1
|
Aigner CS, Sánchez Alarcon MF, D'Astous A, Alonso-Ortiz E, Cohen-Adad J, Schmitter S. Calibration-free parallel transmission of the cervical, thoracic, and lumbar spinal cord at 7T. Magn Reson Med 2024; 92:1496-1510. [PMID: 38733068 DOI: 10.1002/mrm.30137] [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: 02/16/2024] [Revised: 04/16/2024] [Accepted: 04/16/2024] [Indexed: 05/13/2024]
Abstract
PURPOSE To address the limitations of spinal cord imaging at ultra-high field (UHF) due to time-consuming parallel transmit (pTx) adjustments. This study introduces calibration-free offline computed universal shim modes that can be applied seamlessly for different pTx RF coils and spinal cord target regions, substantially enhancing spinal cord imaging efficiency at UHF. METHODS A library of channel-wise relativeB 1 + $$ {B}_1^{+} $$ maps for the cervical spinal cord (six datasets) and thoracic and lumbar spinal cord (nine datasets) was constructed to optimize transmit homogeneity and efficiency for these regions. A tailored B0 shim was optimized for the cervical spine to enhance spatial magnetic field homogeneity further. The performance of the universal shims was validated using absolute saturation basedB 1 + $$ {B}_1^{+} $$ mapping and high-resolution 2D and 3D multi-echo gradient-recalled echo (GRE) data to assess the image quality. RESULTS The proposed universal shims demonstrated a 50% improvement inB 1 + $$ {B}_1^{+} $$ efficiency compared to the default (zero phase) shim mode.B 1 + $$ {B}_1^{+} $$ homogeneity was also improved by 20%. The optimized universal shims achieved performance comparable to subject-specific pTx adjustments, while eliminating the need for lengthy pTx calibration times, saving about 10 min per experiment. CONCLUSION The development of universal shims represents a significant advance by eliminating time-consuming subject-specific pTx adjustments. This approach is expected to make UHF spinal cord imaging more accessible and user-friendly, particularly for non-pTx experts.
Collapse
Affiliation(s)
- Christoph S Aigner
- Physikalisch-Technische Bundesanstalt (PTB), Braunschweig and Berlin, Germany
| | - Manuel F Sánchez Alarcon
- Physikalisch-Technische Bundesanstalt (PTB), Braunschweig and Berlin, Germany
- Working Group on Cardiovascular Magnetic Resonance, Experimental and Clinical Research Center, A Joint Cooperation between the Charité Medical Faculty and the Max-Delbrück Center for Molecular Medicine, Berlin, Germany
| | - Alexandre D'Astous
- NeuroPoly Lab, Institute of Biomedical Engineering, Polytechnique Montréal, Montréal, Quebec, Canada
- Centre de recherche du CHU Sainte-Justine, Université de Montréal, Montréal, Quebec, Canada
| | - Eva Alonso-Ortiz
- Functional Neuroimaging Unit, CRIUGM, Université de Montréal, Montréal, Quebec, Canada
- Mila-Quebec AI Institute, Montréal, Quebec, Canada
| | - Julien Cohen-Adad
- Functional Neuroimaging Unit, CRIUGM, Université de Montréal, Montréal, Quebec, Canada
- Mila-Quebec AI Institute, Montréal, Quebec, Canada
- Medical Physics in Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany
- Center for Magnetic Resonance Research, University of Minnesota, Minneapolis, Minnesota, USA
| | - Sebastian Schmitter
- Physikalisch-Technische Bundesanstalt (PTB), Braunschweig and Berlin, Germany
- Medical Physics in Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany
- Center for Magnetic Resonance Research, University of Minnesota, Minneapolis, Minnesota, USA
| |
Collapse
|
2
|
Peng Y, Dai Y, Zhang S, Deng J, Jia X. Joint k- ω Space Image Reconstruction and Data Fitting for Chemical Exchange Saturation Transfer Magnetic Resonance Imaging. Tomography 2024; 10:1123-1138. [PMID: 39058057 PMCID: PMC11280605 DOI: 10.3390/tomography10070085] [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: 05/31/2024] [Revised: 07/05/2024] [Accepted: 07/08/2024] [Indexed: 07/28/2024] Open
Abstract
Chemical exchange saturation transfer (CEST) magnetic resonance imaging (MRI) is a novel MRI technology to image certain compounds at extremely low concentrations. Long acquisition time to measure signals at a set of offset frequencies of the Z-spectra and to repeat measurements to reduce noise pose significant challenges to its applications. This study explores correlations of CEST MR images along the spatial and Z-spectral dimensions to improve MR image quality and robustness of magnetization transfer ratio (MTR) asymmetry estimation via a joint k-ω reconstruction model. The model was formulated as an optimization problem with respect to MR images at all frequencies ω, while incorporating regularizations along the spatial and spectral dimensions. The solution was subject to a self-consistency condition that the Z-spectrum of each pixel follows a multi-peak data fitting model corresponding to different CEST pools. The optimization problem was solved using the alternating direction method of multipliers. The proposed joint reconstruction method was evaluated on a simulated CEST MRI phantom and semi-experimentally on choline and iopamidol phantoms with added Gaussian noise of various levels. Results demonstrated that the joint reconstruction method was more tolerable to noise and reduction in number of offset frequencies by improving signal-to-noise ratio (SNR) of the reconstructed images and reducing uncertainty in MTR asymmetry estimation. In the choline and iopamidol phantom cases with 10.5% noise in the measurement data, our method achieved an averaged SNR of 31.0 dB and 32.2 dB compared to the SNR of 24.7 dB and 24.4 dB in the conventional reconstruction approach. It reduced uncertainty of the MTR asymmetry estimation over all regions of interest by 54.4% and 43.7%, from 1.71 and 2.38 to 0.78 and 1.71, respectively.
Collapse
Affiliation(s)
- Yuting Peng
- Department of Radiation Oncology and Molecular Radiation Sciences, Johns Hopkins University, Baltimore, MD 21287, USA
| | - Yan Dai
- Department of Radiation Oncology, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Shu Zhang
- Department of Radiology, Houston Methodist Research Institute, Houston, TX 77030, USA
| | - Jie Deng
- Department of Radiation Oncology, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Xun Jia
- Department of Radiation Oncology and Molecular Radiation Sciences, Johns Hopkins University, Baltimore, MD 21287, USA
| |
Collapse
|
3
|
Cronin AE, Liebig P, Detombe SA, Duggal N, Bartha R. Reproducibility of 3D pH-weighted chemical exchange saturation transfer contrast in the healthy cervical spinal cord. NMR IN BIOMEDICINE 2024; 37:e5103. [PMID: 38243648 DOI: 10.1002/nbm.5103] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/07/2023] [Revised: 12/01/2023] [Accepted: 12/20/2023] [Indexed: 01/21/2024]
Abstract
Spinal cord ischemia and hypoxia can be caused by compression, injury, and vascular alterations. Measuring ischemia and hypoxia directly in the spinal cord noninvasively remains challenging. Ischemia and hypoxia alter tissue pH, providing a physiologic parameter that may be more directly related to tissue viability. Chemical exchange saturation transfer (CEST) is an MRI contrast mechanism that can be made sensitive to pH. More specifically, amine/amide concentration independent detection (AACID) is a recently developed endogenous CEST contrast that has demonstrated sensitivity to intracellular pH at 9.4 T. The goal of this study was to evaluate the reproducibility of AACID CEST measurements at different levels of the healthy cervical spinal cord at 3.0 T incorporating B1 correction. Using a 3.0 T MRI scanner, two 3D CEST scans (saturation pulse train followed by a 3D snapshot gradient-echo readout) were performed on 12 healthy subjects approximately 10 days apart, with the CEST volume centered at the C4 level for all subjects. Scan-rescan reproducibility was evaluated by examining between and within-subject coefficients of variation (CVs) and absolute AACID value differences. The C4 level of the spinal cord demonstrated the lowest within-subject CVs (4.1%-4.3%), between-subject CVs (5.6%-6.3%), and absolute AACID percent difference (5.8-6.1%). The B1 correction scheme significantly improved reproducibility (adjusted p-value = 0.002) compared with the noncorrected data, suggesting that implementing B1 corrections in the spinal cord is beneficial. It was concluded that pH-weighted AACID measurements, incorporating B1-inhomogeneity correction, were reproducible within subjects along the healthy cervical spinal cord and that optimal image quality was achieved at the center of the 3D CEST volume.
Collapse
Affiliation(s)
- Alicia E Cronin
- Department of Medical Biophysics, Schulich School of Medicine & Dentistry, Western University, London, Ontario, Canada
- Centre for Functional and Metabolic Mapping, Robarts Research Institute, Schulich School of Medicine & Dentistry, Western University, London, Ontario, Canada
| | | | - Sarah A Detombe
- Department of Clinical Neurological Sciences, London Health Sciences Centre, London, Ontario, Canada
| | - Neil Duggal
- Department of Medical Biophysics, Schulich School of Medicine & Dentistry, Western University, London, Ontario, Canada
- Department of Clinical Neurological Sciences, London Health Sciences Centre, London, Ontario, Canada
| | - Robert Bartha
- Department of Medical Biophysics, Schulich School of Medicine & Dentistry, Western University, London, Ontario, Canada
- Centre for Functional and Metabolic Mapping, Robarts Research Institute, Schulich School of Medicine & Dentistry, Western University, London, Ontario, Canada
| |
Collapse
|
4
|
Chen LM, Wang F, Mishra A, Yang PF, Sengupta A, Reed JL, Gore JC. Longitudinal multiparametric MRI of traumatic spinal cord injury in animal models. Magn Reson Imaging 2023; 102:184-200. [PMID: 37343904 PMCID: PMC10528214 DOI: 10.1016/j.mri.2023.06.007] [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: 03/17/2022] [Revised: 06/14/2023] [Accepted: 06/17/2023] [Indexed: 06/23/2023]
Abstract
Multi-parametric MRI (mpMRI) technology enables non-invasive and quantitative assessments of the structural, molecular, and functional characteristics of various neurological diseases. Despite the recognized importance of studying spinal cord pathology, mpMRI applications in spinal cord research have been somewhat limited, partly due to technical challenges associated with spine imaging. However, advances in imaging techniques and improved image quality now allow longitudinal investigations of a comprehensive range of spinal cord pathological features by exploiting different endogenous MRI contrasts. This review summarizes the use of mpMRI techniques including blood oxygenation level-dependent (BOLD) functional MRI (fMRI), diffusion tensor imaging (DTI), quantitative magnetization transfer (qMT), and chemical exchange saturation transfer (CEST) MRI in monitoring different aspects of spinal cord pathology. These aspects include cyst formation and axonal disruption, demyelination and remyelination, changes in the excitability of spinal grey matter and the integrity of intrinsic functional circuits, and non-specific molecular changes associated with secondary injury and neuroinflammation. These approaches are illustrated with reference to a nonhuman primate (NHP) model of traumatic cervical spinal cord injuries (SCI). We highlight the benefits of using NHP SCI models to guide future studies of human spinal cord pathology, and demonstrate how mpMRI can capture distinctive features of spinal cord pathology that were previously inaccessible. Furthermore, the development of mechanism-based MRI biomarkers from mpMRI studies can provide clinically useful imaging indices for understanding the mechanisms by which injured spinal cords progress and repair. These biomarkers can assist in the diagnosis, prognosis, and evaluation of therapies for SCI patients, potentially leading to improved outcomes.
Collapse
Affiliation(s)
- Li Min Chen
- Vanderbilt University Institute of Imaging Science, Vanderbilt University, Nashville, TN, USA; Department of Radiology and Radiological Sciences, Vanderbilt University Medical Center, Nashville, TN, USA.
| | - Feng Wang
- Vanderbilt University Institute of Imaging Science, Vanderbilt University, Nashville, TN, USA; Department of Radiology and Radiological Sciences, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Arabinda Mishra
- Vanderbilt University Institute of Imaging Science, Vanderbilt University, Nashville, TN, USA; Department of Radiology and Radiological Sciences, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Pai-Feng Yang
- Vanderbilt University Institute of Imaging Science, Vanderbilt University, Nashville, TN, USA; Department of Radiology and Radiological Sciences, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Anirban Sengupta
- Vanderbilt University Institute of Imaging Science, Vanderbilt University, Nashville, TN, USA; Department of Radiology and Radiological Sciences, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Jamie L Reed
- Vanderbilt University Institute of Imaging Science, Vanderbilt University, Nashville, TN, USA; Department of Radiology and Radiological Sciences, Vanderbilt University Medical Center, Nashville, TN, USA
| | - John C Gore
- Vanderbilt University Institute of Imaging Science, Vanderbilt University, Nashville, TN, USA; Department of Radiology and Radiological Sciences, Vanderbilt University Medical Center, Nashville, TN, USA; Department of Biomedical Engineering, Vanderbilt University, Nashville, TN, USA
| |
Collapse
|
5
|
Dan Q, Jiang X, Wang R, Dai Z, Sun D. Biogenic Imaging Contrast Agents. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2023; 10:e2207090. [PMID: 37401173 PMCID: PMC10477908 DOI: 10.1002/advs.202207090] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/02/2022] [Revised: 06/08/2023] [Indexed: 07/05/2023]
Abstract
Imaging contrast agents are widely investigated in preclinical and clinical studies, among which biogenic imaging contrast agents (BICAs) are developing rapidly and playing an increasingly important role in biomedical research ranging from subcellular level to individual level. The unique properties of BICAs, including expression by cells as reporters and specific genetic modification, facilitate various in vitro and in vivo studies, such as quantification of gene expression, observation of protein interactions, visualization of cellular proliferation, monitoring of metabolism, and detection of dysfunctions. Furthermore, in human body, BICAs are remarkably helpful for disease diagnosis when the dysregulation of these agents occurs and can be detected through imaging techniques. There are various BICAs matched with a set of imaging techniques, including fluorescent proteins for fluorescence imaging, gas vesicles for ultrasound imaging, and ferritin for magnetic resonance imaging. In addition, bimodal and multimodal imaging can be realized through combining the functions of different BICAs, which helps overcome the limitations of monomodal imaging. In this review, the focus is on the properties, mechanisms, applications, and future directions of BICAs.
Collapse
Affiliation(s)
- Qing Dan
- Shenzhen Key Laboratory for Drug Addiction and Medication SafetyDepartment of UltrasoundInstitute of Ultrasonic MedicinePeking University Shenzhen HospitalShenzhen Peking University‐The Hong Kong University of Science and Technology Medical CenterShenzhen518036P. R. China
| | - Xinpeng Jiang
- Department of Biomedical EngineeringCollege of Future TechnologyPeking UniversityBeijing100871P. R. China
| | - Run Wang
- Shenzhen Key Laboratory for Drug Addiction and Medication SafetyDepartment of UltrasoundInstitute of Ultrasonic MedicinePeking University Shenzhen HospitalShenzhen Peking University‐The Hong Kong University of Science and Technology Medical CenterShenzhen518036P. R. China
| | - Zhifei Dai
- Department of Biomedical EngineeringCollege of Future TechnologyPeking UniversityBeijing100871P. R. China
| | - Desheng Sun
- Shenzhen Key Laboratory for Drug Addiction and Medication SafetyDepartment of UltrasoundInstitute of Ultrasonic MedicinePeking University Shenzhen HospitalShenzhen Peking University‐The Hong Kong University of Science and Technology Medical CenterShenzhen518036P. R. China
| |
Collapse
|
6
|
Cember ATJ, Nanga RPR, Reddy R. Glutamate-weighted CEST (gluCEST) imaging for mapping neurometabolism: An update on the state of the art and emerging findings from in vivo applications. NMR IN BIOMEDICINE 2023; 36:e4780. [PMID: 35642353 DOI: 10.1002/nbm.4780] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/01/2021] [Revised: 05/27/2022] [Accepted: 05/30/2022] [Indexed: 05/23/2023]
Abstract
Glutamate is the primary excitatory neurotransmitter in the mammalian central nervous system. As such, its proper regulation is essential to the healthy function of the human brain, and dysregulation of glutamate metabolism and compartmentalization underlies numerous neurological and neuropsychiatric pathologies. Glutamate-weighted chemical exchange saturation transfer (gluCEST) MRI is one of the only ways to non-invasively observe the relative concentration and spatial distribution of glutamate in the human brain. In the past 10 years, gluCEST has developed from a proof-of-concept experiment carried out in imaging phantoms and model systems to an increasingly sophisticated technique applied to reveal deviations from baseline neural metabolism in human beings, most notably in patients experiencing seizures of various origins or those on the psychosis spectrum. This article traces that progress, including in-depth discussion of the technical specifics of gluCEST and potential challenges to performing these experiments rigorously. We discuss the neurobiological context of glutamate, including the widely accepted hypotheses and models in the literature regarding its involvement in neurodegenerative diseases and other pathology. We then review the state of the art of in vivo glutamate detection by magnetic resonance imaging and the limitations on this front of in vivo MR spectroscopy. The gluCEST experiment is introduced and its advantages, challenges and limitations are thoroughly explored, beginning with the phantom experiment results demonstrated in the initial publication, through the latest approaches to correcting human brain images for B1 inhomogeneity. We then give a comprehensive overview of preclinical applications demonstrated to date, including Alzheimer's disease, Parkinson's disease, Huntington's disease, Traumatic brain injury and cancer, followed by a similar discussion of human studies. Finally, we highlight emerging applications, and discuss technical improvements on the horizon that hold promise for improving the robustness and versatility of gluCEST and its increasing presence in the arena of translational and precision medicine.
Collapse
Affiliation(s)
- Abigail T J Cember
- Center for Advanced Metabolic Imaging in Precision Medicine (CAMIPM), Department of Radiology, University of Pennsylvania
| | - Ravi Prakash Reddy Nanga
- Center for Advanced Metabolic Imaging in Precision Medicine (CAMIPM), Department of Radiology, University of Pennsylvania
| | - Ravinder Reddy
- Center for Advanced Metabolic Imaging in Precision Medicine (CAMIPM), Department of Radiology, University of Pennsylvania
| |
Collapse
|
7
|
Zheng H, Zheng W, Liu H, Zhang G, Li W, Zhuang J, Guo Y. Imaging of glutamate in acute carbon monoxide poisoning using chemical exchange saturation transfer. Front Neurol 2023; 14:1065490. [PMID: 36816556 PMCID: PMC9932694 DOI: 10.3389/fneur.2023.1065490] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2022] [Accepted: 01/09/2023] [Indexed: 02/05/2023] Open
Abstract
Aims This study adopted the Glutamate Chemical Exchange Saturation Transfer (GluCEST) imaging technique to quantitatively analyze cranial glutamate and discussed the effectiveness of GluCEST values in identifying the pathogenesis of encephalopathy after CO poisoning. Methods The routine MRI and functional MRI scans of two cohorts of subjects (CO group, n = 29; Control group, n = 21) were performed. Between-group comparisons were conducted for GluCEST% in regions of interest (ROI), including the basal ganglia, the thalamus, the frontal lobe, the occipital lobe, the genu of corpus callosum, the cingulate gyrus, and the cuneus. Moreover, an age-stratified subgroup analysis was devised, and a correlational analysis was performed for GluCEST% in each ROI, including the time in coma, Simple Mini-Mental State Examination Scale (MMSE) score, Hamilton Anxiety Scale score, and blood COHb%. Results As compared to the healthy control, the CO group led to significantly increasing GluCEST% in the basal ganglia, the occipital lobe, the genu of the corpus callosum, the cingulate gyrus, and the cuneus (p < 0.05). In the subgroup analysis for age, adult patients had higher GluCEST% in the basal ganglia, the thalamus, the occipital lobe, the cingulate gyrus, and the cuneus compared to healthy adults (p < 0.05). In addition, the correlational analysis of CO-poisoned patients revealed a statistical association between the GluCEST% and the MMSE in the thalamus and the genu of the corpus callosum. Conclusion The GluCEST technique is superior to routine MRI in that it can identify the cerebral biochemical changes sooner after acute CO poisoning, which is significant for our understanding of the role of neurotransmitters in the pathological basis of this disease. Brain injury caused by CO poisoning may be different in adults and children.
Collapse
Affiliation(s)
- Hongyi Zheng
- Department of Radiology, The Second Affiliated Hospital, Medical College of Shantou University, Shantou, China
| | - Wenbin Zheng
- Department of Radiology, The Second Affiliated Hospital, Medical College of Shantou University, Shantou, China,*Correspondence: Wenbin Zheng ✉
| | - Hongkun Liu
- Department of Radiology, Huizhou City Center People's Hospital, Huizhou, China
| | - Gengbiao Zhang
- Department of Radiology, The Second Affiliated Hospital, Medical College of Shantou University, Shantou, China
| | - Weijia Li
- Department of Radiology, The Second Affiliated Hospital, Medical College of Shantou University, Shantou, China
| | - Jiayan Zhuang
- Department of Radiology, The Second Affiliated Hospital, Medical College of Shantou University, Shantou, China
| | - Yuelin Guo
- Department of Radiology, Shenzhen Hospital of Integrated Traditional Chinese and Western Medicine, Shenzhen, China
| |
Collapse
|
8
|
Ji Y, Lu D, Sun PZ, Zhou IY. In vivo pH mapping with omega plot-based quantitative chemical exchange saturation transfer MRI. Magn Reson Med 2023; 89:299-307. [PMID: 36089834 PMCID: PMC9617761 DOI: 10.1002/mrm.29444] [Citation(s) in RCA: 11] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2022] [Revised: 08/05/2022] [Accepted: 08/15/2022] [Indexed: 02/01/2023]
Abstract
PURPOSE Chemical exchange saturation transfer (CEST) MRI is promising for detecting dilute metabolites and microenvironment properties, which has been increasingly adopted in imaging disorders such as acute stroke and cancer. However, in vivo CEST MRI quantification remains challenging because routine asymmetry analysis (MTRasym ) or Lorentzian decoupling measures a combined effect of the labile proton concentration and its exchange rate. Therefore, our study aimed to quantify amide proton concentration and exchange rate independently in a cardiac arrest-induced global ischemia rat model. METHODS The amide proton CEST (APT) effect was decoupled from tissue water, macromolecular magnetization transfer, nuclear Overhauser enhancement, guanidinium, and amine protons using the image downsampling expedited adaptive least-squares (IDEAL) fitting algorithm on Z-spectra obtained under multiple RF saturation power levels, before and after global ischemia. Omega plot analysis was applied to determine amide proton concentration and exchange rate simultaneously. RESULTS Global ischemia induces a significant APT signal drop from intact tissue. Using the modified omega plot analysis, we found that the amide proton exchange rate decreased from 29.6 ± 5.6 to 12.1 ± 1.3 s-1 (P < 0.001), whereas the amide proton concentration showed little change (0.241 ± 0.035% vs. 0.202 ± 0.034%, P = 0.074) following global ischemia. CONCLUSION Our study determined the labile proton concentration and exchange rate underlying the in vivo APT MRI. The significant change in the exchange rate, but not the concentration of amide proton demonstrated that the pH effect dominates the APT contrast during tissue ischemia.
Collapse
Affiliation(s)
- Yang Ji
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital and Harvard Medical School, Charlestown, MA, USA
- Wellcome Centre for Integrative Neuroimaging, FMRIB Division, Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, UK
| | - Dongshuang Lu
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital and Harvard Medical School, Charlestown, MA, USA
| | - Phillip Zhe Sun
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital and Harvard Medical School, Charlestown, MA, USA
- Emory Primate Imaging Center, Emory Primate Research Center, Emory University, Atlanta, GA, USA
- Department of Radiology and Imaging Sciences, Emory University School of Medicine, Atlanta, GA, USA
| | - Iris Y. Zhou
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital and Harvard Medical School, Charlestown, MA, USA
| |
Collapse
|
9
|
Combes AJ, Clarke MA, O'Grady KP, Schilling KG, Smith SA. Advanced spinal cord MRI in multiple sclerosis: Current techniques and future directions. Neuroimage Clin 2022; 36:103244. [PMID: 36306717 PMCID: PMC9668663 DOI: 10.1016/j.nicl.2022.103244] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2022] [Revised: 09/02/2022] [Accepted: 10/19/2022] [Indexed: 11/11/2022]
Abstract
Spinal cord magnetic resonance imaging (MRI) has a central role in multiple sclerosis (MS) clinical practice for diagnosis and disease monitoring. Advanced MRI sequences capable of visualizing and quantifying tissue macro- and microstructure and reflecting different pathological disease processes have been used in MS research; however, the spinal cord remains under-explored, partly due to technical obstacles inherent to imaging this structure. We propose that the study of the spinal cord merits equal ambition in overcoming technical challenges, and that there is much information to be exploited to make valuable contributions to our understanding of MS. We present a narrative review on the latest progress in advanced spinal cord MRI in MS, covering in the first part structural, functional, metabolic and vascular imaging methods. We focus on recent studies of MS and those making significant technical steps, noting the challenges that remain to be addressed and what stands to be gained from such advances. Throughout we also refer to other works that presend more in-depth review on specific themes. In the second part, we present several topics that, in our view, hold particular potential. The need for better imaging of gray matter is discussed. We stress the importance of developing imaging beyond the cervical spinal cord, and explore the use of ultra-high field MRI. Finally, some recommendations are given for future research, from study design to newer developments in analysis, and the need for harmonization of sequences and methods within the field. This review is aimed at researchers and clinicians with an interest in gaining an overview of the current state of advanced MRI research in this field and what is primed to be the future of spinal cord imaging in MS research.
Collapse
Affiliation(s)
- Anna J.E. Combes
- Vanderbilt University Institute of Imaging Science, Vanderbilt University Medical Center, 1161 21st Avenue South, Medical Center North, AA-1105, Nashville, TN 37232-2310, United States,Department of Radiology and Radiological Sciences, Vanderbilt University Medical Center, Medical Center North, 1161 21st Ave. South, Nashville, TN 37232, United States,Corresponding author at: 1161 21st Ave S, MCN AA1105, Nashville, TN 37232, USA.
| | - Margareta A. Clarke
- Vanderbilt University Institute of Imaging Science, Vanderbilt University Medical Center, 1161 21st Avenue South, Medical Center North, AA-1105, Nashville, TN 37232-2310, United States
| | - Kristin P. O'Grady
- Vanderbilt University Institute of Imaging Science, Vanderbilt University Medical Center, 1161 21st Avenue South, Medical Center North, AA-1105, Nashville, TN 37232-2310, United States,Department of Radiology and Radiological Sciences, Vanderbilt University Medical Center, Medical Center North, 1161 21st Ave. South, Nashville, TN 37232, United States,Department of Biomedical Engineering, Vanderbilt University, 2301 Vanderbilt Place, PMB 351826, Nashville, TN 37235-1826, United States
| | - Kurt G. Schilling
- Vanderbilt University Institute of Imaging Science, Vanderbilt University Medical Center, 1161 21st Avenue South, Medical Center North, AA-1105, Nashville, TN 37232-2310, United States,Department of Radiology and Radiological Sciences, Vanderbilt University Medical Center, Medical Center North, 1161 21st Ave. South, Nashville, TN 37232, United States
| | - Seth A. Smith
- Vanderbilt University Institute of Imaging Science, Vanderbilt University Medical Center, 1161 21st Avenue South, Medical Center North, AA-1105, Nashville, TN 37232-2310, United States,Department of Radiology and Radiological Sciences, Vanderbilt University Medical Center, Medical Center North, 1161 21st Ave. South, Nashville, TN 37232, United States,Department of Biomedical Engineering, Vanderbilt University, 2301 Vanderbilt Place, PMB 351826, Nashville, TN 37235-1826, United States
| |
Collapse
|
10
|
Thomas AM, Yang E, Smith MD, Chu C, Calabresi PA, Glunde K, van Zijl PCM, Bulte JWM. CEST MRI and MALDI imaging reveal metabolic alterations in the cervical lymph nodes of EAE mice. J Neuroinflammation 2022; 19:130. [PMID: 35659311 PMCID: PMC9164344 DOI: 10.1186/s12974-022-02493-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2021] [Accepted: 05/15/2022] [Indexed: 11/10/2022] Open
Abstract
Background Multiple sclerosis (MS) is a neurodegenerative disease, wherein aberrant immune cells target myelin-ensheathed nerves. Conventional magnetic resonance imaging (MRI) can be performed to monitor damage to the central nervous system that results from previous inflammation; however, these imaging biomarkers are not necessarily indicative of active, progressive stages of the disease. The immune cells responsible for MS are first activated and sensitized to myelin in lymph nodes (LNs). Here, we present a new strategy for monitoring active disease activity in MS, chemical exchange saturation transfer (CEST) MRI of LNs. Methods and results We studied the potential utility of conventional (T2-weighted) and CEST MRI to monitor changes in these LNs during disease progression in an experimental autoimmune encephalomyelitis (EAE) model. We found CEST signal changes corresponded temporally with disease activity. CEST signals at the 3.2 ppm frequency during the active stage of EAE correlated significantly with the cellular (flow cytometry) and metabolic (mass spectrometry imaging) composition of the LNs, as well as immune cell infiltration into brain and spinal cord tissue. Correlating primary metabolites as identified by matrix-assisted laser desorption/ionization (MALDI) imaging included alanine, lactate, leucine, malate, and phenylalanine. Conclusions Taken together, we demonstrate the utility of CEST MRI signal changes in superficial cervical LNs as a complementary imaging biomarker for monitoring disease activity in MS. CEST MRI biomarkers corresponded to disease activity, correlated with immune activation (surface markers, antigen-stimulated proliferation), and correlated with LN metabolite levels. Supplementary Information The online version contains supplementary material available at 10.1186/s12974-022-02493-z.
Collapse
Affiliation(s)
- Aline M Thomas
- Russell H. Morgan Department of Radiology and Radiological Science, Division of MR Research, Johns Hopkins University School of Medicine, MD, 21205, Baltimore, USA.,Cellular Imaging Section and Vascular Biology Program, Institute for Cell Engineering, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Ethan Yang
- Russell H. Morgan Department of Radiology and Radiological Science, Division of MR Research, Johns Hopkins University School of Medicine, MD, 21205, Baltimore, USA
| | - Matthew D Smith
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD, USA.,Solomon H Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Chengyan Chu
- Russell H. Morgan Department of Radiology and Radiological Science, Division of MR Research, Johns Hopkins University School of Medicine, MD, 21205, Baltimore, USA.,Cellular Imaging Section and Vascular Biology Program, Institute for Cell Engineering, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Peter A Calabresi
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD, USA.,Solomon H Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Kristine Glunde
- Russell H. Morgan Department of Radiology and Radiological Science, Division of MR Research, Johns Hopkins University School of Medicine, MD, 21205, Baltimore, USA.,Department of Oncology, Johns Hopkins University School of Medicine, Baltimore, MD, USA.,Department of Biological Chemistry, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Peter C M van Zijl
- Russell H. Morgan Department of Radiology and Radiological Science, Division of MR Research, Johns Hopkins University School of Medicine, MD, 21205, Baltimore, USA.,F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, MD, USA
| | - Jeff W M Bulte
- Russell H. Morgan Department of Radiology and Radiological Science, Division of MR Research, Johns Hopkins University School of Medicine, MD, 21205, Baltimore, USA. .,Cellular Imaging Section and Vascular Biology Program, Institute for Cell Engineering, Johns Hopkins University School of Medicine, Baltimore, MD, USA. .,Department of Biological Chemistry, Johns Hopkins University School of Medicine, Baltimore, MD, USA. .,F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, MD, USA. .,Department of Biomedical Engineering, Johns Hopkins University School of Medicine, Baltimore, MD, USA. .,Department of Chemical and Biomolecular Engineering, Johns Hopkins University School of Medicine, Baltimore, MD, USA.
| |
Collapse
|
11
|
Kreiter DJ, van den Hurk J, Wiggins CJ, Hupperts RMM, Gerlach OHH. Ultra-high field spinal cord MRI in multiple sclerosis: Where are we standing? A literature review. Mult Scler Relat Disord 2021; 57:103436. [PMID: 34871855 DOI: 10.1016/j.msard.2021.103436] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2021] [Revised: 11/18/2021] [Accepted: 11/27/2021] [Indexed: 12/24/2022]
Abstract
Magnetic resonance imaging (MRI) is a cornerstone in multiple sclerosis (MS) diagnostics and monitoring. Ultra-high field (UHF) MRI is being increasingly used and becoming more accessible. Due to the small diameter and mobility of the spinal cord, imaging this structure at ultra-high fields poses additional challenges compared to brain imaging. Here we review the potential benefits for the MS field by providing a literature overview of the use UHF spinal cord MRI in MS research and we elaborate on the challenges that are faced. Benefits include increased signal- and contrast-to-noise, enabling for higher spatial resolutions, which can improve MS lesion sensitivity in both the spinal white matter as well as grey matter. Additionally, these benefits can aid imaging of microstructural abnormalities in the spinal cord in MS using advanced MRI techniques like functional imaging, MR spectroscopy and diffusion-based techniques. Technical challenges include increased magnetic field inhomogeneities, distortions from physiological motion and optimalisation of sequences. Approaches including parallel imaging techniques, real time shimming and retrospective compensation of physiological motion are making it increasingly possible to unravel the potential of spinal cord UHF MRI in the context of MS research.
Collapse
Affiliation(s)
- Daniël J Kreiter
- Academic MS center Zuyderland, Department of Neurology, Zuyderland Medical Center, Sittard-Geleen, The Netherlands; School for Mental Health and Neuroscience, Department of Neurology, Maastricht University Medical Center, Maastricht, The Netherlands.
| | - Job van den Hurk
- Scannexus, Maastricht, The Netherlands; Maastricht University, Faculty of Health, Medicine & Life Sciences, Maastricht, The Netherlands
| | | | - Raymond M M Hupperts
- Academic MS center Zuyderland, Department of Neurology, Zuyderland Medical Center, Sittard-Geleen, The Netherlands; School for Mental Health and Neuroscience, Department of Neurology, Maastricht University Medical Center, Maastricht, The Netherlands
| | - Oliver H H Gerlach
- Academic MS center Zuyderland, Department of Neurology, Zuyderland Medical Center, Sittard-Geleen, The Netherlands; School for Mental Health and Neuroscience, Department of Neurology, Maastricht University Medical Center, Maastricht, The Netherlands.
| |
Collapse
|
12
|
Imaging of the Spinal Cord in Multiple Sclerosis: Past, Present, Future. Brain Sci 2020; 10:brainsci10110857. [PMID: 33202821 PMCID: PMC7696997 DOI: 10.3390/brainsci10110857] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2020] [Revised: 10/30/2020] [Accepted: 11/11/2020] [Indexed: 11/17/2022] Open
Abstract
Spinal cord imaging in multiple sclerosis (MS) plays a significant role in diagnosing and tracking disease progression. The spinal cord is one of four key areas of the central nervous system where documenting the dissemination in space in the McDonald criteria for diagnosing MS. Spinal cord lesion load and the severity of cord atrophy are believed to be more relevant to disability than white matter lesions in the brain in different phenotypes of MS. Axonal loss contributes to spinal cord atrophy in MS and its degree correlates with disease severity and prognosis. Therefore, measures of axonal loss are often reliable biomarkers for monitoring disease progression. With recent technical advances, more and more qualitative and quantitative MRI techniques have been investigated in an attempt to provide objective and reliable diagnostic and monitoring biomarkers in MS. In this article, we discuss the role of spinal cord imaging in the diagnosis and prognosis of MS and, additionally, we review various techniques that may improve our understanding of the disease.
Collapse
|
13
|
Demetriou E, Kujawa A, Golay X. Pulse sequences for measuring exchange rates between proton species: From unlocalised NMR spectroscopy to chemical exchange saturation transfer imaging. PROGRESS IN NUCLEAR MAGNETIC RESONANCE SPECTROSCOPY 2020; 120-121:25-71. [PMID: 33198968 DOI: 10.1016/j.pnmrs.2020.06.001] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/30/2019] [Revised: 06/27/2020] [Accepted: 06/30/2020] [Indexed: 06/11/2023]
Abstract
Within the field of NMR spectroscopy, the study of chemical exchange processes through saturation transfer techniques has a long history. In the context of MRI, chemical exchange techniques have been adapted to increase the sensitivity of imaging to small fractions of exchangeable protons, including the labile protons of amines, amides and hydroxyls. The MR contrast is generated by frequency-selective irradiation of the labile protons, which results in a reduction of the water signal associated with transfer of the labile protons' saturated magnetization to the protons of the surrounding free water. The signal intensity depends on the rate of chemical exchange and the concentration of labile protons as well as on the properties of the irradiation field. This methodology is referred to as CEST (chemical exchange saturation transfer) imaging. Applications of CEST include imaging of molecules with short transverse relaxation times and mapping of physiological parameters such as pH, temperature, buffer concentration and chemical composition due to the dependency of this chemical exchange effect on all these parameters. This article aims to describe these effects both theoretically and experimentally. In depth analysis and mathematical modelling are provided for all pulse sequences designed to date to measure the chemical exchange rate. Importantly, it has become clear that the background signal from semi-solid protons and the presence of the Nuclear Overhauser Effect (NOE), either through direct dipole-dipole mechanisms or through exchange-relayed signals, complicates the analysis of CEST effects. Therefore, advanced methods to suppress these confounding factors have been developed, and these are also reviewed. Finally, the experimental work conducted both in vitro and in vivo is discussed and the progress of CEST imaging towards clinical practice is presented.
Collapse
Affiliation(s)
- Eleni Demetriou
- Brain Repair & Rehabilitation, Institute of Neurology, University College London, United Kingdom.
| | - Aaron Kujawa
- Brain Repair & Rehabilitation, Institute of Neurology, University College London, United Kingdom.
| | - Xavier Golay
- Brain Repair & Rehabilitation, Institute of Neurology, University College London, United Kingdom.
| |
Collapse
|
14
|
Anterior fissure, central canal, posterior septum and more: New insights into the cervical spinal cord gray and white matter regional organization using T1 mapping at 7T. Neuroimage 2020; 205:116275. [DOI: 10.1016/j.neuroimage.2019.116275] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2019] [Revised: 09/16/2019] [Accepted: 10/10/2019] [Indexed: 12/12/2022] Open
|
15
|
Swanberg KM, Landheer K, Pitt D, Juchem C. Quantifying the Metabolic Signature of Multiple Sclerosis by in vivo Proton Magnetic Resonance Spectroscopy: Current Challenges and Future Outlook in the Translation From Proton Signal to Diagnostic Biomarker. Front Neurol 2019; 10:1173. [PMID: 31803127 PMCID: PMC6876616 DOI: 10.3389/fneur.2019.01173] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2019] [Accepted: 10/21/2019] [Indexed: 01/03/2023] Open
Abstract
Proton magnetic resonance spectroscopy (1H-MRS) offers a growing variety of methods for querying potential diagnostic biomarkers of multiple sclerosis in living central nervous system tissue. For the past three decades, 1H-MRS has enabled the acquisition of a rich dataset suggestive of numerous metabolic alterations in lesions, normal-appearing white matter, gray matter, and spinal cord of individuals with multiple sclerosis, but this body of information is not free of seeming internal contradiction. The use of 1H-MRS signals as diagnostic biomarkers depends on reproducible and generalizable sensitivity and specificity to disease state that can be confounded by a multitude of influences, including experiment group classification and demographics; acquisition sequence; spectral quality and quantifiability; the contribution of macromolecules and lipids to the spectroscopic baseline; spectral quantification pipeline; voxel tissue and lesion composition; T1 and T2 relaxation; B1 field characteristics; and other features of study design, spectral acquisition and processing, and metabolite quantification about which the experimenter may possess imperfect or incomplete information. The direct comparison of 1H-MRS data from individuals with and without multiple sclerosis poses a special challenge in this regard, as several lines of evidence suggest that experimental cohorts may differ significantly in some of these parameters. We review the existing findings of in vivo1H-MRS on central nervous system metabolic abnormalities in multiple sclerosis and its subtypes within the context of study design, spectral acquisition and processing, and metabolite quantification and offer an outlook on technical considerations, including the growing use of machine learning, by future investigations into diagnostic biomarkers of multiple sclerosis measurable by 1H-MRS.
Collapse
Affiliation(s)
- Kelley M Swanberg
- Department of Biomedical Engineering, Columbia University Fu Foundation School of Engineering and Applied Science, New York, NY, United States
| | - Karl Landheer
- Department of Biomedical Engineering, Columbia University Fu Foundation School of Engineering and Applied Science, New York, NY, United States
| | - David Pitt
- Department of Neurology, Yale University School of Medicine, New Haven, CT, United States
| | - Christoph Juchem
- Department of Biomedical Engineering, Columbia University Fu Foundation School of Engineering and Applied Science, New York, NY, United States.,Department of Radiology, Columbia University College of Physicians and Surgeons, New York, NY, United States
| |
Collapse
|
16
|
Thomas AM, Xu J, Calabresi PA, van Zijl PCM, Bulte JWM. Monitoring diffuse injury during disease progression in experimental autoimmune encephalomyelitis with on resonance variable delay multiple pulse (onVDMP) CEST MRI. Neuroimage 2019; 204:116245. [PMID: 31605825 DOI: 10.1016/j.neuroimage.2019.116245] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2019] [Revised: 09/16/2019] [Accepted: 10/03/2019] [Indexed: 12/24/2022] Open
Abstract
Multiple sclerosis (MS) is an autoimmune disorder that targets myelin proteins and results in extensive damage in the central nervous system in the form of focal lesions as well as diffuse molecular changes. Lesions are currently detected using T1-weighted, T2-weighted, and gadolinium-enhanced magnetic resonance imaging (MRI); however, monitoring such lesions has been shown to be a poor predictor of disease progression. Chemical exchange saturation transfer (CEST) MRI is sensitive to many of the biomolecules in the central nervous system altered in MS that cannot be detected using conventional MRI. We monitored disease progression in an experimental autoimmune encephalomyelitis (EAE) model of MS using on resonance variable delay multiple pulse (onVDMP) CEST MRI. Alterations in onVDMP signal were observed in regions responsible for hindlimb function throughout the central nervous system. Histological analysis revealed glial activation in areas highlighted in onVDMP CEST MRI. onVDMP signal changes in the 3rd ventricle preceded paralysis onset that could not be observed with conventional MRI techniques. Hence, the onVDMP CEST MRI signal has potential as a novel imaging biomarker and predictor of disease progression in MS.
Collapse
Affiliation(s)
- Aline M Thomas
- The Russell H. Morgan Department of Radiology and Radiological Science, Division of MR Research, The Johns Hopkins University School of Medicine, Baltimore, MD, USA; Cellular Imaging Section and Vascular Biology Program, Institute for Cell Engineering, The Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Jiadi Xu
- The Russell H. Morgan Department of Radiology and Radiological Science, Division of MR Research, The Johns Hopkins University School of Medicine, Baltimore, MD, USA; F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, MD, USA
| | - Peter A Calabresi
- Department of Neurology, The Johns Hopkins University School of Medicine, Baltimore, MD, USA; The Solomon H. Snyder Department of Neuroscience, The Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Peter C M van Zijl
- The Russell H. Morgan Department of Radiology and Radiological Science, Division of MR Research, The Johns Hopkins University School of Medicine, Baltimore, MD, USA; F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, MD, USA
| | - Jeff W M Bulte
- The Russell H. Morgan Department of Radiology and Radiological Science, Division of MR Research, The Johns Hopkins University School of Medicine, Baltimore, MD, USA; Cellular Imaging Section and Vascular Biology Program, Institute for Cell Engineering, The Johns Hopkins University School of Medicine, Baltimore, MD, USA; F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, MD, USA; Department of Oncology, The Johns Hopkins University School of Medicine, Baltimore, MD, USA; Department of Biomedical Engineering, The Johns Hopkins University School of Medicine, Baltimore, MD, USA; Department of Chemical & Biomolecular Engineering, The Johns Hopkins University School of Medicine, Baltimore, MD, USA.
| |
Collapse
|
17
|
Yu L, Li C, Luo X, Zhou J, Zhang C, Zhang Y, Chen M. Differentiation of Malignant and Benign Head and Neck Tumors with Amide Proton Transfer-Weighted MR Imaging. Mol Imaging Biol 2019; 21:348-355. [PMID: 29987616 DOI: 10.1007/s11307-018-1248-1] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
PURPOSE To prospectively evaluate the feasibility and capability of amide proton transfer-weighted (APTw) imaging for the characterization of head and neck tumors. PROCEDURES Twenty-nine consecutive patients with suspected head and neck tumors were enrolled in this study and underwent APTw magnetic resonance imaging (MRI) on a 3.0-T MRI scanner. The patients were divided into malignant (n = 16) and benign (n = 13) groups, based on pathological results. A map of magnetization transfer ratio asymmetry at 3.5 ppm [MTRasym (3.5 ppm)] was generated for each patient. Interobserver agreement was evaluated and comparisons of MTRasym (3.5 ppm) were made between the malignant and benign groups. Receiver operating characteristic analysis was used to determine the appropriate threshold value of MTRasym (3.5 ppm) for the differentiation of malignant from benign tumors. RESULTS The intraclass correlation coefficients of the malignant and benign groups were 0.96 and 0.90, respectively, which indicated a good interobserver agreement. MTRasym (3.5 ppm) was significantly higher for the malignant group (3.66 ± 1.15 %) than for the benign group (1.94 ± 0.93 %, P < 0.001). APTw MRI revealed an area under the curve of 0.904 in discriminating these two groups, with a sensitivity of 81.3 %, a specificity of 92.3 %, and an accuracy of 86.2 %, at the threshold of 2.62 % of MTRasym (3.5 ppm). CONCLUSIONS APTw MRI is feasible for use in the head and neck tumors and is a valuable imaging biomarker for distinguishing malignant from benign lesions.
Collapse
Affiliation(s)
- Lu Yu
- Department of Radiology, Beijing Hospital, National Center of Gerontology, No. 1 Da-Hua Road, Dong Dan, Beijing, 100730, China.,Graduate School of Peking Union Medical College, No. 9 Dong Dan San Tiao, Beijing, 100730, China
| | - Chunmei Li
- Department of Radiology, Beijing Hospital, National Center of Gerontology, No. 1 Da-Hua Road, Dong Dan, Beijing, 100730, China
| | - Xiaojie Luo
- Department of Radiology, Beijing Hospital, National Center of Gerontology, No. 1 Da-Hua Road, Dong Dan, Beijing, 100730, China
| | - Jinyuan Zhou
- Department of Radiology, Johns Hopkins University, 600 N. Wolfe Street, Park 336, Baltimore, MD, 21287, USA
| | - Chen Zhang
- Department of Radiology, Beijing Hospital, National Center of Gerontology, No. 1 Da-Hua Road, Dong Dan, Beijing, 100730, China
| | - Yi Zhang
- Center for Brain Imaging Science and Technology, Key Laboratory for Biomedical Engineering of Ministry of Education, College of Biomedical Engineering & Instrument Science, Zhejiang University, No. 388 Yuhangtang Road, Hangzhou, 310058, Zhejiang, China
| | - Min Chen
- Department of Radiology, Beijing Hospital, National Center of Gerontology, No. 1 Da-Hua Road, Dong Dan, Beijing, 100730, China. .,Graduate School of Peking Union Medical College, No. 9 Dong Dan San Tiao, Beijing, 100730, China.
| |
Collapse
|
18
|
Chemical exchange saturation transfer (CEST) as a new method of signal obtainment in magnetic resonance molecular imaging in clinical and research practice. Pol J Radiol 2019; 84:e147-e152. [PMID: 31019609 PMCID: PMC6479148 DOI: 10.5114/pjr.2019.84242] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2019] [Accepted: 02/14/2019] [Indexed: 01/04/2023] Open
Abstract
The work describes the physical basis of the chemical exchange saturation transfer (CEST) technique; it presents the beginnings of the implementation of the method and its possible applications. The principles of correct data acquisition and possible solutions used during the design of the CEST sequence are shown. The main problems related to data analysis are indicated, and an example Z-spectrum from in vivo study of the rat brain is introduced. Furthermore, the parameters related to spectrum analyses such as magnetisation transfer asymmetry (MTRasym) and amide proton transfer asymmetry (APTasym) are presented. In the following part, different types of the CEST method often mentioned in the literature are discussed. Subsequently, the possible applications of the CEST method in both clinical and experimental practice are described.
Collapse
|
19
|
O'Grady KP, Dula AN, Lyttle BD, Thompson LM, Conrad BN, Box BA, McKeithan LJ, Pawate S, Bagnato F, Landman BA, Newhouse P, Smith SA. Glutamate-sensitive imaging and evaluation of cognitive impairment in multiple sclerosis. Mult Scler 2018; 25:1580-1592. [PMID: 30230400 DOI: 10.1177/1352458518799583] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
BACKGROUND Cognitive impairment (CI) profoundly impacts quality of life for patients with multiple sclerosis (MS). Dysfunctional regulation of glutamate in gray matter (GM) has been implicated in the pathogenesis of MS by post-mortem pathological studies and in CI by in vivo magnetic resonance spectroscopy, yet GM pathology is subtle and difficult to detect using conventional T1- and T2-weighted magnetic resonance imaging (MRI). There is a need for high-resolution, clinically accessible imaging techniques that probe molecular changes in GM. OBJECTIVE To study cortical GM pathology related to CI in MS using glutamate-sensitive chemical exchange saturation transfer (GluCEST) MRI at 7.0 Tesla (7T). METHODS A total of 20 patients with relapsing-remitting MS and 20 healthy controls underwent cognitive testing, anatomical imaging, and GluCEST imaging. Glutamate-sensitive image contrast was quantified for cortical GM, compared between cohorts, and correlated with clinical measures of CI. RESULTS AND CONCLUSION Glutamate-sensitive contrast was significantly increased in the prefrontal cortex of MS patients with accumulated disability (p < 0.05). In addition, glutamate-sensitive contrast in the prefrontal cortex was significantly correlated with symbol digit modality test (rS = -0.814) and choice reaction time (rS = 0.772) scores in patients (p < 0.05), suggesting that GluCEST MRI may have utility as a marker for GM pathology and CI.
Collapse
Affiliation(s)
- Kristin P O'Grady
- Vanderbilt University Institute of Imaging Science, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Adrienne N Dula
- Department of Neurology, Dell Medical School, The University of Texas at Austin, Austin, TX, USA
| | - Bailey D Lyttle
- Vanderbilt University Institute of Imaging Science, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Lindsey M Thompson
- Vanderbilt University Institute of Imaging Science, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Benjamin N Conrad
- Neuroscience Graduate Program, Vanderbilt Brain Institute, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Bailey A Box
- Vanderbilt University Institute of Imaging Science, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Lydia J McKeithan
- Vanderbilt University Institute of Imaging Science, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Siddharama Pawate
- Vanderbilt Department of Neurology, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Francesca Bagnato
- Neuroimaging Unit, Neuroimmunology Division, Vanderbilt Department of Neurology, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Bennett A Landman
- Vanderbilt University Institute of Imaging Science, Vanderbilt University Medical Center, Nashville, TN, USA/Department of Electrical Engineering and Computer Science, Vanderbilt University, Nashville, TN, USA/Department of Biomedical Engineering, Vanderbilt University, Nashville, TN, USA/Department of Radiology and Radiological Sciences, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Paul Newhouse
- Department of Psychiatry and Behavioral Sciences, Center for Cognitive Medicine, Vanderbilt University Medical Center, Nashville, TN, USA/Veterans Affairs Tennessee Valley Healthcare System Geriatric Research, Education, and Clinical Center (VA TVHS GRECC), Nashville, TN, USA
| | - Seth A Smith
- Vanderbilt University Institute of Imaging Science, Vanderbilt University Medical Center, Nashville, TN, USA/Department of Biomedical Engineering, Vanderbilt University, Nashville, TN, USA/Department of Radiology and Radiological Sciences, Vanderbilt University Medical Center, Nashville, TN, USA
| |
Collapse
|
20
|
Abstract
Spinal cord (SC) MRI in multiple sclerosis (MS) has significant usefulness in clinical and investigational settings. Conventional MRI of the SC is used in clinical practice, because it has both diagnostic and prognostic value. A number of advanced, quantitative SC MRI measures that assess the structural and functional integrity of the SC have been evaluated in investigational settings. These techniques have collectively demonstrated usefulness in providing insight into microstructural and functional changes relevant to disability in MS. With further development, these techniques may be useful in clinical trial settings as biomarkers of neurodegeneration and protection, and in day-to-day clinical practice.
Collapse
Affiliation(s)
- Alexandra Muccilli
- Division of Neurology, St. Michael's Hospital, University of Toronto, 30 Bond Street, Toronto, Ontario, M5B 1W8, Canada; Division of Neurology, Centre Hospitalier de L'Université de Montréal, Université de Montréal, 1058 Saint-Denis Street, Montreal, Quebec H2X 3J4, Canada
| | - Estelle Seyman
- Division of Neurology, St. Michael's Hospital, University of Toronto, 30 Bond Street, Toronto, Ontario, M5B 1W8, Canada
| | - Jiwon Oh
- Division of Neurology, St. Michael's Hospital, University of Toronto, 30 Bond Street, Toronto, Ontario, M5B 1W8, Canada; Department of Neurology, Johns Hopkins University, Baltimore, MD, USA.
| |
Collapse
|
21
|
Barry RL, Vannesjo SJ, By S, Gore JC, Smith SA. Spinal cord MRI at 7T. Neuroimage 2018; 168:437-451. [PMID: 28684332 PMCID: PMC5894871 DOI: 10.1016/j.neuroimage.2017.07.003] [Citation(s) in RCA: 57] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2016] [Revised: 06/30/2017] [Accepted: 07/02/2017] [Indexed: 11/25/2022] Open
Abstract
Magnetic resonance imaging (MRI) of the human spinal cord at 7T has been demonstrated by a handful of research sites worldwide, and the spinal cord remains one of the areas in which higher fields and resolution could have high impact. The small diameter of the cord (∼1 cm) necessitates high spatial resolution to minimize partial volume effects between gray and white matter, and so MRI of the cord can greatly benefit from increased signal-to-noise ratio and contrasts at ultra-high field (UHF). Herein we review the current state of UHF spinal cord imaging. Technical challenges to successful UHF spinal cord MRI include radiofrequency (B1) nonuniformities and a general lack of optimized radiofrequency coils, amplified physiological noise, and an absence of methods for robust B0 shimming along the cord to mitigate image distortions and signal losses. Numerous solutions to address these challenges have been and are continuing to be explored, and include novel approaches for signal excitation and acquisition, dynamic shimming and specialized shim coils, and acquisitions with increased coverage or optimal slice angulations.
Collapse
Affiliation(s)
- Robert L Barry
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Charlestown, MA, USA; Department of Radiology, Harvard Medical School, Boston, MA, USA.
| | - S Johanna Vannesjo
- Oxford Centre for Functional MRI of the Brain (FMRIB), Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, UK
| | - Samantha By
- Vanderbilt University Institute of Imaging Science, Vanderbilt University Medical Center, Nashville, TN, USA; Department of Biomedical Engineering, Vanderbilt University, Nashville, TN, USA
| | - John C Gore
- Vanderbilt University Institute of Imaging Science, Vanderbilt University Medical Center, Nashville, TN, USA; Department of Biomedical Engineering, Vanderbilt University, Nashville, TN, USA; Department of Radiology and Radiological Sciences, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Seth A Smith
- Vanderbilt University Institute of Imaging Science, Vanderbilt University Medical Center, Nashville, TN, USA; Department of Biomedical Engineering, Vanderbilt University, Nashville, TN, USA; Department of Radiology and Radiological Sciences, Vanderbilt University Medical Center, Nashville, TN, USA
| |
Collapse
|
22
|
Massire A, Rasoanandrianina H, Taso M, Guye M, Ranjeva JP, Feiweier T, Callot V. Feasibility of single-shot multi-level multi-angle diffusion tensor imaging of the human cervical spinal cord at 7T. Magn Reson Med 2018; 80:947-957. [DOI: 10.1002/mrm.27087] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2017] [Revised: 12/07/2017] [Accepted: 12/26/2017] [Indexed: 01/11/2023]
Affiliation(s)
- Aurélien Massire
- Aix-Marseille Univ, CNRS, AP-HM, CRMBM, Hôpital de la Timone; CEMEREM Marseille France
- iLab-Spine - Laboratoire international associé - Imagerie et Biomécanique du rachis, France; Canada
| | - Henitsoa Rasoanandrianina
- Aix-Marseille Univ, CNRS, AP-HM, CRMBM, Hôpital de la Timone; CEMEREM Marseille France
- iLab-Spine - Laboratoire international associé - Imagerie et Biomécanique du rachis, France; Canada
| | - Manuel Taso
- Aix-Marseille Univ, CNRS, AP-HM, CRMBM, Hôpital de la Timone; CEMEREM Marseille France
- iLab-Spine - Laboratoire international associé - Imagerie et Biomécanique du rachis, France; Canada
- Division of MRI Research, Department of Radiology; Beth Israel Deaconess Medical Center & Harvard Medical School; Boston Massachusetts USA
| | - Maxime Guye
- Aix-Marseille Univ, CNRS, AP-HM, CRMBM, Hôpital de la Timone; CEMEREM Marseille France
| | - Jean-Philippe Ranjeva
- Aix-Marseille Univ, CNRS, AP-HM, CRMBM, Hôpital de la Timone; CEMEREM Marseille France
- iLab-Spine - Laboratoire international associé - Imagerie et Biomécanique du rachis, France; Canada
| | | | - Virginie Callot
- Aix-Marseille Univ, CNRS, AP-HM, CRMBM, Hôpital de la Timone; CEMEREM Marseille France
- iLab-Spine - Laboratoire international associé - Imagerie et Biomécanique du rachis, France; Canada
| |
Collapse
|
23
|
Jones KM, Pollard AC, Pagel MD. Clinical applications of chemical exchange saturation transfer (CEST) MRI. J Magn Reson Imaging 2017; 47:11-27. [PMID: 28792646 DOI: 10.1002/jmri.25838] [Citation(s) in RCA: 184] [Impact Index Per Article: 26.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2017] [Accepted: 05/30/2017] [Indexed: 02/06/2023] Open
Abstract
Chemical exchange saturation transfer (CEST) magnetic resonance imaging (MRI) has been developed and employed in multiple clinical imaging research centers worldwide. Selective radiofrequency (RF) saturation pulses with standard 2D and 3D MRI acquisition schemes are now routinely performed, and CEST MRI can produce semiquantitative results using magnetization transfer ratio asymmetry (MTRasym ) analysis while accounting for B0 inhomogeneity. Faster clinical CEST MRI acquisition methods and more quantitative acquisition and analysis routines are under development. Endogenous biomolecules with amide, amine, and hydroxyl groups have been detected during clinical CEST MRI studies, and exogenous CEST agents have also been administered to patients. These CEST MRI tools show promise for contributing to assessments of cerebral ischemia, neurological disorders, lymphedema, osteoarthritis, muscle physiology, and solid tumors. This review summarizes the salient features of clinical CEST MRI protocols and critically evaluates the utility of CEST MRI for these clinical imaging applications. LEVEL OF EVIDENCE 5 Technical Efficacy: Stage 1 J. Magn. Reson. Imaging 2018;47:11-27.
Collapse
Affiliation(s)
- Kyle M Jones
- Department of Biomedical Engineering, University of Arizona, Tucson, Arizona, USA
| | | | - Mark D Pagel
- Department of Biomedical Engineering, University of Arizona, Tucson, Arizona, USA.,Department of Chemistry, Rice University, Houston, Texas, USA.,Department of Cancer Systems Imaging, MD Anderson Cancer Center, Houston, Texas, USA
| |
Collapse
|
24
|
By S, Barry RL, Smith AK, Lyttle BD, Box BA, Bagnato FR, Pawate S, Smith SA. Amide proton transfer CEST of the cervical spinal cord in multiple sclerosis patients at 3T. Magn Reson Med 2017; 79:806-814. [PMID: 28474409 DOI: 10.1002/mrm.26736] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2016] [Revised: 04/03/2017] [Accepted: 04/04/2017] [Indexed: 12/12/2022]
Abstract
PURPOSE The ability to evaluate pathological changes in the spinal cord in multiple sclerosis (MS) is limited because T1 - and T2 -w MRI imaging are not sensitive to biochemical changes in vivo. Amide proton transfer (APT) chemical exchange saturation transfer (CEST) can indirectly detect amide protons associated with proteins and peptides, potentially providing more pathological specificity. Here, we implement APT CEST in the cervical spinal cord of healthy and MS cohorts at 3T. METHODS APT CEST of the cervical spinal cord was obtained in a cohort of 10 controls and 10 MS patients using a novel respiratory correction methodology. APT was quantified using two methods: 1) APTw , based off the conventional magnetization transfer ratio asymmetry, and 2) ΔAPT, a spatial characterization of APT changes in MS patients relative to the controls. RESULTS Respiratory correction yielded highly reproducible z-spectra in white matter (intraclass correlation coefficient = 0.82). APTw signals in normal-appearing white matter (NAWM) of MS patients were significantly different from healthy controls (P = 0.04), whereas ΔAPT of MS patients highlighted large APT differences in NAWM. CONCLUSION Respiration correction in the spinal cord is necessary to accurately quantify APT CEST, which can provide unique biochemical information regarding disease processes within the spinal cord. Magn Reson Med 79:806-814, 2018. © 2017 International Society for Magnetic Resonance in Medicine.
Collapse
Affiliation(s)
- Samantha By
- Department of Biomedical Engineering, Vanderbilt University, Nashville, Tennessee, USA.,Vanderbilt University Institute of Imaging Science, Vanderbilt University Medical Center, Nashville, Tennessee, USA
| | - Robert L Barry
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Charlestown, Massachusetts, USA.,Department of Radiology, Harvard Medical School, Boston, Massachusetts, USA
| | - Alex K Smith
- Department of Biomedical Engineering, Vanderbilt University, Nashville, Tennessee, USA.,Vanderbilt University Institute of Imaging Science, Vanderbilt University Medical Center, Nashville, Tennessee, USA.,Functional MRI of the Brain Centre, Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, United Kingdom
| | - Bailey D Lyttle
- Vanderbilt University Institute of Imaging Science, Vanderbilt University Medical Center, Nashville, Tennessee, USA
| | - Bailey A Box
- Vanderbilt University Institute of Imaging Science, Vanderbilt University Medical Center, Nashville, Tennessee, USA
| | - Francesca R Bagnato
- Department of Neurology, Vanderbilt University Medical Center, Nashville, Tennessee, USA
| | - Siddharama Pawate
- Department of Neurology, Vanderbilt University Medical Center, Nashville, Tennessee, USA
| | - Seth A Smith
- Department of Biomedical Engineering, Vanderbilt University, Nashville, Tennessee, USA.,Vanderbilt University Institute of Imaging Science, Vanderbilt University Medical Center, Nashville, Tennessee, USA.,Department of Radiology and Radiological Sciences, Vanderbilt University Medical Center, Nashville, Tennessee, USA
| |
Collapse
|