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Vasireddi A, Schaefer PW, Rohatgi S. Metabolic Imaging of Acute Ischemic Stroke (PET, 1Hydrogen Spectroscopy, 17Oxygen Imaging, 23Sodium MRI, pH Imaging). Neuroimaging Clin N Am 2024; 34:271-280. [PMID: 38604711 DOI: 10.1016/j.nic.2024.01.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/13/2024]
Abstract
Acute stroke imaging plays a vital and time-sensitive role in therapeutic decision-making. Current clinical workflows widely use computed tomography (CT) and magnetic resonance (MR) techniques including CT and MR perfusion to estimate the volume of ischemic penumbra at risk for infarction without acute intervention. The use of imaging techniques aimed toward evaluating the metabolic derangements underlying a developing infarct may provide additional information for differentiating the penumbra from benign oligemia and infarct core. The authors review several modalities of metabolic imaging including PET, hydrogen and oxygen spectroscopy, sodium MRI, and pH-weighted MRI.
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Affiliation(s)
- Anil Vasireddi
- Division of Neuroradiology, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, 55 Fruit Street, Boston, MA 02114, USA.
| | - Pamela W Schaefer
- Division of Neuroradiology, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, 55 Fruit Street, Boston, MA 02114, USA
| | - Saurabh Rohatgi
- Division of Neuroradiology, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, 55 Fruit Street, Boston, MA 02114, USA
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2
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Pinto SMA, Ferreira ARR, Teixeira DSS, Nunes SCC, Batista de Carvalho ALM, Almeida JMS, Garda Z, Pallier A, Pais AACC, Brett CMA, Tóth É, Marques MPM, Pereira MM, Geraldes CFGC. Fluorinated Mn(III)/(II)-Porphyrin with Redox-Responsive 1 H and 19 F Relaxation Properties. Chemistry 2023; 29:e202301442. [PMID: 37606898 DOI: 10.1002/chem.202301442] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2023] [Indexed: 08/23/2023]
Abstract
A new fluorinated manganese porphyrin, (Mn-TPP-p-CF3 ) is reported capable of providing, based on the Mn(III)/Mn(II) equilibrium, dual 1 H relaxivity and 19 F NMR response to redox changes. The physical-chemical characterization of both redox states in DMSO-d6 /H2 O evidenced that the 1 H relaxometric and 19 F NMR properties are appropriate for differential redox MRI detection. The Mn(III)-F distance (dMn-F =9.7-10 Å), as assessed by DFT calculations, is well tailored to allow for adequate paramagnetic effect of Mn(III) on 19 F T1 and T2 relaxation times. Mn-TPP-p-CF3 has a reversible Mn(II)/Mn(III) redox potential of 0.574 V vs. NHE in deoxygenated aqueous HEPES/ THF solution. The reduction of Mn(III)-TPP-p-CF3 in the presence of ascorbic acid is slowly, but fully reversed in the presence of air oxygen, as monitored by UV-Vis spectrometry and 19 F NMR. The broad 1 H and 19 F NMR signals of Mn(III)-TPP-p-CF3 disappear in the presence of 1 equivalent ascorbate replaced by a shifted and broadened 19 F NMR signal from Mn(II)-TPP-p-CF3 . Phantom 19 F MR images in DMSO show a MRI signal intensity decrease upon reduction of Mn(III)-TPP-p-CF3 , retrieved upon complete reoxidation in air within ~24 h. 1 H NMRD curves of the Mn(III)/(II)-TPP-p-CF3 chelates in mixed DMSO/water solvent have the typical shape of Mn(II)/Mn(III) porphyrins.
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Affiliation(s)
- Sara M A Pinto
- University of Coimbra, CQC-IMS, Department of Chemistry, P-3004-535, Coimbra, Portugal
- Coimbra Chemistry Center, University of Coimbra, Rua Larga Largo D. Dinis, 3004-535, Coimbra, Portugal
| | - Ana R R Ferreira
- University of Coimbra, CQC-IMS, Department of Chemistry, P-3004-535, Coimbra, Portugal
- Coimbra Chemistry Center, University of Coimbra, Rua Larga Largo D. Dinis, 3004-535, Coimbra, Portugal
| | - Daniela S S Teixeira
- University of Coimbra, CQC-IMS, Department of Chemistry, P-3004-535, Coimbra, Portugal
- Coimbra Chemistry Center, University of Coimbra, Rua Larga Largo D. Dinis, 3004-535, Coimbra, Portugal
| | - Sandra C C Nunes
- University of Coimbra, CQC-IMS, Department of Chemistry, P-3004-535, Coimbra, Portugal
- Coimbra Chemistry Center, University of Coimbra, Rua Larga Largo D. Dinis, 3004-535, Coimbra, Portugal
| | - Ana L M Batista de Carvalho
- Molecular Physical Chemistry R&D Unit Department of Chemistry, University of Coimbra, Rua Larga, 3004-535, Coimbra, Portugal
- Department of Life Sciences, Faculty of Science and Technology, Calçada Martim de Freitas, 3000-393, Coimbra, Portugal
| | - Joseany M S Almeida
- University of Coimbra, CQC-IMS, Department of Chemistry, P-3004-535, Coimbra, Portugal
- CEMMPRE, University of Coimbra, Pinhal de Marrocos, 3030-788, Coimbra, Portugal
| | - Zoltan Garda
- Centre de Biophysique Moléculaire, CNRS, UPR 4301, Université d'Orléans, Rue Charles Sadron, 45071, Orléans Cedex 2, France
| | - Agnés Pallier
- Centre de Biophysique Moléculaire, CNRS, UPR 4301, Université d'Orléans, Rue Charles Sadron, 45071, Orléans Cedex 2, France
| | - Alberto A C C Pais
- University of Coimbra, CQC-IMS, Department of Chemistry, P-3004-535, Coimbra, Portugal
- Coimbra Chemistry Center, University of Coimbra, Rua Larga Largo D. Dinis, 3004-535, Coimbra, Portugal
| | - Christopher M A Brett
- University of Coimbra, CQC-IMS, Department of Chemistry, P-3004-535, Coimbra, Portugal
- CEMMPRE, University of Coimbra, Pinhal de Marrocos, 3030-788, Coimbra, Portugal
| | - Éva Tóth
- Centre de Biophysique Moléculaire, CNRS, UPR 4301, Université d'Orléans, Rue Charles Sadron, 45071, Orléans Cedex 2, France
| | - Maria P M Marques
- Molecular Physical Chemistry R&D Unit Department of Chemistry, University of Coimbra, Rua Larga, 3004-535, Coimbra, Portugal
- Department of Life Sciences, Faculty of Science and Technology, Calçada Martim de Freitas, 3000-393, Coimbra, Portugal
| | - Mariette M Pereira
- University of Coimbra, CQC-IMS, Department of Chemistry, P-3004-535, Coimbra, Portugal
- Coimbra Chemistry Center, University of Coimbra, Rua Larga Largo D. Dinis, 3004-535, Coimbra, Portugal
| | - Carlos F G C Geraldes
- Coimbra Chemistry Center, University of Coimbra, Rua Larga Largo D. Dinis, 3004-535, Coimbra, Portugal
- Department of Life Sciences, Faculty of Science and Technology, Calçada Martim de Freitas, 3000-393, Coimbra, Portugal
- CIBIT/ICNAS, University of Coimbra, Azinhaga de Santa Comba, 3000-548, Coimbra, Portugal
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Little PV, Arnberg F, Jussing E, Lu L, Ingemann Jensen A, Mitsios N, Mulder J, Tran TA, Holmin S. The cellular basis of increased PET hypoxia tracer uptake in focal cerebral ischemia with comparison between [ 18F]FMISO and [ 64Cu]CuATSM. J Cereb Blood Flow Metab 2021; 41:617-629. [PMID: 32423333 PMCID: PMC7922752 DOI: 10.1177/0271678x20923857] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
PET hypoxia imaging can assess tissue viability in acute ischemic stroke (AIS). [18F]FMISO is an established tracer but requires substantial accumulation time, limiting its use in hyperacute AIS. [64Cu]CuATSM requires less accumulation time and has shown promise as a hypoxia tracer. We compared these tracers in a M2-occlusion model (M2CAO) with preserved collateral blood flow. Rats underwent M2CAO and [18F]FMISO (n = 12) or [64Cu]CuATSM (n = 6) examinations. [64Cu]CuATSM animals were also examined with MRI. Pimonidazole was used as a surrogate for [18F]FMISO in an immunofluorescence analysis employed to profile levels of hypoxia in neurons (NeuN) and astrocytes (GFAP). There was increased [18F]FMISO uptake in the M2CAO cortex. No increase in [64Cu]CuATSM activity was found. The pimonidazole intensity of neurons and astrocytes was increased in hypoxic regions. The pimonidazole intensity ratio was higher in neurons than in astrocytes. In the majority of animals, immunofluorescence revealed a loss of astrocytes within the core of regions with increased pimonidazole uptake. We conclude that [18F]FMISO is superior to [64Cu]CuATSM in detecting hypoxia in AIS, consistent with an earlier study. [18F]FMISO may provide efficient diagnostic imaging beyond the hyperacute phase. Results do not provide encouragement for the use of [64Cu]CuATSM in experimental AIS.
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Affiliation(s)
- Philip V Little
- The Department of Clinical Neuroscience, Karolinska Institutet, Stockholm Sweden.,The Department of Neuroradiology, BioClinicum, Karolinska University Hospital, Stockholm, Sweden
| | - Fabian Arnberg
- The Department of Clinical Neuroscience, Karolinska Institutet, Stockholm Sweden.,The Department of Neuroradiology, BioClinicum, Karolinska University Hospital, Stockholm, Sweden
| | - Emma Jussing
- The Department of Clinical Neuroscience, Karolinska Institutet, Stockholm Sweden.,The Department of Radiopharmacy, Karolinska University Hospital, Stockholm, Sweden.,The Department of Oncology and Pathology, Karolinska Institutet, Stockholm Sweden
| | - Li Lu
- The Department of Clinical Neuroscience, Karolinska Institutet, Stockholm Sweden.,The Department of Radiopharmacy, Karolinska University Hospital, Stockholm, Sweden.,The Department of Oncology and Pathology, Karolinska Institutet, Stockholm Sweden
| | | | - Nicholas Mitsios
- The Department of Neuroscience, Karolinska Institutet, Stockholm, Sweden
| | - Jan Mulder
- The Department of Neuroscience, Karolinska Institutet, Stockholm, Sweden
| | - Thuy A Tran
- The Department of Clinical Neuroscience, Karolinska Institutet, Stockholm Sweden.,The Department of Radiopharmacy, Karolinska University Hospital, Stockholm, Sweden.,The Department of Oncology and Pathology, Karolinska Institutet, Stockholm Sweden
| | - Staffan Holmin
- The Department of Clinical Neuroscience, Karolinska Institutet, Stockholm Sweden.,The Department of Neuroradiology, BioClinicum, Karolinska University Hospital, Stockholm, Sweden
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Abstract
The discovery that brain tissue could potentially be salvaged from ischaemia due to stroke, has led to major advances in the development of therapies for ischemic stroke. In this review, we detail the advances in the understanding of this area termed the ischaemic penumbra, from its discovery to the evolution of imaging techniques, and finally some of the treatments developed. Evolving from animal studies from the 70s and 80s and translated to clinical practice, the field of ischemic reperfusion therapy has largely been guided by an array of imaging techniques developed to positively identify the ischemic penumbra, including positron emission tomography, computed tomography and magnetic resonance imaging. More recently, numerous penumbral identification imaging studies have allowed for a better understanding of the progression of the ischaemic core at the expense of the penumbra, and identification of patients than can benefit from reperfusion therapies in the acute phase. Importantly, 40 years of critical imaging research on the ischaemic penumbra have allowed for considerable extension of the treatment time window and better patient selection for reperfusion therapy. The translation of the penumbra concept into routine clinical practice has shown that "tissue is at least as important as time."
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Affiliation(s)
- Charlotte M Ermine
- Florey Institute of Neuroscience and Mental Health, Melbourne, Australia
| | - Andrew Bivard
- Department of Medicine, Melbourne Brain Centre at The Royal Melbourne Hospital, Parkville, Australia.,Department of Neurology, Melbourne Brain Centre at The Royal Melbourne Hospital, Parkville, Australia
| | - Mark W Parsons
- Department of Medicine, Melbourne Brain Centre at The Royal Melbourne Hospital, Parkville, Australia.,Department of Neurology, Melbourne Brain Centre at The Royal Melbourne Hospital, Parkville, Australia
| | - Jean-Claude Baron
- Institute of Psychiatry and Neuroscience of Paris (IPNP), Université de Paris, Paris, France.,GHU Paris Psychiatrie et Neurosciences, Hôpital Sainte Anne, Paris, France
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Little PV, Kraft SE, Chireh A, Damberg P, Holmin S. Oxygen metabolism MRI - A comparison with perfusion imaging in a rat model of MCA branch occlusion and reperfusion. J Cereb Blood Flow Metab 2020; 40:2315-2327. [PMID: 31842668 PMCID: PMC7585917 DOI: 10.1177/0271678x19892271] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
The penumbra is sustained by an increased extraction of oxygen (OEF) from blood to brain tissue. Metabolic imaging may improve penumbra specificity when examining stroke patients with wake-up stroke and a long time between admission and symptom onset. We used MRI to examine OEF, and compared the volume of regions with elevated OEF to the volume of regions with perfusion deficit in a M2 occlusion model (M2CAO) with preserved collateral blood flow. OEF was calculated from BOLD MRI examining tissue R2', with ASL perfusion imaging employed to determine cerebral blood flows (CBF) and volumes. Diffusion imaging was used to identify the ischemic core (IC). Examinations were performed during and after transient M2CAO in rats. The IC-OEF mismatch was significantly smaller than the IC-CBF mismatch during M2CAO. The penumbra OEF was significantly increased during M2CAO, and decreased significantly after reperfusion. The IC-OEF mismatch may provide increased penumbra specificity compared to IC-CBF mismatch regimens. Results strongly indicate the potential of metabolic MRI for thrombectomy patient selection in cases with a long time from symptom onset to admission. Results demonstrate the effectiveness of reperfusion in alleviating metabolic disturbances in ischemic regions, emphasizing fast treatment to achieve significant neurological recovery in stroke patients.
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Affiliation(s)
- Philip V Little
- Department of Clinical Neuroscience, Karolinska Institutet, Stockholm, Sweden.,Department of Neuroradiology, BioClinicum, Karolinska University Hospital, Stockholm, Sweden
| | - Sandra E Kraft
- Karolinska Experimental Research and Imaging Center (KERIC), Karolinska University Hospital-Solna, Stockholm, Sweden
| | - Arvin Chireh
- Department of Clinical Neuroscience, Karolinska Institutet, Stockholm, Sweden.,Department of Neuroradiology, BioClinicum, Karolinska University Hospital, Stockholm, Sweden
| | - Peter Damberg
- Karolinska Experimental Research and Imaging Center (KERIC), Karolinska University Hospital-Solna, Stockholm, Sweden
| | - Staffan Holmin
- Department of Clinical Neuroscience, Karolinska Institutet, Stockholm, Sweden.,Department of Neuroradiology, BioClinicum, Karolinska University Hospital, Stockholm, Sweden
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Wang Z, Mascarenhas C, Jia X. Positron Emission Tomography After Ischemic Brain Injury: Current Challenges and Future Developments. Transl Stroke Res 2020; 11:628-642. [PMID: 31939060 PMCID: PMC7347441 DOI: 10.1007/s12975-019-00765-0] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2019] [Revised: 11/22/2019] [Accepted: 12/04/2019] [Indexed: 12/19/2022]
Abstract
Positron emission tomography (PET) is widely used in clinical and animal studies, along with the development of diverse tracers. The biochemical characteristics of PET tracers may help uncover the pathophysiological consequences of cardiac arrest (CA) and ischemic stroke, which include cerebral ischemia and reperfusion, depletion of oxygen and glucose, and neuroinflammation. PubMed was searched for studies of the application of PET for "cardiac arrest," "ischemic stroke," and "targeted temperature management." Available studies were included and classified according to the biochemical properties involved and metabolic processes of PET tracers, and were summarized. The mechanisms of ischemic brain injuries were investigated by PET with various tracers to elucidate the pathological process from the initial decrease of cerebral blood flow (CBF) to the subsequent abnormalities in energy and oxygen metabolism, to the monitoring of inflammation. In general, the trends of cerebral blood flow and oxygen metabolism after ischemic attack are not unidirectional but closely related to the time point of injury and recovery. Glucose metabolism after injury showed significant differences in different brain regions whereas global cerebral metabolic rate of glucose (CMRglc) declined. PET monitoring of neuroinflammation shows comparable efficacy to immunostaining. The technology of PET targeting in brain metabolism and the development of tracers provide new tools to track and evaluate the brain's pathological changes after ischemic brain injury. Despite no existing evidence for an available PET-based prediction method, discoveries of new tracers are expected to provide more possibilities for the whole field.
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Affiliation(s)
- Zhuoran Wang
- Department of Critical Care Medicine, Zhongnan Hospital of Wuhan University, Wuhan, 43007, China
- Department of Neurosurgery, University of Maryland School of Medicine, 10 South Pine Street, MSTF Building 823, Baltimore, MD, 21201, USA
| | - Conrad Mascarenhas
- Department of Neurosurgery, University of Maryland School of Medicine, 10 South Pine Street, MSTF Building 823, Baltimore, MD, 21201, USA
| | - Xiaofeng Jia
- Department of Neurosurgery, University of Maryland School of Medicine, 10 South Pine Street, MSTF Building 823, Baltimore, MD, 21201, USA.
- Department of Orthopedics, University of Maryland School of Medicine, Baltimore, MD, 21201, USA.
- Department of Anatomy and Neurobiology, University of Maryland School of Medicine, Baltimore, MD, 21201, USA.
- Department of Biomedical Engineering, Johns Hopkins University School of Medicine, Baltimore, MD, 21205, USA.
- Department of Anesthesiology and Critical Care Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, 21205, USA.
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Boss SM, Moustafa RR, Moustafa MA, El Sadek A, Mostafa MM, Aref HM. Lesion homogeneity on diffusion-weighted imaging is a marker of outcome in acute ischemic stroke. THE EGYPTIAN JOURNAL OF NEUROLOGY, PSYCHIATRY AND NEUROSURGERY 2019. [DOI: 10.1186/s41983-019-0101-z] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
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Liebeskind DS, Jüttler E, Shapovalov Y, Yegin A, Landen J, Jauch EC. Cerebral Edema Associated With Large Hemispheric Infarction. Stroke 2019; 50:2619-2625. [DOI: 10.1161/strokeaha.118.024766] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Affiliation(s)
- David S. Liebeskind
- From the Department of Neurology, Neurovascular Imaging Research Core and UCLA Stroke Center, University of California Los Angeles (D.S.L.)
| | - Eric Jüttler
- Department of Neurology, University of Heidelberg, Germany (E.J.)
- Department of Neurology, University of Ulm, University and Rehabilitation Hospitals, Ulm, and the Center for Stroke Research Berlin, Germany (E.J.)
| | | | | | | | - Edward C. Jauch
- Mission Research Institute, Mission Health System, Asheville, NC (E.C.J.)
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The Roles of Hypoxia Imaging Using 18F-Fluoromisonidazole Positron Emission Tomography in Glioma Treatment. J Clin Med 2019; 8:jcm8081088. [PMID: 31344848 PMCID: PMC6723061 DOI: 10.3390/jcm8081088] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2019] [Revised: 07/16/2019] [Accepted: 07/22/2019] [Indexed: 12/14/2022] Open
Abstract
Glioma is the most common malignant brain tumor. Hypoxia is closely related to the malignancy of gliomas, and positron emission tomography (PET) can noninvasively visualize the degree and the expansion of hypoxia. Currently, 18F-fluoromisonidazole (FMISO) is the most common radiotracer for hypoxia imaging. The clinical usefulness of FMISO PET has been established; it can distinguish glioblastomas from lower-grade gliomas and can predict the microenvironment of a tumor, including necrosis, vascularization, and permeability. FMISO PET provides prognostic information, including survival and treatment response information. Because hypoxia decreases a tumor’s sensitivity to radiation therapy, dose escalation to an FMISO-positive volume is an attractive strategy. Although this idea is not new, an insufficient amount of evidence has been obtained regarding this concept. New tracers for hypoxia imaging such as 18F-DiFA are being tested. In the future, hypoxia imaging will play an important role in glioma management.
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Seiler A, Blockley NP, Deichmann R, Nöth U, Singer OC, Chappell MA, Klein JC, Wagner M. The relationship between blood flow impairment and oxygen depletion in acute ischemic stroke imaged with magnetic resonance imaging. J Cereb Blood Flow Metab 2019; 39:454-465. [PMID: 28929836 PMCID: PMC6421246 DOI: 10.1177/0271678x17732448] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Oxygenation-sensitive spin relaxation time T2' and relaxation rate R2' (1/T2') are presumed to be markers of the cerebral oxygen extraction fraction (OEF) in acute ischemic stroke. In this study, we investigate the relationship of T2'/R2' with dynamic susceptibility contrast-based relative cerebral blood flow (rCBF) in acute ischemic stroke to assess their plausibility as surrogate markers of the ischemic penumbra. Twenty-one consecutive patients with internal carotid artery and/or middle cerebral artery occlusion were studied at 3.0 T. A physiological model of the cerebral vasculature (VM) was used to process PWI raw data in addition to a conventional deconvolution technique. T2', R2', and rCBF values were extracted from the ischemic core and hypoperfused areas. Within hypoperfused tissue, no correlation was found between deconvolved rCBF and T2' ( r = -0.05, p = 0.788), or R2' ( r = 0.039, p = 0.836). In contrast, we found a strong positive correlation with T2' ( r = 0.444, p = 0.006) and negative correlation with R2' ( r = -0.494, p = 0.0025) for rCBFVM, indicating increasing OEF with decreasing CBF and that rCBF based on the vascular model may be more closely related to metabolic disturbances. Further research to refine and validate these techniques may enable their use as MRI-based surrogate markers of the ischemic penumbra for selecting stroke patients for interventional treatment strategies.
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Affiliation(s)
- Alexander Seiler
- 1 Department of Neurology, Goethe University Frankfurt, Frankfurt, Germany
| | - Nicholas P Blockley
- 2 Nuffield Department of Clinical Neurosciences, Oxford Center for Functional MRI of the Brain, University of Oxford, Oxford, UK
| | - Ralf Deichmann
- 3 Brain Imaging Center, Goethe University Frankfurt, Frankfurt, Germany
| | - Ulrike Nöth
- 3 Brain Imaging Center, Goethe University Frankfurt, Frankfurt, Germany
| | - Oliver C Singer
- 1 Department of Neurology, Goethe University Frankfurt, Frankfurt, Germany
| | - Michael A Chappell
- 2 Nuffield Department of Clinical Neurosciences, Oxford Center for Functional MRI of the Brain, University of Oxford, Oxford, UK.,4 Department of Engineering Science, Institute of Biomedical Engineering, University of Oxford, Oxford, UK
| | - Johannes C Klein
- 5 Nuffield Department of Clinical Neurosciences, Oxford University, and Department of Neurology, Oxford University Hospitals NHS Trust, Oxford, UK
| | - Marlies Wagner
- 6 Institute of Neuroradiology, Goethe University Frankfurt, Frankfurt, Germany
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11
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Pinto SMA, Calvete MJF, Ghica ME, Soler S, Gallardo I, Pallier A, Laranjo MB, Cardoso AMS, Castro MMCA, Brett CMA, Pereira MM, Tóth É, Geraldes CFGC. A biocompatible redox MRI probe based on a Mn(ii)/Mn(iii) porphyrin. Dalton Trans 2019; 48:3249-3262. [DOI: 10.1039/c8dt04775h] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
A water-soluble fluorinated MnIII/II porphyrin responds reversibly to ascorbate redox state as a turn-on MRI probe.
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12
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The Effect of Neoadjuvant Androgen Deprivation Therapy on Tumor Hypoxia in High-Grade Prostate Cancer: An 18F-MISO PET-MRI Study. Int J Radiat Oncol Biol Phys 2018; 102:1210-1218. [DOI: 10.1016/j.ijrobp.2018.02.170] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2017] [Revised: 02/16/2018] [Accepted: 02/28/2018] [Indexed: 12/16/2022]
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13
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Effects of hyperoxia on 18F-fluoro-misonidazole brain uptake and tissue oxygen tension following middle cerebral artery occlusion in rodents: Pilot studies. PLoS One 2017; 12:e0187087. [PMID: 29091934 PMCID: PMC5665507 DOI: 10.1371/journal.pone.0187087] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2017] [Accepted: 10/15/2017] [Indexed: 12/11/2022] Open
Abstract
PURPOSE Mapping brain hypoxia is a major goal for stroke diagnosis, pathophysiology and treatment monitoring. 18F-fluoro-misonidazole (FMISO) positron emission tomography (PET) is the gold standard hypoxia imaging method. Normobaric hyperoxia (NBO) is a promising therapy in acute stroke. In this pilot study, we tested the straightforward hypothesis that NBO would markedly reduce FMISO uptake in ischemic brain in Wistar and spontaneously hypertensive rats (SHRs), two rat strains with distinct vulnerability to brain ischemia, mimicking clinical heterogeneity. METHODS Thirteen adult male rats were randomized to distal middle cerebral artery occlusion under either 30% O2 or 100% O2. FMISO was administered intravenously and PET data acquired dynamically for 3hrs, after which magnetic resonance imaging (MRI) and tetrazolium chloride (TTC) staining were carried out to map the ischemic lesion. Both FMISO tissue uptake at 2-3hrs and FMISO kinetic rate constants, determined based on previously published kinetic modelling, were obtained for the hypoxic area. In a separate group (n = 9), tissue oxygen partial pressure (PtO2) was measured in the ischemic tissue during both control and NBO conditions. RESULTS As expected, the FMISO PET, MRI and TTC lesion volumes were much larger in SHRs than Wistar rats in both the control and NBO conditions. NBO did not appear to substantially reduce FMISO lesion size, nor affect the FMISO kinetic rate constants in either strain. Likewise, MRI and TTC lesion volumes were unaffected. The parallel study showed the expected increases in ischemic cortex PtO2 under NBO, although these were small in some SHRs with very low baseline PtO2. CONCLUSIONS Despite small samples, the apparent lack of marked effects of NBO on FMISO uptake suggests that in permanent ischemia the cellular mechanisms underlying FMISO trapping in hypoxic cells may be disjointed from PtO2. Better understanding of FMISO trapping processes will be important for future applications of FMISO imaging.
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Evans NR, Tarkin JM, Buscombe JR, Markus HS, Rudd JHF, Warburton EA. PET imaging of the neurovascular interface in cerebrovascular disease. Nat Rev Neurol 2017; 13:676-688. [PMID: 28984315 DOI: 10.1038/nrneurol.2017.129] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Cerebrovascular disease encompasses a range of pathologies that affect different components of the cerebral vasculature and brain parenchyma. Large artery atherosclerosis, acute cerebral ischaemia, and intracerebral small vessel disease all demonstrate altered metabolic processes that are key to their pathogenesis. Although structural imaging techniques such as MRI are the mainstay of clinical care and research in cerebrovascular disease, they have limited ability to detect these pathophysiological processes in vivo. By contrast, PET can detect and quantify metabolic processes that are relevant to each facet of cerebrovascular disease. Information obtained from PET studies has helped to shape the understanding of key concepts in cerebrovascular medicine, including vulnerable atherosclerotic plaque, salvageable ischaemic penumbra, neuroinflammation and selective neuronal loss after ischaemic insult. PET has also helped to elucidate the relationships between chronic hypoxia, neuroinflammation, and amyloid-β deposition in cerebral small vessel disease. This Review describes how PET-based imaging of metabolic processes at the neurovascular interface has contributed to our understanding of cerebrovascular disease.
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Affiliation(s)
- Nicholas R Evans
- Department of Clinical Neurosciences, University of Cambridge, Box 83, Addenbrooke's Hospital, Hills Road, Cambridge CB2 0QQ, UK
| | - Jason M Tarkin
- Division of Cardiovascular Medicine, Department of Medicine, University of Cambridge, Box 157, Addenbrooke's Hospital, Hills Road, Cambridge CB2 0QQ, UK
| | - John R Buscombe
- Department of Nuclear Medicine, Box 219, Cambridge University Hospitals NHS Foundation Trust, Hills Road, Cambridge CB2 0QQ, UK
| | - Hugh S Markus
- Department of Clinical Neurosciences, University of Cambridge, Box 83, Addenbrooke's Hospital, Hills Road, Cambridge CB2 0QQ, UK
| | - James H F Rudd
- Division of Cardiovascular Medicine, Department of Medicine, University of Cambridge, Box 157, Addenbrooke's Hospital, Hills Road, Cambridge CB2 0QQ, UK
| | - Elizabeth A Warburton
- Department of Clinical Neurosciences, University of Cambridge, Box 83, Addenbrooke's Hospital, Hills Road, Cambridge CB2 0QQ, UK
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Valable S, Corroyer-Dulmont A, Chakhoyan A, Durand L, Toutain J, Divoux D, Barré L, MacKenzie ET, Petit E, Bernaudin M, Touzani O, Barbier EL. Imaging of brain oxygenation with magnetic resonance imaging: A validation with positron emission tomography in the healthy and tumoural brain. J Cereb Blood Flow Metab 2017; 37:2584-2597. [PMID: 27702880 PMCID: PMC5531354 DOI: 10.1177/0271678x16671965] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
The partial pressure in oxygen remains challenging to map in the brain. Two main strategies exist to obtain surrogate measures of tissue oxygenation: the tissue saturation studied by magnetic resonance imaging (StO2-MRI) and the identification of hypoxia by a positron emission tomography (PET) biomarker with 3-[18F]fluoro-1-(2-nitro-1-imidazolyl)-2-propanol ([18F]-FMISO) as the leading radiopharmaceutical. Nonetheless, a formal validation of StO2-MRI against FMISO-PET has not been performed. The objective of our studies was to compare the two approaches in (a) the normal rat brain when the rats were submitted to hypoxemia; (b) animals implanted with four tumour types differentiated by their oxygenation. Rats were submitted to normoxic and hypoxemic conditions. For the brain tumour experiments, U87-MG, U251-MG, 9L and C6 glioma cells were orthotopically inoculated in rats. For both experiments, StO2-MRI and [18F]-FMISO PET were performed sequentially. Under hypoxemia conditions, StO2-MRI revealed a decrease in oxygen saturation in the brain. Nonetheless, [18F]-FMISO PET, pimonidazole immunohistochemistry and molecular biology were insensitive to hypoxia. Within the context of tumours, StO2-MRI was able to detect hypoxia in the hypoxic models, mimicking [18F]-FMISO PET with high sensitivity/specificity. Altogether, our data clearly support that, in brain pathologies, StO2-MRI could be a robust and specific imaging biomarker to assess hypoxia.
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Affiliation(s)
- Samuel Valable
- 1 Normandie Université, UNICAEN, CEA, CNRS, ISTCT/CERVOxy Group, Caen, France
| | | | - Ararat Chakhoyan
- 1 Normandie Université, UNICAEN, CEA, CNRS, ISTCT/CERVOxy Group, Caen, France
| | - Lucile Durand
- 1 Normandie Université, UNICAEN, CEA, CNRS, ISTCT/CERVOxy Group, Caen, France
| | - Jérôme Toutain
- 1 Normandie Université, UNICAEN, CEA, CNRS, ISTCT/CERVOxy Group, Caen, France
| | - Didier Divoux
- 1 Normandie Université, UNICAEN, CEA, CNRS, ISTCT/CERVOxy Group, Caen, France
| | - Louisa Barré
- 2 Normandie Université, UNICAEN, CEA, CNRS, ISTCT/LDM-TEP Group, Caen, France
| | - Eric T MacKenzie
- 1 Normandie Université, UNICAEN, CEA, CNRS, ISTCT/CERVOxy Group, Caen, France
| | - Edwige Petit
- 1 Normandie Université, UNICAEN, CEA, CNRS, ISTCT/CERVOxy Group, Caen, France
| | - Myriam Bernaudin
- 1 Normandie Université, UNICAEN, CEA, CNRS, ISTCT/CERVOxy Group, Caen, France
| | - Omar Touzani
- 1 Normandie Université, UNICAEN, CEA, CNRS, ISTCT/CERVOxy Group, Caen, France
| | - Emmanuel L Barbier
- 3 Inserm, U1216, Grenoble, France.,4 Université Grenoble Alpes, Grenoble Institut des Neurosciences, Grenoble, France
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16
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Boisserand LSB, Lemasson B, Hirschler L, Moisan A, Hubert V, Barbier EL, Rémy C, Detante O. Multiparametric magnetic resonance imaging including oxygenation mapping of experimental ischaemic stroke. J Cereb Blood Flow Metab 2017; 37:2196-2207. [PMID: 27466373 PMCID: PMC5464712 DOI: 10.1177/0271678x16662044] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Recent advances in MRI methodology, such as microvascular and brain oxygenation (StO2) imaging, may prove useful in obtaining information about the severity of the acute stroke. We assessed the potential of StO2 to detect the ischaemic core in the acute phase compared to apparent diffusion coefficient and to predict the final necrosis. Sprague-Dawley rats (n = 38) were imaged during acute stroke (D0) and 21 days after (D21). A multiparametric MRI protocol was performed at 4.7T to characterize brain damage within three region of interest: 'LesionD0' (diffusion), 'Mismatch' representing penumbra (perfusion/diffusion) and 'Hypoxia' (voxels < 40% of StO2 within the region of interest LesionD0). Voxel-based analysis of stroke revealed heterogeneity of the region of interest LesionD0, which included voxels with different degrees of oxygenation decrease. This finding was supported by a dramatic decrease of vascular and perfusion parameters within the region of interest hypoxia. This zone presented the lowest values of almost all parameters analysed, indicating a higher severity. Our study demonstrates the potential of StO2 magnetic resonance imaging to more accurately detect the ischaemic core without the inclusion of any reversible ischaemic damage. Our follow-up study indicates that apparent diffusion coefficient imaging overestimated the final necrosis while StO2 imaging did not.
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Affiliation(s)
- Ligia Simões Braga Boisserand
- 1 Univ. Grenoble Alpes, Grenoble Institut des Neurosciences, Grenoble, France.,2 Inserm, U1216, Grenoble, France.,3 CAPES Foundation, Ministry of Education of Brazil, Brasilia, Brazil
| | - Benjamin Lemasson
- 1 Univ. Grenoble Alpes, Grenoble Institut des Neurosciences, Grenoble, France.,2 Inserm, U1216, Grenoble, France
| | - Lydiane Hirschler
- 1 Univ. Grenoble Alpes, Grenoble Institut des Neurosciences, Grenoble, France.,2 Inserm, U1216, Grenoble, France.,4 Bruker Biospin, Ettlingen, Germany
| | - Anaïck Moisan
- 1 Univ. Grenoble Alpes, Grenoble Institut des Neurosciences, Grenoble, France.,2 Inserm, U1216, Grenoble, France.,5 Cell Therapy and Engineering Unit, EFS Rhône Alpes, Saint Ismier, France
| | - Violaine Hubert
- 1 Univ. Grenoble Alpes, Grenoble Institut des Neurosciences, Grenoble, France
| | - Emmanuel L Barbier
- 1 Univ. Grenoble Alpes, Grenoble Institut des Neurosciences, Grenoble, France.,2 Inserm, U1216, Grenoble, France
| | - Chantal Rémy
- 1 Univ. Grenoble Alpes, Grenoble Institut des Neurosciences, Grenoble, France.,2 Inserm, U1216, Grenoble, France
| | - Olivier Detante
- 1 Univ. Grenoble Alpes, Grenoble Institut des Neurosciences, Grenoble, France.,2 Inserm, U1216, Grenoble, France.,6 CHU Grenoble Alpes, Grenoble, France
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17
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Jensen-Kondering U, Manavaki R, Ejaz S, Sawiak SJ, Carpenter TA, Fryer TD, Aigbirhio FI, Williamson DJ, Baron JC. Brain hypoxia mapping in acute stroke: Back-to-back T2' MR versus 18F-fluoromisonidazole PET in rodents. Int J Stroke 2017; 12:752-760. [PMID: 28523963 DOI: 10.1177/1747493017706221] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Background Mapping the hypoxic brain in acute ischemic stroke has considerable potential for both diagnosis and treatment monitoring. PET using 18F-fluoro-misonidazole (FMISO) is the reference method; however, it lacks clinical accessibility and involves radiation exposure. MR-based T2' mapping may identify tissue hypoxia and holds clinical potential. However, its validation against FMISO imaging is lacking. Here we implemented back-to-back FMISO-PET and T2' MR in rodents subjected to acute middle cerebral artery occlusion. For direct clinical relevance, regions of interest delineating reduced T2' signal areas were manually drawn. Methods Wistar rats were subjected to filament middle cerebral artery occlusion, immediately followed by intravenous FMISO injection. Multi-echo T2 and T2* sequences were acquired twice during FMISO brain uptake, interleaved with diffusion-weighted imaging. Perfusion-weighted MR was also acquired whenever feasible. Immediately following MR, PET data reflecting the history of FMISO brain uptake during MR acquisition were acquired. T2' maps were generated voxel-wise from T2 and T2*. Two raters independently drew T2' lesion regions of interest. FMISO uptake and perfusion data were obtained within T2' consensus regions of interest, and their overlap with the automatically generated FMISO lesion and apparent diffusion coefficient lesion regions of interest was computed. Results As predicted, consensus T2' lesion regions of interest exhibited high FMISO uptake as well as substantial overlap with the FMISO lesion and significant hypoperfusion, but only small overlap with the apparent diffusion coefficient lesion. Overlap of the T2' lesion regions of interest between the two raters was ∼50%. Conclusions This study provides formal validation of T2' to map non-core hypoxic tissue in acute stroke. T2' lesion delineation reproducibility was suboptimal, reflecting unclear lesion borders.
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Affiliation(s)
- Ulf Jensen-Kondering
- 1 Stroke Research Group, Department of Clinical Neurosciences, University of Cambridge, Cambridge, UK.,2 Wolfson Brain Imaging Centre, Department of Clinical Neurosciences, University of Cambridge, Cambridge, UK.,3 Department of Radiology and Neuroradiology, University Medical Center Schleswig-Holstein, Kiel, Germany
| | - Roido Manavaki
- 4 Department of Radiology, University of Cambridge, Cambridge, UK
| | - Sohail Ejaz
- 1 Stroke Research Group, Department of Clinical Neurosciences, University of Cambridge, Cambridge, UK
| | - Stephen J Sawiak
- 2 Wolfson Brain Imaging Centre, Department of Clinical Neurosciences, University of Cambridge, Cambridge, UK
| | - T Adrian Carpenter
- 2 Wolfson Brain Imaging Centre, Department of Clinical Neurosciences, University of Cambridge, Cambridge, UK
| | - Tim D Fryer
- 2 Wolfson Brain Imaging Centre, Department of Clinical Neurosciences, University of Cambridge, Cambridge, UK
| | - Franklin I Aigbirhio
- 2 Wolfson Brain Imaging Centre, Department of Clinical Neurosciences, University of Cambridge, Cambridge, UK
| | - David J Williamson
- 2 Wolfson Brain Imaging Centre, Department of Clinical Neurosciences, University of Cambridge, Cambridge, UK
| | - Jean-Claude Baron
- 1 Stroke Research Group, Department of Clinical Neurosciences, University of Cambridge, Cambridge, UK.,5 INSERM U894, Université Paris Descartes, Hôpital Sainte-Anne, Paris, France
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18
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Evidence for an enduring ischaemic penumbra following central retinal artery occlusion, with implications for fibrinolytic therapy. Prog Retin Eye Res 2015; 49:82-119. [PMID: 26113210 DOI: 10.1016/j.preteyeres.2015.06.001] [Citation(s) in RCA: 62] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2015] [Revised: 06/13/2015] [Accepted: 06/18/2015] [Indexed: 12/15/2022]
Abstract
The rationale behind hyperacute fibrinolytic therapy for cerebral and retinal arterial occlusion is to rescue ischaemic cells from irreversible damage through timely restitution of tissue perfusion. In cerebral stroke, an anoxic tissue compartment (the "infarct core") is surrounded by a hypoxic compartment (the "ischaemic penumbra"). The latter comprises electrically-silent neurons that undergo delayed apoptotic cell death within 1-6 h unless salvaged by arterial recanalisation. Establishment of an equivalent hypoxic compartment within the inner retina following central retinal artery occlusion (CRAO) isn't widely acknowledged. During experimental CRAO, electroretinography reveals 3 oxygenation-based tissue compartments (anoxic, hypoxic and normoxic) that contribute 32%, 27% and 41% respectively to the pre-occlusion b-wave amplitude. Thus, once the anoxia survival time (≈2 h) expires, the contribution from the infarcted posterior retina is irreversibly extinguished, but electrical activity continues in the normoxic periphery. Inbetween these compartments, an annular hypoxic zone (the "penumbra obscura") endures in a structurally-intact but functionally-impaired state until retinal reperfusion allows rapid recovery from electrical silence. Clinically, residual circulation of sufficient volume flow rate generates the heterogeneous fundus picture of "partial" CRAO. Persistent retinal venous hypoxaemia signifies maximal extraction of oxygen by an enduring "polar penumbra" that permeates or largely replaces the infarct core. On retinal reperfusion some days later, the retinal venous oxygen saturation reverts to normal and vision improves. Thus, penumbral inner retina, marginally oxygenated by the choroid or by residual circulation, isn't at risk of delayed apoptotic infarction (unlike hypoxic cerebral cortex). Emergency fibrinolytic intervention is inappropriate, therefore, once the duration of CRAO exceeds 2 h.
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19
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Saura H, Ogasawara K, Beppu T, Yoshida K, Kobayashi M, Yoshida K, Terasaki K, Takai Y, Ogawa A. Hypoxic viable tissue in human chronic cerebral ischemia because of unilateral major cerebral artery steno-occlusive disease. Stroke 2015; 46:1250-6. [PMID: 25873597 DOI: 10.1161/strokeaha.114.008238] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2014] [Accepted: 03/16/2015] [Indexed: 01/07/2023]
Abstract
BACKGROUND AND PURPOSE Positron emission tomography (PET) with radiolabeled 2-nitroimidazoles directly detects hypoxic but viable tissue present in an acute ischemic area in the human brain. This study using PET with 1-(2-(18)F-fluoro-1-[hydroxymethyl]ethoxy) methyl-2-nitroimidazole ((18)F-FRP170) aimed to determine whether tissue with an abnormally elevated uptake of (18)F-FRP170 exists in human chronic cerebral ischemia because of unilateral atherosclerotic major cerebral artery steno-occlusive disease. METHODS (18)F-FRP170 PET was performed, and cerebral blood flow and metabolism were assessed using (15)O-gas PET in 20 healthy subjects and 52 patients. A region of interest (ROI) was automatically placed in 3 segments of the middle cerebral artery territory in both cerebral hemispheres with a 3-dimensional stereotaxic ROI template using SPM2, and each PET value was determined in each ROI. The ratio of values in the affected versus contralateral hemispheres was calculated for the (18)F-FRP170 PET image. RESULTS A significant correlation was observed between oxygen extraction fraction and (18)F-FRP170 ratios (ρ=0.509; P<0.0001) in a total of 156 ROIs in 52 patients. The specificity and positive-predictive value for a combination of an elevated oxygen extraction fraction and a moderately reduced cerebral oxygen metabolism for detection of an abnormally elevated (18)F-FRP170 ratio (19 ROIs: 12%) were significantly greater than those for the individual categories (elevated oxygen extraction fraction, moderately reduced cerebral oxygen metabolism, or reduced cerebral blood flow). CONCLUSIONS Tissues with abnormally elevated uptake of (18)F-FRP170 exist in human chronic cerebral ischemia characterized by a combination of misery perfusion and moderately reduced oxygen metabolism because of unilateral atherosclerotic major cerebral artery steno-occlusive disease.
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Affiliation(s)
- Hiroaki Saura
- From the Department of Neurosurgery (H.S., K.O., T.B., Koji Yoshida, M.K., Kenji Yoshida, A.O.) and Cyclotron Research Center (K.T.), School of Medicine, Iwate Medical University, Morioka, Japan; and Department of Radiology and Radiation Oncology, Hirosaki University Graduate School of Medicine, Hirosaki, Japan (Y.T.).
| | - Kuniaki Ogasawara
- From the Department of Neurosurgery (H.S., K.O., T.B., Koji Yoshida, M.K., Kenji Yoshida, A.O.) and Cyclotron Research Center (K.T.), School of Medicine, Iwate Medical University, Morioka, Japan; and Department of Radiology and Radiation Oncology, Hirosaki University Graduate School of Medicine, Hirosaki, Japan (Y.T.)
| | - Takaaki Beppu
- From the Department of Neurosurgery (H.S., K.O., T.B., Koji Yoshida, M.K., Kenji Yoshida, A.O.) and Cyclotron Research Center (K.T.), School of Medicine, Iwate Medical University, Morioka, Japan; and Department of Radiology and Radiation Oncology, Hirosaki University Graduate School of Medicine, Hirosaki, Japan (Y.T.)
| | - Koji Yoshida
- From the Department of Neurosurgery (H.S., K.O., T.B., Koji Yoshida, M.K., Kenji Yoshida, A.O.) and Cyclotron Research Center (K.T.), School of Medicine, Iwate Medical University, Morioka, Japan; and Department of Radiology and Radiation Oncology, Hirosaki University Graduate School of Medicine, Hirosaki, Japan (Y.T.)
| | - Masakazu Kobayashi
- From the Department of Neurosurgery (H.S., K.O., T.B., Koji Yoshida, M.K., Kenji Yoshida, A.O.) and Cyclotron Research Center (K.T.), School of Medicine, Iwate Medical University, Morioka, Japan; and Department of Radiology and Radiation Oncology, Hirosaki University Graduate School of Medicine, Hirosaki, Japan (Y.T.)
| | - Kenji Yoshida
- From the Department of Neurosurgery (H.S., K.O., T.B., Koji Yoshida, M.K., Kenji Yoshida, A.O.) and Cyclotron Research Center (K.T.), School of Medicine, Iwate Medical University, Morioka, Japan; and Department of Radiology and Radiation Oncology, Hirosaki University Graduate School of Medicine, Hirosaki, Japan (Y.T.)
| | - Kazunori Terasaki
- From the Department of Neurosurgery (H.S., K.O., T.B., Koji Yoshida, M.K., Kenji Yoshida, A.O.) and Cyclotron Research Center (K.T.), School of Medicine, Iwate Medical University, Morioka, Japan; and Department of Radiology and Radiation Oncology, Hirosaki University Graduate School of Medicine, Hirosaki, Japan (Y.T.)
| | - Yoshihiro Takai
- From the Department of Neurosurgery (H.S., K.O., T.B., Koji Yoshida, M.K., Kenji Yoshida, A.O.) and Cyclotron Research Center (K.T.), School of Medicine, Iwate Medical University, Morioka, Japan; and Department of Radiology and Radiation Oncology, Hirosaki University Graduate School of Medicine, Hirosaki, Japan (Y.T.)
| | - Akira Ogawa
- From the Department of Neurosurgery (H.S., K.O., T.B., Koji Yoshida, M.K., Kenji Yoshida, A.O.) and Cyclotron Research Center (K.T.), School of Medicine, Iwate Medical University, Morioka, Japan; and Department of Radiology and Radiation Oncology, Hirosaki University Graduate School of Medicine, Hirosaki, Japan (Y.T.)
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21
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Gale EM, Mukherjee S, Liu C, Loving GS, Caravan P. Structure-redox-relaxivity relationships for redox responsive manganese-based magnetic resonance imaging probes. Inorg Chem 2014; 53:10748-61. [PMID: 25226090 PMCID: PMC4186673 DOI: 10.1021/ic502005u] [Citation(s) in RCA: 66] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2014] [Indexed: 12/11/2022]
Abstract
A library of 10 Mn-containing complexes capable of switching reversibly between the Mn(II) and Mn(III) oxidation states was prepared and evaluated for potential usage as MRI reporters of tissue redox activity. We synthesized N-(2-hydroxybenzyl)-N,N',N'-ethylenediaminetriacetic acid (HBET) and N-(2-hydroxybenzyl-N,N',N'-trans-1,2-cyclohexylenediaminetriacetic acid (CyHBET) ligands functionalized (-H, -OMe, -NO2) at the 5-position of the aromatic ring. The Mn(II) complexes of all ligands and the Mn(III) complexes of the 5-H and 5-NO2 functionalized ligands were synthesized and isolated, but the Mn(III) complexes with the 5-OMe functionalized ligands were unstable. (1)H relaxivity of the 10 isolable complexes was measured at pH 7.4 and 37 °C, 1.4 T. Thermodynamic stability, pH-dependent complex speciation, hydration state, water exchange kinetics of the Mn(II) complexes, and pseudo-first order reduction kinetics of the Mn(III) complexes were studied using a combination of pH-potentiometry, UV-vis spectroscopy, and (1)H and (17)O NMR measurements. The effects of ligand structural and electronic modifications on the Mn(II/III) redox couple were studied by cyclic voltammetry. The Mn(II) complexes are potent relaxation agents as compared to the corresponding Mn(III) species with [Mn(II)(CyHBET)(H2O)](2-) exhibiting a 7.5-fold higher relaxivity (3.3 mM(-1) s(-1)) than the oxidized form (0.4 mM(-1) s(-1)). At pH 7.4, Mn(II) exists as a mixture of fully deprotonated (ML) and monoprotonated (HML) complexes and Mn(II) complex stability decreases as the ligands become more electron-releasing (pMn for 10 μM [Mn(II)(CyHBET-R')(H2O)](2-) decreases from 7.6 to 6.2 as R' goes from -NO2 to -OMe, respectively). HML speciation increases as the electron-releasing nature of the phenolato-O donor increases. The presence of a water coligand is maintained upon conversion from HML to ML, but the water exchange rate of ML is faster by up to 2 orders of magnitude (k(ex)(310) for H[Mn(II)(CyHBET)(H2O)](-) and [Mn(II)(CyHBET)(H2O)](2-) are 1.2 × 10(8) and 1.0 × 10(10) s(-1), respectively). The Mn(II/III) redox potential can be tuned over a range of 0.30 V (E(1/2) = 0.27-0.57 V) through electronic modifications to the 5-substituent of the aromatic ligand component. However, care must be taken in tuning the ligand electronics to avoid Mn(III)-ligand autoredox. Taken together, these results serve to establish criteria for optimizing Mn(III) versus Mn(II) relaxivity differentials, complex stability, and Mn(II/III) redox potential.
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Affiliation(s)
| | | | - Cynthia Liu
- The Athinoula
A. Martinos Center for Biomedical Imaging, Department of Radiology,
Massachusetts General Hospital, Harvard
Medical School, 149 Thirteenth
Street, Suite 2301, Charlestown, Massachusetts 02129, United States
| | - Galen S. Loving
- The Athinoula
A. Martinos Center for Biomedical Imaging, Department of Radiology,
Massachusetts General Hospital, Harvard
Medical School, 149 Thirteenth
Street, Suite 2301, Charlestown, Massachusetts 02129, United States
| | - Peter Caravan
- The Athinoula
A. Martinos Center for Biomedical Imaging, Department of Radiology,
Massachusetts General Hospital, Harvard
Medical School, 149 Thirteenth
Street, Suite 2301, Charlestown, Massachusetts 02129, United States
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PET imaging in ischemic cerebrovascular disease: current status and future directions. Neurosci Bull 2014; 30:713-32. [PMID: 25138055 DOI: 10.1007/s12264-014-1463-y] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2014] [Accepted: 04/10/2014] [Indexed: 01/08/2023] Open
Abstract
Cerebrovascular diseases are caused by interruption or significant impairment of the blood supply to the brain, which leads to a cascade of metabolic and molecular alterations resulting in functional disturbance and morphological damage. These pathophysiological changes can be assessed by positron emission tomography (PET), which permits the regional measurement of physiological parameters and imaging of the distribution of molecular markers. PET has broadened our understanding of the flow and metabolic thresholds critical for the maintenance of brain function and morphology: in this application, PET has been essential in the transfer of the concept of the penumbra (tissue with perfusion below the functional threshold but above the threshold for the preservation of morphology) to clinical stroke and thereby has had great impact on developing treatment strategies. Radioligands for receptors can be used as early markers of irreversible neuronal damage and thereby can predict the size of the final infarcts; this is also important for decisions concerning invasive therapy in large ("malignant") infarctions. With PET investigations, the reserve capacity of blood supply to the brain can be tested in obstructive arteriosclerosis of the supplying arteries, and this again is essential for planning interventions. The effect of a stroke on the surrounding and contralateral primarily unaffected tissue can be investigated, and these results help to understand the symptoms caused by disturbances in functional networks. Chronic cerebrovascular disease causes vascular cognitive disorders, including vascular dementia. PET permits the detection of the metabolic disturbances responsible for cognitive impairment and dementia, and can differentiate vascular dementia from degenerative diseases. It may also help to understand the importance of neuroinflammation after stroke and its interaction with amyloid deposition in the development of dementia. Although the clinical application of PET investigations is limited, this technology had and still has a great impact on research into cerebrovascular diseases.
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