse sequence. The data were motion-corrected using a prototype diffeomorphism-based motion compensation technique. For both the data with and that without motion correction (datac, datauc), CEST evaluation was performed using the magnetisation transfer ratio asymmetry (MTRasym) as a means of quantifying CEST effects. MTRasym and the signal-to-noise ratio (SNR) of the MTRasym map in the nucleus pulposus (NP) were compared for datac and datauc. A visual grading analysis was performed by a radiologist in order to subjectively quantify the quality of the MTRasym analysis (score 1: best quality, score 5: worst quality). Furthermore, a landmark analysis was performed in order to objectively quantify the motion between CEST images using the mean landmark distance dmean. RESULTS MTRasym and SNR were significantly higher for the motion-corrected data than for the uncorrected CEST data (MTRasym(datac) = 3.77 % ± 0.95 %, MTRasym(datauc) = 3.41 % ± 1.54 %, p value = 0.001; SNR(datac) = 3.88 ± 2.04, SNR(datauc) = 2.77 ± 1.55, p value < 0.001, number of IVDs = 48). The visual grading analysis revealed a higher reliability for datac (maximum score = 2) compared with datauc (maximum score = 5). The landmark analysis demonstrated the superiority of the motion-corrected data (dmean(datac) = 0.08 mm ± 0.09 mm, dmean(datauc) = 0.36 mm ± 0.09 mm, p value = 0.001). CONCLUSION Our study showed significant improvements in the ability to quantify CEST imaging in IVDs after the application of motion correction compared with uncorrected datasets.
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Affiliation(s)
- Anja Müller-Lutz
- Medical Faculty, Department of Diagnostic and Interventional Radiology, University Dusseldorf, Moorenstrasse 5, 40225, Dusseldorf, Germany
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Kim J, Wu Y, Guo Y, Zheng H, Sun PZ. A review of optimization and quantification techniques for chemical exchange saturation transfer MRI toward sensitive in vivo imaging. CONTRAST MEDIA & MOLECULAR IMAGING 2015; 10:163-178. [PMID: 25641791 DOI: 10.1002/cmmi.1628] [Citation(s) in RCA: 89] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/05/2014] [Revised: 08/26/2014] [Accepted: 09/10/2014] [Indexed: 01/10/2023]
Abstract
Chemical exchange saturation transfer (CEST) MRI is a versatile imaging method that probes the chemical exchange between bulk water and exchangeable protons. CEST imaging indirectly detects dilute labile protons via bulk water signal changes following selective saturation of exchangeable protons, which offers substantial sensitivity enhancement and has sparked numerous biomedical applications. Over the past decade, CEST imaging techniques have rapidly evolved owing to contributions from multiple domains, including the development of CEST mathematical models, innovative contrast agent designs, sensitive data acquisition schemes, efficient field inhomogeneity correction algorithms, and quantitative CEST (qCEST) analysis. The CEST system that underlies the apparent CEST-weighted effect, however, is complex. The experimentally measurable CEST effect depends not only on parameters such as CEST agent concentration, pH and temperature, but also on relaxation rate, magnetic field strength and more importantly, experimental parameters including repetition time, RF irradiation amplitude and scheme, and image readout. Thorough understanding of the underlying CEST system using qCEST analysis may augment the diagnostic capability of conventional imaging. In this review, we provide a concise explanation of CEST acquisition methods and processing algorithms, including their advantages and limitations, for optimization and quantification of CEST MRI experiments.
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Affiliation(s)
- Jinsuh Kim
- Department of Radiology, University of Iowa, Iowa City, IA, USA
| | - Yin Wu
- Paul C. Lauterbur Research Center for Biomedical Imaging, Shenzhen Key Laboratory for MRI, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, China.,Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital and Harvard Medical School, Charlestown, MA, USA
| | - Yingkun Guo
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital and Harvard Medical School, Charlestown, MA, USA
| | - Hairong Zheng
- Paul C. Lauterbur Research Center for Biomedical Imaging, Shenzhen Key Laboratory for MRI, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, China
| | - Phillip Zhe Sun
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital and Harvard Medical School, Charlestown, MA, USA
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Kijowski R, Chaudhary R. Quantitative magnetic resonance imaging of the articular cartilage of the knee joint. Magn Reson Imaging Clin N Am 2014; 22:649-69. [PMID: 25442027 DOI: 10.1016/j.mric.2014.07.005] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Osteoarthritis is characterized by a decrease in the proteoglycan content and disruption of the highly organized collagen fiber network of articular cartilage. Various quantitative magnetic resonance imaging techniques have been developed for noninvasive assessment of the proteoglycan and collagen components of cartilage. These techniques have been extensively used in clinical practice to detect early cartilage degeneration and in osteoarthritis research studies to monitor disease-related and treatment-related changes in cartilage over time. This article reviews the role of quantitative magnetic resonance imaging in evaluating the composition and ultrastructure of the articular cartilage of the knee joint.
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Affiliation(s)
- Richard Kijowski
- Department of Radiology, University of Wisconsin School of Medicine and Public Health, 600 Highland Avenue, Madison, WI 53792-3252, USA.
| | - Rajeev Chaudhary
- Department of Radiology, University of Wisconsin School of Medicine and Public Health, 600 Highland Avenue, Madison, WI 53792-3252, USA
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Comparison of biochemical cartilage imaging techniques at 3 T MRI. Osteoarthritis Cartilage 2014; 22:1732-42. [PMID: 25278082 DOI: 10.1016/j.joca.2014.04.020] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/13/2013] [Revised: 04/11/2014] [Accepted: 04/22/2014] [Indexed: 02/02/2023]
Abstract
OBJECTIVE To prospectively compare chemical-exchange saturation-transfer (CEST) with delayed gadolinium-enhanced MRI of cartilage (dGEMRIC) and T2 mapping to assess the biochemical cartilage properties of the knee. METHOD Sixty-nine subjects were prospectively included (median age, 42 years; male/female = 32/37) in three cohorts: 10 healthy volunteers, 40 patients with clinically suspected cartilage lesions, and 19 patients about 1 year after microfracture therapy. T2 mapping, dGEMRIC, and CEST were performed at a 3 T MRI unit using a 15-channel knee coil. Parameter maps were evaluated using region-of-interest analysis of healthy cartilage, areas of chondromalacia and repair tissue. Differentiation of damaged from healthy cartilage was assessed using receiver-operating characteristic (ROC) analysis. RESULTS Chondromalacia grade 2-3 had significantly higher CEST values (P = 0.001), lower dGEMRIC (T1-) values (P < 0.001) and higher T2 values (P < 0.001) when compared to the normal appearing cartilage. dGEMRIC and T2 mapping correlated moderately negative (Spearman coefficient r = -0.56, P = 0.0018) and T2 mapping and CEST moderately positive (r = 0.5, P = 0.007), while dGEMRIC and CEST did not significantly correlate (r = -0.311, P = 0.07). The repair tissue revealed lower dGEMRIC values (P < 0.001) and higher CEST values (P < 0.001) with a significant negative correlation (r = -0.589, P = 0.01), whereas T2 values were not different (P = 0.54). In healthy volunteers' cartilage, CEST and dGEMRIC showed moderate positive correlation (r = 0.56), however not reaching significance (P = 0.09). ROC-analysis demonstrated non-significant differences of T2 mapping vs CEST (P = 0.14), CEST vs dGEMRIC (P = 0.89), and T2 mapping vs dGEMRIC (P = 0.12). CONCLUSION CEST is able to detect normal and damaged cartilage and is non-inferior in distinguishing both when compared to dGEMRIC and T2 mapping.
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Yuan J, Chen S, King AD, Zhou J, Bhatia KS, Zhang Q, Yeung DKW, Wei J, Mok GSP, Wang YX. Amide proton transfer-weighted imaging of the head and neck at 3 T: a feasibility study on healthy human subjects and patients with head and neck cancer. NMR IN BIOMEDICINE 2014; 27:1239-47. [PMID: 25137521 PMCID: PMC4160398 DOI: 10.1002/nbm.3184] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/02/2014] [Revised: 06/04/2014] [Accepted: 07/14/2014] [Indexed: 05/03/2023]
Abstract
The aim of this study was to explore the feasibility and repeatability of amide proton transfer-weighted (APTw) MRI for the head and neck on clinical MRI scanners. Six healthy volunteers and four patients with head and neck tumors underwent APTw MRI scanning at 3 T. The APTw signal was quantified by the asymmetric magnetization transfer ratio (MTRasym) at 3.5 ppm. Z spectra of normal tissues in the head and neck (masseter muscle, parotid glands, submandibular glands and thyroid glands) were analyzed in healthy volunteers. Inter-scan repeatability of APTw MRI was evaluated in six healthy volunteers. Z spectra of patients with head and neck tumors were produced and APTw signals in these tumors were analyzed. APTw MRI scanning was successful for all 10 subjects. The parotid glands showed the highest APTw signal (~7.6% average), whereas the APTw signals in other tissues were relatively moderate. The repeatability of APTw signals from the masseter muscle, parotid gland, submandibular gland and thyroid gland of healthy volunteers was established. Four head and neck tumors showed positive mean APTw ranging from 1.2% to 3.2%, distinguishable from surrounding normal tissues. APTw MRI was feasible for use in the head and neck regions at 3 T. The preliminary results on patients with head and neck tumors indicated the potential of APTw MRI for clinical applications.
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Affiliation(s)
- Jing Yuan
- Medical Physics and Research Department, Hong Kong Sanatorium & Hospital, Happy Valley, Hong Kong, China
- Department of Imaging and Interventional Radiology, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong, China
- CUHK Shenzhen Research Institute, Shenzhen, Guangdong, China
- Correspondence to: Jing Yuan, Ph.D., Medical Physics and Research Department, Hong Kong Sanatorium & Hospital, Happy Valley, Hong Kong, China, Tel: 852-2835-7004,
| | - Shuzhong Chen
- Department of Imaging and Interventional Radiology, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong, China
| | - Ann D. King
- Department of Imaging and Interventional Radiology, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong, China
| | - Jinyuan Zhou
- Department of Radiology, Johns Hopkins University, Baltimore, Maryland, USA
- F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, Maryland, USA
| | - Kunwar S. Bhatia
- Department of Imaging and Interventional Radiology, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong, China
| | - Qinwei Zhang
- Department of Imaging and Interventional Radiology, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong, China
| | - David Ka Wei Yeung
- Department of Imaging and Interventional Radiology, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong, China
| | - Juan Wei
- Philips Healthcare Asia, Shanghai, China
| | - Greta Seng Peng Mok
- Department of Electrical and Computer Engineering, University of Macau, Taipa, Macau SAR, China
| | - Yi-Xiang Wang
- Department of Imaging and Interventional Radiology, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong, China
- CUHK Shenzhen Research Institute, Shenzhen, Guangdong, China
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