1
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Mason EE, Mattingly E, Herb K, Cauley SF, Śliwiak M, Drago JM, Graeser M, Mandeville ET, Mandeville JB, Wald LL. Functional magnetic particle imaging (fMPI) of cerebrovascular changes in the rat brain during hypercapnia. Phys Med Biol 2023; 68:175032. [PMID: 37531961 PMCID: PMC10461175 DOI: 10.1088/1361-6560/acecd1] [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: 05/18/2023] [Revised: 07/09/2023] [Accepted: 08/01/2023] [Indexed: 08/04/2023]
Abstract
Objective.Non-invasive functional brain imaging modalities are limited in number, each with its own complex trade-offs between sensitivity, spatial and temporal resolution, and the directness with which the measured signals reflect neuronal activation. Magnetic particle imaging (MPI) directly maps the cerebral blood volume (CBV), and its high sensitivity derives from the nonlinear magnetization of the superparamagnetic iron oxide nanoparticle (SPION) tracer confined to the blood pool. Our work evaluates functional MPI (fMPI) as a new hemodynamic functional imaging modality by mapping the CBV response in a rodent model where CBV is modulated by hypercapnic breathing manipulation.Approach.The rodent fMPI time-series data were acquired with a mechanically rotating field-free line MPI scanner capable of 5 s temporal resolution and 3 mm spatial resolution. The rat's CBV was modulated for 30 min with alternating 5 min hyper-/hypocapnic states, and processed using conventional fMRI tools. We compare our results to fMRI responses undergoing similar hypercapnia protocols found in the literature, and reinforce this comparison in a study of one rat with 9.4T BOLD fMRI using the identical protocol.Main results.The initial image in the time-series showed mean resting brain voxel SNR values, averaged across rats, of 99.9 following the first 10 mg kg-1SPION injection and 134 following the second. The time-series fit a conventional General Linear Model with a 15%-40% CBV change and a peak pixel CNR between 12 and 29, 2-6× higher than found in fMRI.Significance.This work introduces a functional modality with high sensitivity, although currently limited spatial and temporal resolution. With future clinical-scale development, a large increase in sensitivity could supplement other modalities and help transition functional brain imaging from a neuroscience tool focusing on population averages to a clinically relevant modality capable of detecting differences in individual patients.
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Affiliation(s)
- Erica E Mason
- A. A. Martinos Center for Biomedical Imaging, Dept. of Radiology, Massachusetts General Hospital, Charlestown, MA, United States of America
| | - Eli Mattingly
- A. A. Martinos Center for Biomedical Imaging, Dept. of Radiology, Massachusetts General Hospital, Charlestown, MA, United States of America
- Harvard-MIT Division of Health Sciences & Technology, Cambridge, MA, United States of America
- Harvard Medical School, Boston, MA, United States of America
| | - Konstantin Herb
- A. A. Martinos Center for Biomedical Imaging, Dept. of Radiology, Massachusetts General Hospital, Charlestown, MA, United States of America
- ETH Zurich, Department of Physics, Zurich, Switzerland
| | - Stephen F Cauley
- A. A. Martinos Center for Biomedical Imaging, Dept. of Radiology, Massachusetts General Hospital, Charlestown, MA, United States of America
- Harvard Medical School, Boston, MA, United States of America
| | - Monika Śliwiak
- A. A. Martinos Center for Biomedical Imaging, Dept. of Radiology, Massachusetts General Hospital, Charlestown, MA, United States of America
| | - John M Drago
- A. A. Martinos Center for Biomedical Imaging, Dept. of Radiology, Massachusetts General Hospital, Charlestown, MA, United States of America
- Harvard Medical School, Boston, MA, United States of America
- Massachusetts Institute of Technology, Department of Electrical Engineering & Computer Science, Cambridge, MA, United States of America
| | - Matthias Graeser
- Fraunhofer Research Institution for Individualized and Cell-Based Medical Engineering, IMTE, Lübeck, Germany
| | - Emiri T Mandeville
- A. A. Martinos Center for Biomedical Imaging, Dept. of Radiology, Massachusetts General Hospital, Charlestown, MA, United States of America
- Harvard Medical School, Boston, MA, United States of America
| | - Joseph B Mandeville
- A. A. Martinos Center for Biomedical Imaging, Dept. of Radiology, Massachusetts General Hospital, Charlestown, MA, United States of America
- Harvard Medical School, Boston, MA, United States of America
| | - Lawrence L Wald
- A. A. Martinos Center for Biomedical Imaging, Dept. of Radiology, Massachusetts General Hospital, Charlestown, MA, United States of America
- Harvard-MIT Division of Health Sciences & Technology, Cambridge, MA, United States of America
- Harvard Medical School, Boston, MA, United States of America
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2
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Liu Z, Zhu Y, Zhang L, Jiang W, Liu Y, Tang Q, Cai X, Li J, Wang L, Tao C, Yin X, Li X, Hou S, Jiang D, Liu K, Zhou X, Zhang H, Liu M, Fan C, Tian Y. Structural and functional imaging of brains. Sci China Chem 2022; 66:324-366. [PMID: 36536633 PMCID: PMC9753096 DOI: 10.1007/s11426-022-1408-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2022] [Accepted: 09/28/2022] [Indexed: 12/23/2022]
Abstract
Analyzing the complex structures and functions of brain is the key issue to understanding the physiological and pathological processes. Although neuronal morphology and local distribution of neurons/blood vessels in the brain have been known, the subcellular structures of cells remain challenging, especially in the live brain. In addition, the complicated brain functions involve numerous functional molecules, but the concentrations, distributions and interactions of these molecules in the brain are still poorly understood. In this review, frontier techniques available for multiscale structure imaging from organelles to the whole brain are first overviewed, including magnetic resonance imaging (MRI), computed tomography (CT), positron emission tomography (PET), serial-section electron microscopy (ssEM), light microscopy (LM) and synchrotron-based X-ray microscopy (XRM). Specially, XRM for three-dimensional (3D) imaging of large-scale brain tissue with high resolution and fast imaging speed is highlighted. Additionally, the development of elegant methods for acquisition of brain functions from electrical/chemical signals in the brain is outlined. In particular, the new electrophysiology technologies for neural recordings at the single-neuron level and in the brain are also summarized. We also focus on the construction of electrochemical probes based on dual-recognition strategy and surface/interface chemistry for determination of chemical species in the brain with high selectivity and long-term stability, as well as electrochemophysiological microarray for simultaneously recording of electrochemical and electrophysiological signals in the brain. Moreover, the recent development of brain MRI probes with high contrast-to-noise ratio (CNR) and sensitivity based on hyperpolarized techniques and multi-nuclear chemistry is introduced. Furthermore, multiple optical probes and instruments, especially the optophysiological Raman probes and fiber Raman photometry, for imaging and biosensing in live brain are emphasized. Finally, a brief perspective on existing challenges and further research development is provided.
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Affiliation(s)
- Zhichao Liu
- Shanghai Key Laboratory of Green Chemistry and Chemical Processes, School of Chemistry and Molecular Engineering, East China Normal University, Shanghai, 200241 China
| | - Ying Zhu
- Interdisciplinary Research Center, Shanghai Synchrotron Radiation Facility, Zhangjiang Laboratory, Shanghai Advanced Research Institute, Chinese Academy of Sciences, University of Chinese Academy of Sciences, Shanghai, 201210 China
| | - Liming Zhang
- Shanghai Key Laboratory of Green Chemistry and Chemical Processes, School of Chemistry and Molecular Engineering, East China Normal University, Shanghai, 200241 China
| | - Weiping Jiang
- State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Chinese Academy of Sciences, Wuhan National Laboratory for Optoelectronics, Wuhan, 430071 China
| | - Yawei Liu
- State Key Laboratory of Rare Earth Resource Utilization, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun, 130022 China
| | - Qiaowei Tang
- Interdisciplinary Research Center, Shanghai Synchrotron Radiation Facility, Zhangjiang Laboratory, Shanghai Advanced Research Institute, Chinese Academy of Sciences, University of Chinese Academy of Sciences, Shanghai, 201210 China
| | - Xiaoqing Cai
- Interdisciplinary Research Center, Shanghai Synchrotron Radiation Facility, Zhangjiang Laboratory, Shanghai Advanced Research Institute, Chinese Academy of Sciences, University of Chinese Academy of Sciences, Shanghai, 201210 China
| | - Jiang Li
- Interdisciplinary Research Center, Shanghai Synchrotron Radiation Facility, Zhangjiang Laboratory, Shanghai Advanced Research Institute, Chinese Academy of Sciences, University of Chinese Academy of Sciences, Shanghai, 201210 China
| | - Lihua Wang
- Interdisciplinary Research Center, Shanghai Synchrotron Radiation Facility, Zhangjiang Laboratory, Shanghai Advanced Research Institute, Chinese Academy of Sciences, University of Chinese Academy of Sciences, Shanghai, 201210 China
| | - Changlu Tao
- Interdisciplinary Center for Brain Information, Brain Cognition and Brain Disease Institute, Shenzhen-Hong Kong Institute of Brain Science-Shenzhen Fundamental Research Institutions, Faculty of Life and Health Sciences, Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, Shenzhen, 518055 China
| | | | - Xiaowei Li
- School of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai, 200240 China
| | - Shangguo Hou
- Institute of Systems and Physical Biology, Shenzhen Bay Laboratory, Shenzhen, 518055 China
| | - Dawei Jiang
- Department of Nuclear Medicine, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430022 China
| | - Kai Liu
- Department of Chemistry, Tsinghua University, Beijing, 100084 China
| | - Xin Zhou
- State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Chinese Academy of Sciences, Wuhan National Laboratory for Optoelectronics, Wuhan, 430071 China
| | - Hongjie Zhang
- State Key Laboratory of Rare Earth Resource Utilization, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun, 130022 China
- Department of Chemistry, Tsinghua University, Beijing, 100084 China
| | - Maili Liu
- State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Chinese Academy of Sciences, Wuhan National Laboratory for Optoelectronics, Wuhan, 430071 China
| | - Chunhai Fan
- School of Chemistry and Chemical Engineering, Frontiers Science Center for Transformative Molecules, Institute of Translational Medicine, Shanghai Jiao Tong University, Shanghai, 200240 China
| | - Yang Tian
- Shanghai Key Laboratory of Green Chemistry and Chemical Processes, School of Chemistry and Molecular Engineering, East China Normal University, Shanghai, 200241 China
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3
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Analysis of task-based functional MRI data preprocessed with fMRIPrep. Nat Protoc 2020; 15:2186-2202. [PMID: 32514178 DOI: 10.1038/s41596-020-0327-3] [Citation(s) in RCA: 62] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2019] [Accepted: 04/06/2020] [Indexed: 12/21/2022]
Abstract
Functional magnetic resonance imaging (fMRI) is a standard tool to investigate the neural correlates of cognition. fMRI noninvasively measures brain activity, allowing identification of patterns evoked by tasks performed during scanning. Despite the long history of this technique, the idiosyncrasies of each dataset have led to the use of ad-hoc preprocessing protocols customized for nearly every different study. This approach is time consuming, error prone and unsuitable for combining datasets from many sources. Here we showcase fMRIPrep (http://fmriprep.org), a robust tool to prepare human fMRI data for statistical analysis. This software instrument addresses the reproducibility concerns of the established protocols for fMRI preprocessing. By leveraging the Brain Imaging Data Structure to standardize both the input datasets (MRI data as stored by the scanner) and the outputs (data ready for modeling and analysis), fMRIPrep is capable of preprocessing a diversity of datasets without manual intervention. In support of the growing popularity of fMRIPrep, this protocol describes how to integrate the tool in a task-based fMRI investigation workflow.
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Netto JP, Iliff J, Stanimirovic D, Krohn KA, Hamilton B, Varallyay C, Gahramanov S, Daldrup-Link H, d'Esterre C, Zlokovic B, Sair H, Lee Y, Taheri S, Jain R, Panigrahy A, Reich DS, Drewes LR, Castillo M, Neuwelt EA. Neurovascular Unit: Basic and Clinical Imaging with Emphasis on Advantages of Ferumoxytol. Neurosurgery 2019; 82:770-780. [PMID: 28973554 DOI: 10.1093/neuros/nyx357] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2016] [Accepted: 06/27/2017] [Indexed: 12/11/2022] Open
Abstract
Physiological and pathological processes that increase or decrease the central nervous system's need for nutrients and oxygen via changes in local blood supply act primarily at the level of the neurovascular unit (NVU). The NVU consists of endothelial cells, associated blood-brain barrier tight junctions, basal lamina, pericytes, and parenchymal cells, including astrocytes, neurons, and interneurons. Knowledge of the NVU is essential for interpretation of central nervous system physiology and pathology as revealed by conventional and advanced imaging techniques. This article reviews current strategies for interrogating the NVU, focusing on vascular permeability, blood volume, and functional imaging, as assessed by ferumoxytol an iron oxide nanoparticle.
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Affiliation(s)
- Joao Prola Netto
- Department of Neurology, Oregon Health & Science University, Portland, Oregon.,Department of Neuroradiology, Oregon Health & Science University, Portland, Oregon
| | - Jeffrey Iliff
- Department of Anesthesiology & Perioperative Medicine, Oregon Health & Science University, Portland, Oregon
| | - Danica Stanimirovic
- Human Health Therapeutics Portfolio, National Research Council of Canada, Ottawa, Ontario, Canada
| | - Kenneth A Krohn
- Department of Radiology, University of Washington, Seattle, Washington.,Department of Radiology, Oregon Health & Science University, Portland, Oregon
| | - Bronwyn Hamilton
- Department of Neuroradiology, Oregon Health & Science University, Portland, Oregon
| | - Csanad Varallyay
- Department of Neurology, Oregon Health & Science University, Portland, Oregon.,Department of Radiology, Oregon Health & Science University, Portland, Oregon
| | - Seymur Gahramanov
- Department of Neurosurgery, University of New Mexico, Albuquerque, New Mexico
| | | | - Christopher d'Esterre
- Department of Radiology, University of Calgary, Foothills Medical Center, Calgary, Alberta, Canada
| | - Berislav Zlokovic
- Zikha Neurogenetic Institute, University of Southern California, Los Angeles, California
| | - Haris Sair
- Department of Radiology and Radiological Science, Johns Hopkins University, Baltimore, Maryland
| | - Yueh Lee
- Department of Radiology, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina
| | - Saeid Taheri
- Department of Radiology and Radiological Sciences, Medical University of South Carolina, Charleston, South Carolina
| | - Rajan Jain
- Department of Radiology and Neurosurgery, New York University School of Medicine, New York, New York
| | - Ashok Panigrahy
- Department of Radiology, Children's Hospital of Pittsburgh, Pittsburgh, Pennsylvania
| | - Daniel S Reich
- Translational Neuroradiology Unit, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, Maryland
| | - Lester R Drewes
- Department of Biomedical Sciences, University of Minnesota, Duluth, Minnesota
| | - Mauricio Castillo
- Department of Radiology, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina
| | - Edward A Neuwelt
- Department of Neurology, Oregon Health & Science University, Portland, Oregon.,Department of Neurosurgery, Oregon Health & Science University, Portland, Oregon.,Portland Veterans Affairs Medical Center, Portland, Oregon
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5
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Non-BOLD contrast for laminar fMRI in humans: CBF, CBV, and CMRO2. Neuroimage 2019; 197:742-760. [DOI: 10.1016/j.neuroimage.2017.07.041] [Citation(s) in RCA: 78] [Impact Index Per Article: 15.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2017] [Revised: 07/10/2017] [Accepted: 07/19/2017] [Indexed: 12/22/2022] Open
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Hua J, Liu P, Kim T, Donahue M, Rane S, Chen JJ, Qin Q, Kim SG. MRI techniques to measure arterial and venous cerebral blood volume. Neuroimage 2019; 187:17-31. [PMID: 29458187 PMCID: PMC6095829 DOI: 10.1016/j.neuroimage.2018.02.027] [Citation(s) in RCA: 63] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2017] [Revised: 02/12/2018] [Accepted: 02/14/2018] [Indexed: 12/14/2022] Open
Abstract
The measurement of cerebral blood volume (CBV) has been the topic of numerous neuroimaging studies. To date, however, most in vivo imaging approaches can only measure CBV summed over all types of blood vessels, including arterial, capillary and venous vessels in the microvasculature (i.e. total CBV or CBVtot). As different types of blood vessels have intrinsically different anatomy, function and physiology, the ability to quantify CBV in different segments of the microvascular tree may furnish information that is not obtainable from CBVtot, and may provide a more sensitive and specific measure for the underlying physiology. This review attempts to summarize major efforts in the development of MRI techniques to measure arterial (CBVa) and venous CBV (CBVv) separately. Advantages and disadvantages of each type of method are discussed. Applications of some of the methods in the investigation of flow-volume coupling in healthy brains, and in the detection of pathophysiological abnormalities in brain diseases such as arterial steno-occlusive disease, brain tumors, schizophrenia, Huntington's disease, Alzheimer's disease, and hypertension are demonstrated. We believe that the continual development of MRI approaches for the measurement of compartment-specific CBV will likely provide essential imaging tools for the advancement and refinement of our knowledge on the exquisite details of the microvasculature in healthy and diseased brains.
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Affiliation(s)
- Jun Hua
- Neurosection, Div. of MRI Research, Dept. of Radiology, Johns Hopkins University School of Medicine, Baltimore, MD, USA; F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, MD, USA.
| | - Peiying Liu
- Neurosection, Div. of MRI Research, Dept. of Radiology, Johns Hopkins University School of Medicine, Baltimore, MD, USA; F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, MD, USA
| | - Tae Kim
- Department of Radiology, University of Pittsburgh, Pittsburgh, PA, USA; Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA, USA
| | - Manus Donahue
- Department of Radiology and Radiological Sciences, Vanderbilt University Medical Center, Nashville, TN, USA; Department of Neurology, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Swati Rane
- Radiology, University of Washington Medical Center, Seattle, WA, USA
| | - J Jean Chen
- Rotman Research Institute, Baycrest Centre, Canada; Department of Medical Biophysics, University of Toronto, Canada
| | - Qin Qin
- Neurosection, Div. of MRI Research, Dept. of Radiology, Johns Hopkins University School of Medicine, Baltimore, MD, USA; F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, MD, USA
| | - Seong-Gi Kim
- Center for Neuroscience Imaging Research, Institute for Basic Science (IBS), Suwon, South Korea; Department of Biomedical Engineering, Sungkyunkwan University, Suwon, South Korea
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Cheng X, Berman AJL, Polimeni JR, Buxton RB, Gagnon L, Devor A, Sakadžić S, Boas DA. Dependence of the MR signal on the magnetic susceptibility of blood studied with models based on real microvascular networks. Magn Reson Med 2019; 81:3865-3874. [PMID: 30659643 DOI: 10.1002/mrm.27660] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2018] [Revised: 12/05/2018] [Accepted: 12/21/2018] [Indexed: 01/02/2023]
Abstract
PURPOSE The primary goal of this study was to estimate the value of β , the exponent in the power law relating changes of the transverse relaxation rate and intra-extravascular local magnetic susceptibility differences as Δ R 2 ∗ ∝ ( Δ χ ) β . The secondary objective was to evaluate any differences that might exist in the value of β obtained using a deoxyhemoglobin-weighted Δ χ distribution versus a constant Δ χ distribution assumed in earlier computations. The third objective was to estimate the value of β that is relevant for methods based on susceptibility contrast agents with a concentration of Δ χ higher than that used for BOLD fMRI calculations. METHODS Our recently developed model of real microvascular anatomical networks is used to extend the original simplified Monte-Carlo simulations to compute β from the first principles. RESULTS Our results show that β = 1 for most BOLD fMRI measurements of real vascular networks, as opposed to earlier predictions of β = 1 .5 using uniform Δ χ distributions. For perfusion or fMRI methods based on contrast agents, which generate larger values for Δ χ , β = 1 for B 0 ≤ 9.4 T, whereas at 14 T β can drop below 1 and the variation across subjects is large, indicating that a lower concentration of contrast agent with a lower value of Δ χ is desired for experiments at high B0 . CONCLUSION These results improve our understanding of the relationship between R2 * and the underlying microvascular properties. The findings will help to infer the cerebral metabolic rate of oxygen and cerebral blood volume from BOLD and perfusion MRI, respectively.
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Affiliation(s)
- Xiaojun Cheng
- Neurophotonics Center, Department of Biomedical Engineering, Boston University, Massachusetts.,Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Charlestown, Massachusetts
| | - Avery J L Berman
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Charlestown, Massachusetts
| | - Jonathan R Polimeni
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Charlestown, Massachusetts.,Division of Health Sciences and Technology, Massachusetts Institute of Technology, Cambridge, Massachusetts
| | - Richard B Buxton
- Department of Radiology, University of California, San Diego, La Jolla, California
| | - Louis Gagnon
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Charlestown, Massachusetts.,Department of Radiology and Nuclear Medicine, Faculty of Medicine, Laval University, Quebec, Canada
| | - Anna Devor
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Charlestown, Massachusetts.,Department of Radiology, University of California, San Diego, La Jolla, California.,Department of Neurosciences, University of California, San Diego, La Jolla, California
| | - Sava Sakadžić
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Charlestown, Massachusetts
| | - David A Boas
- Neurophotonics Center, Department of Biomedical Engineering, Boston University, Massachusetts.,Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Charlestown, Massachusetts
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8
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Zarghami N, Khrapitchev AA, Perez-Balderas F, Soto MS, Larkin JR, Bau L, Sibson NR. Optimization of molecularly targeted MRI in the brain: empirical comparison of sequences and particles. Int J Nanomedicine 2018; 13:4345-4359. [PMID: 30100719 PMCID: PMC6064157 DOI: 10.2147/ijn.s158071] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
BACKGROUND Molecular MRI is an evolving field of research with strong translational potential. Selection of the appropriate MRI sequence, field strength and contrast agent depend largely on the application. The primary aims of the current study were to: 1) assess the sensitivity of different MRI sequences for detection of iron oxide particles in mouse brain; 2) determine the effect of magnetic field strength on detection of iron oxide particles in vivo; and 3) compare the sensitivity of targeted microparticles of iron oxide (MPIO) or ultra-small superparamagnetic iron oxide (USPIO) for detection of vascular cell adhesion molecule-1 (VCAM-1) in vivo. METHODS Mice were injected intrastriatally with interleukin 1β to induce VCAM-1 expression on the cerebral vasculature. Subsequently, animals were injected intravenously with either VCAM-MPIO or VCAM-USPIO and imaged 1 or 13 hours post-injection, respectively. MRI was performed at 4.7, 7.0, or 9.4 T, using three different T2*-weighted sequences: single gradient echo 3D (GE3D), multi-gradient echo 3D (MGE3D) and balanced steady-state free precession 3D (bSSFP3D). RESULTS MGE3D yielded the highest signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) for the detection of iron oxide particles. All sequences showed a significant increase in SNR and CNR from 4.7 to 7.0 T, but no further improvement at 9.4 T. However, whilst targeted MPIO enabled sensitive detection of VCAM-1 expression on the cerebral vasculature, the long half-life (16.5 h vs 1.2 min) and lower relaxivity per particle (1.29×10-14 vs 1.18×10-9 Hz L/particle) of USPIO vs. MPIO rendered them impractical for molecular MRI. CONCLUSION These findings demonstrate clear advantages of MPIO compared to USPIO for molecularly-targeted MRI, and indicate that the MGE3D sequence is optimal for MPIO detection. Moreover, higher field strengths (7.0/9.4 T) showed enhanced sensitivity over lower field strengths (4.7 T). With the development of biodegradable MPIO, these agents hold promise for clinical translation.
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Affiliation(s)
- Niloufar Zarghami
- Cancer Research UK and Medical Research Council Oxford Institute for Radiation Oncology, Department of Oncology, University of Oxford, Oxford, UK,
| | - Alexandre A Khrapitchev
- Cancer Research UK and Medical Research Council Oxford Institute for Radiation Oncology, Department of Oncology, University of Oxford, Oxford, UK,
| | - Francisco Perez-Balderas
- Cancer Research UK and Medical Research Council Oxford Institute for Radiation Oncology, Department of Oncology, University of Oxford, Oxford, UK,
| | - Manuel Sarmiento Soto
- Cancer Research UK and Medical Research Council Oxford Institute for Radiation Oncology, Department of Oncology, University of Oxford, Oxford, UK,
| | - James R Larkin
- Cancer Research UK and Medical Research Council Oxford Institute for Radiation Oncology, Department of Oncology, University of Oxford, Oxford, UK,
| | - Luca Bau
- Institute of Biomedical Engineering, Department of Engineering Sciences, University of Oxford, Oxford, UK
| | - Nicola R Sibson
- Cancer Research UK and Medical Research Council Oxford Institute for Radiation Oncology, Department of Oncology, University of Oxford, Oxford, UK,
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9
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Impulse response timing differences in BOLD and CBV weighted fMRI. Neuroimage 2018; 181:292-300. [PMID: 29981905 DOI: 10.1016/j.neuroimage.2018.07.011] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2018] [Revised: 07/03/2018] [Accepted: 07/04/2018] [Indexed: 11/23/2022] Open
Abstract
Recent advances in BOLD fMRI scan techniques have substantially improved spatial and temporal resolution, currently reaching to sub-millimeter and sub-second levels respectively. Unfortunately, there remain physiological barriers that prevent achieving this resolution in practice. BOLD contrast relies on the hemodynamic response to neuronal activity, whose associated cerebral blood oxygenation (CBO) changes may spread over several millimeters and last several seconds. Recent reports have suggested that significant improvements may be possible with cerebral blood volume (CBV)-weighted fMRI, which highlights the CBV changes rather than the BOLD changes associated with the hemodynamic response. Nevertheless, quantitative comparisons between CBV and BOLD are sparse, in particular regarding their temporal characteristics in human brain. To address this, we studied a cohort of subjects that received injection of ferumoxytol, an intravascular iron-oxide based contrast agent that introduces strong CBV contrast. An event-related visual stimulus paradigm was used to compare the impulse response (IR) for CBV and BOLD contrast, obtained with and without ferumoxytol, respectively. Experiments performed at 7 T (n = 5) at 1.2-1.5 mm spatial and 1 s temporal resolution showed that the onset time and time-to-peak of the CBV IR averaged 0.8 and 3.5 s respectively, both 0.6 s shorter than the BOLD IR. While significant, these improvements are relatively small and not expected to lead to practical advantages for the extraction of temporal information about neural activity. Nonlinearities in the observed IR were also compared and found to be similar between the CBV and BOLD, indicating that these are likely not caused by a 'ceiling' effect in the CBO response, but rather support a previously proposed model of vascular compliance, in which changes in vascular tone elicited by a preceding stimulus affect the IR.
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10
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Magnetic Resonance Imaging technology-bridging the gap between noninvasive human imaging and optical microscopy. Curr Opin Neurobiol 2018; 50:250-260. [PMID: 29753942 DOI: 10.1016/j.conb.2018.04.026] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2017] [Revised: 04/20/2018] [Accepted: 04/24/2018] [Indexed: 12/23/2022]
Abstract
Technological advances in Magnetic Resonance Imaging (MRI) have provided substantial gains in the sensitivity and specificity of functional neuroimaging. Mounting evidence demonstrates that the hemodynamic changes utilized in functional MRI can be far more spatially and thus neuronally specific than previously believed. This has motivated a push toward novel, high-resolution MR imaging strategies that can match this biological resolution limit while recording from the entire human brain. Although sensitivity increases are a necessary component, new MR encoding technologies are required to convert improved sensitivity into higher resolution. These new sampling strategies improve image acquisition efficiency and enable increased image encoding in the time-frame needed to follow hemodynamic changes associated with brain activation.
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11
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Cooley CZ, Mandeville JB, Mason EE, Mandeville ET, Wald LL. Rodent Cerebral Blood Volume (CBV) changes during hypercapnia observed using Magnetic Particle Imaging (MPI) detection. Neuroimage 2018; 178:713-720. [PMID: 29738908 DOI: 10.1016/j.neuroimage.2018.05.004] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2017] [Revised: 04/18/2018] [Accepted: 05/01/2018] [Indexed: 01/07/2023] Open
Abstract
Magnetic Particle Imaging (MPI) is a rapidly developing imaging modality that directly measures and maps the concentration of injected superparamagnetic iron oxide nanoparticles (SPIOs). Since the agent does not cross the blood-brain barrier, cerebral SPIO concentration provides a direct probe of Cerebral Blood Volume (CBV). Here we provide an initial demonstration of the ability of MPI to detect functional CBV changes (fCBV) by monitoring SPIO concentration during hypercapnic manipulation in a rat model. As a tracer detection method, MPI offers a more direct probe of agent concentration and therefore fCBV than MRI measurements in which the agent is indirectly detected through perturbation of water relaxation time constants such as T2∗. We found that MPI detection could measure CBV changes during hypercapnia with high CNR (CNR = 50) and potentially with high temporal resolution. Although the detection process more closely resembles a tracer method, we also identify evidence of physiological noise in the MPI time-series, with higher time-series variance at higher concentration levels. Our findings suggest that CBV-based MPI can provide a detection modality for hemodynamic changes. Further investigation with tomographic imaging is needed to assess tomographic ability of the method and further study the presence of time-series fluctuations which scale with signal level similar to physiological noise in resting fMRI time-courses.
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Affiliation(s)
- Clarissa Zimmerman Cooley
- A. A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Charlestown, MA, USA.
| | - Joseph B Mandeville
- A. A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Charlestown, MA, USA
| | - Erica E Mason
- A. A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Charlestown, MA, USA; Harvard-MIT Division of Health Sciences Technology, Cambridge, MA, USA
| | - Emiri T Mandeville
- Neuroprotection Research Laboratory, Department of Radiology, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA; Neuroprotection Research Laboratory, Department of Neurology, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA
| | - Lawrence L Wald
- A. A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Charlestown, MA, USA; Harvard-MIT Division of Health Sciences Technology, Cambridge, MA, USA
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12
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Mannheim JG, Schmid AM, Schwenck J, Katiyar P, Herfert K, Pichler BJ, Disselhorst JA. PET/MRI Hybrid Systems. Semin Nucl Med 2018; 48:332-347. [PMID: 29852943 DOI: 10.1053/j.semnuclmed.2018.02.011] [Citation(s) in RCA: 37] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Over the last decade, the combination of PET and MRI in one system has proven to be highly successful in basic preclinical research, as well as in clinical research. Nowadays, PET/MRI systems are well established in preclinical imaging and are progressing into clinical applications to provide further insights into specific diseases, therapeutic assessments, and biological pathways. Certain challenges in terms of hardware had to be resolved concurrently with the development of new techniques to be able to reach the full potential of both combined techniques. This review provides an overview of these challenges and describes the opportunities that simultaneous PET/MRI systems can exploit in comparison with stand-alone or other combined hybrid systems. New approaches were developed for simultaneous PET/MRI systems to correct for attenuation of 511 keV photons because MRI does not provide direct information on gamma photon attenuation properties. Furthermore, new algorithms to correct for motion were developed, because MRI can accurately detect motion with high temporal resolution. The additional information gained by the MRI can be employed to correct for partial volume effects as well. The development of new detector designs in combination with fast-decaying scintillator crystal materials enabled time-of-flight detection and incorporation in the reconstruction algorithms. Furthermore, this review lists the currently commercially available systems both for preclinical and clinical imaging and provides an overview of applications in both fields. In this regard, special emphasis has been placed on data analysis and the potential for both modalities to evolve with advanced image analysis tools, such as cluster analysis and machine learning.
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Affiliation(s)
- Julia G Mannheim
- Department of Preclinical Imaging and Radiopharmacy, Werner Siemens Imaging Center, Eberhard Karls University Tuebingen, Tuebingen, Germany
| | - Andreas M Schmid
- Department of Preclinical Imaging and Radiopharmacy, Werner Siemens Imaging Center, Eberhard Karls University Tuebingen, Tuebingen, Germany
| | - Johannes Schwenck
- Department of Preclinical Imaging and Radiopharmacy, Werner Siemens Imaging Center, Eberhard Karls University Tuebingen, Tuebingen, Germany; Department of Nuclear Medicine and Clinical Molecular Imaging, Eberhard Karls University Tuebingen, Tuebingen, Germany
| | - Prateek Katiyar
- Department of Preclinical Imaging and Radiopharmacy, Werner Siemens Imaging Center, Eberhard Karls University Tuebingen, Tuebingen, Germany
| | - Kristina Herfert
- Department of Preclinical Imaging and Radiopharmacy, Werner Siemens Imaging Center, Eberhard Karls University Tuebingen, Tuebingen, Germany
| | - Bernd J Pichler
- Department of Preclinical Imaging and Radiopharmacy, Werner Siemens Imaging Center, Eberhard Karls University Tuebingen, Tuebingen, Germany.
| | - Jonathan A Disselhorst
- Department of Preclinical Imaging and Radiopharmacy, Werner Siemens Imaging Center, Eberhard Karls University Tuebingen, Tuebingen, Germany
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13
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Gorman AW, Deh KM, Schwiedrzik CM, White JR, Groman EV, Fisher CA, Gillen KM, Spincemaille P, Rasmussen S, Prince MR, Voss HU, Freiwald WA, Wang Y. Brain Iron Distribution after Multiple Doses of Ultra-small Superparamagnetic Iron Oxide Particles in Rats. Comp Med 2018; 68:139-147. [PMID: 29663939 PMCID: PMC5897970] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2017] [Revised: 07/16/2017] [Accepted: 09/26/2017] [Indexed: 06/08/2023]
Abstract
The purpose of this study is to determine the effects of high cumulative doses of ultra-small paramagnetic iron oxide (USPIO) used in neuroimaging studies. We intravenously administered 8 mg/kg of 2 USPIO compounds daily for 4 wk to male Sprague-Dawley rats (Crl:SD). Multiecho gradient-echo MRI, serum iron levels, and histology were performed at the end of dosing and after a 7-d washout period. R2* maps and quantitative susceptibility maps (QSM) were generated from multiecho gradient-echo data. R2* maps and QSM showed iron accumulation in brain ventricles on MR images acquired at the 4- and 5-wk time points. Estimates from QSM data showed ventricular iron concentration was equal to or higher than serum iron concentration. Histologic analysis revealed choroid plexus hemosiderosis and midbrain vacuolation, without iron deposition in brain parenchyma. Serum iron levels increased with administration of both compounds, and a 7-d washout period effectively reduced serum iron levels of one but not both of the compounds. High cumulative doses from multiple, frequent administrations of USPIO can lead to iron deposition in brain ventricles, resulting in persistent signal loss on T2*-weighted images. Techniques such as QSM are helpful in quantifying iron biodistribution in this situation.
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Affiliation(s)
- Andrew W Gorman
- Institute of Comparative Medicine, Columbia University, New York, New York, USA. Center of Comparative Medicine and Pathology, Memorial Sloan-Kettering Center, Tri Institutional Training Program in Laboratory Animal Medicine and Science, New York, New York, USA.,
| | - Kofi M Deh
- Joan and Sanford I Weill Medical College, Cornell University, New York, New York, USA
| | - Caspar M Schwiedrzik
- Laboratory of Neural Systems, Rockefeller University, New York, New York, USA. Neural Circuits and Cognition Lab, European Neuroscience Institute, Gottingen, Germany
| | - Julie R White
- Center of Comparative Medicine and Pathology, Memorial Sloan-Kettering Cancer Center, Tri Institutional Training Program in Laboratory Animal Medicine and Science, New York, New York, USA
| | - Ernest Victor Groman
- Skaggs School of Pharmacy and Pharmaceutical Sciences, University of Colorado, Aurora, Colorado, USA
| | - Clark A Fisher
- Laboratory of Neural Systems, Rockefeller University, New York, New York, USA
| | - Kelly M Gillen
- Joan and Sanford I Weill Medical College, Cornell University, New York, New York, USA
| | - Pascal Spincemaille
- Joan and Sanford I Weill Medical College, Cornell University, New York, New York, USA
| | - Skye Rasmussen
- Comparative Bioscience Center, Rockefeller University, New York, New York, USA
| | - Martin R Prince
- Joan and Sanford I Weill Medical College, Cornell University, New York, New York, USA
| | - Henning U Voss
- Joan and Sanford I Weill Medical College, Cornell University, New York, New York, USA
| | - Winrich A Freiwald
- Laboratory of Neural Systems, Rockefeller University, New York, New York, USA
| | - Yi Wang
- Joan and Sanford I Weill Medical College, Cornell University, New York, New York, USA
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Abstract
Metabolism is central to neuroimaging because it can reveal pathways by which neuronal and glial cells use nutrients to fuel their growth and function. We focus on advanced magnetic resonance imaging (MRI) and magnetic resonance spectroscopy (MRS) methods used in brain metabolic studies. 17O-MRS and 31P-MRS, respectively, provide rates of oxygen use and ATP synthesis inside mitochondria, whereas 19F-MRS enables measurement of cytosolic glucose metabolism. Calibrated functional MRI (fMRI), an advanced form of fMRI that uses contrast generated by deoxyhemoglobin, provides maps of oxygen use that track neuronal firing across brain regions. 13C-MRS is the only noninvasive method of measuring both glutamatergic neurotransmission and cell-specific energetics with signaling and nonsignaling purposes. Novel MRI contrasts, arising from endogenous diamagnetic agents and exogenous paramagnetic agents, permit pH imaging of glioma. Overall, these magnetic resonance methods for imaging brain metabolism demonstrate translational potential to better understand brain disorders and guide diagnosis and treatment.
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Affiliation(s)
- Fahmeed Hyder
- Department of Biomedical Engineering, Department of Radiology and Biomedical Imaging, Magnetic Resonance Research Center, and Quantitative Neuroscience with Magnetic Resonance Core Center, Yale University, New Haven, Connecticut 06520;
| | - Douglas L Rothman
- Department of Biomedical Engineering, Department of Radiology and Biomedical Imaging, Magnetic Resonance Research Center, and Quantitative Neuroscience with Magnetic Resonance Core Center, Yale University, New Haven, Connecticut 06520;
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15
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Functional Characterization of 5-HT 1B Receptor Drugs in Nonhuman Primates Using Simultaneous PET-MR. J Neurosci 2017; 37:10671-10678. [PMID: 28972127 DOI: 10.1523/jneurosci.1971-17.2017] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2017] [Revised: 08/24/2017] [Accepted: 09/22/2017] [Indexed: 11/21/2022] Open
Abstract
In the present study, we used a simultaneous PET-MR experimental design to investigate the effects of functionally different compounds (agonist, partial agonist, and antagonist) on 5-HT1B receptor (5-HT1BR) occupancy and the associated hemodynamic responses. In anesthetized male nonhuman primates (n = 3), we used positron emission tomography (PET) imaging with the radioligand [11C]AZ10419369 administered as a bolus followed by constant infusion to measure changes in 5-HT1BR occupancy. Simultaneously, we measured changes in cerebral blood volume (CBV) as a proxy of drug effects on neuronal activity. The 5-HT1BR partial agonist AZ10419369 elicited a dose-dependent biphasic hemodynamic response that was related to the 5-HT1BR occupancy. The magnitude of the response was spatially overlapping with high cerebral 5-HT1BR densities. High doses of AZ10419369 exerted an extracranial tissue vasoconstriction that was comparable to the less blood-brain barrier-permeable 5-HT1BR agonist sumatriptan. By contrast, injection of the antagonist GR127935 did not elicit significant hemodynamic responses, even at a 5-HT1BR cerebral occupancy similar to the one obtained with a high dose of AZ10419369. Given the knowledge we have of the 5-HT1BR and its function and distribution in the brain, the hemodynamic response informs us about the functionality of the given drug: changes in CBV are only produced when the receptor is stimulated by the partial agonist AZ10419369 and not by the antagonist GR127935, consistent with low basal occupancy by endogenous serotonin.SIGNIFICANCE STATEMENT We here show that combined simultaneous positron emission tomography and magnetic resonance imaging uniquely enables the assessment of CNS active compounds. We conducted a series of pharmacological interventions to interrogate 5-HT1B receptor binding and function and determined blood-brain barrier passage of drugs and demonstrate target involvement. Importantly, we show how the spatial and temporal effects on brain hemodynamics provide information about pharmacologically driven downstream CNS drug effects; the brain hemodynamic response shows characteristic dose-related effects that differ depending on agonistic or antagonistic drug characteristics and on local 5-HT1B receptor density. The technique lends itself to a comprehensive in vivo investigation and understanding of drugs' effects in the brain.
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16
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Polymer-coated superparamagnetic iron oxide nanoparticles as T 2 contrast agent for MRI and their uptake in liver. Future Sci OA 2017; 5:FSO235. [PMID: 30652014 PMCID: PMC6331706 DOI: 10.4155/fsoa-2017-0054] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2017] [Accepted: 06/28/2017] [Indexed: 11/19/2022] Open
Abstract
Aim: To study the efficiency of multifunctional polymer-based superparamagnetic iron oxide nanoparticles (bioferrofluids) as a T2 magnetic resonance contrast agent and their uptake and toxicity in liver. Materials & methods: Mice were intravenously injected with bioferrofluids and Endorem®. The magnetic resonance efficiency, uptake and in vivo toxicity were investigated by means of magnetic resonance imaging (MRI) and histological techniques. Results: Bioferrofluids are a good T2 contrast agent with a higher r2/r1 ratio than Endorem. Bioferrofluids have a shorter blood circulation time and persist in liver for longer time period compared with Endorem. Both bioferrofluids and Endorem do not generate any noticeable histological lesions in liver over a period of 60 days post-injection. Conclusion: Our bioferrofluids are powerful diagnostic tool without any observed toxicity over a period of 60 days post-injection. Several superparamagnetic iron oxide nanoparticles (SPIONs) preparations have been approved by US FDA for clinical use as MRI contrast agents. In recent years, we have been developing a synthetic multifunctional platform for SPIONs based on the use of polymers. In this report, we explored the diagnostic potential of these nanoparticles (herein called bioferrofluids) as an MRI contrast agent and their uptake in liver, without neglecting their toxicological effects. Results show that our bioferrofluids are a good T2 contrast agent without any observed toxicity in liver.
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17
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Mason EE, Cooley CZ, Cauley SF, Griswold MA, Conolly SM, Wald LL. Design analysis of an MPI human functional brain scanner. INTERNATIONAL JOURNAL ON MAGNETIC PARTICLE IMAGING 2017; 3. [PMID: 28752130 PMCID: PMC5526464 DOI: 10.18416/ijmpi.2017.1703008] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
MPI’s high sensitivity makes it a promising modality for imaging brain function. Functional contrast is proposed based on blood SPION concentration changes due to Cerebral Blood Volume (CBV) increases during activation, a mechanism utilized in fMRI studies. MPI offers the potential for a direct and more sensitive measure of SPION concentration, and thus CBV, than fMRI. As such, fMPI could surpass fMRI in sensitivity, enhancing the scientific and clinical value of functional imaging. As human-sized MPI systems have not been attempted, we assess the technical challenges of scaling MPI from rodent to human brain. We use a full-system MPI simulator to test arbitrary hardware designs and encoding practices, and we examine tradeoffs imposed by constraints that arise when scaling to human size as well as safety constraints (PNS and central nervous system stimulation) not considered in animal scanners, thereby estimating spatial resolutions and sensitivities achievable with current technology. Using a projection FFL MPI system, we examine coil hardware options and their implications for sensitivity and spatial resolution. We estimate that an fMPI brain scanner is feasible, although with reduced sensitivity (20×) and spatial resolution (5×) compared to existing rodent systems. Nonetheless, it retains sufficient sensitivity and spatial resolution to make it an attractive future instrument for studying the human brain; additional technical innovations can result in further improvements.
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Affiliation(s)
- Erica E Mason
- MGH-HST A.A. Martinos Center for Biomedical Imaging, Dept. of Radiology, Massachusetts General Hospital, Charlestown, MA, USA.,Harvard-MIT Health Sciences and Technology, Cambridge, MA, USA
| | - Clarissa Z Cooley
- MGH-HST A.A. Martinos Center for Biomedical Imaging, Dept. of Radiology, Massachusetts General Hospital, Charlestown, MA, USA
| | - Stephen F Cauley
- MGH-HST A.A. Martinos Center for Biomedical Imaging, Dept. of Radiology, Massachusetts General Hospital, Charlestown, MA, USA
| | | | | | - Lawrence L Wald
- MGH-HST A.A. Martinos Center for Biomedical Imaging, Dept. of Radiology, Massachusetts General Hospital, Charlestown, MA, USA.,Harvard Medical School, Boston, MA, USA
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18
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Rodrigues D, Freitas M, Marisa Costa V, Arturo Lopez-Quintela M, Rivas J, Freitas P, Carvalho F, Fernandes E, Silva P. Quantitative histochemistry for macrophage biodistribution on mice liver and spleen after the administration of a pharmacological-relevant dose of polyacrylic acid-coated iron oxide nanoparticles. Nanotoxicology 2017; 11:256-266. [PMID: 28166432 DOI: 10.1080/17435390.2017.1291865] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Affiliation(s)
- Daniela Rodrigues
- UCIBIO, REQUIMTE, Laboratory of Applied Chemistry, Department of Chemical Sciences, Faculty of Pharmacy, University of Porto, Porto, Portugal
| | - Marisa Freitas
- UCIBIO, REQUIMTE, Laboratory of Applied Chemistry, Department of Chemical Sciences, Faculty of Pharmacy, University of Porto, Porto, Portugal
| | - Vera Marisa Costa
- UCIBIO, REQUIMTE, Laboratory of Toxicology, Department of Biological Sciences, Faculty of Pharmacy, University of Porto, Porto, Portugal
| | - Manuel Arturo Lopez-Quintela
- Laboratory of Nanotechnology and Magnetism, Institute of Technological Research, IIT, University of Santiago de Compostela (USC), Santiago de Compostela, Spain
| | - José Rivas
- Laboratory of Nanotechnology and Magnetism, Institute of Technological Research, IIT, University of Santiago de Compostela (USC), Santiago de Compostela, Spain
- International Iberian Nanotechnology Laboratory, Braga, Portugal
| | - Paulo Freitas
- International Iberian Nanotechnology Laboratory, Braga, Portugal
| | - Félix Carvalho
- UCIBIO, REQUIMTE, Laboratory of Toxicology, Department of Biological Sciences, Faculty of Pharmacy, University of Porto, Porto, Portugal
| | - Eduarda Fernandes
- UCIBIO, REQUIMTE, Laboratory of Applied Chemistry, Department of Chemical Sciences, Faculty of Pharmacy, University of Porto, Porto, Portugal
| | - Paula Silva
- UCIBIO, REQUIMTE, Laboratory of Histology and Embryology, Institute of Biomedical Sciences Abel Salazar (ICBAS), University of Porto, Porto, Portugal
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19
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Wáng YXJ, Idée JM. A comprehensive literatures update of clinical researches of superparamagnetic resonance iron oxide nanoparticles for magnetic resonance imaging. Quant Imaging Med Surg 2017; 7:88-122. [PMID: 28275562 DOI: 10.21037/qims.2017.02.09] [Citation(s) in RCA: 146] [Impact Index Per Article: 20.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
This paper aims to update the clinical researches using superparamagnetic iron oxide (SPIO) nanoparticles as magnetic resonance imaging (MRI) contrast agent published during the past five years. PubMed database was used for literature search, and the search terms were (SPIO OR superparamagnetic iron oxide OR Resovist OR Ferumoxytol OR Ferumoxtran-10) AND (MRI OR magnetic resonance imaging). The literature search results show clinical research on SPIO remains robust, particularly fuelled by the approval of ferumoxytol for intravenously administration. SPIOs have been tested on MR angiography, sentinel lymph node detection, lymph node metastasis evaluation; inflammation evaluation; blood volume measurement; as well as liver imaging. Two experimental SPIOs with unique potentials are also discussed in this review. A curcumin-conjugated SPIO can penetrate brain blood barrier (BBB) and bind to amyloid plaques in Alzheime's disease transgenic mice brain, and thereafter detectable by MRI. Another SPIO was fabricated with a core of Fe3O4 nanoparticle and a shell coating of concentrated hydrophilic polymer brushes and are almost not taken by peripheral macrophages as well as by mononuclear phagocytes and reticuloendothelial system (RES) due to the suppression of non-specific protein binding caused by their stealthy ''brush-afforded'' structure. This SPIO may offer potentials for the applications such as drug targeting and tissue or organ imaging other than liver and lymph nodes.
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Affiliation(s)
- Yì Xiáng J Wáng
- Department of Imaging and Interventional Radiology, Faculty of Medicine, The Chinese University of Hong Kong, Prince of Wales Hospital, Sha Tin, New Territories, Hong Kong SAR, China
| | - Jean-Marc Idée
- Guerbet, Research and Innovation Division, Roissy-Charles de Gaulle, France
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20
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Baumgartner R, Cho W, Coimbra A, Chen C, Wang Z, Struyk A, Venketasubramanian N, Low M, Gargano C, Zhao F, Williams D, Reese T, Seah S, Feng D, Apreleva S, Petersen E, Evelhoch JL. Evaluation of an fMRI USPIO-based assay in healthy human volunteers. J Magn Reson Imaging 2016; 46:124-133. [PMID: 27775841 DOI: 10.1002/jmri.25499] [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: 11/06/2015] [Accepted: 09/12/2016] [Indexed: 11/09/2022] Open
Abstract
PURPOSE To present the testretest and contrast dose effect results of cerebral blood volume (CBV) functional MRI (fMRI) in healthy human volunteers using ferumoxytol (Feraheme), an ultrasmall-superparamagnetic iron oxide (USPIO) nanoparticle. MATERIALS AND METHODS This was an open-label, two-period, fixed-sequence study in healthy young volunteers. In eight subjects, using a 3 Tesla field strength system, blood oxygen level dependent (BOLD) and CBV fMRI were acquired in response to a visual black-and-white checkboard stimulation paradigm using an escalating ferumoxytol dose design (250, 350, and 510 mg iron). Multiple outcome measures were analyzed including absolute percent signal change (|PSC|, primary endpoint), its contrast-to-noise ratio (CNR) and corresponding z-score, percent CBV change (ΔCBV) and respective CNR, concentration of Fe, and baseline CBV. RESULTS The |PSC| in the visual cortex increased with ferumoxytol dose and was up to 3 × higher than BOLD fMRI. Test-retest reliability was comparable for BOLD and CBV fMRI. Intraclass correlation coefficients (ICCs) for |PSC| were 0.3 (one-sided 95% lower confidence limit = 0.00), 0.81 (0.47), 0.48 (0.00), and 0.3 (0.00) for BOLD and the 250-, 350-, and 510-mg doses of ferumoxytol, respectively. For ΔCBV, ICCs were 0.77 (0.37), 0.48 (0.00), and 0.49 (0.00) for 250 mg, 350 mg, and 510 mg, respectively. CONCLUSION This work demonstrates that CBV fMRI techniques and endpoints are dose dependent, robust and have good test-retest repeatability. It also confirms previous findings that USPIO enhances sensitivity of fMRI stimulus-response endpoints. LEVEL OF EVIDENCE 1 J. MAGN. RESON. IMAGING 2017;46:124-133.
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Affiliation(s)
| | - William Cho
- Merck & Co. Inc, Kenilworth, New Jersey, USA
| | | | - Christopher Chen
- Memory Aging & Cognition Centre at National University Health System, Singapore
| | - Zaiqi Wang
- Merck & Co. Inc, Kenilworth, New Jersey, USA
| | - Arie Struyk
- Merck & Co. Inc, Kenilworth, New Jersey, USA
| | | | - May Low
- Merck & Co. Inc, Kenilworth, New Jersey, USA
| | | | | | | | | | | | - Dai Feng
- Merck & Co. Inc, Kenilworth, New Jersey, USA
| | | | - Esben Petersen
- Department of Diagnostic Radiology, National University Singapore
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21
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Mandeville ET, Ayata C, Zheng Y, Mandeville JB. Translational MR Neuroimaging of Stroke and Recovery. Transl Stroke Res 2016; 8:22-32. [PMID: 27578048 DOI: 10.1007/s12975-016-0497-z] [Citation(s) in RCA: 42] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2016] [Revised: 08/16/2016] [Accepted: 08/18/2016] [Indexed: 12/26/2022]
Abstract
Multiparametric magnetic resonance imaging (MRI) has become a critical clinical tool for diagnosing focal ischemic stroke severity, staging treatment, and predicting outcome. Imaging during the acute phase focuses on tissue viability in the stroke vicinity, while imaging during recovery requires the evaluation of distributed structural and functional connectivity. Preclinical MRI of experimental stroke models provides validation of non-invasive biomarkers in terms of cellular and molecular mechanisms, while also providing a translational platform for evaluation of prospective therapies. This brief review of translational stroke imaging discusses the acute to chronic imaging transition, the principles underlying common MRI methods employed in stroke research, and the experimental results obtained by clinical and preclinical imaging to determine tissue viability, vascular remodeling, structural connectivity of major white matter tracts, and functional connectivity using task-based and resting-state fMRI during the stroke recovery process.
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Affiliation(s)
- Emiri T Mandeville
- Neuroprotection Research Laboratory, Massachusetts General Hospital, Charlestown, MA, USA. .,Department of Radiology, Massachusetts General Hospital, Bldg 149 13th Street, Charlestown, MA, 02129, USA.
| | - Cenk Ayata
- Neurovascular Research Laboratory, Massachusetts General Hospital, Charlestown, MA, USA.,Department of Radiology, Massachusetts General Hospital, Bldg 149 13th Street, Charlestown, MA, 02129, USA
| | - Yi Zheng
- Neurovascular Research Laboratory, Massachusetts General Hospital, Charlestown, MA, USA.,Department of Radiology, Massachusetts General Hospital, Bldg 149 13th Street, Charlestown, MA, 02129, USA
| | - Joseph B Mandeville
- Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Charlestown, MA, USA.,Department of Radiology, Massachusetts General Hospital, Bldg 149 13th Street, Charlestown, MA, 02129, USA
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22
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Abstract
Gadolinium has been widely used as the contrast agent of choice for magnetic resonance imaging (MRI). However, gadolinium administration is not always desired due to its inherent enhancement properties and potential side effects (nephrogenic systemic fibrosis). This article reviews gadolinium alternatives, iron-, and manganese- based agents, and their current clinical usage for contrast-enhanced MRI examinations.
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23
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Williams RJ, Reutens DC, Hocking J. Influence of BOLD Contributions to Diffusion fMRI Activation of the Visual Cortex. Front Neurosci 2016; 10:279. [PMID: 27445654 PMCID: PMC4923189 DOI: 10.3389/fnins.2016.00279] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2016] [Accepted: 06/06/2016] [Indexed: 11/24/2022] Open
Abstract
Reliance on the hemodynamic response as a surrogate marker of neural activity imposes an intrinsic limit on the spatial specificity of functional MRI. An alternative approach based on diffusion-weighted functional MRI (DfMRI) has been reported as a contrast less reliant on hemodynamic effects, however current evidence suggests that both hemodynamic and unique neural sources contribute to the diffusion signal. Here we compare activation patterns obtained with the standard blood oxygenation level-dependent (BOLD) contrast to DfMRI in order to gain a deeper understanding of how the BOLD proportion contributes to the observable diffusion signal. Both individual and group-level activation patterns obtained with DfMRI and BOLD to a visual field stimulation paradigm were analyzed. At the individual level, the DfMRI contrast showed a strong, positive relationship between the volumes of cortex activated in response to quadrant- and hemi-field visual stimulation. This was not observed in the corresponding BOLD experiment. Overall, the DfMRI response indicated less between-subject variability, with random effects analyses demonstrating higher statistical values at the peak voxel for DfMRI. Furthermore, the spatial extent of the activation was more restricted to the primary visual region for DfMRI than BOLD. However, the diffusion signal was sensitive to the hemodynamic response in a manner dependent on experimental manipulation. It was also limited by its low signal-to-noise ratio (SNR), demonstrating lower sensitivity than BOLD. Together these findings both support DfMRI as a contrast that bears a closer spatial relationship to the underlying neural activity than BOLD, and raise important caveats regarding its utilization. Models explaining the DfMRI signal change need to consider the dynamic vascular contributions that may vary with neural activity.
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Affiliation(s)
- Rebecca J Williams
- Hotchkiss Brain Institute and Department of Radiology, University of CalgaryCalgary, AB, Canada; Centre for Advanced Imaging, The University of QueenslandSt. Lucia, QLD, Australia; Queensland Brain Institute, The University of QueenslandSt. Lucia, QLD, Australia; Centre for Clinical Research, The University of QueenslandBrisbane, QLD, Australia
| | - David C Reutens
- Centre for Advanced Imaging, The University of Queensland St. Lucia, QLD, Australia
| | - Julia Hocking
- School of Psychology and Counselling, Faculty of Health, Queensland University of Technology Kelvin Grove, QLD, Australia
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Couto D, Freitas M, Costa VM, Chisté RC, Almeida A, Lopez-Quintela MA, Rivas J, Freitas P, Silva P, Carvalho F, Fernandes E. Biodistribution of polyacrylic acid-coated iron oxide nanoparticles is associated with proinflammatory activation and liver toxicity. J Appl Toxicol 2016; 36:1321-31. [PMID: 27102234 DOI: 10.1002/jat.3323] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2016] [Revised: 02/19/2016] [Accepted: 02/22/2016] [Indexed: 01/30/2023]
Abstract
Iron oxide nanoparticles (IONs) have physical and chemical properties that render them useful for several new biomedical applications. Still, so far, in vivo safety studies of IONs with coatings of biomedical interest are still scarce. The aim of this study, therefore, was to clarify the acute biological effects of polyacrylic acid (PAA)-coated IONs, by determining their biodistribution and their potential proinflammatory and toxic effects in CD-1 mice. The biodistribution of PAA-coated IONs in several organs (liver, spleen, kidneys, brain, heart, testes and lungs), the plasma cytokines, chemokine and aminotransferases levels, white blood cell count, oxidative stress parameters, adenosine triphosphate and histologic features of liver, spleen and kidneys were evaluated 24 h after a single acute (8, 20 or 50 mg kg(-1) ) intravenous administration of PAA-coated IONs in magnetite form. The obtained results showed that these IONs accumulate mainly in the liver and spleen and, to a lesser extent, in the lungs. Although our data showed that PAA-coated IONs do not cause severe organ damage, an inflammatory process was triggered in vivo, as evidenced by as evidenced by increased neutrophils and large lymphocytes in the differential blood count. Moreover, an accumulation of iron in macrophages of the liver and spleen was observed and hepatic lipid peroxidation was elicited, showing that the IONs are able to induce oxidative stress. The effects of these nanoparticles need to be further investigated regarding the mechanisms involved and the long-term consequences of intravenous administration of PAA-coated IONs. Copyright © 2016 John Wiley & Sons, Ltd.
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Affiliation(s)
- Diana Couto
- UCIBIO-REQUIMTE, Laboratory of Applied Chemistry, Department of Chemical Sciences, Faculty of Pharmacy, University of Porto, Porto, Portugal
| | - Marisa Freitas
- UCIBIO-REQUIMTE, Laboratory of Applied Chemistry, Department of Chemical Sciences, Faculty of Pharmacy, University of Porto, Porto, Portugal
| | - Vera Marisa Costa
- UCIBIO-REQUIMTE, Laboratory of Toxicology, Department of Biological Sciences, Faculty of Pharmacy, University of Porto, Porto, Portugal
| | - Renan Campos Chisté
- UCIBIO-REQUIMTE, Laboratory of Applied Chemistry, Department of Chemical Sciences, Faculty of Pharmacy, University of Porto, Porto, Portugal
| | - Agostinho Almeida
- LAQV-REQUIMTE, Laboratory of Applied Chemistry, Department of Chemical Sciences, Faculty of Pharmacy, University of Porto, Porto, Portugal
| | - M Arturo Lopez-Quintela
- Laboratory of Nanotechnology and Magnetism, Institute of Technological Research, IIT, University of Santiago de Compostela (USC), Spain
| | - José Rivas
- International Iberian Nanotechnology Laboratory, Braga, Portugal
| | - Paulo Freitas
- International Iberian Nanotechnology Laboratory, Braga, Portugal
| | - Paula Silva
- UCIBIO-REQUIMTE, Laboratory of Histology and Embryology, Institute of Biomedical Sciences Abel Salazar (ICBAS), University of Porto, Porto, Portugal
| | - Félix Carvalho
- UCIBIO-REQUIMTE, Laboratory of Toxicology, Department of Biological Sciences, Faculty of Pharmacy, University of Porto, Porto, Portugal
| | - Eduarda Fernandes
- UCIBIO-REQUIMTE, Laboratory of Applied Chemistry, Department of Chemical Sciences, Faculty of Pharmacy, University of Porto, Porto, Portugal
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Shu CY, Sanganahalli BG, Coman D, Herman P, Hyder F. New horizons in neurometabolic and neurovascular coupling from calibrated fMRI. PROGRESS IN BRAIN RESEARCH 2016; 225:99-122. [PMID: 27130413 DOI: 10.1016/bs.pbr.2016.02.003] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Neurovascular coupling relates changes in neuronal activity to constriction/dilation of microvessels. However neurometabolic coupling, which is less well known, relates alterations in neuronal activity with metabolic demands. The link between the blood oxygenation level dependent (BOLD) signal and neural activity opened doors for functional MRI (fMRI) to be a powerful neuroimaging tool in the neurosciences. But due to the complex makeup of BOLD contrast, researchers began to investigate the relationship between BOLD signal and blood flow and/or volume changes during functional brain activation, which together provided the tools to measure oxygen consumption on the basis of the biophysical model of BOLD. This field is called calibrated fMRI, thereby allowed probing of both neurometabolic and neurovascular couplings for a variety of health conditions in animals and humans. Calibrated fMRI may provide brain disorder biomarkers that could be used for monitoring effective therapies.
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Affiliation(s)
- C Y Shu
- Yale University, New Haven, CT, United States
| | - B G Sanganahalli
- Yale University, New Haven, CT, United States; Magnetic Resonance Research Center (MRRC), Yale University, New Haven, CT, United States
| | - D Coman
- Yale University, New Haven, CT, United States; Magnetic Resonance Research Center (MRRC), Yale University, New Haven, CT, United States
| | - P Herman
- Yale University, New Haven, CT, United States; Magnetic Resonance Research Center (MRRC), Yale University, New Haven, CT, United States
| | - F Hyder
- Yale University, New Haven, CT, United States; Magnetic Resonance Research Center (MRRC), Yale University, New Haven, CT, United States.
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26
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Gozzi A, Schwarz AJ. Large-scale functional connectivity networks in the rodent brain. Neuroimage 2015; 127:496-509. [PMID: 26706448 DOI: 10.1016/j.neuroimage.2015.12.017] [Citation(s) in RCA: 139] [Impact Index Per Article: 15.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2015] [Revised: 12/04/2015] [Accepted: 12/11/2015] [Indexed: 02/08/2023] Open
Abstract
Resting-state functional Magnetic Resonance Imaging (rsfMRI) of the human brain has revealed multiple large-scale neural networks within a hierarchical and complex structure of coordinated functional activity. These distributed neuroanatomical systems provide a sensitive window on brain function and its disruption in a variety of neuropathological conditions. The study of macroscale intrinsic connectivity networks in preclinical species, where genetic and environmental conditions can be controlled and manipulated with high specificity, offers the opportunity to elucidate the biological determinants of these alterations. While rsfMRI methods are now widely used in human connectivity research, these approaches have only relatively recently been back-translated into laboratory animals. Here we review recent progress in the study of functional connectivity in rodent species, emphasising the ability of this approach to resolve large-scale brain networks that recapitulate neuroanatomical features of known functional systems in the human brain. These include, but are not limited to, a distributed set of regions identified in rats and mice that may represent a putative evolutionary precursor of the human default mode network (DMN). The impact and control of potential experimental and methodological confounds are also critically discussed. Finally, we highlight the enormous potential and some initial application of connectivity mapping in transgenic models as a tool to investigate the neuropathological underpinnings of the large-scale connectional alterations associated with human neuropsychiatric and neurological conditions. We conclude by discussing the translational potential of these methods in basic and applied neuroscience.
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Affiliation(s)
- Alessandro Gozzi
- Istituto Italiano di Tecnologia, Center for Neuroscience and Cognitive Systems at UniTn, Rovereto, Italy.
| | - Adam J Schwarz
- Department of Psychological and Brain Sciences, Indiana University, Bloomington, IN 47405, USA; Department of Radiology and Imaging Sciences, Indiana University, Indianapolis, IN 46202, USA
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Arami H, Khandhar A, Liggitt D, Krishnan KM. In vivo delivery, pharmacokinetics, biodistribution and toxicity of iron oxide nanoparticles. Chem Soc Rev 2015; 44:8576-607. [PMID: 26390044 PMCID: PMC4648695 DOI: 10.1039/c5cs00541h] [Citation(s) in RCA: 492] [Impact Index Per Article: 54.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Iron oxide nanoparticles (IONPs) have been extensively used during the last two decades, either as effective bio-imaging contrast agents or as carriers of biomolecules such as drugs, nucleic acids and peptides for controlled delivery to specific organs and tissues. Most of these novel applications require elaborate tuning of the physiochemical and surface properties of the IONPs. As new IONPs designs are envisioned, synergistic consideration of the body's innate biological barriers against the administered nanoparticles and the short and long-term side effects of the IONPs become even more essential. There are several important criteria (e.g. size and size-distribution, charge, coating molecules, and plasma protein adsorption) that can be effectively tuned to control the in vivo pharmacokinetics and biodistribution of the IONPs. This paper reviews these crucial parameters, in light of biological barriers in the body, and the latest IONPs design strategies used to overcome them. A careful review of the long-term biodistribution and side effects of the IONPs in relation to nanoparticle design is also given. While the discussions presented in this review are specific to IONPs, some of the information can be readily applied to other nanoparticle systems, such as gold, silver, silica, calcium phosphates and various polymers.
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Affiliation(s)
- Hamed Arami
- Department of Materials Science and Engineering, University of Washington, Seattle, Washington, 98195
| | - Amit Khandhar
- Department of Materials Science and Engineering, University of Washington, Seattle, Washington, 98195
| | - Denny Liggitt
- Department of Comparative Medicine, University of Washington School of Medicine, Seattle, Washington, 98195
| | - Kannan M. Krishnan
- Department of Materials Science and Engineering, University of Washington, Seattle, Washington, 98195
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Gkagkanasiou M, Ploussi A, Gazouli M, Efstathopoulos EP. USPIO-Enhanced MRI Neuroimaging: A Review. J Neuroimaging 2015; 26:161-8. [PMID: 26932522 DOI: 10.1111/jon.12318] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2015] [Accepted: 10/23/2015] [Indexed: 11/28/2022] Open
Abstract
MRI is a powerful tool for the diagnosis and management for a variety of central nervous system (CNS) diseases. Ultrasmall superparamagnetic iron oxide (USPIO) nanoparticles are a novel category of MRI contrast agents that seem to play a crucial role in the imaging of CNS. Due to their physical properties, USPIOs act as blood pool agents. USPIOs improve visualization of tumor vasculature and relative cerebral blood volume measurements, tumor-associated inflammation, inflammatory-immune mediated disorders, stroke and vascular malformations. Ferumoxytol, a new type of USPIO agent, appears to have ideal characteristics for the imaging of CNS. The last few years, ferumoxytol has been successfully used to image CNS neoplasms, CNS inflammations and cerebral malformations offering useful information on cellular and molecular level. In addition, ferumoxytol studies focused on the pathophysiology of other CNS disorders like multiple sclerosis and epilepsy are already in progress. Aim of this review article is to provide the potential role of USPIO-enhanced MRI and the latest clinical applications of ferumoxytol agent in CNS imaging.
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Affiliation(s)
- Maria Gkagkanasiou
- Department of Computed Tomography, 251 HAF and VA Hospital, Athens, Greece
| | - Agapi Ploussi
- Department of Radiology, Medical School, National and Kapodistrian University of Athens, Athens, Greece
| | - Maria Gazouli
- Department of Basic Medical Science, Laboratory of Biology, School of Medicine, University of Athens, Athens, Greece
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Zhao F, Holahan MA, Houghton AK, Hargreaves R, Evelhoch JL, Winkelmann CT, Williams DS. Functional imaging of olfaction by CBV fMRI in monkeys: Insight into the role of olfactory bulb in habituation. Neuroimage 2015; 106:364-72. [DOI: 10.1016/j.neuroimage.2014.12.001] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2014] [Revised: 11/04/2014] [Accepted: 12/01/2014] [Indexed: 11/26/2022] Open
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Liu CH. Anatomical, functional and molecular biomarker applications of magnetic resonance neuroimaging. FUTURE NEUROLOGY 2015; 10:49-65. [DOI: 10.2217/fnl.14.60] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
ABSTRACT MRI and magnetic resonance spectroscopy (MRS) along with computed tomography and PET are the most common imaging modalities used in the clinics to detect structural abnormalities and pathological conditions in the brain. MRI generates superb image resolution/contrast without radiation exposure that is associated with computed tomography and PET; MRS and spectroscopic imaging technologies allow us to measure changes in brain biochemistry. Increasingly, neurobiologists and MRI scientists are collaborating to solve neuroscience problems across sub-cellular through anatomical levels. To achieve successful cross-disciplinary collaborations, neurobiologists must have sufficient knowledge of magnetic resonance principles and applications in order to effectively communicate with their MRI colleagues. This review provides an overview of magnetic resonance techniques and how they can be used to gain insight into the active brain at the anatomical, functional and molecular levels with the goal of encouraging neurobiologists to include MRI/MRS as a research tool in their endeavors.
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Shulman RG, Hyder F, Rothman DL. Insights from neuroenergetics into the interpretation of functional neuroimaging: an alternative empirical model for studying the brain's support of behavior. J Cereb Blood Flow Metab 2014; 34:1721-35. [PMID: 25160670 PMCID: PMC4269754 DOI: 10.1038/jcbfm.2014.145] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/12/2014] [Revised: 06/12/2014] [Accepted: 07/21/2014] [Indexed: 02/05/2023]
Abstract
Functional neuroimaging measures quantitative changes in neurophysiological parameters coupled to neuronal activity during observable behavior. These results have usually been interpreted by assuming that mental causation of behavior arises from the simultaneous actions of distinct psychological mechanisms or modules. However, reproducible localization of these modules in the brain using functional magnetic resonance imaging (MRI) and positron emission tomography (PET) imaging has been elusive other than for sensory systems. In this paper, we show that neuroenergetic studies using PET, calibrated functional magnetic resonance imaging (fMRI), (13)C magnetic resonance spectroscopy, and electrical recordings do not support the standard approach, which identifies the location of mental modules from changes in brain activity. Of importance in reaching this conclusion is that changes in neuronal activities underlying the fMRI signal are many times smaller than the high ubiquitous, baseline neuronal activity, or energy in resting, awake humans. Furthermore, the incremental signal depends on the baseline activity contradicting theoretical assumptions about linearity and insertion of mental modules. To avoid these problems, while making use of these valuable results, we propose that neuroimaging should be used to identify observable brain activities that are necessary for a person's observable behavior rather than being used to seek hypothesized mental processes.
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Affiliation(s)
- Robert G Shulman
- Magnetic Resonance Research Center, Yale University, New Haven, Connecticut, USA
| | - Fahmeed Hyder
- Magnetic Resonance Research Center, Yale University, New Haven, Connecticut, USA
- Departments of Diagnostic Radiology, Yale University, New Haven, Connecticut, USA
- Biomedical Engineering, Yale University, New Haven, Connecticut, USA
- Quantitative Neuroscience with Magnetic Resonance Core Center, Yale University, New Haven, Connecticut, USA
| | - Douglas L Rothman
- Magnetic Resonance Research Center, Yale University, New Haven, Connecticut, USA
- Departments of Diagnostic Radiology, Yale University, New Haven, Connecticut, USA
- Biomedical Engineering, Yale University, New Haven, Connecticut, USA
- Quantitative Neuroscience with Magnetic Resonance Core Center, Yale University, New Haven, Connecticut, USA
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32
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Walker JP, Nosova E, Sigovan M, Rapp J, Grenon MS, Owens CD, Gasper WJ, Saloner DA. Ferumoxytol-enhanced magnetic resonance angiography is a feasible method for the clinical evaluation of lower extremity arterial disease. Ann Vasc Surg 2014; 29:63-8. [PMID: 25269682 DOI: 10.1016/j.avsg.2014.09.003] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2014] [Revised: 08/26/2014] [Accepted: 09/08/2014] [Indexed: 11/29/2022]
Abstract
BACKGROUND Renal toxicity from conventional, iodinated, intravenous contrast agents is a common complication in patients with peripheral artery disease (PAD). Similarly, the potential for serious side effects prevents the use of gadolinium-based agents in many patients with depressed renal function. Ferumoxytol-enhanced magnetic resonance angiography (Fe-MRA) is a novel technique that uses an intravenous, ultrasmall, superparamagnetic, iron oxide preparation, currently approved by the Food and Drug Administration for the treatment of iron deficiency anemia in adults with chronic kidney disease. Our objective was to determine the feasibility of Fe-MRA for clinical decision making in PAD patients. METHODS This was a prospective pilot study assessing 10 patients with suspected arterial occlusive disease with contrast-enhanced MRA of the aorta and lower extremities. Of those, 5 had renal insufficiency and were imaged with Fe-MRA, whereas the remainder underwent gadolinium-enhanced MRA. Qualitative and quantitative evaluations of deidentified images at each arterial station were independently performed by 4 blinded vascular surgeons. RESULTS All patients were men, with an average age of 68 ± 4 years. The 2 groups had similar incidences of diabetes, hypertension, hyperlipidemia, and coronary artery disease. Patients undergoing Fe-MRA had significantly decreased renal function (estimated glomerular filtration rate, 35.4 vs. 77.6; P = 0.02). There were no adverse events during contrast administration in either group. No difference was found in the overall quality of the ferumoxytol versus the gadolinium studies (7.1 ± 2.0 vs. 7.4 ± 2.4, P = 0.67). Similarly, reviewers felt comfortable basing clinical decisions on the images 89% of the time with both the ferumoxytol and gadolinium groups (P = 1.00). CONCLUSIONS This is the first report of an important alternative to conventional computed tomography angiography and MRA in PAD patients, particularly in the setting of renal insufficiency. Fe-MRA provides a useful tool in patients with suspected lower extremity PAD without the potential risks of gadolinium.
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Affiliation(s)
- Joy P Walker
- Department of Vascular and Endovascular Surgery, San Francisco, CA.
| | - Emily Nosova
- Department of Vascular and Endovascular Surgery, San Francisco, CA
| | - Monica Sigovan
- Department of Radiology, University of California, San Francisco, CA
| | - Joseph Rapp
- Department of Vascular and Endovascular Surgery, San Francisco, CA
| | - Marlene S Grenon
- Department of Vascular and Endovascular Surgery, San Francisco, CA
| | | | - Warren J Gasper
- Department of Vascular and Endovascular Surgery, San Francisco, CA
| | - David A Saloner
- Department of Radiology, University of California, San Francisco, CA
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33
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Fujiwara S, Uhrig L, Amadon A, Jarraya B, Le Bihan D. Quantification of iron in the non-human primate brain with diffusion-weighted magnetic resonance imaging. Neuroimage 2014; 102 Pt 2:789-97. [PMID: 25192653 DOI: 10.1016/j.neuroimage.2014.08.049] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2014] [Revised: 08/23/2014] [Accepted: 08/26/2014] [Indexed: 01/12/2023] Open
Abstract
Pathological iron deposits in the brain, especially within basal ganglia, are linked to severe neurodegenerative disorders like Parkinson's disease. As iron induces local changes in magnetic susceptibility, its presence can be visualized with magnetic resonance imaging (MRI). The usual approach, based on iron induced changes in magnetic relaxation (T2/T2'), is often prone, however, to confounding artifacts and lacks specificity. Here, we propose a new method to quantify and map iron deposits using water diffusion MRI. This method is based on the differential sensitivity of two image acquisition schemes to the local magnetic field gradients induced by iron deposits and their cross-term with gradient pulses used for diffusion encoding. Iron concentration could be imaged and estimated with high accuracy in the brain cortex, the thalamus, the substantia nigra and the globus pallidus of macaques, showing iron distributions in agreement with literature. Additionally, iron maps could clearly show a dramatic increase in iron content upon injection of an UltraSmall Particle Iron Oxide (USPIO) contrast agent, notably in the cortex and the thalamus, reflecting regional differences in blood volume. The method will benefit clinical investigations on the effect of iron deposits in the brain or other organs, as iron deposits are increasingly seen as a biomarker for a wide range of diseases, notably, neurodegenerative diseases in the pre-symptomatic stage. It also has the potential for quantifying variations in blood volume induced by brain activation in fMRI studies using USPIOs.
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Affiliation(s)
- Shunro Fujiwara
- Neurospin, Bâtiment 145, CEA-Saclay, Gif-sur-Yvette, 91191 Gif-sur-Yvette, France; Department of Neurosurgery, Iwate Medical University, 19-1 Uchimaru, Morioka, 0208505 Iwate, Japan
| | - Lynn Uhrig
- Neurospin, Bâtiment 145, CEA-Saclay, Gif-sur-Yvette, 91191 Gif-sur-Yvette, France; Equipe Avenir INSERM Bettencourt Schueller, Institut Fédératif de Recherche n°49, NeuroSpin, Bât. 145, CEA-Saclay, Gif-sur-Yvette, 91191 Gif-sur-Yvette, France
| | - Alexis Amadon
- Neurospin, Bâtiment 145, CEA-Saclay, Gif-sur-Yvette, 91191 Gif-sur-Yvette, France
| | - Béchir Jarraya
- Neurospin, Bâtiment 145, CEA-Saclay, Gif-sur-Yvette, 91191 Gif-sur-Yvette, France; Equipe Avenir INSERM Bettencourt Schueller, Institut Fédératif de Recherche n°49, NeuroSpin, Bât. 145, CEA-Saclay, Gif-sur-Yvette, 91191 Gif-sur-Yvette, France; Department of Neurosurgery, Neuromodulation unit, Foch Hospital, University of Versailles-Saint Quentin, 40 rue Worth, 92150 Suresnes, France
| | - Denis Le Bihan
- Neurospin, Bâtiment 145, CEA-Saclay, Gif-sur-Yvette, 91191 Gif-sur-Yvette, France.
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Pohlmann A, Karczewski P, Ku MC, Dieringer B, Waiczies H, Wisbrun N, Kox S, Palatnik I, Reimann HM, Eichhorn C, Waiczies S, Hempel P, Lemke B, Niendorf T, Bimmler M. Cerebral blood volume estimation by ferumoxytol-enhanced steady-state MRI at 9.4 T reveals microvascular impact of α1 -adrenergic receptor antibodies. NMR IN BIOMEDICINE 2014; 27:1085-1093. [PMID: 25060359 DOI: 10.1002/nbm.3160] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/28/2014] [Revised: 05/11/2014] [Accepted: 06/05/2014] [Indexed: 06/03/2023]
Abstract
Cerebrovascular abnormality is frequently accompanied by cognitive dysfunctions, such as dementia. Antibodies against the α1 -adrenoceptor (α1 -AR) can be found in patients with Alzheimer's disease with cerebrovascular disease, and have been shown to affect the larger vessels of the brain in rodents. However, the impact of α1 -AR antibodies on the cerebral vasculature remains unclear. In the present study, we established a neuroimaging method to measure the relative cerebral blood volume (rCBV) in small rodents with the ultimate goal to detect changes in blood vessel density and/or vessel size induced by α1 -AR antibodies. For this purpose, mapping of R2 * and R2 was performed using MRI at 9.4 T, before and after the injection of intravascular iron oxide particles (ferumoxytol). The change in the transverse relaxation rates (ΔR2 *, ΔR2 ) showed a significant rCBV decrease in the cerebrum, cortex and hippocampus of rats (except hippocampal ΔR2 ), which was more pronounced for ΔR2 * than for ΔR2 . Immunohistological analyses confirmed that the α1 -AR antibody induced blood vessel deficiencies. Our findings support the hypothesis that α1 -AR antibodies lead to cerebral vessel damage throughout the brain, which can be monitored by MRI-derived rCBV, a non-invasive neuroimaging method. This demonstrates the value of rCBV estimation by ferumoxytol-enhanced MRI at 9.4 T, and further underlines the significance of this antibody in brain diseases involving vasculature impairments, such as dementia.
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Affiliation(s)
- Andreas Pohlmann
- Berlin Ultrahigh Field Facility (B.U.F.F.), Max Delbrück Center for Molecular Medicine, Berlin, Germany
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Mandeville JB, Liu CH, Vanduffel W, Marota JJA, Jenkins BG. Data collection and analysis strategies for phMRI. Neuropharmacology 2014; 84:65-78. [PMID: 24613447 PMCID: PMC4058391 DOI: 10.1016/j.neuropharm.2014.02.018] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2013] [Revised: 02/07/2014] [Accepted: 02/25/2014] [Indexed: 12/24/2022]
Abstract
Although functional MRI traditionally has been applied mainly to study changes in task-induced brain function, evolving acquisition methodologies and improved knowledge of signal mechanisms have increased the utility of this method for studying responses to pharmacological stimuli, a technique often dubbed "phMRI". The proliferation of higher magnetic field strengths and the use of exogenous contrast agent have boosted detection power, a critical factor for successful phMRI due to the restricted ability to average multiple stimuli within subjects. Receptor-based models of neurovascular coupling, including explicit pharmacological models incorporating receptor densities and affinities and data-driven models that incorporate weak biophysical constraints, have demonstrated compelling descriptions of phMRI signal induced by dopaminergic stimuli. This report describes phMRI acquisition and analysis methodologies, with an emphasis on data-driven analyses. As an example application, statistically efficient data-driven regressors were used to describe the biphasic response to the mu-opioid agonist remifentanil, and antagonism using dopaminergic and GABAergic ligands revealed modulation of the mesolimbic pathway. Results illustrate the power of phMRI as well as our incomplete understanding of mechanisms underlying the signal. Future directions are discussed for phMRI acquisitions in human studies, for evolving analysis methodologies, and for interpretative studies using the new generation of simultaneous PET/MRI scanners. This article is part of the Special Issue Section entitled 'Neuroimaging in Neuropharmacology'.
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Affiliation(s)
- Joseph B Mandeville
- Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Charlestown, MA 02129, USA.
| | - Christina H Liu
- National Institute of Biomedical Imaging and Bioengineering, Bethesda, MD 20817, USA
| | - Wim Vanduffel
- Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Charlestown, MA 02129, USA
| | - John J A Marota
- Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Charlestown, MA 02129, USA
| | - Bruce G Jenkins
- Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Charlestown, MA 02129, USA
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Renal transplant imaging using magnetic resonance angiography with a nonnephrotoxic contrast agent. Transplantation 2013; 96:91-6. [PMID: 23680931 DOI: 10.1097/tp.0b013e318295464c] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
BACKGROUND In renal allograft recipients presenting with graft dysfunction, it is critical to determine the patency of the transplant vasculature to guide clinical management. Conventional modalities such as Doppler ultrasound, contrast-enhanced computed tomography, magnetic resonance angiography (MRA), and noncontrast MRA are each of limited use because of technical factors and toxicity of standard contrast agents. The purpose of this study was to retrospectively review our institutional experience with renal transplant MRA using ferumoxytol (a nonnephrotoxic medication) as a contrast agent and evaluate its use in the assessment of allograft vascular patency in patients with graft dysfunction, either delayed or slow graft function within hours to days after kidney transplantation or acute kidney injury weeks to months after kidney transplantation. METHODS Sixteen kidney transplant recipients were retrospectively identified who underwent ferumoxytol-enhanced MRA after a nondiagnostic ultrasound for kidney dysfunction after transplantation. Image evaluation was performed by two radiologists, and clinical follow-up data were collected. RESULTS In 1 of 16 subjects, MRA with ferumoxytol demonstrated complete arterial occlusion of an allograft. In 2 of 16 subjects, MRA detected moderate to severe anastomotic stenoses, which were confirmed at catheter angiography and successfully treated, resulting in the improvement of graft function. In 13 of 16 subjects, MRA demonstrated normal graft vasculature, and an alternative cause of allograft dysfunction was ultimately confirmed. CONCLUSIONS Our study suggests that ferumoxytol-enhanced MRA may be a novel, safe method to accurately detect graft artery abnormalities in renal transplant recipients without the risk of nephrotoxicity, when transplant ultrasound is nondiagnostic.
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Quantitative basis for neuroimaging of cortical laminae with calibrated functional MRI. Proc Natl Acad Sci U S A 2013; 110:15115-20. [PMID: 23980158 DOI: 10.1073/pnas.1307154110] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Layer-specific neurophysiologic, hemodynamic, and metabolic measurements are needed to interpret high-resolution functional magnetic resonance imaging (fMRI) data in the cerebral cortex. We examined how neurovascular and neurometabolic couplings vary vertically in the rat's somatosensory cortex. During sensory stimulation we measured dynamic layer-specific responses of local field potential (LFP) and multiunit activity (MUA) as well as blood oxygenation level-dependent (BOLD) signal and cerebral blood volume (CBV) and blood flow (CBF), which in turn were used to calculate changes in oxidative metabolism (CMR(O2)) with calibrated fMRI. Both BOLD signal and CBV decreased from superficial to deep laminae, but these responses were not well correlated with either layer-specific LFP or MUA. However, CBF changes were quite stable across laminae, similar to LFP. However, changes in CMR(O2) and MUA varied across cortex in a correlated manner and both were reduced in superficial lamina. These results lay the framework for quantitative neuroimaging across cortical laminae with calibrated fMRI methods.
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Kim SG, Harel N, Jin T, Kim T, Lee P, Zhao F. Cerebral blood volume MRI with intravascular superparamagnetic iron oxide nanoparticles. NMR IN BIOMEDICINE 2013; 26. [PMID: 23208650 PMCID: PMC3700592 DOI: 10.1002/nbm.2885] [Citation(s) in RCA: 88] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
The cerebral blood volume (CBV) is a crucial physiological indicator of tissue viability and vascular reactivity. Thus, noninvasive CBV mapping has been of great interest. For this, ultrasmall superparamagnetic iron oxide (USPIO) nanoparticles, including monocrystalline iron oxide nanoparticles, can be used as long-half-life, intravascular susceptibility agents of CBV MRI measurements. Moreover, CBV-weighted functional MRI (fMRI) with USPIO nanoparticles provides enhanced sensitivity, reduced large vessel contribution and improved spatial specificity relative to conventional blood oxygenation level-dependent fMRI, and measures a single physiological parameter that is easily interpretable. We review the physiochemical and magnetic properties, and pharmacokinetics, of USPIO nanoparticles in brief. We then extensively discuss quantifications of baseline CBV, vessel size index and functional CBV change. We also provide reviews of dose-dependent sensitivity, vascular filter function, specificity, characteristics and impulse response function of CBV fMRI. Examples of CBV fMRI specificity at the laminar and columnar resolution are provided. Finally, we briefly review the application of CBV measurements to functional and pharmacological studies in animals. Overall, the use of USPIO nanoparticles can determine baseline CBV and its changes induced by functional activity and pharmacological interventions.
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Affiliation(s)
- Seong-Gi Kim
- Neuroimaging Laboratory, Department of Radiology, University of Pittsburgh, PA, USA.
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D'Arceuil H, Coimbra A, Triano P, Dougherty M, Mello J, Moseley M, Glover G, Lansberg M, Blankenberg F. Ferumoxytol enhanced resting state fMRI and relative cerebral blood volume mapping in normal human brain. Neuroimage 2013; 83:200-9. [PMID: 23831413 DOI: 10.1016/j.neuroimage.2013.06.066] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2013] [Revised: 06/03/2013] [Accepted: 06/22/2013] [Indexed: 10/26/2022] Open
Abstract
The brain demonstrates spontaneous low-frequency (<0.1 Hz) cerebral blood flow (CBF) fluctuations, measurable by resting state functional MRI (rs-fMRI). Ultra small superparamagnetic iron oxide particles have been shown to enhance task-based fMRI signals (cerebral blood volume fMRI or CBV-fMRI), compared to the BOLD effect, by a factor of ≈2.5 at 3 T in primates and humans. We evaluated the use of ferumoxytol for steady state, resting state FMRI (CBV-rs-fMRI) and relative cerebral blood volume (rCBV) mapping, at 3T, in healthy volunteers. All standard resting state networks (RSNs) were identified in all subjects. On average the RSN Z statistics (MELODIC independent components) and volumes of the visual and default mode (DMN) networks were comparable. rCBV values were averaged for the visual (Vis) and DMN networks and correlated with the corresponding DMN and visual network Z statistics. There was a negative correlation between the rCBV and the Z statistics for the DMN, for both BOLD and CBV-rs-fMRI contrast (R2=0.63, 0.76). A similar correlation was not found for the visual network. Short repetition time rs-fMRI data were Fourier transformed to evaluate the effect of ferumoxytol on cardiac and respiratory fluctuations in the brain rs-BOLD, CBV signals. Cardiac and respiratory fluctuations decreased to baseline within large vessels post ferumoxytol. Robust rs-fMRI and CBV mapping is possible in normal human brain.
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Neurovascular coupling to D2/D3 dopamine receptor occupancy using simultaneous PET/functional MRI. Proc Natl Acad Sci U S A 2013; 110:11169-74. [PMID: 23723346 DOI: 10.1073/pnas.1220512110] [Citation(s) in RCA: 96] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
This study employed simultaneous neuroimaging with positron emission tomography (PET) and functional magnetic resonance imaging (fMRI) to demonstrate the relationship between changes in receptor occupancy measured by PET and changes in brain activity inferred by fMRI. By administering the D2/D3 dopamine receptor antagonist [(11)C]raclopride at varying specific activities to anesthetized nonhuman primates, we mapped associations between changes in receptor occupancy and hemodynamics [cerebral blood volume (CBV)] in the domains of space, time, and dose. Mass doses of raclopride above tracer levels caused increases in CBV and reductions in binding potential that were localized to the dopamine-rich striatum. Moreover, similar temporal profiles were observed for specific binding estimates and changes in CBV. Injection of graded raclopride mass doses revealed a monotonic coupling between neurovascular responses and receptor occupancies. The distinct CBV magnitudes between putamen and caudate at matched occupancies approximately matched literature differences in basal dopamine levels, suggesting that the relative fMRI measurements reflect basal D2/D3 dopamine receptor occupancy. These results can provide a basis for models that relate dopaminergic occupancies to hemodynamic changes in the basal ganglia. Overall, these data demonstrate the utility of simultaneous PET/fMRI for investigations of neurovascular coupling that correlate neurochemistry with hemodynamic changes in vivo for any receptor system with an available PET tracer.
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A receptor-based model for dopamine-induced fMRI signal. Neuroimage 2013; 75:46-57. [PMID: 23466936 DOI: 10.1016/j.neuroimage.2013.02.036] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2012] [Revised: 02/11/2013] [Accepted: 02/20/2013] [Indexed: 01/22/2023] Open
Abstract
This report describes a multi-receptor physiological model of the fMRI temporal response and signal magnitude evoked by drugs that elevate synaptic dopamine in basal ganglia. The model is formulated as a summation of dopamine's effects at D1-like and D2-like receptor families, which produce functional excitation and inhibition, respectively, as measured by molecular indicators like adenylate cyclase or neuroimaging techniques like fMRI. Functional effects within the model are described in terms of relative changes in receptor occupancies scaled by receptor densities and neuro-vascular coupling constants. Using literature parameters, the model reconciles many discrepant observations and interpretations of pre-clinical data. Additionally, we present data showing that amphetamine stimulation produces fMRI inhibition at low doses and a biphasic response at higher doses in the basal ganglia of non-human primates (NHP), in agreement with model predictions based upon the respective levels of evoked dopamine. Because information about dopamine release is required to inform the fMRI model, we simultaneously acquired PET (11)C-raclopride data in several studies to evaluate the relationship between raclopride displacement and assumptions about dopamine release. At high levels of dopamine release, results suggest that refinements of the model will be required to consistently describe the PET and fMRI data. Overall, the remarkable success of the model in describing a wide range of preclinical fMRI data indicate that this approach will be useful for guiding the design and analysis of basic science and clinical investigations and for interpreting the functional consequences of dopaminergic stimulation in normal subjects and in populations with dopaminergic neuroadaptations.
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Abstract
In this issue of Neuron, Goense et al. (2012) report on high-resolution, layer-specific measurements of BOLD, cerebral blood volume, and cerebral blood flow in regions of positive and negative BOLD associated with a simple visual stimulus. The findings strongly suggest that the hemodynamic mechanisms behind negative signal changes are quite different from those behind positive signal changes.
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Christen T, Ni W, Qiu D, Schmiedeskamp H, Bammer R, Moseley M, Zaharchuk G. High-resolution cerebral blood volume imaging in humans using the blood pool contrast agent ferumoxytol. Magn Reson Med 2012; 70:705-10. [PMID: 23001902 DOI: 10.1002/mrm.24500] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2012] [Revised: 08/08/2012] [Accepted: 08/22/2012] [Indexed: 01/03/2023]
Abstract
Cerebral blood volume maps are usually acquired using dynamic susceptibility contrast imaging which inherently limits the spatial resolution and signal to noise ratio of the images. In this study, we used ferumoxytol (AMAG Pharmaceuticals, Inc., Cambridge, MA), an FDA-approved compound, to obtain high-resolution cerebral blood volume maps with a steady-state approach in seven healthy volunteers. R2* maps (0.8 × 0.8 × 1 mm(3)) were acquired before and after injection of ferumoxytol and an intraindividual normalization protocol was used to obtain quantitative values. The results show excellent contrast between white and gray matter as well as fine highly detailed vascular structures. An average blood volume of 4% was found in the brain of all volunteers, consistent with prior literature values. A linear relationship was found between ferumoxytol dose (mg/kg) and ΔR2* (1/s) in gray (R(2) = 0.98) and white matter (R(2) = 0.98). A quadratic relationship was found in the sagittal sinus (R(2) = 0.98). The cerebral blood volume maps compare well with lower resolution dynamic susceptibility contrast-MRI and their use should improve the evaluation of small and heterogeneous lesions and facilitate intrapatient and interpatient comparisons.
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Affiliation(s)
- Thomas Christen
- Department of Radiology, Stanford University, Stanford, California, USA
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