1
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Hunt RD, Cipolla MJ. Chronic hypertension alters the relationship between collateral blood flow, cortical cerebral blood flow, and brain tissue oxygenation. J Cereb Blood Flow Metab 2024:271678X241258569. [PMID: 38806143 DOI: 10.1177/0271678x241258569] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 05/30/2024]
Abstract
This study measured the relationship between pial collateral (leptomeningeal anastomoses, LMA) flow, intraparenchymal cortical cerebral blood flow (cCBF) and brain tissue oxygenation (btO2) during acute ischemic stroke to investigate how pial flow translates to downstream cCBF and btO2 and examined how this relationship is altered in hypertension. Proximal transient middle cerebral artery occlusion (tMCAO) was performed in male Wistar (n = 8/group) and Spontaneously Hypertensive Rats (SHR, n = 8/group). A combination laser Doppler-oxygen probe was placed within the expected cortical peri-infarct in addition to a surface laser doppler probe which measured LMA flow. Phenylephrine (PE) was infused 30 minutes into tMCAO to increase blood pressure (BP) by 30% for 10 minutes and assessed CBF autoregulation. During the initial 30-minute period of tMCAO, btO2 and cCBF were lower in SHR compared to Wistar rats (btO2: 11.5 ± 10.5 vs 17.5 ± 10.8 mmHg and cCBF: -29.7 ± 23.3% vs -17.8 ± 41.9%); however, LMA flow was similar between groups. The relationship between LMA flow, cCBF and btO2 were interdependent in Wistar rats. However, this relationship was disrupted in SHR rats and partially restored by induced hypertension. This study provides evidence that cCBF and btO2 were diminished during tMCAO in chronic hypertension, and that induced hypertension was beneficial regardless of hypertensive status.
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Affiliation(s)
- Ryan D Hunt
- Department of Neurological Sciences, University of Vermont, Larner College of Medicine, Burlington, VT, USA
| | - Marilyn J Cipolla
- Department of Neurological Sciences, University of Vermont, Larner College of Medicine, Burlington, VT, USA
- Department of Electrical and Biomedical Engineering, University of Vermont, College of Engineering and Mathematical Sciences, Burlington, VT, USA
- Department of Pharmacology, University of Vermont, Larner College of Medicine, Burlington, VT, USA
- Department of Obstetrics, Gynecology and Reproductive Sciences, University of Vermont, Larner College of Medicine, Burlington, VT, USA
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2
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Walther J, Kirsch EM, Hellwig L, Schmerbeck SS, Holloway PM, Buchan AM, Mergenthaler P. Reinventing the Penumbra - the Emerging Clockwork of a Multi-modal Mechanistic Paradigm. Transl Stroke Res 2023; 14:643-666. [PMID: 36219377 PMCID: PMC10444697 DOI: 10.1007/s12975-022-01090-9] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2022] [Revised: 09/16/2022] [Accepted: 09/21/2022] [Indexed: 11/25/2022]
Abstract
The concept of the ischemic penumbra was originally defined as the area around a necrotic stroke core and seen as the tissue at imminent risk of further damage. Today, the penumbra is generally considered as time-sensitive hypoperfused brain tissue with decreased oxygen and glucose availability, salvageable tissue as treated by intervention, and the potential target for neuroprotection in focal stroke. The original concept entailed electrical failure and potassium release but one short of neuronal cell death and was based on experimental stroke models, later confirmed in clinical imaging studies. However, even though the basic mechanisms have translated well, conferring brain protection, and improving neurological outcome after stroke based on the pathophysiological mechanisms in the penumbra has yet to be achieved. Recent findings shape the modern understanding of the penumbra revealing a plethora of molecular and cellular pathophysiological mechanisms. We now propose a new model of the penumbra, one which we hope will lay the foundation for future translational success. We focus on the availability of glucose, the brain's central source of energy, and bioenergetic failure as core pathophysiological concepts. We discuss the relation of mitochondrial function in different cell types to bioenergetics and apoptotic cell death mechanisms, autophagy, and neuroinflammation, to glucose metabolism in what is a dynamic ischemic penumbra.
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Affiliation(s)
- Jakob Walther
- Charité - Universitätsmedizin Berlin, Department of Neurology with Experimental Neurology, Charitéplatz 1, 10117, Berlin, Germany
- Charité - Universitätsmedizin Berlin, Center for Stroke Research Berlin, Charitéplatz 1, 10117, Berlin, Germany
| | - Elena Marie Kirsch
- Charité - Universitätsmedizin Berlin, Department of Neurology with Experimental Neurology, Charitéplatz 1, 10117, Berlin, Germany
- Charité - Universitätsmedizin Berlin, Center for Stroke Research Berlin, Charitéplatz 1, 10117, Berlin, Germany
| | - Lina Hellwig
- Charité - Universitätsmedizin Berlin, Department of Neurology with Experimental Neurology, Charitéplatz 1, 10117, Berlin, Germany
- Charité - Universitätsmedizin Berlin, Center for Stroke Research Berlin, Charitéplatz 1, 10117, Berlin, Germany
| | - Sarah S Schmerbeck
- Charité - Universitätsmedizin Berlin, Department of Neurology with Experimental Neurology, Charitéplatz 1, 10117, Berlin, Germany
- Charité - Universitätsmedizin Berlin, Center for Stroke Research Berlin, Charitéplatz 1, 10117, Berlin, Germany
| | - Paul M Holloway
- Acute Stroke Programme, Radcliffe Department of Medicine, University of Oxford, Oxford, OX3 9DU, UK
| | - Alastair M Buchan
- Charité - Universitätsmedizin Berlin, Center for Stroke Research Berlin, Charitéplatz 1, 10117, Berlin, Germany.
- Acute Stroke Programme, Radcliffe Department of Medicine, University of Oxford, Oxford, OX3 9DU, UK.
| | - Philipp Mergenthaler
- Charité - Universitätsmedizin Berlin, Department of Neurology with Experimental Neurology, Charitéplatz 1, 10117, Berlin, Germany.
- Charité - Universitätsmedizin Berlin, Center for Stroke Research Berlin, Charitéplatz 1, 10117, Berlin, Germany.
- Charité - Universitätsmedizin Berlin, NeuroCure Clinical Research Center, Charitéplatz 1, 10117, Berlin, Germany.
- Acute Stroke Programme, Radcliffe Department of Medicine, University of Oxford, Oxford, OX3 9DU, UK.
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3
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Zedde M, Napoli M, Grisendi I, Assenza F, Moratti C, Valzania F, Pascarella R. Perfusion Status in Lacunar Stroke: A Pathophysiological Issue. Diagnostics (Basel) 2023; 13:2003. [PMID: 37370898 DOI: 10.3390/diagnostics13122003] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2023] [Revised: 06/02/2023] [Accepted: 06/05/2023] [Indexed: 06/29/2023] Open
Abstract
The pathophysiology of lacunar infarction is an evolving and debated field, where relevant information comes from histopathology, old anatomical studies and animal models. Only in the last years, have neuroimaging techniques allowed a sufficient resolution to directly or indirectly assess the dynamic evolution of small vessel occlusion and to formulate hypotheses about the tissue status and the mechanisms of damage. The core-penumbra concept was extensively explored in large vessel occlusions (LVOs) both from the experimental and clinical point of view. Then, the perfusion thresholds on one side and the neuroimaging techniques studying the perfusion of brain tissue were focused and optimized for LVOs. The presence of a perfusion deficit in the territory of a single small perforating artery was negated for years until the recent proposal of the existence of a perfusion defect in a subgroup of lacunar infarcts by using magnetic resonance imaging (MRI). This last finding opens pathophysiological hypotheses and triggers a neurovascular multidisciplinary reasoning about how to image this perfusion deficit in the acute phase in particular. The aim of this review is to summarize the pathophysiological issues and the application of the core-penumbra hypothesis to lacunar stroke.
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Affiliation(s)
- Marialuisa Zedde
- Neurology Unit, Stroke Unit, AUSL-IRCCS di Reggio Emilia, Via Amendola 2, 42122 Reggio Emilia, Italy
| | - Manuela Napoli
- Neuroradiology Unit, AUSL-IRCCS di Reggio Emilia, Via Amendola 2, 42122 Reggio Emilia, Italy
| | - Ilaria Grisendi
- Neurology Unit, Stroke Unit, AUSL-IRCCS di Reggio Emilia, Via Amendola 2, 42122 Reggio Emilia, Italy
| | - Federica Assenza
- Neurology Unit, Stroke Unit, AUSL-IRCCS di Reggio Emilia, Via Amendola 2, 42122 Reggio Emilia, Italy
| | - Claudio Moratti
- Neuroradiology Unit, AUSL-IRCCS di Reggio Emilia, Via Amendola 2, 42122 Reggio Emilia, Italy
| | - Franco Valzania
- Neurology Unit, Stroke Unit, AUSL-IRCCS di Reggio Emilia, Via Amendola 2, 42122 Reggio Emilia, Italy
| | - Rosario Pascarella
- Neuroradiology Unit, AUSL-IRCCS di Reggio Emilia, Via Amendola 2, 42122 Reggio Emilia, Italy
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4
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Sotome W, Ito Y, Higuchi N, Asami Y, Satomi N. Increased Accumulation of 18F-FDG Incidentally Observed in Hyperacute Cerebral Infarction. Clin Nucl Med 2022; 47:439-440. [PMID: 35025813 DOI: 10.1097/rlu.0000000000004003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
ABSTRACT A 75-year-old man with lung cancer undertook an 18F-FDG PET/CT for staging. He presented neurological symptoms immediately after the 30-minute scan. An emergent MRI study revealed hyperacute cerebral infarction with occlusion of a left MCA branch. At PET/CT, an increased 18F-FDG uptake was observed in the corresponding areas of infarction. In literature, acceleration of compensatory anaerobic glycolysis has been proposed as 1 of the causes of increased uptake in the penumbra of acute cerebral infarction, and a similar process was hypothesized in this case. In addition, a decreased 18F-FDG uptake in the ipsilateral thalamus was noted on the PET/CT images.
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Affiliation(s)
- Wataru Sotome
- From the Department of Radiology, National Hospital Organization Tokyo Medical Center, Tokyo, Japan
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5
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Taha A, Bobi J, Dammers R, Dijkhuizen RM, Dreyer AY, van Es ACGM, Ferrara F, Gounis MJ, Nitzsche B, Platt S, Stoffel MH, Volovici V, Del Zoppo GJ, Duncker DJ, Dippel DWJ, Boltze J, van Beusekom HMM. Comparison of Large Animal Models for Acute Ischemic Stroke: Which Model to Use? Stroke 2022; 53:1411-1422. [PMID: 35164533 PMCID: PMC10962757 DOI: 10.1161/strokeaha.121.036050] [Citation(s) in RCA: 34] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Translation of acute ischemic stroke research to the clinical setting remains limited over the last few decades with only one drug, recombinant tissue-type plasminogen activator, successfully completing the path from experimental study to clinical practice. To improve the selection of experimental treatments before testing in clinical studies, the use of large gyrencephalic animal models of acute ischemic stroke has been recommended. Currently, these models include, among others, dogs, swine, sheep, and nonhuman primates that closely emulate aspects of the human setting of brain ischemia and reperfusion. Species-specific characteristics, such as the cerebrovascular architecture or pathophysiology of thrombotic/ischemic processes, significantly influence the suitability of a model to address specific research questions. In this article, we review key characteristics of the main large animal models used in translational studies of acute ischemic stroke, regarding (1) anatomy and physiology of the cerebral vasculature, including brain morphology, coagulation characteristics, and immune function; (2) ischemic stroke modeling, including vessel occlusion approaches, reproducibility of infarct size, procedural complications, and functional outcome assessment; and (3) implementation aspects, including ethics, logistics, and costs. This review specifically aims to facilitate the selection of the appropriate large animal model for studies on acute ischemic stroke, based on specific research questions and large animal model characteristics.
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Affiliation(s)
- Aladdin Taha
- Division of Experimental Cardiology, Department of Cardiology (A.T., J.B., D.J.D., H.M.M.v.B.), Erasmus MC University Medical Center, Rotterdam, the Netherlands
- Department of Neurology, Stroke Center (A.T., D.W.J.D.), Erasmus MC University Medical Center, Rotterdam, the Netherlands
| | - Joaquim Bobi
- Division of Experimental Cardiology, Department of Cardiology (A.T., J.B., D.J.D., H.M.M.v.B.), Erasmus MC University Medical Center, Rotterdam, the Netherlands
| | - Ruben Dammers
- Department of Neurosurgery, Stroke Center (R.D., V.V.), Erasmus MC University Medical Center, Rotterdam, the Netherlands
| | - Rick M Dijkhuizen
- Biomedical MR Imaging and Spectroscopy Group, Center for Image Sciences, University Medical Center Utrecht, Utrecht University, the Netherlands (R.M.D.)
| | - Antje Y Dreyer
- Max Planck Institute for Infection Biology, Campus Charité Mitte, Berlin, Germany (A.Y.D.)
| | - Adriaan C G M van Es
- Department of Radiology, Leiden University Medical Center, the Netherlands (A.C.G.M.v.E.)
| | - Fabienne Ferrara
- Fraunhofer Institute for Cell Therapy and Immunology, Leipzig, Germany (F.F.)
| | - Matthew J Gounis
- Department of Radiology, New England Center for Stroke Research, University of Massachusetts Medical School, Worcester (M.J.G.)
| | - Björn Nitzsche
- Institute of Anatomy, Faculty of Veterinary Medicine (B.N.), University of Leipzig, Germany
- Department of Nuclear Medicine (B.N.), University of Leipzig, Germany
| | - Simon Platt
- Department of Small Animal Medicine and Surgery, College of Veterinary Medicine, University of Georgia, Athens (S.P.)
| | - Michael H Stoffel
- Division of Veterinary Anatomy, Vetsuisse Faculty, University of Bern, Switzerland (M.H.S.)
| | - Victor Volovici
- Department of Neurosurgery, Stroke Center (R.D., V.V.), Erasmus MC University Medical Center, Rotterdam, the Netherlands
| | - Gregory J Del Zoppo
- Division of Hematology (G.J.d.Z.), University of Washington School of Medicine, Seattle
- Department of Medicine (G.J.d.Z.), University of Washington School of Medicine, Seattle
- Department of Neurology (G.J.d.Z.), University of Washington School of Medicine, Seattle
| | - Dirk J Duncker
- Division of Experimental Cardiology, Department of Cardiology (A.T., J.B., D.J.D., H.M.M.v.B.), Erasmus MC University Medical Center, Rotterdam, the Netherlands
| | - Diederik W J Dippel
- Department of Neurology, Stroke Center (A.T., D.W.J.D.), Erasmus MC University Medical Center, Rotterdam, the Netherlands
| | - Johannes Boltze
- School of Life Sciences, Faculty of Science, University of Warwick, Coventry, United Kingdom (J.B.)
| | - Heleen M M van Beusekom
- Division of Experimental Cardiology, Department of Cardiology (A.T., J.B., D.J.D., H.M.M.v.B.), Erasmus MC University Medical Center, Rotterdam, the Netherlands
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6
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Powers WJ, An H, Diringer MN. Cerebral Blood Flow and Metabolism. Stroke 2022. [DOI: 10.1016/b978-0-323-69424-7.00003-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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7
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Davis SM, Donnan GA. Ischemic Penumbra: A Personal View. Cerebrovasc Dis 2021; 50:656-665. [PMID: 34736251 DOI: 10.1159/000519730] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2021] [Accepted: 09/16/2021] [Indexed: 11/19/2022] Open
Abstract
The concept of the ischemic penumbra was defined over 40 years ago by Lindsay Symon and his group and is now an established principle of all acute ischemic stroke therapies. These reperfusion treatments rescue threatened, critically hypoperfused brain tissue and have been proven to improve clinical outcomes. We have been fortunate to have observed and played a small part in the penumbral story from its beginnings in the 1970s to its pivotal position today. Over this period, we have witnessed penumbral imaging evolve from positron emission tomography through to magnetic resonance imaging and now predominantly computed tomography perfusion, with the advent of automated imaging facilitating case selection for reperfusion therapies. We and others have conducted clinical trials using penumbral imaging to extend the time window for intravenous thrombolysis and select patients for thrombectomy. Together with the concept of fast- and slow-growing ischemic infarct patterns, this embeds the penumbral principle in everyday clinical management. The opportunity now exists to make penumbral imaging even more portable, affordable, and more widely available using mobile platforms, novel imaging techniques, digital linkage, and artificial intelligence.
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Affiliation(s)
- Stephen M Davis
- Departments of Medicine and Neurology, Melbourne Brain Centre at the Royal Melbourne Hospital, University of Melbourne, Victoria, Victoria, Australia
| | - Geoffrey A Donnan
- Departments of Medicine and Neurology, Melbourne Brain Centre at the Royal Melbourne Hospital, University of Melbourne, Victoria, Victoria, Australia
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8
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Lu J, Mei Q, Hou X, Manaenko A, Zhou L, Liebeskind DS, Zhang JH, Li Y, Hu Q. Imaging Acute Stroke: From One-Size-Fit-All to Biomarkers. Front Neurol 2021; 12:697779. [PMID: 34630278 PMCID: PMC8497192 DOI: 10.3389/fneur.2021.697779] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2021] [Accepted: 06/30/2021] [Indexed: 12/27/2022] Open
Abstract
In acute stroke management, time window has been rigidly used as a guide for decades and the reperfusion treatment is only available in the first few limited hours. Recently, imaging-based selection of patients has successfully expanded the treatment window out to 16 and even 24 h in the DEFUSE 3 and DAWN trials, respectively. Recent guidelines recommend the use of imaging techniques to guide therapeutic decision-making and expanded eligibility in acute ischemic stroke. A tissue window is proposed to replace the time window and serve as the surrogate marker for potentially salvageable tissue. This article reviews the evolution of time window, addresses the advantage of a tissue window in precision medicine for ischemic stroke, and discusses both the established and emerging techniques of neuroimaging and their roles in defining a tissue window. We also emphasize the metabolic imaging and molecular imaging of brain pathophysiology, and highlight its potential in patient selection and treatment response prediction in ischemic stroke.
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Affiliation(s)
- Jianfei Lu
- Central Laboratory, Renji Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Qiyong Mei
- Department of Neurosurgery, Changzheng Hospital, Navy Medical University, Shanghai, China
| | - Xianhua Hou
- Department of Neurology, Southwest Hospital, Army Medical University, Chongqing, China
| | - Anatol Manaenko
- National Health Commission Key Laboratory of Diagnosis and Treatment on Brain Functional Diseases, The First Affiliated Hospital of Chongqing Medical University, Chongqing, China
| | - Lili Zhou
- Department of Neurology, Chinese People's Liberation Army General Hospital, Beijing, China
| | - David S. Liebeskind
- Neurovascular Imaging Research Core and University of California Los Angeles Stroke Center, University of California, Los Angeles, Los Angeles, CA, United States
| | - John H. Zhang
- Department of Anesthesiology, Loma Linda University School of Medicine, Loma Linda, CA, United States
| | - Yao Li
- School of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai, China
| | - Qin Hu
- Central Laboratory, Renji Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
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9
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van Putten MJ, Fahlke C, Kafitz KW, Hofmeijer J, Rose CR. Dysregulation of Astrocyte Ion Homeostasis and Its Relevance for Stroke-Induced Brain Damage. Int J Mol Sci 2021; 22:5679. [PMID: 34073593 PMCID: PMC8198632 DOI: 10.3390/ijms22115679] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2021] [Revised: 05/21/2021] [Accepted: 05/22/2021] [Indexed: 12/14/2022] Open
Abstract
Ischemic stroke is a leading cause of mortality and chronic disability. Either recovery or progression towards irreversible failure of neurons and astrocytes occurs within minutes to days, depending on remaining perfusion levels. Initial damage arises from energy depletion resulting in a failure to maintain homeostasis and ion gradients between extra- and intracellular spaces. Astrocytes play a key role in these processes and are thus central players in the dynamics towards recovery or progression of stroke-induced brain damage. Here, we present a synopsis of the pivotal functions of astrocytes at the tripartite synapse, which form the basis of physiological brain functioning. We summarize the evidence of astrocytic failure and its consequences under ischemic conditions. Special emphasis is put on the homeostasis and stroke-induced dysregulation of the major monovalent ions, namely Na+, K+, H+, and Cl-, and their involvement in maintenance of cellular volume and generation of cerebral edema.
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Affiliation(s)
- Michel J.A.M. van Putten
- Department of Clinical Neurophysiology, University of Twente, 7522 NB Enschede, The Netherlands; (M.J.A.M.v.P.); (J.H.)
| | - Christoph Fahlke
- Institut für Biologische Informationsprozesse, Molekular-und Zellphysiologie (IBI-1), Forschungszentrum Jülich, 52425 Jülich, Germany;
| | - Karl W. Kafitz
- Institute of Neurobiology, Heinrich Heine University Düsseldorf, 40225 Düsseldorf, Germany;
| | - Jeannette Hofmeijer
- Department of Clinical Neurophysiology, University of Twente, 7522 NB Enschede, The Netherlands; (M.J.A.M.v.P.); (J.H.)
| | - Christine R. Rose
- Institute of Neurobiology, Heinrich Heine University Düsseldorf, 40225 Düsseldorf, Germany;
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10
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Nogueira RC, Beishon L, Bor-Seng-Shu E, Panerai RB, Robinson TG. Cerebral Autoregulation in Ischemic Stroke: From Pathophysiology to Clinical Concepts. Brain Sci 2021; 11:511. [PMID: 33923721 PMCID: PMC8073938 DOI: 10.3390/brainsci11040511] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2021] [Revised: 04/02/2021] [Accepted: 04/09/2021] [Indexed: 11/17/2022] Open
Abstract
Ischemic stroke (IS) is one of the most impacting diseases in the world. In the last decades, new therapies have been introduced to improve outcomes after IS, most of them aiming for recanalization of the occluded vessel. However, despite this advance, there are still a large number of patients that remain disabled. One interesting possible therapeutic approach would be interventions guided by cerebral hemodynamic parameters such as dynamic cerebral autoregulation (dCA). Supportive hemodynamic therapies aiming to optimize perfusion in the ischemic area could protect the brain and may even extend the therapeutic window for reperfusion therapies. However, the knowledge of how to implement these therapies in the complex pathophysiology of brain ischemia is challenging and still not fully understood. This comprehensive review will focus on the state of the art in this promising area with emphasis on the following aspects: (1) pathophysiology of CA in the ischemic process; (2) methodology used to evaluate CA in IS; (3) CA studies in IS patients; (4) potential non-reperfusion therapies for IS patients based on the CA concept; and (5) the impact of common IS-associated comorbidities and phenotype on CA status. The review also points to the gaps existing in the current research to be further explored in future trials.
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Affiliation(s)
- Ricardo C. Nogueira
- Neurology Department, School of Medicine, Hospital das Clinicas, University of São Paulo, São Paulo 01246-904, Brazil;
- Department of Neurology, Hospital Nove de Julho, São Paulo 01409-002, Brazil
| | - Lucy Beishon
- Cerebral Haemodynamics in Ageing and Stroke Medicine Research Group, Department of Cardiovascular Sciences, University of Leicester, Leicester LE2 7LX, UK; (L.B.); (R.B.P.); (T.G.R.)
| | - Edson Bor-Seng-Shu
- Neurology Department, School of Medicine, Hospital das Clinicas, University of São Paulo, São Paulo 01246-904, Brazil;
| | - Ronney B. Panerai
- Cerebral Haemodynamics in Ageing and Stroke Medicine Research Group, Department of Cardiovascular Sciences, University of Leicester, Leicester LE2 7LX, UK; (L.B.); (R.B.P.); (T.G.R.)
- National Institute for Health Research (NIHR) Leicester Biomedical Research Centre, University of Leicester, Leicester LE5 4PW, UK
| | - Thompson G. Robinson
- Cerebral Haemodynamics in Ageing and Stroke Medicine Research Group, Department of Cardiovascular Sciences, University of Leicester, Leicester LE2 7LX, UK; (L.B.); (R.B.P.); (T.G.R.)
- National Institute for Health Research (NIHR) Leicester Biomedical Research Centre, University of Leicester, Leicester LE5 4PW, UK
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11
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Wu K, Xiong Z, Ding Y. Management of Elevated Blood Pressure After Stroke Thrombectomy for Anterior Circulation. Risk Manag Healthc Policy 2021; 14:405-413. [PMID: 33568958 PMCID: PMC7868952 DOI: 10.2147/rmhp.s285316] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2020] [Accepted: 01/25/2021] [Indexed: 12/11/2022] Open
Abstract
Thrombectomy is superior to intravenous thrombolysis for patients with large vessel occlusion in acute ischemic stroke, but nearly half of the patients still experience poor functional outcomes. Elevated blood pressure (BP) is widely observed in acute ischemic stroke, and BP may be one of the modifiable parameters that can potentially influence the outcomes; however, only observational studies exist to support current guidelines, and the recommended range for BP after thrombectomy is too wide to meet the clinical requirement. Randomized controlled trials are therefore needed to better understand the relationship between BP and outcomes after thrombectomy. In this review, we introduce the current management of BP after thrombectomy and several aspects of postthrombectomy BP management that should be resolved in future clinical trials.
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Affiliation(s)
- Kexin Wu
- Postgraduate School, Dalian Medical University, Dalian, People's Republic of China.,Department of Neurosurgery, Taizhou People's Hospital, Taizhou, People's Republic of China
| | - Zhencheng Xiong
- Institute of Medical Technology, Peking University Health Science Center, Beijing, People's Republic of China.,Peking University Third Hospital, Beijing, People's Republic of China
| | - Yasuo Ding
- Postgraduate School, Dalian Medical University, Dalian, People's Republic of China.,Department of Neurosurgery, Taizhou People's Hospital, Taizhou, People's Republic of China
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12
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Transcranial chronic optical access to longitudinally measure cerebral blood flow. J Neurosci Methods 2020; 350:109044. [PMID: 33340556 DOI: 10.1016/j.jneumeth.2020.109044] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2020] [Revised: 12/10/2020] [Accepted: 12/11/2020] [Indexed: 11/22/2022]
Abstract
BACKGROUND The regulation of cerebral blood flow is critical for normal brain functioning, and many physiological and pathological conditions can have long-term impacts on cerebral blood flow. However, minimally invasive tools to study chronic changes in animal models are limited. NEW METHOD We developed a minimally invasive surgical technique (cyanoacrylate skull, CAS) allowing us to image cerebral blood flow longitudinally through the intact mouse skull using laser speckle imaging. RESULTS With CAS we were able to detect acute changes in cerebral blood flow induced by hypercapnic challenge. We were also able to image cerebral blood flow dynamics with laser speckle imaging for over 100 days. Furthermore, the relative cerebral blood flow remained stable in mice from 30 days to greater than 100 days after the surgery. COMPARISON WITH EXISTING METHODS Previously, achieving continuous long-term optical access to measure cerebral blood flow in individual vessels in a mouse model involved invasive surgery. In contrast, the CAS technique presented here is relatively non-invasive, as it allows stable optical access through an intact mouse skull. CONCLUSIONS The CAS technique allows researcher to chronically measure cerebral blood flow dynamics for a significant portion of a mouse's lifespan. This approach may be useful for studying changes in blood flow due to cerebral pathology or for examining the therapeutic effects of modifying cerebral blood flow in mouse models relevant to human disease.
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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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14
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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] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/19/2019] [Revised: 10/29/2019] [Accepted: 11/01/2019] [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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15
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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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16
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Hausburg MA, Banton KL, Roman PE, Salgado F, Baek P, Waxman MJ, Tanner A, Yoder J, Bar-Or D. Effects of propofol on ischemia-reperfusion and traumatic brain injury. J Crit Care 2019; 56:281-287. [PMID: 32001426 DOI: 10.1016/j.jcrc.2019.12.021] [Citation(s) in RCA: 39] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2019] [Revised: 12/07/2019] [Accepted: 12/24/2019] [Indexed: 12/14/2022]
Abstract
Oxidative stress exacerbates brain damage following ischemia-reperfusion and traumatic brain injury (TBI). Management of TBI and critically ill patients commonly involves use of propofol, a sedation medication that acts as a general anesthetic with inherent antioxidant properties. Here we review available evidence from animal model systems and clinical studies that propofol protects against ischemia-reperfusion injury. However, evidence of propofol toxicity in humans exists and manifests as a rare complication, "propofol infusion syndrome" (PRIS). Evidence in animal models suggests that brain injury induces expression of the p75 neurotrophin receptor (p75NTR), which is associated with proapoptotic signaling. p75NTR-mediated apoptosis of neurons is further exacerbated by propofol's superinduction of p75NTR and concomitant inhibition of neurotrophin processing. Propofol is toxic to neurons but not astrocytes, a type of glial cell. Evidence suggests that propofol protects astrocytes from oxidative stress and stimulates astroglial-mediated protection of neurons. One may speculate that in brain injury patients under sedation/anesthesia, propofol provides brain tissue protection or aids in recovery by enhancing astrocyte function. Nevertheless, our understanding of neurologic recovery versus long-term neurological sequelae leading to neurodegeneration is poor, and it is also conceivable that propofol plays a partial as yet unrecognized role in long-term impairment of the injured brain.
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Affiliation(s)
- Melissa A Hausburg
- Trauma Research Department, Swedish Medical Center, 501 E Hampden, Englewood, CO 80113, USA; Trauma Research Department, St. Anthony Hospital, 11600 W 2nd Pl, Lakewood, CO 80228, USA; Trauma Research Department, Medical City Plano, 3901 W 15th St, Plano, TX 75075, USA; Trauma Research Department, Penrose Hospital, 2222 N Nevada Ave, Colorado Springs, CO 80907, USA; Trauma Research Department, Research Medical Center, 2316 E Meyer Blvd, Kansas City, MO 64132, USA; Trauma Research Department, Wesley Medical Center, 550 N Hillside St, Wichita, KS 67214, USA
| | - Kaysie L Banton
- Trauma Research Department, Swedish Medical Center, 501 E Hampden, Englewood, CO 80113, USA
| | - Phillip E Roman
- Trauma Research Department, St. Anthony Hospital, 11600 W 2nd Pl, Lakewood, CO 80228, USA; Department of Anesthesiology, St. Anthony Hospital, Lakewood, CO 80228, USA
| | - Fernando Salgado
- Trauma Research Department, Wesley Medical Center, 550 N Hillside St, Wichita, KS 67214, USA; Department of Anesthesiology, Wesley Medical Center, Wichita, KS 67214, USA
| | - Peter Baek
- Trauma Research Department, Medical City Plano, 3901 W 15th St, Plano, TX 75075, USA; Department of Anesthesiology, Medical City Plano, Plano, TX 75075, USA
| | - Michael J Waxman
- Department of Critical Care, Research Medical Center, Kansas City, MO 64132, USA
| | - Allen Tanner
- Trauma Research Department, Penrose Hospital, 2222 N Nevada Ave, Colorado Springs, CO 80907, USA
| | - Jeffrey Yoder
- Trauma Research Department, St. Anthony Hospital, 11600 W 2nd Pl, Lakewood, CO 80228, USA; Department of Anesthesiology, St. Anthony Hospital, Lakewood, CO 80228, USA
| | - David Bar-Or
- Trauma Research Department, Swedish Medical Center, 501 E Hampden, Englewood, CO 80113, USA; Trauma Research Department, St. Anthony Hospital, 11600 W 2nd Pl, Lakewood, CO 80228, USA; Trauma Research Department, Medical City Plano, 3901 W 15th St, Plano, TX 75075, USA; Trauma Research Department, Penrose Hospital, 2222 N Nevada Ave, Colorado Springs, CO 80907, USA; Trauma Research Department, Research Medical Center, 2316 E Meyer Blvd, Kansas City, MO 64132, USA; Trauma Research Department, Wesley Medical Center, 550 N Hillside St, Wichita, KS 67214, USA; Department of Molecular Biology, Rocky Vista University, 8401 S Chambers Rd, Parker, CO 80134, USA.
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17
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Significantly Increased Accumulation of 18F-FDG Throughout the Left Middle Cerebral Artery Territory Corresponding to Acute-Phase Infarction. Clin Nucl Med 2019; 44:907-910. [PMID: 31592826 DOI: 10.1097/rlu.0000000000002796] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
A 70-year-old woman had spontaneous resolution of an embolism in her right middle cerebral artery (MCA) (day 1); another embolism occurred in her left MCA (day 3), which was promptly removed. On day 5, F-FDG PET/CT performed for staging mediastinal lymphoma showed marked FDG accumulation in the left MCA territory, whereas a defect was seen in the right insular region. Eventually, bilateral lesions developed irreversible infarction. Anaerobic metabolism and/or inflammation in acute-phase infarction were the supposed mechanism for the increased accumulation of FDG in her left MCA territory.
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18
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Brunner C, Korostelev M, Raja S, Montaldo G, Urban A, Baron JC. Evidence from functional ultrasound imaging of enhanced contralesional microvascular response to somatosensory stimulation in acute middle cerebral artery occlusion/reperfusion in rats: A marker of ultra-early network reorganization? J Cereb Blood Flow Metab 2018; 38:1690-1700. [PMID: 29972329 PMCID: PMC6168914 DOI: 10.1177/0271678x18786359] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Following middle cerebral artery (MCA) stroke, enhanced contralesional evoked responses have been consistently reported both in man and rodents as part of plastic processes thought to influence motor recovery. How early this marker of large-scale network reorganization develops has however been little addressed, yet has clinical relevance for rehabilitation strategies targeting plasticity. Previous work in mice has reported enhanced contralesional responses to unaffected-side forepaw stimulation as early as 45 min after MCA small branch occlusion. Using functional ultrasound imaging (fUSi) in anesthetized rats subjected to distal temporary MCA occlusion (MCAo), we assessed here (i) whether enhanced contralesional responses also occurred with unaffected-side whisker pad stimulation, and if so, how early after MCAo; and (ii) the time course of this abnormal response during occlusion and after reperfusion. We replicate in a more proximal MCA occlusion model the earlier findings of ultra-early enhanced contralesional evoked responses. In addition, we document this phenomenon within minutes after MCAo, and its persistence throughout the entire 90-min occlusion as well as 90-min reperfusion periods studied. These findings suggest that plastic processes may start within minutes following MCAo in rodents. If replicated in man, they might have implications regarding how early plasticity-enhancing therapies can be initiated after stroke.
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Affiliation(s)
- Clément Brunner
- 1 Inserm U894, Université Paris Descartes, Paris, France.,2 Neuro-Electronics Research Flanders (NERF; A Research Initiative by IMEC, VIB and KU Leuven), Catholic University Leuven, Leuven, Belgium
| | | | - Sushmitha Raja
- 1 Inserm U894, Université Paris Descartes, Paris, France
| | - Gabriel Montaldo
- 2 Neuro-Electronics Research Flanders (NERF; A Research Initiative by IMEC, VIB and KU Leuven), Catholic University Leuven, Leuven, Belgium
| | - Alan Urban
- 2 Neuro-Electronics Research Flanders (NERF; A Research Initiative by IMEC, VIB and KU Leuven), Catholic University Leuven, Leuven, Belgium
| | - Jean-Claude Baron
- 1 Inserm U894, Université Paris Descartes, Paris, France.,3 Department of Neurology, Hôpital Sainte-Anne, Paris, France
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19
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Abstract
Gaining insights into brain oxygen metabolism has been one of the key areas of research in neurosciences. Extensive efforts have been devoted to developing approaches capable of providing measures of brain oxygen metabolism not only under normal physiological conditions but, more importantly, in various pathophysiological conditions such as cerebral ischemia. In particular, quantitative measures of cerebral metabolic rate of oxygen using positron emission tomography (PET) have been shown to be capable of discerning brain tissue viability during ischemic insults. However, the complex logistics associated with oxygen-15 PET have substantially hampered its wide clinical applicability. In contrast, magnetic resonance imaging (MRI)-based approaches have provided quantitative measures of cerebral oxygen metabolism similar to that obtained using PET. Given the wide availability, MRI-based approaches may have broader clinical impacts, particularly in cerebral ischemia, when time is a critical factor in deciding treatment selection. In this article, we review the pathophysiological basis of altered cerebral hemodynamics and oxygen metabolism in cerebral ischemia, how quantitative measures of cerebral metabolism were obtained using the Kety-Schmidt approach, the physical concepts of non-invasive oxygen metabolism imaging approaches, and, finally, clinical applications of the discussed imaging approaches.
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Affiliation(s)
- Weili Lin
- 1 Biomedical Research Imaging Center and Department of Radiology, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA.,2 Department of Neurology, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - William J Powers
- 2 Department of Neurology, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
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20
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Thirugnanachandran T, Ma H, Singhal S, Slater LA, Davis SM, Donnan GA, Phan T. Refining the ischemic penumbra with topography. Int J Stroke 2017; 13:277-284. [DOI: 10.1177/1747493017743056] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
It has been 40 years since the ischemic penumbra was first conceptualized through work on animal models. The topography of penumbra has been portrayed as an infarcted core surrounded by penumbral tissue and an extreme rim of oligemic tissue. This picture has been used in many review articles and textbooks before the advent of modern imaging. In this paper, we review our understanding of the topography of the ischemic penumbra from the initial experimental animal models to current developments with neuroimaging which have helped to further define the temporal and spatial evolution of the penumbra and refine our knowledge. The concept of the penumbra has been successfully applied in clinical trials of endovascular therapies with a time window as long as 24 h from onset. Further, there are reports of “good” outcome even in patients with a large ischemic core. This latter observation of good outcome despite having a large core requires an understanding of the topography of the penumbra and the function of the infarcted regions. It is proposed that future research in this area takes departure from a time-dependent approach to a more individualized tissue and location-based approach.
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Affiliation(s)
- Tharani Thirugnanachandran
- Stroke & Ageing Research (STARC), Department of Medicine, School of Clinical Sciences at Monash Health, Monash University, Clayton, VIC, Australia
| | - Henry Ma
- Stroke & Ageing Research (STARC), Department of Medicine, School of Clinical Sciences at Monash Health, Monash University, Clayton, VIC, Australia
| | - Shaloo Singhal
- Stroke & Ageing Research (STARC), Department of Medicine, School of Clinical Sciences at Monash Health, Monash University, Clayton, VIC, Australia
| | - Lee-Anne Slater
- Diagnostic Imaging, Monash Health, The Royal Melbourne Hospital and the University of Melbourne, Parkville, VIC, Australia
| | - Stephen M Davis
- Melbourne Brain Centre, The Royal Melbourne Hospital and the University of Melbourne, Parkville, VIC, Australia
| | - Geoffrey A Donnan
- Florey Neuroscience Institute, The Royal Melbourne Hospital and the University of Melbourne, Parkville, VIC, Australia
| | - Thanh Phan
- Stroke & Ageing Research (STARC), Department of Medicine, School of Clinical Sciences at Monash Health, Monash University, Clayton, VIC, Australia
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21
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Liu Q, Chen S, Soetikno B, Liu W, Tong S, Zhang HF. Monitoring Acute Stroke in Mouse Model Using Laser Speckle Imaging-Guided Visible-Light Optical Coherence Tomography. IEEE Trans Biomed Eng 2017; 65:2136-2142. [PMID: 28541195 DOI: 10.1109/tbme.2017.2706976] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
OBJECTIVE Monitoring hemodynamic and vascular changes in the acute stages of mouse stroke models is invaluable in studying ischemic stroke pathophysiology. However, there lacks a tool to simultaneously and dynamically investigate these changes. METHODS We integrated laser speckle imaging (LSI) and visible-light optical coherence tomography (Vis-OCT) to reveal dynamic vascular responses in acute stages in the distal middle cerebral artery occlusion (dMCAO) model in rodents. LSI provides full-field, real-time imaging to guide Vis-OCT imaging and monitor the dynamic cerebral blood flow (CBF). Vis-OCT offers depth-resolved angiography and oxygen saturation (sO2) measurements. RESULTS Our results showed detailed CBF and vasculature changes before, during, and after dMCAO. After dMCAO, we observed insignificant sO2 variation in arteries and arterioles and location-dependent sO2 drop in veins and venules. We observed that higher branch-order veins had larger drops in sO2 at the reperfusion stage after dMCAO. CONCLUSION This work suggests that integrated LSI and Vis-OCT is a promising tool for investigating ischemic stroke in mouse models. SIGNIFICANCE For the first time, LSI and Vis-OCT are integrated to investigate ischemic strokes in rodent models.
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22
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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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23
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Brunner C, Isabel C, Martin A, Dussaux C, Savoye A, Emmrich J, Montaldo G, Mas JL, Baron JC, Urban A. Mapping the dynamics of brain perfusion using functional ultrasound in a rat model of transient middle cerebral artery occlusion. J Cereb Blood Flow Metab 2017; 37:263-276. [PMID: 26721392 PMCID: PMC5363744 DOI: 10.1177/0271678x15622466] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/24/2015] [Revised: 11/17/2015] [Accepted: 11/18/2015] [Indexed: 01/07/2023]
Abstract
Following middle cerebral artery occlusion, tissue outcome ranges from normal to infarcted depending on depth and duration of hypoperfusion as well as occurrence and efficiency of reperfusion. However, the precise time course of these changes in relation to tissue and behavioral outcome remains unsettled. To address these issues, a three-dimensional wide field-of-view and real-time quantitative functional imaging technique able to map perfusion in the rodent brain would be desirable. Here, we applied functional ultrasound imaging, a novel approach to map relative cerebral blood volume without contrast agent, in a rat model of brief proximal transient middle cerebral artery occlusion to assess perfusion in penetrating arterioles and venules acutely and over six days thanks to a thinned-skull preparation. Functional ultrasound imaging efficiently mapped the acute changes in relative cerebral blood volume during occlusion and following reperfusion with high spatial resolution (100 µm), notably documenting marked focal decreases during occlusion, and was able to chart the fine dynamics of tissue reperfusion (rate: one frame/5 s) in the individual rat. No behavioral and only mild post-mortem immunofluorescence changes were observed. Our study suggests functional ultrasound is a particularly well-adapted imaging technique to study cerebral perfusion in acute experimental stroke longitudinally from the hyper-acute up to the chronic stage in the same subject.
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Affiliation(s)
- Clément Brunner
- Stroke Research Group, Centre de Psychiatrie et Neuroscience, INSERM U894, Hôpital Sainte-Anne, Paris, France.,SANOFI Research and Development, Lead Generation to Candidate Realization, Chilly-Mazarin, France
| | - Clothilde Isabel
- Stroke Research Group, Centre de Psychiatrie et Neuroscience, INSERM U894, Hôpital Sainte-Anne, Paris, France
| | - Abraham Martin
- Molecular Imaging Unit, CIC biomaGUNE, San Sebastián, Spain
| | - Clara Dussaux
- Stroke Research Group, Centre de Psychiatrie et Neuroscience, INSERM U894, Hôpital Sainte-Anne, Paris, France
| | - Anne Savoye
- Stroke Research Group, Centre de Psychiatrie et Neuroscience, INSERM U894, Hôpital Sainte-Anne, Paris, France
| | | | - Gabriel Montaldo
- Stroke Research Group, Centre de Psychiatrie et Neuroscience, INSERM U894, Hôpital Sainte-Anne, Paris, France
| | - Jean-Louis Mas
- Stroke Research Group, Centre de Psychiatrie et Neuroscience, INSERM U894, Hôpital Sainte-Anne, Paris, France
| | - Jean-Claude Baron
- Stroke Research Group, Centre de Psychiatrie et Neuroscience, INSERM U894, Hôpital Sainte-Anne, Paris, France
| | - Alan Urban
- Stroke Research Group, Centre de Psychiatrie et Neuroscience, INSERM U894, Hôpital Sainte-Anne, Paris, France
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24
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Lövblad KO, Kiefer C, Oswald H, Arnold M, Nedeltchev K, Mattle H, Schroth G. Imaging the Ischemic Penumbra. ACTA ACUST UNITED AC 2016. [DOI: 10.1177/197140090301600534] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Affiliation(s)
| | | | | | - M. Arnold
- Department of Neurology, Inselspital, Bern; Switzerland
| | - K. Nedeltchev
- Department of Neurology, Inselspital, Bern; Switzerland
| | - H. Mattle
- Department of Neurology, Inselspital, Bern; Switzerland
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25
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Determination of oxygen extraction fraction using magnetic resonance imaging in canine models with internal carotid artery occlusion. Sci Rep 2016; 6:30332. [PMID: 27443195 PMCID: PMC4957224 DOI: 10.1038/srep30332] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2016] [Accepted: 07/04/2016] [Indexed: 01/13/2023] Open
Abstract
Perfusion of the penumbra tissue below the flow threshold for functional disturbance but above that for the maintenance of morphological integrity is the target for therapy in acute ischaemic stroke. The measurement of the oxygen extraction fraction (OEF) may provide a direct assessment of tissue viability, so that irreversible tissue damage and penumbra can be reliably identified. By using an asymmetric spin echo single-shot echo planar imaging (ASE-SSEPI) sequence, the quantitative OEF was obtained in the ischaemic brain tissues of canine models with internal carotid artery occlusion. TTC staining, which delineated the regions of infarct and penumbra, was used for defining the corresponding regions on OEF maps. The threshold of the OEF to discriminate the infarct cores and penumbral tissues was then determined according to the OEF values at different times. With repeated-measures ANOVA, the OEF of the infarcted regions was found to be time dependent. An OEF greater than 0.48 best predicted cortical infarction at 1.5 hr, with an area under the receiving operating characteristic curve of 0.968, a sensitivity of 97.5%, and a specificity of 92.5%. Our results may be helpful in the evaluation of tissue viability during stroke events.
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Moreau F, Yang R, Nambiar V, Demchuk AM, Dunn JF. Near-infrared measurements of brain oxygenation in stroke. NEUROPHOTONICS 2016; 3:031403. [PMID: 26958577 PMCID: PMC4750462 DOI: 10.1117/1.nph.3.3.031403] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/01/2015] [Accepted: 01/13/2016] [Indexed: 05/17/2023]
Abstract
We investigated the feasibility of using frequency-domain near-infrared spectroscopy (fdNIRS) to study brain oxygenation in the first few hours of stroke onset. The OxiplexTS(®) fdNIRS system was used in this study. Using a standard probing protocol based on surface landmarks, we measured brain tHb and [Formula: see text] in healthy volunteers, cadavers, and acute stroke patients within 9 h of stroke onset and 3 days later. We obtained measurements from 11 controls, 5 cadavers, and 5 acute stroke patients. [Formula: see text] values were significantly lower in cadavers compared to the controls and stroke patients. Each stroke patient had at least one area with reduced [Formula: see text] on the stroke side compared to the contralateral side. The evolution of tHb and [Formula: see text] at 3 days differed depending on whether a large infarct occurred. This study shows the proof of principle that quantified measurements of brain oxygenation using NIRS could be used in the hectic environment of acute stroke management. It also highlights the current technical limitations and future challenges in the development of this unique bedside monitoring tool for stroke.
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Affiliation(s)
- François Moreau
- Université de Sherbrooke, Department of Medicine, CHUS-Hôpital Fleurimont 3001, 12e Avenue Nord, bureau 6501, Québec, Sherbrooke J1H 5N4, Canada
- Calgary Stroke Program, Department of Clinical Neurosciences, Foothills Medical Centre, 12th Floor, 1403-29th Street NW Calgary, Alberta T2N 2T9, Canada
- Address all correspondence to: François Moreau, E-mail:
| | - Runze Yang
- University of Calgary, Department of Radiology, Foothills Medical Centre, Room 812, North Tower, 1403-29th Street NW Calgary, Alberta T2N 2T9, Canada
- University of Calgary, Hotchkiss Brain Institute, Health Research Innovation Centre, Room 1A10, 3330 Hospital Drive NW, Calgary, Alberta T2N 4N1, Canada
| | - Vivek Nambiar
- Calgary Stroke Program, Department of Clinical Neurosciences, Foothills Medical Centre, 12th Floor, 1403-29th Street NW Calgary, Alberta T2N 2T9, Canada
- Amrita Institute Medical Sciences, Department of Neurology, Center of Neurosciences, Ponekkara, Kochi 682041, India
| | - Andrew M. Demchuk
- Calgary Stroke Program, Department of Clinical Neurosciences, Foothills Medical Centre, 12th Floor, 1403-29th Street NW Calgary, Alberta T2N 2T9, Canada
- University of Calgary, Hotchkiss Brain Institute, Health Research Innovation Centre, Room 1A10, 3330 Hospital Drive NW, Calgary, Alberta T2N 4N1, Canada
| | - Jeff F. Dunn
- University of Calgary, Department of Radiology, Foothills Medical Centre, Room 812, North Tower, 1403-29th Street NW Calgary, Alberta T2N 2T9, Canada
- University of Calgary, Hotchkiss Brain Institute, Health Research Innovation Centre, Room 1A10, 3330 Hospital Drive NW, Calgary, Alberta T2N 4N1, Canada
- University of Calgary, Experimental Imaging Center, TRW building, Basement level P2, Foothills Medical Centre, 1403-29th Street NW Calgary, Alberta T2N 2T9, Canada
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Abstract
Ischemic brain injury produced by stroke or cardiac arrest is a major cause of human neurological disability. Steady advances in the neurosciences have elucidated pathophysiological mechanisms of brain ischemia and have suggested many therapeutic approaches directed at specific injury mechanisms to achieve neuroprotection of the acutely ischemic brain. The first portion of this two-part review highlights the differentiating features and pathological mechanisms of focal and global cerebral ischemic injury and summarizes a wealth of recent evidence as to how antagonism of excitatory amino acid neurotoxicity, mediated via NMDA as well as non-NMDA receptors, may offer a means of diminishing the extent of ischemic injury. The Neuroscientist 1:95-103, 1995
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Affiliation(s)
- Myron D. Ginsberg
- Cerebral Vascular Disease Research Center Department
of Neurology University of Miami School of Medicine Miami, Florida
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Cheripelli BK, Huang X, McVerry F, Muir KW. What is the relationship among penumbra volume, collaterals, and time since onset in the first 6 h after acute ischemic stroke? Int J Stroke 2016; 11:338-46. [DOI: 10.1177/1747493015620807] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2015] [Accepted: 11/05/2015] [Indexed: 12/13/2022]
Abstract
Background The steep, time-dependent loss of benefit from reperfusion in clinical trials is consistent with loss of penumbra over the early hours of ischemia, as observed in animal models. Human imaging studies, however, show persistent penumbra for up to 48 h. We investigated core and penumbra volumes and collateral status in relation to time after stroke onset within the first 6 h. Methods Using data from three multimodal computer tomography-based studies in acute ischemic stroke patients <6 h after onset, we measured core and penumbra volumes, collateral status, and target mismatch (defined as core volume < 50 ml, perfusion lesion volume > 15 ml, mismatch ratio > 1.8). Patients were grouped by onset to imaging time (<3, 3–4.5, 4.5–6 h). We explored correlates of penumbra proportion by multivariable linear regression. Results Analysis included 144 subjects. Across time epochs, neither proportions of penumbra (59%, 64%, 75% at <3, 3–4.5, >4. 5 h, respectively, p = 0.4) nor poor collaterals (15/56 (27%), 14/47 (30%), 4/15 (27%) at <3, 3–4.5, >4.5 h, p = 0.9) differed significantly. Penumbra proportion was not clearly related to time to imaging ( R2 = 0.003; p = 0.5) but a trend for divergent effects by collateral status was seen (slight increase in penumbra over time with good collaterals versus reduced with poor, interaction = 0.08). The proportion of patients with target mismatch did not vary by time (56%, 74%, and 67% at <3, 3–4.5, >4.5 h, p = 0.09). Conclusions In a cross-sectional sample imaged within 6 h, neither the proportions of penumbral tissue nor “target mismatch” varied by time from onset. A trend for reducing penumbra proportion only among those with poor collaterals may have pathophysiological and therapeutic importance.
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Affiliation(s)
- Bharath Kumar Cheripelli
- Institute of Neuroscience and Psychology, University of Glasgow, Queen Elizabeth University Hospital, Glasgow, Scotland, UK
| | - Xuya Huang
- Institute of Neuroscience and Psychology, University of Glasgow, Queen Elizabeth University Hospital, Glasgow, Scotland, UK
| | - Ferghal McVerry
- Neurology Department, Altnagelvin Area Hospital, Derry, Northern Ireland
| | - Keith W Muir
- Institute of Neuroscience and Psychology, University of Glasgow, Queen Elizabeth University Hospital, Glasgow, Scotland, UK
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Cerebral Blood Flow and Metabolism. Stroke 2016. [DOI: 10.1016/b978-0-323-29544-4.00003-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
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Backes H, Walberer M, Ladwig A, Rueger MA, Neumaier B, Endepols H, Hoehn M, Fink GR, Schroeter M, Graf R. Glucose consumption of inflammatory cells masks metabolic deficits in the brain. Neuroimage 2015; 128:54-62. [PMID: 26747749 PMCID: PMC4767221 DOI: 10.1016/j.neuroimage.2015.12.044] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2015] [Revised: 12/16/2015] [Accepted: 12/23/2015] [Indexed: 01/06/2023] Open
Abstract
Inflammatory cells such as microglia need energy to exert their functions and to maintain their cellular integrity and membrane potential. Subsequent to cerebral ischemia, inflammatory cells infiltrate tissue with limited blood flow where neurons and astrocytes died due to insufficient supply with oxygen and glucose. Using dual tracer positron emission tomography (PET), we found that concomitant with the presence of inflammatory cells, transport and consumption of glucose increased up to normal levels but returned to pathological levels as soon as inflammatory cells disappeared. Thus, inflammatory cells established sufficient glucose supply to satisfy their energy demands even in regions with insufficient supply for neurons and astrocytes to survive. Our data suggest that neurons and astrocytes died from oxygen deficiency and inflammatory cells metabolized glucose non-oxidatively in regions with residual availability. As a consequence, glucose metabolism of inflammatory cells can mask metabolic deficits in neurodegenerative diseases. We further found that the PET tracer did not bind to inflammatory cells in severely hypoperfused regions and thus only a part of the inflammation was detected. We conclude that glucose consumption of inflammatory cells should be taken into account when analyzing disease-related alterations of local cerebral metabolism. Inflammatory cells consume high amounts of glucose in supply-limited brain regions. Glucose metabolism of inflammatory cells masks metabolic deficits in the brain. In vivo markers only reach inflammatory cells in regions with residual blood supply. Measuring inflammation and metabolism provide complementary information.
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Affiliation(s)
- Heiko Backes
- Max Planck Institute for Metabolism Research, Cologne, Germany.
| | - Maureen Walberer
- Max Planck Institute for Metabolism Research, Cologne, Germany; Department of Neurology, University Hospital, Cologne, Germany
| | - Anne Ladwig
- Max Planck Institute for Metabolism Research, Cologne, Germany; Department of Neurology, University Hospital, Cologne, Germany
| | - Maria A Rueger
- Max Planck Institute for Metabolism Research, Cologne, Germany; Department of Neurology, University Hospital, Cologne, Germany
| | - Bernd Neumaier
- Max Planck Institute for Metabolism Research, Cologne, Germany; Department of Radiochemistry and Experimental Molecular Imaging, University of Cologne, Germany
| | - Heike Endepols
- Department of Radiochemistry and Experimental Molecular Imaging, University of Cologne, Germany
| | - Mathias Hoehn
- Max Planck Institute for Metabolism Research, Cologne, Germany
| | - Gereon R Fink
- Department of Neurology, University Hospital, Cologne, Germany; Institute of Neuroscience and Medicine (INM-3), Cognitive Neurology Section, Research Centre Juelich, Germany
| | - Michael Schroeter
- Max Planck Institute for Metabolism Research, Cologne, Germany; Department of Neurology, University Hospital, Cologne, Germany
| | - Rudolf Graf
- Max Planck Institute for Metabolism Research, Cologne, Germany
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Li C, Wu PM, Wu Z, Limnuson K, Mehan N, Mozayan C, Golanov EV, Ahn CH, Hartings JA, Narayan RK. Highly accurate thermal flow microsensor for continuous and quantitative measurement of cerebral blood flow. Biomed Microdevices 2015; 17:87. [DOI: 10.1007/s10544-015-9992-3] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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Li H, Li Y, Yuan L, Wu C, Lu H, Tong S. Intraoperative cerebral blood flow imaging of rodents. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2014; 85:094301. [PMID: 25273744 DOI: 10.1063/1.4895657] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Intraoperative monitoring of cerebral blood flow (CBF) is of interest to neuroscience researchers, which offers the assessment of hemodynamic responses throughout the process of neurosurgery and provides an early biomarker for surgical guidance. However, intraoperative CBF imaging has been challenging due to animal's motion and position change during the surgery. In this paper, we presented a design of an operation bench integrated with laser speckle contrast imager which enables monitoring of the CBF intraoperatively. With a specially designed stereotaxic frame and imager, we were able to monitor the CBF changes in both hemispheres during the rodent surgery. The rotatable design of the operation plate and implementation of online image registration allow the technician to move the animal without disturbing the CBF imaging during surgery. The performance of the system was tested by middle cerebral artery occlusion model of rats.
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Affiliation(s)
- Hangdao Li
- Med-X Research Institute, Shanghai Jiao Tong University, Shanghai 200030, China
| | - Yao Li
- Med-X Research Institute, Shanghai Jiao Tong University, Shanghai 200030, China
| | - Lu Yuan
- Med-X Research Institute, Shanghai Jiao Tong University, Shanghai 200030, China
| | - Caihong Wu
- School of Media and Design, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Hongyang Lu
- Med-X Research Institute, Shanghai Jiao Tong University, Shanghai 200030, China
| | - Shanbao Tong
- Med-X Research Institute, Shanghai Jiao Tong University, Shanghai 200030, China
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Meoded A, Poretti A, Benson JE, Tekes A, Huisman TA. Evaluation of the ischemic penumbra focusing on the venous drainage: The role of susceptibility weighted imaging (SWI) in pediatric ischemic cerebral stroke. J Neuroradiol 2014; 41:108-16. [DOI: 10.1016/j.neurad.2013.04.002] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2012] [Revised: 03/31/2013] [Accepted: 04/04/2013] [Indexed: 11/30/2022]
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Kneipp M, Turner J, Hambauer S, Krieg SM, Lehmberg J, Lindauer U, Razansky D. Functional real-time optoacoustic imaging of middle cerebral artery occlusion in mice. PLoS One 2014; 9:e96118. [PMID: 24776997 PMCID: PMC4002478 DOI: 10.1371/journal.pone.0096118] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2014] [Accepted: 04/03/2014] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND AND PURPOSE Longitudinal functional imaging studies of stroke are key in identifying the disease progression and possible therapeutic interventions. Here we investigate the applicability of real-time functional optoacoustic imaging for monitoring of stroke progression in the whole brain of living animals. MATERIALS AND METHODS The middle cerebral artery occlusion (MCAO) was used to model stroke in mice, which were imaged preoperatively and the occlusion was kept in place for 60 minutes, after which optoacoustic scans were taken at several time points. RESULTS Post ischemia an asymmetry of deoxygenated hemoglobin in the brain was observed as a region of hypoxia in the hemisphere affected by the ischemic event. Furthermore, we were able to visualize the penumbra in-vivo as a localized hemodynamically-compromised area adjacent to the region of stroke-induced perfusion deficit. CONCLUSION The intrinsic sensitivity of the new imaging approach to functional blood parameters, in combination with real time operation and high spatial resolution in deep living tissues, may see it become a valuable and unique tool in the development and monitoring of treatments aimed at suspending the spread of an infarct area.
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Affiliation(s)
- Moritz Kneipp
- Faculty of Medicine and Faculty of Electrical Engineering, Technische Universität München, Munich, Germany
- Institute for Biological and Medical Imaging, Helmholtz Zentrum München, Neuherberg, Germany
| | - Jake Turner
- Faculty of Medicine and Faculty of Electrical Engineering, Technische Universität München, Munich, Germany
- Institute for Biological and Medical Imaging, Helmholtz Zentrum München, Neuherberg, Germany
| | - Sebastian Hambauer
- Department of Neurosurgery, Klinikum rechts der Isar, Technische Universität München, Munich, Germany
| | - Sandro M. Krieg
- Department of Neurosurgery, Klinikum rechts der Isar, Technische Universität München, Munich, Germany
- TUM-Neuroimaging Center, Technical University Munich, Munich, Germany
| | - Jens Lehmberg
- Department of Neurosurgery, Klinikum rechts der Isar, Technische Universität München, Munich, Germany
| | - Ute Lindauer
- Department of Neurosurgery, Klinikum rechts der Isar, Technische Universität München, Munich, Germany
- TUM-Neuroimaging Center, Technical University Munich, Munich, Germany
- Munich Cluster for Systems Neurology (SyNergy), Munich, Germany
| | - Daniel Razansky
- Faculty of Medicine and Faculty of Electrical Engineering, Technische Universität München, Munich, Germany
- Institute for Biological and Medical Imaging, Helmholtz Zentrum München, Neuherberg, Germany
- * E-mail:
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Gramer M, Feuerstein D, Steimers A, Takagaki M, Kumagai T, Sué M, Vollmar S, Kohl-Bareis M, Backes H, Graf R. Device for simultaneous positron emission tomography, laser speckle imaging and RGB reflectometry: validation and application to cortical spreading depression and brain ischemia in rats. Neuroimage 2014; 94:250-262. [PMID: 24657778 DOI: 10.1016/j.neuroimage.2014.03.027] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2013] [Revised: 02/06/2014] [Accepted: 03/10/2014] [Indexed: 11/16/2022] Open
Abstract
Brain function critically relies on the supply with energy substrates (oxygen and glucose) via blood flow. Alterations in energy demand as during neuronal activation induce dynamic changes in substrate fluxes and blood flow. To study the complex system that regulates cerebral metabolism requires the combination of methods for the simultaneous assessment of multiple parameters. We developed a multimodal imaging device to combine positron emission tomography (PET) with laser speckle imaging (LSI) and RGB reflectometry (RGBR). Depending on the radiotracer, PET provides 3-dimensional quantitative information of specific molecular processes, while LSI and RGBR measure cerebral blood flow (CBF) and hemoglobin oxygenation at high temporal and spatial resolution. We first tested the functional capability of each modality within our system and showed that interference between the modalities is negligible. We then cross-calibrated the system by simultaneously measuring absolute CBF using (15)O-H2O PET (CBF(PET)) and the inverse correlation time (ICT), the LSI surrogate for CBF. ICT and CBF(PET) correlated in multiple measurements in individuals as well as across different animals (R(2)=0.87, n=44 measurements) indicating that ICT can be used for absolute quantitative assessment of CBF. To demonstrate the potential of the combined system, we applied it to cortical spreading depression (CSD), a wave of transient cellular depolarization that served here as a model system for neurovascular and neurometabolic coupling. We analyzed time courses of hemoglobin oxygenation and CBF alterations coupled to CSD, and simultaneously measured regional uptake of (18)F-2-fluoro-2-deoxy-D-glucose ((18)F-FDG) used as a radiotracer for regional glucose metabolism, in response to a single CSD and to a cluster of CSD waves. With this unique combination, we characterized the changes in cerebral metabolic rate of oxygen (CMRO2) in real-time and showed a correlation between (18)F-FDG uptake and the number of CSD waves that passed the local tissue. Finally, we examined CSD spontaneously occurring during focal ischemia also referred to as peri-infarct depolarization (PID). In the vicinity of the ischemic territory, we observed PIDs that were characterized by reduced CMRO2 and increased oxygen extraction fraction (OEF), indicating a limitation of oxygen supply. Simultaneously measured PET showed an increased (18)F-FDG uptake in these regions. Our combined system proved to be a novel tool for the simultaneous study of dynamic spatiotemporal alterations of cortical blood flow, oxygen metabolism and glucose consumption under normal and pathologic conditions.
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Affiliation(s)
- M Gramer
- Max-Planck-Institute of Neurological Research, Gleueler Str. 50, 50825 Cologne, Germany.
| | - D Feuerstein
- Max-Planck-Institute of Neurological Research, Gleueler Str. 50, 50825 Cologne, Germany
| | - A Steimers
- RheinAhrCampus Remagen, University of Applied Sciences Koblenz, Joseph-Rovan Allee 2, 53424 Remagen, Germany
| | - M Takagaki
- Osaka University Graduate School of Medicine, 2-2 Yamadaoka, Suita, Osaka 565-0871, Japan
| | - T Kumagai
- Osaka University Graduate School of Medicine, 2-2 Yamadaoka, Suita, Osaka 565-0871, Japan
| | - M Sué
- Max-Planck-Institute of Neurological Research, Gleueler Str. 50, 50825 Cologne, Germany
| | - S Vollmar
- Max-Planck-Institute of Neurological Research, Gleueler Str. 50, 50825 Cologne, Germany
| | - M Kohl-Bareis
- RheinAhrCampus Remagen, University of Applied Sciences Koblenz, Joseph-Rovan Allee 2, 53424 Remagen, Germany
| | - H Backes
- Max-Planck-Institute of Neurological Research, Gleueler Str. 50, 50825 Cologne, Germany
| | - R Graf
- Max-Planck-Institute of Neurological Research, Gleueler Str. 50, 50825 Cologne, Germany
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Zhao Y, Lai W, Xu Y, Li L, Chen Z, Wu W. Exogenous and endogenous therapeutic effects of combination Sodium Ferulate and bone marrow stromal cells (BMSCs) treatment enhance neurogenesis after rat focal cerebral ischemia. Metab Brain Dis 2013; 28:655-66. [PMID: 23955489 DOI: 10.1007/s11011-013-9425-z] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/16/2013] [Accepted: 07/22/2013] [Indexed: 01/16/2023]
Abstract
Combining bone marrow stromal cells (BMSCs) with pharmacological therapy is an attractive approach for neurological function recovery of stroke. Our previous reports demonstrated that Sodium Ferulate (SF) combined with BMSCs administration could facilitate BMSCs migration into the ischemic brain by up-regulation of stromal cell-derived factor-1 alpha (SDF-1α)/chemokine (CXC motif) receptor-4 axis after stroke. To further investigate whether combination treatment could enhance neurogenesis through exogenous and endogenous therapeutic effects, we established rat permanent middle cerebral artery occlusion (pMCAo) model and measured ischemic infarct size by magnetic resonance imaging (MRI) scanning in the present study. The results showed that combination treatment could dramatically reduce ischemic infarction size which may be attributed to the effects on decreasing brain edema and enhancing cerebral tissue perfusion at 3 days after stroke. Immunofluorescence staining results indicated that combination treatment could not only promote expression of Glucose transporter 1(Glut1) and Neuron-specific class III beta-tubulin (Tuj1) in the periinfarct area, but also improve BMSCs expression of Glut1, GFAP and Tuj1. Moreover, it showed combination treatment could enhance the endogenous expression of Tuj-1 in ischemic boundary zone. These results perhaps associated with combination treatment up-regulating bone morphogenetic proteins (BMP)2/4 expressions and down-regulating Notch-1, Hes1 and Hes5 expressions as detected by Western Blot analysis. Our study firstly demonstrated in vivo that combination treatment could facilitate exogenous BMSCs differentiation into neural-and astrocytic-like cells, as well as enhance repair capacity of brain parenchymal cells by promoting glucose metabolism and endogenous neurogenesis after stroke. These results illustrate that administration of SF and BMSCs is a potential pathway of cell-based pharmacological treatment towards ischemic stroke.
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Affiliation(s)
- Yonghua Zhao
- State Key Laboratory of Quality Research in Chinese Medicine, Faculty of Chinese Medicine, Macau University of Science and Technology, Taipa, Macao,
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Barber PA. Magnetic resonance imaging of ischemia viability thresholds and the neurovascular unit. SENSORS 2013; 13:6981-7003. [PMID: 23711462 PMCID: PMC3715273 DOI: 10.3390/s130606981] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/16/2013] [Revised: 05/02/2013] [Accepted: 05/06/2013] [Indexed: 01/24/2023]
Abstract
Neuroimaging has improved our understanding of the evolution of stroke at discreet time points helping to identify irreversibly damaged and potentially reversible ischemic brain. Neuroimaging has also contributed considerably to the basic premise of acute stroke therapy which is to salvage some portion of the ischemic region from evolving into infarction, and by doing so, maintaining brain function and improving outcome. The term neurovascular unit (NVU) broadens the concept of the ischemic penumbra by linking the microcirculation with neuronal-glial interactions during ischemia reperfusion. Strategies that attempt to preserve the individual components (endothelium, glia and neurons) of the NVU are unlikely to be helpful if blood flow is not fully restored to the microcirculation. Magnetic resonance imaging (MRI) is the foremost imaging technology able to bridge both basic science and the clinic via non-invasive real time high-resolution anatomical delineation of disease manifestations at the molecular and ionic level. Current MRI based technologies have focused on the mismatch between perfusion-weighted imaging (PWI) and diffusion weighted imaging (DWI) signals to estimate the tissue that could be saved if reperfusion was achieved. Future directions of MRI may focus on the discordance of recanalization and reperfusion, providing complimentary pathophysiological information to current compartmental paradigms of infarct core (DWI) and penumbra (PWI) with imaging information related to cerebral blood flow, BBB permeability, inflammation, and oedema formation in the early acute phase. In this review we outline advances in our understanding of stroke pathophysiology with imaging, transcending animal stroke models to human stroke, and describing the potential translation of MRI to image important interactions relevant to acute stroke at the interface of the neurovascular unit.
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Affiliation(s)
- Philip A Barber
- Department of Clinical Neurosciences, University of Calgary, Calgary, Canada.
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The potential roles of 18F-FDG-PET in management of acute stroke patients. BIOMED RESEARCH INTERNATIONAL 2013; 2013:634598. [PMID: 23762852 PMCID: PMC3671294 DOI: 10.1155/2013/634598] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/21/2013] [Accepted: 04/14/2013] [Indexed: 01/17/2023]
Abstract
Extensive efforts have recently been devoted to developing noninvasive imaging tools capable of delineating brain tissue viability (penumbra) during acute ischemic stroke. These efforts could have profound clinical implications for identifying patients who may benefit from tPA beyond the currently approved therapeutic time window and/or patients undergoing neuroendovascular treatments. To date, the DWI/PWI MRI and perfusion CT have received the most attention for identifying ischemic penumbra. However, their routine use in clinical settings remains limited. Preclinical and clinical PET studies with [18F]-fluoro-2-deoxy-D-glucose (18F-FDG) have consistently revealed a decreased 18F-FDG uptake in regions of presumed ischemic core. More importantly, an elevated 18F-FDG uptake in the peri-ischemic regions has been reported, potentially reflecting viable tissues. To this end, this paper provides a comprehensive review of the literature on the utilization of 14C-2-DG and 18F-FDG-PET in experimental as well as human stroke studies. Possible cellular mechanisms and physiological underpinnings attributed to the reported temporal and spatial uptake patterns of 18F-FDG are addressed. Given the wide availability of 18F-FDG in routine clinical settings, 18F-FDG PET may serve as an alternative, non-invasive tool to MRI and CT for the management of acute stroke patients.
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Fisher M. The Interface Between Technology and Acute Ischemic Therapy Development. Cardiovasc Eng Technol 2013. [DOI: 10.1007/s13239-013-0138-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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de la Rosa X, Santalucía T, Fortin PY, Purroy J, Calvo M, Salas-Perdomo A, Justicia C, Couillaud F, Planas AM. In vivo imaging of induction of heat-shock protein-70 gene expression with fluorescence reflectance imaging and intravital confocal microscopy following brain ischaemia in reporter mice. Eur J Nucl Med Mol Imaging 2013; 40:426-38. [PMID: 23135322 DOI: 10.1007/s00259-012-2277-7] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2012] [Accepted: 10/04/2012] [Indexed: 01/07/2023]
Abstract
PURPOSE Stroke induces strong expression of the 72-kDa heat-shock protein (HSP-70) in the ischaemic brain, and neuronal expression of HSP-70 is associated with the ischaemic penumbra. The aim of this study was to image induction of Hsp-70 gene expression in vivo after brain ischaemia using reporter mice. METHODS A genomic DNA sequence of the Hspa1b promoter was used to generate an Hsp70-mPlum far-red fluorescence reporter vector. The construct was tested in cellular systems (NIH3T3 mouse fibroblast cell line) by transient transfection and examining mPlum and Hsp-70 induction under a challenge. After construct validation, mPlum transgenic mice were generated. Focal brain ischaemia was induced by transient intraluminal occlusion of the middle cerebral artery and the mice were imaged in vivo with fluorescence reflectance imaging (FRI) with an intact skull, and with confocal microscopy after opening a cranial window. RESULTS Cells transfected with the Hsp70-mPlum construct showed mPlum fluorescence after stimulation. One day after induction of ischaemia, reporter mice showed a FRI signal located in the HSP-70-positive zone within the ipsilateral hemisphere, as validated by immunohistochemistry. Live confocal microscopy allowed brain tissue to be visualized at the cellular level. mPlum fluorescence was observed in vivo in the ipsilateral cortex 1 day after induction of ischaemia in neurons, where it is compatible with penumbra and neuronal viability, and in blood vessels in the core of the infarction. CONCLUSION This study showed in vivo induction of Hsp-70 gene expression in ischaemic brain using reporter mice. The fluorescence signal showed in vivo the induction of Hsp-70 in penumbra neurons and in the vasculature within the ischaemic core.
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Affiliation(s)
- Xavier de la Rosa
- Department of Brain Ischemia and Neurodegeneration, Institute for Biomedical Research of Barcelona, Consejo Superior de Investigaciones Científicas, Institut d'Investigacions Biomèdiques August Pi i Sunyer, Rosselló 161, planta 6, 08036, Barcelona, Spain
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Mackenzie JM, Clayton JA. Early cellular events in the penumbra of human spontaneous intracerebral hemorrhage. J Stroke Cerebrovasc Dis 2012; 8:1-8. [PMID: 17895130 DOI: 10.1016/s1052-3057(99)80032-9] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/1998] [Accepted: 07/24/1998] [Indexed: 11/29/2022] Open
Abstract
Spontaneous intracerebral hemorrhage causes high morbidity and mortality rates, and yet its treatment remains controversial, partly because of a poor understanding of the pathogenesis and timescale of injury in the surrounding brain. This study was undertaken to clarify the cellular reactions around human spontaneous intracerebral hematomas and relate these to hematoma duration and volume, in order to provide further data that might aid the development of therapeutic strategies. Brain tissue from the margin of the hematoma in 33 fatal cases of spontaneous intracerebral hemorrhage and corresponding tissue from 13 normal controls was studied using immunohistochemistry for heat-shock proteins, metallothionein, and various neuronal, glial, macrophage, and endothelial markers. Hematoma volumes were calculated from computed tomographic (CT) scans and autopsy measurements, whereas hematoma age was estimated from clinical records. The results showed that cellular events are time dependent, but not related to hematoma volume, and are identifiable in neurons, glia, and endothelium as early as 5 hours after hemorrhage. Peripheral macrophage infiltration begins at 5 days. The results suggest that the therapeutic window in humans for reperfusion of the ischemic penumbra of a hematoma is less than 5 hours, although progression of the infarcted core to the penumbral periphery within 1 to 3 days suggests a wider cytoprotective window. Edema, caused by blood-brain barrier breakdown, was also identified at 5 hours, and prompt treatment of this may reduce the space-occupying effects of the hematoma and, possibly, the morbidity and mortality.
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Martín A, Macé E, Boisgard R, Montaldo G, Thézé B, Tanter M, Tavitian B. Imaging of perfusion, angiogenesis, and tissue elasticity after stroke. J Cereb Blood Flow Metab 2012; 32:1496-507. [PMID: 22491156 PMCID: PMC3421095 DOI: 10.1038/jcbfm.2012.49] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Blood flow interruption in a cerebral artery causes brain ischemia and induces dramatic changes of perfusion and metabolism in the corresponding territory. We performed in parallel positron emission tomography (PET) with [(15)O]H(2)O, single photon emission computed tomography (SPECT) with [(99m)Tc]hexamethylpropylene-amino-oxime ([(99m)Tc]HMPAO) and ultrasonic ultrafast shear wave imaging (SWI) during, immediately after, and 1, 2, 4, and 7 days after middle cerebral artery occlusion (MCAO) in rats. Positron emission tomography and SPECT showed initial hypoperfusion followed by recovery at immediate reperfusion, hypoperfusion at day 1, and hyperperfusion at days 4 to 7. Hyperperfusion interested the whole brain, including nonischemic areas. Immunohistochemical analysis indicated active angiogenesis at days 2 to 7, strongly suggestive that hyperperfusion was supported by an increase in microvessel density in both brain hemispheres after ischemia. The SWI detected elastic changes of cerebral tissue in the ischemic area as early as day 1 after MCAO appearing as a softening of cerebral tissue whose local internal elasticity decreased continuously from day 1 to 7. Taken together, these results suggest that hyperperfusion after cerebral ischemia is due to formation of neovessels, and indicate that brain softening is an early and continuous process. The SWI is a promising novel imaging method for monitoring the evolution of cerebral ischemia over time in animals.
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Affiliation(s)
- Abraham Martín
- Inserm U1023, Université Paris Sud, CEA, DSV, I2BM, Orsay, France
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43
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Walberer M, Backes H, Rueger MA, Neumaier B, Endepols H, Hoehn M, Fink GR, Schroeter M, Graf R. Potential of Early [
18
F]-2-Fluoro-2-Deoxy-D-Glucose Positron Emission Tomography for Identifying Hypoperfusion and Predicting Fate of Tissue in a Rat Embolic Stroke Model. Stroke 2012; 43:193-8. [DOI: 10.1161/strokeaha.111.624551] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Background and Purpose—
Experimental stroke models are essential to study in vivo pathophysiological processes of focal cerebral ischemia. In this study, an embolic stroke model in rats was applied (1) to characterize early development of regional cerebral blood flow and metabolism with positron emission tomography (PET) using [
15
O]H
2
O and [
18
F]-2-fluoro-2-deoxy-D-glucose (FDG); and (2) to identify potential parameters for predicting tissue fate.
Methods—
Remote occlusion of the middle cerebral artery was induced in 10 Wistar rats by injection of 4 TiO
2
macrospheres. Sequential [
15
O]H
2
O-PET (baseline, 5, 30, 60 minutes after middle cerebral artery occlusion) and FDG-PET measurements (75 minutes after middle cerebral artery occlusion) were performed. [
15
O]H
2
O-PET data and FDG kinetic parameters were compared with MRIs and histology at 24 hours.
Results—
Regional cerebral blood flow decreased substantially within 30 minutes after middle cerebral artery occlusion (41% to 58% of baseline regional cerebral blood flow;
P
<0.001) with no relevant changes between 30 and 60 minutes. At 60 minutes, regional cerebral blood flow correlated well with the unidirectional transport parameter
K1
of FDG in all animals (
r
=0.86±0.09;
P
<0.001). Tissue fate could be accurately predicted taking into account
K1
and net influx rate constant
Ki
of FDG. The infarct volume predicted by FDG-PET (375.8±102.3 mm
3
) correlated significantly with the infarct size determined by MRI after 24 hours (360.8±93.7 mm
3
;
r
=0.85).
Conclusions—
Hypoperfused tissue can be identified by decreased
K1
of FDG. Acute ischemic tissue can be well characterized using
K1
and
Ki
allowing for discrimination between infarct core and early viable tissue. Because FDG-PET is widely spread, our findings can be easily translated into clinical application for early diagnoses of ischemia.
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Affiliation(s)
- Maureen Walberer
- From the Department of Neurology (M.W., M.A.R., G.R.F., M.S.), University Hospital, Cologne, Germany; Max Planck Institute for Neurological Research (M.W., H.B., M.A.R., B.N., H.E., M.H., M.S., R.G.), Cologne, Germany; and the Institute of Neuroscience and Medicine (INM-3; G.R.F.), Cognitive Neurology Section, Research Centre Juelich, Juelich, Germany
| | - Heiko Backes
- From the Department of Neurology (M.W., M.A.R., G.R.F., M.S.), University Hospital, Cologne, Germany; Max Planck Institute for Neurological Research (M.W., H.B., M.A.R., B.N., H.E., M.H., M.S., R.G.), Cologne, Germany; and the Institute of Neuroscience and Medicine (INM-3; G.R.F.), Cognitive Neurology Section, Research Centre Juelich, Juelich, Germany
| | - Maria A. Rueger
- From the Department of Neurology (M.W., M.A.R., G.R.F., M.S.), University Hospital, Cologne, Germany; Max Planck Institute for Neurological Research (M.W., H.B., M.A.R., B.N., H.E., M.H., M.S., R.G.), Cologne, Germany; and the Institute of Neuroscience and Medicine (INM-3; G.R.F.), Cognitive Neurology Section, Research Centre Juelich, Juelich, Germany
| | - Bernd Neumaier
- From the Department of Neurology (M.W., M.A.R., G.R.F., M.S.), University Hospital, Cologne, Germany; Max Planck Institute for Neurological Research (M.W., H.B., M.A.R., B.N., H.E., M.H., M.S., R.G.), Cologne, Germany; and the Institute of Neuroscience and Medicine (INM-3; G.R.F.), Cognitive Neurology Section, Research Centre Juelich, Juelich, Germany
| | - Heike Endepols
- From the Department of Neurology (M.W., M.A.R., G.R.F., M.S.), University Hospital, Cologne, Germany; Max Planck Institute for Neurological Research (M.W., H.B., M.A.R., B.N., H.E., M.H., M.S., R.G.), Cologne, Germany; and the Institute of Neuroscience and Medicine (INM-3; G.R.F.), Cognitive Neurology Section, Research Centre Juelich, Juelich, Germany
| | - Mathias Hoehn
- From the Department of Neurology (M.W., M.A.R., G.R.F., M.S.), University Hospital, Cologne, Germany; Max Planck Institute for Neurological Research (M.W., H.B., M.A.R., B.N., H.E., M.H., M.S., R.G.), Cologne, Germany; and the Institute of Neuroscience and Medicine (INM-3; G.R.F.), Cognitive Neurology Section, Research Centre Juelich, Juelich, Germany
| | - Gereon R. Fink
- From the Department of Neurology (M.W., M.A.R., G.R.F., M.S.), University Hospital, Cologne, Germany; Max Planck Institute for Neurological Research (M.W., H.B., M.A.R., B.N., H.E., M.H., M.S., R.G.), Cologne, Germany; and the Institute of Neuroscience and Medicine (INM-3; G.R.F.), Cognitive Neurology Section, Research Centre Juelich, Juelich, Germany
| | - Michael Schroeter
- From the Department of Neurology (M.W., M.A.R., G.R.F., M.S.), University Hospital, Cologne, Germany; Max Planck Institute for Neurological Research (M.W., H.B., M.A.R., B.N., H.E., M.H., M.S., R.G.), Cologne, Germany; and the Institute of Neuroscience and Medicine (INM-3; G.R.F.), Cognitive Neurology Section, Research Centre Juelich, Juelich, Germany
| | - Rudolf Graf
- From the Department of Neurology (M.W., M.A.R., G.R.F., M.S.), University Hospital, Cologne, Germany; Max Planck Institute for Neurological Research (M.W., H.B., M.A.R., B.N., H.E., M.H., M.S., R.G.), Cologne, Germany; and the Institute of Neuroscience and Medicine (INM-3; G.R.F.), Cognitive Neurology Section, Research Centre Juelich, Juelich, Germany
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Noninvasive Measurements of Cerebral Blood Flow, Oxygen Extraction Fraction, and Oxygen Metabolic Index in Human with Inhalation of Air and Carbogen using Magnetic Resonance Imaging. Transl Stroke Res 2011; 3:246-54. [PMID: 24323780 DOI: 10.1007/s12975-011-0142-9] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2011] [Revised: 11/16/2011] [Accepted: 12/15/2011] [Indexed: 10/14/2022]
Abstract
Noninvasive magnetic resonance (MR) methods have been explored to provide quantitative measurements of cerebral blood flow (CBF), oxygen extraction fraction (OEF), and oxygen metabolic index (OMI = CBF × OEF). In this study, we sought to evaluate whether MR measured OEF, CBF, and OMI can consistently detect the expected physiological changes in humans under normal and hyperoxic hypercapnic conditions. Nine healthy human subjects were scanned while breathing through a mask, alternating inhaled gas in a sequential order as room air, carbogen (3% CO2 mixed with 97% O2), room air, carbogen, and room air. OEF, CBF, and OMI were obtained from the whole brain, gray matter (GM), and white matter (WM) at each gas inhalation state. Similar to previous positron emission tomography findings, our study consistently demonstrated a 10-12% decrease in OEF with a 10% increase of CBF and a stable OMI during carbogen inhalation. Moreover, GM/WM ratio in CBF and OMI remained constant during air and carbogen breathing. In addition, OEF, CBF, and OMI were highly reproducible if the same inhaled gas was used. In summary, our results demonstrate that noninvasive MR measurements can provide reproducible measurements of OEF, CBF, and OMI in normal subjects under normal and altered physiological conditions.
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45
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An H, Liu Q, Chen Y, Vo KD, Ford AL, Lee JM, Lin W. Oxygen metabolism in ischemic stroke using magnetic resonance imaging. Transl Stroke Res 2011; 3:65-75. [PMID: 24323755 DOI: 10.1007/s12975-011-0141-x] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2011] [Revised: 12/01/2011] [Accepted: 12/05/2011] [Indexed: 12/22/2022]
Abstract
Detecting "at-risk" but potentially salvageable brain tissue, known as the ischemic penumbra, is of importance for identifying patients who may benefit from thrombolytic or other treatments beyond the currently FDA-approved short therapeutic window for tissue plasminogen activator. Since the magnetic resonance blood oxygenation level-dependent (BOLD) contrast may provide information concerning tissue oxygen metabolism, its utilization in ischemic stroke has been explored. The focus of this review is to provide an introduction of several BOLD-based methods, including susceptibility-weighted imaging, R2 BOLD, R2*, R2', MR_OEF, and MR_OMI approaches to assess cerebral oxygenation changes induced by ischemia. Specifically, we will review the underlying pathophysiological basis of the imaging approaches, followed by a brief introduction of BOLD contrast, and finally the applications of BOLD approaches in ischemic stroke. The advantages and disadvantages of each method are addressed. In summary, the BOLD-based methods are promising for imaging oxygenation in ischemic tissue. Future steps would include technical refinement and vigorous validation against another independent method, such as positron emission tomography.
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Affiliation(s)
- Hongyu An
- Department of Radiology and Biomedical Research Imaging Center, CB#7513, University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599, USA,
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46
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An H, Liu Q, Eldeniz C, Lin W. Absolute oxygenation metabolism measurements using magnetic resonance imaging. Open Neuroimag J 2011; 5:120-35. [PMID: 22276084 PMCID: PMC3256581 DOI: 10.2174/1874440001105010120] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2011] [Revised: 02/02/2011] [Accepted: 03/03/2011] [Indexed: 11/29/2022] Open
Abstract
Cerebral oxygen metabolism plays a critical role in maintaining normal function of the brain. It is the primary energy source to sustain neuronal functions. Abnormalities in oxygen metabolism occur in various neuro-pathologic conditions such as ischemic stroke, cerebral trauma, cancer, Alzheimer’s disease and shock. Therefore, the ability to quantitatively measure tissue oxygenation and oxygen metabolism is essential to the understanding of pathophysiology and treatment of various diseases. The focus of this review is to provide an introduction of various blood oxygenation level dependent (BOLD) contrast methods for absolute measurements of tissue oxygenation, including both magnitude and phase image based approaches. The advantages and disadvantages of each method are discussed.
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Affiliation(s)
- Hongyu An
- Department of Radiology and Biomedical Research Imaging Center, University of North Carolina at Chapel Hill, USA
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47
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Heiss WD. The ischemic penumbra: correlates in imaging and implications for treatment of ischemic stroke. The Johann Jacob Wepfer award 2011. Cerebrovasc Dis 2011; 32:307-20. [PMID: 21921593 DOI: 10.1159/000330462] [Citation(s) in RCA: 105] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
The concept of the ischemic penumbra was formulated 30 years ago based on experiments in animal models showing functional impairment and electrophysiological disturbances with decreasing flow to the brain below defined values (the threshold for function) and irreversible tissue damage with the blood supply further decreased (the threshold for infarction). The perfusion range between these thresholds was termed 'penumbra', and restitution of flow above the functional threshold was able to reverse the deficits without permanent damage. However, in further experiments, the dependency of the development of irreversible lesions on the interaction of the severity and duration of critically reduced blood flow was established - proving that the lower the flow, the shorter the time for efficient reperfusion. Therefore, infarction develops from the core of ischemia to the areas of less severe hypoperfusion. The propagation of irreversible tissue damage is characterized by a complex cascade of interconnected electrophysiological, molecular, metabolic and perfusional disturbances. Waves of depolarizations, the peri-infarct spreading depression-like depolarizations, inducing activation of ion pumps and liberation of excitatory transmitters, have dramatic consequences as drastically increased metabolic demand cannot be satisfied in regions with critically reduced blood supply. The translation of experimental concept into the basis for efficient treatment of stroke requires non-invasive methods by which regional flow and energy metabolism can be repeatedly investigated to demonstrate penumbra tissue that can benefit from therapeutic interventions. Positron emission tomography (PET) allows the quantification of regional cerebral blood flow, the regional metabolic rate for oxygen and the regional oxygen extraction fraction. From these variables, clear definitions of irreversible tissue damage and critically perfused but potentially salvageable tissue (i.e. the penumbra) can be achieved in animal models and stroke patients. Additionally, further tracers can be used for early detection of irreversible tissue damage, e.g. by the central benzodiazepine receptor ligand flumazenil. However, PET is a research tool and its complex logistics limit clinical routine applications. As a widely applicable clinical tool, perfusion/diffusion-weighted (PW/DW) MRI is used, and the 'mismatch' between the PW and the DW abnormalities serve as an indicator of the penumbra. However, comparative studies of PW/DW-MRI and PET have pointed to an overestimation of the core of irreversible infarction as well as of the penumbra by MRI modalities. Some of these discrepancies can be explained by unselective application of relative perfusion thresholds, which might be improved by more complex analytical procedures. Heterogeneity of the MRI signatures used for the definition of the mismatch are also responsible for disappointing results in the application of PW/DW-MRI for the selection of patients for clinical trials. As long as a validation of the mismatch selection paradigm is lacking, its use as a surrogate marker of outcome is limited.
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48
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Abstract
Original experimental studies in nonhuman primate models of focal ischemia showed flow-related changes in evoked potentials that suggested a circumferential zone of low regional cerebral blood flow with normal K(+) homeostasis, around a core of permanent injury in the striatum or the cortex. This became the basis for the definition of the ischemic penumbra. Imaging techniques of the time suggested a homogeneous core of injury, while positing a surrounding 'penumbral' region that could be salvaged. However, both molecular studies and observations of vascular integrity indicate a more complex and dynamic situation in the ischemic core that also changes with time. The microvascular, cellular, and molecular events in the acute setting are compatible with heterogeneity of the injury within the injury center, which at early time points can be described as multiple 'mini-cores' associated with multiple 'mini-penumbras'. These observations suggest the progression of injury from many small foci to a homogeneous defect over time after the onset of ischemia. Recent observations with updated imaging techniques and data processing support these dynamic changes within the core and the penumbra in humans following focal ischemia.
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Affiliation(s)
- Gregory J del Zoppo
- Department of Medicine (Division of Hematology), University of Washington School of Medicine, Seattle, Washington 98104, USA.
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49
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Rosso C, Colliot O, Valabrègue R, Crozier S, Dormont D, Lehéricy S, Samson Y. Tissue at risk in the deep middle cerebral artery territory is critical to stroke outcome. Neuroradiology 2011; 53:763-71. [DOI: 10.1007/s00234-011-0916-5] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2011] [Accepted: 07/08/2011] [Indexed: 10/18/2022]
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50
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Backes H, Walberer M, Endepols H, Neumaier B, Graf R, Wienhard K, Mies G. Whiskers area as extracerebral reference tissue for quantification of rat brain metabolism using (18)F-FDG PET: application to focal cerebral ischemia. J Nucl Med 2011; 52:1252-60. [PMID: 21764786 DOI: 10.2967/jnumed.110.085266] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
UNLABELLED Diseases and dysfunction of the central nervous system are often associated with regional changes in cerebral glucose metabolism, which can be measured in vivo by PET using (18)F-FDG as the tracer. For quantification, the arterial tracer input function must be determined. For rodents in particular, direct measurement of blood radioactivity concentration is scarcely feasible for follow-up of individual animals because of the invasiveness of blood sampling. We show that the whiskers area of the rat's muzzle serves as an extracerebral reference region. The derived model also takes into account local variations of the lumped constant, which is crucial in pathologic tissue. METHODS In 11 rats, the reference tissue kinetic parameters were determined from PET data and measured whole blood radioactivity concentration. Parametric images of cerebral kinetic rate constants were calculated using the directly measured input function, the reference tissue time-activity curve with individually fitted reference kinetic parameters, and the reference time-activity curve with fixed reference kinetic parameters calculated from the fitted parameters averaged over all animals. The need for kinetic modeling in disease models is demonstrated in 5 rats subjected to acute focal cerebral ischemia. (18)F-FDG metabolism and transport rate constants and local cerebral glucose metabolic rates were calculated. RESULTS Cerebral kinetic constants derived from the 3 methods corresponded closely. The maximum difference in whole-brain kinetic parameters observed between the directly measured input function and the reference tissue time-activity curve with individually fitted reference kinetic parameters was less than 5%. Taking fixed reference parameters (the reference time-activity curve with fixed reference kinetic parameters calculated from the fitted parameters averaged over all animals) still provided whole-brain kinetic parameters with an accuracy of approximately 90%. In the rats subjected to focal cerebral ischemia, (18)F-FDG kinetic parameters in healthy tissue were not significantly different from whole-brain kinetic parameters in naive rats. The ischemic region was characterized by preserved glucose metabolism, although (18)F-FDG uptake was elevated significantly-that is, the lumped constant in the ischemic region was different from that of healthy brain tissue. CONCLUSION The method presented here allows for the quantitative noninvasive determination of cerebral glucose consumption in rats, takes into account local variations of the lumped constant, and is suitable for follow-up measurements of individuals.
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Affiliation(s)
- Heiko Backes
- Max Planck Institute for Neurological Research, Cologne, Germany.
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