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Jiang M, Cao F, Zhang Q, Qi Z, Gao Y, Zhang Y, Song B, Wu C, Li M, Xu Y, Zhang X, Wang Y, Wei M, Ji X. Model-predicted brain temperature computational imaging by multimodal noninvasive functional neuromonitoring of cerebral oxygen metabolism and hemodynamics: MRI-derived and clinical validation. J Cereb Blood Flow Metab 2024:271678X241270485. [PMID: 39129194 DOI: 10.1177/0271678x241270485] [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: 08/13/2024]
Abstract
Brain temperature, a crucial yet under-researched neurophysiological parameter, is governed by the equilibrium between cerebral oxygen metabolism and hemodynamics. Therapeutic hypothermia has been demonstrated as an effective intervention for acute brain injuries, enhancing survival rates and prognosis. The success of this treatment hinges on the precise regulation of brain temperature. However, the absence of comprehensive brain temperature monitoring methods during therapy, combined with a limited understanding of human brain heat transmission mechanisms, significantly hampers the advancement of hypothermia-based neuroprotective therapies. Leveraging the principles of bioheat transfer and MRI technology, this study conducted quantitative analyses of brain heat transfer during mild hypothermia therapy. Utilizing MRI, we reconstructed brain structures, estimated cerebral blood flow and oxygen consumption parameters, and developed a brain temperature calculation model founded on bioheat transfer theory. Employing computational cerebral hemodynamic simulation analysis, we established an intracranial arterial fluid dynamics model to predict brain temperature variations across different therapeutic hypothermia modalities. We introduce a noninvasive, spatially resolved, and optimized mathematical bio-heat model that synergizes model-predicted and MRI-derived data for brain temperature prediction and imaging. Our findings reveal that the brain temperature images generated by our model reflect distinct spatial variations across individual participants, aligning with experimentally observed temperatures.
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Affiliation(s)
- Miaowen Jiang
- Beijing Institute for Brain Disorders, Capital Medical University, Beijing, 100069, China
| | - Fuzhi Cao
- School of Engineering Medicine, Beihang University, Beijing 100083, China
| | - Qihan Zhang
- Department of Neurology and Neurosurgery, Xuanwu Hospital, Capital Medical University, Beijing 100053, China
| | - Zhengfei Qi
- Beijing Institute for Brain Disorders, Capital Medical University, Beijing, 100069, China
| | - Yuan Gao
- School of Engineering Medicine, Beihang University, Beijing 100083, China
| | - Yang Zhang
- Department of Neurology and Neurosurgery, Xuanwu Hospital, Capital Medical University, Beijing 100053, China
| | - Baoyin Song
- Department of Neurology and Neurosurgery, Xuanwu Hospital, Capital Medical University, Beijing 100053, China
| | - Chuanjie Wu
- Department of Neurology and Neurosurgery, Xuanwu Hospital, Capital Medical University, Beijing 100053, China
| | - Ming Li
- China-America Institute of Neuroscience and Beijing Institute of Geriatrics, Xuanwu Hospital, Capital Medical University, Beijing 100053, China
| | - Yongbo Xu
- Clinical College of Neurology, Neurosurgery and Neurorehabilitation, Tianjin Medical University, Tianjin 300203, China
| | - Xin Zhang
- Brainnetome Center, Laboratory of Brain Atlas and Brain-inspired Intelligence, Institute of Automation, Chinese Academy of Sciences, Beijing 100190, China
| | - Yuan Wang
- Department of Neurology and Neurosurgery, Xuanwu Hospital, Capital Medical University, Beijing 100053, China
| | - Ming Wei
- Beijing Institute for Brain Disorders, Capital Medical University, Beijing, 100069, China
- Clinical College of Neurology, Neurosurgery and Neurorehabilitation, Tianjin Medical University, Tianjin 300203, China
- Tianjin University, Tianjin Huanhu Hospital, Tianjin 300203, China
| | - Xunming Ji
- Beijing Institute for Brain Disorders, Capital Medical University, Beijing, 100069, China
- Department of Neurology and Neurosurgery, Xuanwu Hospital, Capital Medical University, Beijing 100053, China
- China-America Institute of Neuroscience and Beijing Institute of Geriatrics, Xuanwu Hospital, Capital Medical University, Beijing 100053, China
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Rehman S, Nadeem A, Akram U, Sarwar A, Quraishi A, Siddiqui H, Malik MAJ, Nabi M, Ul Haq I, Cho A, Mazumdar I, Kim M, Chen K, Sepehri S, Wang R, Balar AB, Lakhani DA, Yedavalli VS. Molecular Mechanisms of Ischemic Stroke: A Review Integrating Clinical Imaging and Therapeutic Perspectives. Biomedicines 2024; 12:812. [PMID: 38672167 PMCID: PMC11048412 DOI: 10.3390/biomedicines12040812] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/29/2024] [Revised: 03/28/2024] [Accepted: 04/01/2024] [Indexed: 04/28/2024] Open
Abstract
Ischemic stroke poses a significant global health challenge, necessitating ongoing exploration of its pathophysiology and treatment strategies. This comprehensive review integrates various aspects of ischemic stroke research, emphasizing crucial mechanisms, therapeutic approaches, and the role of clinical imaging in disease management. It discusses the multifaceted role of Netrin-1, highlighting its potential in promoting neurovascular repair and mitigating post-stroke neurological decline. It also examines the impact of blood-brain barrier permeability on stroke outcomes and explores alternative therapeutic targets such as statins and sphingosine-1-phosphate signaling. Neurocardiology investigations underscore the contribution of cardiac factors to post-stroke mortality, emphasizing the importance of understanding the brain-heart axis for targeted interventions. Additionally, the review advocates for early reperfusion and neuroprotective agents to counter-time-dependent excitotoxicity and inflammation, aiming to preserve tissue viability. Advanced imaging techniques, including DWI, PI, and MR angiography, are discussed for their role in evaluating ischemic penumbra evolution and guiding therapeutic decisions. By integrating molecular insights with imaging modalities, this interdisciplinary approach enhances our understanding of ischemic stroke and offers promising avenues for future research and clinical interventions to improve patient outcomes.
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Affiliation(s)
- Sana Rehman
- Russell H. Morgan Department of Radiology and Radiological Sciences, Johns Hopkins School of Medicine, Baltimore, MD 21205, USA; (M.N.); (A.C.); (I.M.); (M.K.); (K.C.); (S.S.); (R.W.); (A.B.B.); (D.A.L.); (V.S.Y.)
| | - Arsalan Nadeem
- Department of Medicine, Allama Iqbal Medical College, Lahore 54700, Pakistan;
| | - Umar Akram
- Department of Medicine, Allama Iqbal Medical College, Lahore 54700, Pakistan;
| | - Abeer Sarwar
- Department of Medicine, Fatima Memorial Hospital College of Medicine and Dentistry, Lahore 54000, Pakistan; (A.S.); (H.S.)
| | - Ammara Quraishi
- Department of Medicine, Dow University of Health Sciences, Karachi 74200, Pakistan;
| | - Hina Siddiqui
- Department of Medicine, Fatima Memorial Hospital College of Medicine and Dentistry, Lahore 54000, Pakistan; (A.S.); (H.S.)
| | | | - Mehreen Nabi
- Russell H. Morgan Department of Radiology and Radiological Sciences, Johns Hopkins School of Medicine, Baltimore, MD 21205, USA; (M.N.); (A.C.); (I.M.); (M.K.); (K.C.); (S.S.); (R.W.); (A.B.B.); (D.A.L.); (V.S.Y.)
| | - Ihtisham Ul Haq
- Department of Medicine, Amna Inayat Medical College, Sheikhupura 54300, Pakistan;
| | - Andrew Cho
- Russell H. Morgan Department of Radiology and Radiological Sciences, Johns Hopkins School of Medicine, Baltimore, MD 21205, USA; (M.N.); (A.C.); (I.M.); (M.K.); (K.C.); (S.S.); (R.W.); (A.B.B.); (D.A.L.); (V.S.Y.)
| | - Ishan Mazumdar
- Russell H. Morgan Department of Radiology and Radiological Sciences, Johns Hopkins School of Medicine, Baltimore, MD 21205, USA; (M.N.); (A.C.); (I.M.); (M.K.); (K.C.); (S.S.); (R.W.); (A.B.B.); (D.A.L.); (V.S.Y.)
| | - Minsoo Kim
- Russell H. Morgan Department of Radiology and Radiological Sciences, Johns Hopkins School of Medicine, Baltimore, MD 21205, USA; (M.N.); (A.C.); (I.M.); (M.K.); (K.C.); (S.S.); (R.W.); (A.B.B.); (D.A.L.); (V.S.Y.)
| | - Kevin Chen
- Russell H. Morgan Department of Radiology and Radiological Sciences, Johns Hopkins School of Medicine, Baltimore, MD 21205, USA; (M.N.); (A.C.); (I.M.); (M.K.); (K.C.); (S.S.); (R.W.); (A.B.B.); (D.A.L.); (V.S.Y.)
| | - Sadra Sepehri
- Russell H. Morgan Department of Radiology and Radiological Sciences, Johns Hopkins School of Medicine, Baltimore, MD 21205, USA; (M.N.); (A.C.); (I.M.); (M.K.); (K.C.); (S.S.); (R.W.); (A.B.B.); (D.A.L.); (V.S.Y.)
| | - Richard Wang
- Russell H. Morgan Department of Radiology and Radiological Sciences, Johns Hopkins School of Medicine, Baltimore, MD 21205, USA; (M.N.); (A.C.); (I.M.); (M.K.); (K.C.); (S.S.); (R.W.); (A.B.B.); (D.A.L.); (V.S.Y.)
| | - Aneri B. Balar
- Russell H. Morgan Department of Radiology and Radiological Sciences, Johns Hopkins School of Medicine, Baltimore, MD 21205, USA; (M.N.); (A.C.); (I.M.); (M.K.); (K.C.); (S.S.); (R.W.); (A.B.B.); (D.A.L.); (V.S.Y.)
| | - Dhairya A. Lakhani
- Russell H. Morgan Department of Radiology and Radiological Sciences, Johns Hopkins School of Medicine, Baltimore, MD 21205, USA; (M.N.); (A.C.); (I.M.); (M.K.); (K.C.); (S.S.); (R.W.); (A.B.B.); (D.A.L.); (V.S.Y.)
| | - Vivek S. Yedavalli
- Russell H. Morgan Department of Radiology and Radiological Sciences, Johns Hopkins School of Medicine, Baltimore, MD 21205, USA; (M.N.); (A.C.); (I.M.); (M.K.); (K.C.); (S.S.); (R.W.); (A.B.B.); (D.A.L.); (V.S.Y.)
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Jiang M, Li M, Gao Y, Wu L, Zhao W, Li C, Hou C, Qi Z, Wang K, Zheng S, Yin Z, Wu C, Ji X. The intra-arterial selective cooling infusion system: A mathematical temperature analysis and in vitro experiments for acute ischemic stroke therapy. CNS Neurosci Ther 2022; 28:1303-1314. [PMID: 35702957 PMCID: PMC9344093 DOI: 10.1111/cns.13883] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2022] [Revised: 04/27/2022] [Accepted: 05/13/2022] [Indexed: 11/28/2022] Open
Abstract
INTRODUCTION The neuroprotection of acute ischemic stroke patients can be achieved by intra-arterial selective cooling infusion using cold saline, which can decrease brain temperature without influencing the body core temperature. This approach can lead to high burdens on the heart and decreased hematocrit in the scenario of loading a high amount of liquid for longtime usage. Therefore, autologous blood is utilized as perfusate to circumvent those side effects. METHODS In this study, a prototype instrument with an autologous blood cooling system was developed and further evaluated by a mathematical model for brain temperature estimation. RESULTS Hypothermia could be achieved due to the adequate cooling capacity of the prototype system, which could provide the lowest cooling temperature into the blood vessel of 10.5°C at 25 rpm (209.7 ± 0.8 ml/min). And, the core body temperature did not alter significantly (-0.7 ~ -0.2°C) after 1-h perfusion. The cooling rate and temperature distributions of the brain were analyzed, which showed a 2°C decrease within the initial 5 min infusion by 44 ml/min and 13.7°C perfusate. CONCLUSION This prototype instrument system could safely cool simulated blood in vitro and reperfuse it to the target cerebral blood vessel. This technique could promote the clinical application of an autologous blood perfusion system for stroke therapy.
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Affiliation(s)
- Miaowen Jiang
- School of Instrumentation and Optoelectronic EngineeringBeihang UniversityBeijingChina
- Beijing Institute of Geriatrics, Xuanwu HospitalCapital Medical UniversityBeijingChina
| | - Ming Li
- Beijing Institute of Geriatrics, Xuanwu HospitalCapital Medical UniversityBeijingChina
| | - Yuan Gao
- School of Instrumentation and Optoelectronic EngineeringBeihang UniversityBeijingChina
| | - Longfei Wu
- Beijing Institute of Geriatrics, Xuanwu HospitalCapital Medical UniversityBeijingChina
- Department of Neurosurgery, Xuanwu HospitalCapital Medical UniversityBeijingChina
| | - Wenbo Zhao
- Beijing Institute of Geriatrics, Xuanwu HospitalCapital Medical UniversityBeijingChina
- Department of Neurosurgery, Xuanwu HospitalCapital Medical UniversityBeijingChina
| | - Chuanhui Li
- Beijing Institute of Geriatrics, Xuanwu HospitalCapital Medical UniversityBeijingChina
- Department of Neurosurgery, Xuanwu HospitalCapital Medical UniversityBeijingChina
| | - Chengbei Hou
- Center for Evidence‐Based Medicine, Xuanwu HospitalCapital Medical UniversityBeijingChina
| | - Zhengfei Qi
- Beijing Institute for Brain DisordersCapital Medical UniversityBeijingChina
| | - Kun Wang
- School of Instrumentation and Optoelectronic EngineeringBeihang UniversityBeijingChina
| | - Shiqiang Zheng
- School of Instrumentation and Optoelectronic EngineeringBeihang UniversityBeijingChina
| | - Zhichen Yin
- Beijing Institute of Geriatrics, Xuanwu HospitalCapital Medical UniversityBeijingChina
- Beijing Institute for Brain DisordersCapital Medical UniversityBeijingChina
| | - Chuanjie Wu
- Beijing Institute of Geriatrics, Xuanwu HospitalCapital Medical UniversityBeijingChina
- Department of Neurosurgery, Xuanwu HospitalCapital Medical UniversityBeijingChina
| | - Xunming Ji
- School of Instrumentation and Optoelectronic EngineeringBeihang UniversityBeijingChina
- Beijing Institute of Geriatrics, Xuanwu HospitalCapital Medical UniversityBeijingChina
- Department of Neurosurgery, Xuanwu HospitalCapital Medical UniversityBeijingChina
- Beijing Institute for Brain DisordersCapital Medical UniversityBeijingChina
- BUAA‐CCMU Advanced Innovation Center for Big Data‐based Precision MedicineBeihang UniversityBeijingChina
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Jiang M, Gao Y, Wu C, Wu L, Tang S, Yin Z, Li A, Wang K, Zheng S, Lee H, Ding Y, Li M, Ji X. The blood heat exchanger in intra-arterial selective cooling infusion for acute ischemic stroke: A computational fluid-thermodynamics performance, experimental assessment and evaluation on the brain temperature. Comput Biol Med 2022; 145:105497. [DOI: 10.1016/j.compbiomed.2022.105497] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2022] [Revised: 04/01/2022] [Accepted: 04/03/2022] [Indexed: 02/07/2023]
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Systemic Administration of the TLR7/8 Agonist Resiquimod (R848) to Mice Is Associated with Transient, In Vivo-Detectable Brain Swelling. BIOLOGY 2022; 11:biology11020274. [PMID: 35205140 PMCID: PMC8869423 DOI: 10.3390/biology11020274] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/06/2022] [Revised: 01/24/2022] [Accepted: 01/26/2022] [Indexed: 11/17/2022]
Abstract
Peripheral administration of the E. coli endotoxin lipopolysaccharide (LPS) to rats promotes secretion of pro-inflammatory cytokines and in previous studies was associated with transient enlargement of cortical volumes. Here, resiquimod (R848) was administered to mice to stimulate peripheral immune activation, and the effects on brain volumes and neurometabolites determined. After baseline scans, 24 male, wild-type C57BL mice were triaged into three groups including R848 at low (50 μg) and high (100 μg) doses and saline controls. Animals were scanned again at 3 h and 24 h following treatment. Sickness indices of elevated temperature and body weight loss were observed in all R848 animals. Animals that received 50 μg R848 exhibited decreases in hippocampal N-acetylaspartate and phosphocreatine at the 3 h time point that returned to baseline levels at 24 h. Animals that received the 100 μg R848 dose demonstrated transient, localized, volume expansion (~5%) detectable at 3 h in motor, somatosensory, and olfactory cortices; and pons. A metabolic response evident at the lower dose and a volumetric change at the higher dose suggests a temporal evolution of the effect wherein the neurochemical change is demonstrable earlier than neurostructural change. Transient volume expansion in response to peripheral immune stimulation corresponds with previous results and is consistent with brain swelling that may reflect CNS edema.
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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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Jiang M, Li M, Gao Y, Yin Z, Ding Y, Zheng Y, Zheng S, Wu C, Li A, Fang J, Ji X. Design and evaluation of an air-insulated catheter for intra-arterial selective cooling infusion from numerical simulation and in vitro experiment. Med Eng Phys 2022; 99:103736. [DOI: 10.1016/j.medengphy.2021.103736] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2021] [Revised: 11/13/2021] [Accepted: 12/05/2021] [Indexed: 11/26/2022]
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Identification of penumbra in acute ischemic stroke using multimodal MR imaging analysis: A case report study. Radiol Case Rep 2020; 15:2041-2046. [PMID: 32922584 PMCID: PMC7475068 DOI: 10.1016/j.radcr.2020.07.066] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2020] [Revised: 07/21/2020] [Accepted: 07/24/2020] [Indexed: 11/24/2022] Open
Abstract
Ischemic etiology of stroke is the most common health issue. Differentiating the ischemic core from the associated penumbra is tremendously important in tailoring an effective therapeutic strategy and potential intervention. Additionally, the degree of cell damage adjacent to the ischemic core may be either reversible or irreversible, which may also affect clinical outcomes. We describe a case of a 58-year-old female, who was diagnosed with global aphasia and fluctuating right-sided hypoesthesia. Multimodal MR imaging analysis was obtained, with cerebral blood flow and mean transit time , demonstrating an infarcted core with an even larger penumbra, suggesting potentially salvageable tissue. We concluded that quantified perfusion imaging data should be used in combination with other MR protocols to determine at-risk tissues. This case substantiates the role of multimodal imaging of the penumbra as a routine part of acute stroke workup and management.
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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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Karaszewski B, Jabłoński B, Żukowicz W. The salvageable brain in acute ischemic stroke. The concept of a reverse mismatch: a mini-review. Metab Brain Dis 2020; 35:237-240. [PMID: 31858389 DOI: 10.1007/s11011-019-00517-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/26/2019] [Accepted: 11/14/2019] [Indexed: 02/07/2023]
Abstract
Recent studies have opened a new era in treatment of acute ischemic stroke, enabling thrombolysis or thrombectomy far beyond the standard therapeutic "time windows". These therapeutic protocols are built on various combinations of perfusion parameters, lesion volume, and neurological assessment. However, on top of the brain perfusion, there are other multiple factors that might modify the probability of neuronal apoptosis and necrosis following focal cerebral ischemia. We hypothesize that a diagnostic approach with measurements of selected biochemical parameters in the brain, in addition to those based solely on perfusion or MR diffusion, might allow for more personalized management protocols. Moreover, some local processes in the brain, triggered by acute ischemia or its consequences other than hypoperfusion directly, like, for example, excitotoxicity, might lead to apoptosis of the cells in the brain localized also beyond the area of hypoperfusion. This phenomenon might be responsible for the expansion of the brain damage much beyond the initial perfusion deficit or beyond the initial diffusion (DWI) restriction area, reported for example in T2W or FLAIR MRI in some stroke patients who have no other reasons to deteriorate (a reverse DWI - T2W / FLAIR, a reverse perfusion - DWI, or a reverse DWI - DWI mismatch).
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Affiliation(s)
- Bartosz Karaszewski
- Department (Chair) of Neurology, Medical University of Gdansk, Gdansk, Poland.
- Department of Adult Neurology, Medical University of Gdansk and University Clinical Center in Gdansk, ul. Dębinki 7, 80-952, Gdańsk, Poland.
- The Main Expert in Stroke Medicine for the Polish Ministry of Health, Warsaw, Poland.
| | - Bartosz Jabłoński
- Department (Chair) of Neurology, Medical University of Gdansk, Gdansk, Poland
- Department of Adult Neurology, Medical University of Gdansk and University Clinical Center in Gdansk, ul. Dębinki 7, 80-952, Gdańsk, Poland
| | - Wioletta Żukowicz
- Department (Chair) of Neurology, Medical University of Gdansk, Gdansk, Poland
- Department of Adult Neurology, Medical University of Gdansk and University Clinical Center in Gdansk, ul. Dębinki 7, 80-952, Gdańsk, Poland
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Inducing therapeutic hypothermia via selective brain cooling: a finite element modeling analysis. Med Biol Eng Comput 2019; 57:1313-1322. [PMID: 30756230 DOI: 10.1007/s11517-019-01962-7] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2018] [Accepted: 02/04/2019] [Indexed: 02/06/2023]
Abstract
Therapeutic hypothermia is a treatment method to reduce brain injuries after stroke, especially for cerebral ischemia. This study investigates in the temperature distribution of the head within selective brain cooling (SBC). Anatomically accurate geometries based on CT images of head and neck regions are used to develop the 3D geometry and physical model for the finite element modeling. Two cooling methods, the direct head surface cooling strategy and the combination cooling strategy of both head and neck, are evaluated to analyze the inducing hypothermia. The results show that for direct head surface cooling, the scalp and skull temperatures decrease significantly as the blood perfusion rate is constrained, but it is hard to affect the brain core temperature. To achieve a lower cerebral temperature, combination cooling strategy of both head and neck is an effective method in improving deep brain cooling. In normal condition, the cerebral temperature is reduced by about 0.12 °C in 60 min of hypothermia, while the temperature drop is approximately 0.98 °C in ischemic condition. Graphical abstract In this study, the 3D geometry of the head and carotid artery model based on the computed tomography (CT) were derived separately and the corresponding investigations were conducted to validate the reliability of the model. Direct head surface cooling strategy and the combination cooling strategy of both the head and neck were numerically researched.
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Wynn G, Gupta D, Maille B, Snowdon R, Waktare J, Todd D, Hall M, Mahida S, Modi S. Demonstration of pulmonary vein exit block following pulmonary vein isolation: A novel use for adenosine. J Cardiovasc Electrophysiol 2018; 29:1493-1499. [PMID: 30230085 DOI: 10.1111/jce.13744] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/26/2018] [Revised: 07/23/2018] [Accepted: 08/06/2018] [Indexed: 11/26/2022]
Abstract
INTRODUCTION Demonstration of exit block after pulmonary vein isolation (PVI) is the cornerstone of ablation for atrial fibrillation (AF). It requires the demonstration of local pulmonary vein (PV) capture and absence of conduction to the atrium but is often challenging due to the inability to see local paced PV-evoked potentials. We retrospectively examined the ability of adenosine to augment this technique during CARTO-based radiofrequency ablation procedures. METHODS Retrospective analysis of evoked PV potentials during adenosine administration while testing for PV exit block at a single UK center. RESULTS One hundred and twenty-nine PVs in 33 patients were isolated using radiofrequency energy to demonstrate entry block. Of those, the pacing of 24 veins under baseline conditions did not clearly demonstrate local PV-evoked potentials sufficient to be sure that the local vein was truly captured and dissociated from the atrium. Adenosine was administered in 19 of these, with 10 of 19 (52.6%) veins then demonstrating clear local PV-evoked potentials transiently during adenosine administration, sufficient to allow assessment of definite exit block. CONCLUSION Adenosine administered during PV pacing allows transient visualization of local PV-evoked potentials after PVI facilitating the clearer demonstration of PV exit block in over 50% veins.
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Affiliation(s)
- Gareth Wynn
- Liverpool Heart and Chest Hospital, Liverpool, UK
| | - Dhiraj Gupta
- Liverpool Heart and Chest Hospital, Liverpool, UK
| | | | | | | | - Derick Todd
- Liverpool Heart and Chest Hospital, Liverpool, UK
| | - Mark Hall
- Liverpool Heart and Chest Hospital, Liverpool, UK
| | | | - Simon Modi
- Liverpool Heart and Chest Hospital, Liverpool, UK
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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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Related Research and Recent Progress of Ischemic Penumbra. World Neurosurg 2018; 116:5-13. [DOI: 10.1016/j.wneu.2018.04.193] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2018] [Revised: 04/24/2018] [Accepted: 04/25/2018] [Indexed: 11/20/2022]
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15
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Kudomi N, Maeda Y, Yamamoto H, Yamamoto Y, Hatakeyama T, Nishiyama Y. Reconstruction of input functions from a dynamic PET image with sequential administration of 15O 2 and [Formula: see text] for noninvasive and ultra-rapid measurement of CBF, OEF, and CMRO 2. J Cereb Blood Flow Metab 2018; 38:780-792. [PMID: 28595496 PMCID: PMC5987943 DOI: 10.1177/0271678x17713574] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/02/2017] [Revised: 04/19/2017] [Accepted: 05/15/2017] [Indexed: 11/16/2022]
Abstract
CBF, OEF, and CMRO2 images can be quantitatively assessed using PET. Their image calculation requires arterial input functions, which require invasive procedure. The aim of the present study was to develop a non-invasive approach with image-derived input functions (IDIFs) using an image from an ultra-rapid O2 and C15O2 protocol. Our technique consists of using a formula to express the input using tissue curve with rate constants. For multiple tissue curves, the rate constants were estimated so as to minimize the differences of the inputs using the multiple tissue curves. The estimated rates were used to express the inputs and the mean of the estimated inputs was used as an IDIF. The method was tested in human subjects ( n = 24). The estimated IDIFs were well-reproduced against the measured ones. The difference in the calculated CBF, OEF, and CMRO2 values by the two methods was small (<10%) against the invasive method, and the values showed tight correlations ( r = 0.97). The simulation showed errors associated with the assumed parameters were less than ∼10%. Our results demonstrate that IDIFs can be reconstructed from tissue curves, suggesting the possibility of using a non-invasive technique to assess CBF, OEF, and CMRO2.
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Affiliation(s)
- Nobuyuki Kudomi
- Department of Medical Physics, Kagawa University, Kagawa, Japan
| | - Yukito Maeda
- Department of Radiology, Kagawa University Hospital, Kagawa, Japan
| | | | - Yuka Yamamoto
- Department of Radiology, Kagawa University, Kagawa, Japan
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16
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Li H, Chen RK, Tang Y, Meurer W, Shih AJ. An experimental study and finite element modeling of head and neck cooling for brain hypothermia. J Therm Biol 2017; 71:99-111. [PMID: 29301706 DOI: 10.1016/j.jtherbio.2017.10.022] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2017] [Revised: 10/31/2017] [Accepted: 10/31/2017] [Indexed: 11/28/2022]
Abstract
Reducing brain temperature by head and neck cooling is likely to be the protective treatment for humans when subjects to sudden cardiac arrest. This study develops the experimental validation model and finite element modeling (FEM) to study the head and neck cooling separately, which can induce therapeutic hypothermia focused on the brain. Anatomically accurate geometries based on CT images of the skull and carotid artery are utilized to find the 3D geometry for FEM to analyze the temperature distributions and 3D-printing to build the physical model for experiment. The results show that FEM predicted and experimentally measured temperatures have good agreement, which can be used to predict the temporal and spatial temperature distributions of the tissue and blood during the head and neck cooling process. Effects of boundary condition, perfusion, blood flow rate, and size of cooling area are studied. For head cooling, the cooling penetration depth is greatly depending on the blood perfusion in the brain. In the normal blood flow condition, the neck internal carotid artery temperature is decreased only by about 0.13°C after 60min of hypothermia. In an ischemic (low blood flow rate) condition, such temperature can be decreased by about 1.0°C. In conclusion, decreasing the blood perfusion and metabolic reduction factor could be more beneficial to cool the core zone. The results also suggest that more SBC researches should be explored, such as the optimization of simulation and experimental models, and to perform the experiment on human subjects.
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Affiliation(s)
- Hui Li
- Mechanical Engineering, University of Michigan, Ann Arbor, MI 48109, USA; Mechanical and Automotive Engineering, South China University of Technology, Guangzhou 510640, China; Electronic Paper Display Institute, South China Normal University, Guangzhou 510006, China.
| | - Roland K Chen
- Mechanical and Materials Engineering, Washington State University, Pullman, WA 99164-2920, USA
| | - Yong Tang
- Mechanical and Automotive Engineering, South China University of Technology, Guangzhou 510640, China
| | - William Meurer
- Department of Emergency Medicine, Department of Neurology, Michigan Center for Integrative Research in Critical Care, University of Michigan Health System, Ann Arbor, MI 48109-5303, USA
| | - Albert J Shih
- Mechanical Engineering, University of Michigan, Ann Arbor, MI 48109, USA
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17
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Noguchi K, Itoh T, Naruto N, Takashima S, Tanaka K, Kuroda S. A Novel Imaging Technique (X-Map) to Identify Acute Ischemic Lesions Using Noncontrast Dual-Energy Computed Tomography. J Stroke Cerebrovasc Dis 2016; 26:34-41. [PMID: 27639587 DOI: 10.1016/j.jstrokecerebrovasdis.2016.08.025] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2016] [Revised: 07/22/2016] [Accepted: 08/17/2016] [Indexed: 10/21/2022] Open
Abstract
BACKGROUND We evaluated whether X-map, a novel imaging technique, can visualize ischemic lesions within 20 hours after the onset in patients with acute ischemic stroke, using noncontrast dual-energy computed tomography (DECT). MATERIALS AND METHODS Six patients with acute ischemic stroke were included in this study. Noncontrast head DECT scans were acquired with 2 X-ray tubes operated at 80 kV and Sn150 kV between 32 minutes and 20 hours after the onset. Using these DECT scans, the X-map was reconstructed based on 3-material decomposition and compared with a simulated standard (120 kV) computed tomography (CT) and diffusion-weighted imaging (DWI). RESULTS The X-map showed more sensitivity to identify the lesions as an area of lower attenuation value than a simulated standard CT in all 6 patients. The lesions on the X-map correlated well with those on DWI. In 3 of 6 patients, the X-map detected a transient decrease in the attenuation value in the peri-infarct area within 1 day after the onset. CONCLUSIONS The X-map is a powerful tool to supplement a simulated standard CT and characterize acute ischemic lesions. However, the X-map cannot replace a simulated standard CT to diagnose acute cerebral infarction.
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Affiliation(s)
- Kyo Noguchi
- Departments of Radiology, Graduate School of Medicine and Pharmaceutical Science, University of Toyama, Toyama, Japan.
| | - Toshihide Itoh
- Department of Research & Collaboration, Siemens Healthcare, Tokyo, Japan
| | - Norihito Naruto
- Departments of Radiology, Graduate School of Medicine and Pharmaceutical Science, University of Toyama, Toyama, Japan
| | - Shutaro Takashima
- Department of Neurology, Graduate School of Medicine and Pharmaceutical Science, University of Toyama, Toyama, Japan
| | - Kortaro Tanaka
- Department of Neurology, Graduate School of Medicine and Pharmaceutical Science, University of Toyama, Toyama, Japan
| | - Satoshi Kuroda
- Department of Neurosurgery, Graduate School of Medicine and Pharmaceutical Science, University of Toyama, Toyama, Japan
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18
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Weller P, Wittsack HJ, Siebler M, Hömberg V, Seitz RJ. Motor Recovery as Assessed with Isometric Finger Movements and Perfusion Magnetic Resonance Imaging after Acute Ischemic Stroke. Neurorehabil Neural Repair 2016; 20:390-7. [PMID: 16885425 DOI: 10.1177/1545968305285037] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Objective. Recovery from hemiparetic stroke is variable. An important goal for clinicians and clinical researchers is to identify predictors of recovery. The initial phase after acute ischemic stroke is considered to be of major importance for neurological outcome. The authors sought to determine in patients with acute ischemic stroke whether early motor recovery, as measured by repetitive isometric index-thumb oppositions, is correlated with ischemic lesion volume. Methods. Thirty-six acute hemiparetic stroke patients with residual hand function were investigated. The European Stroke Scale (ESS) score was determined on admission and at discharge. Performance of repetitive index finger-thumb pinch movements was measured daily during the 1st 8 days after stroke onset. Brain ischemia volume was determined digitally in time-to-peak magnetic resonance images of per-fusion. Results. The recovery of patients with ( P = 0.002) and without ( P < 0.001) thrombolysis as assessed with the ESS was paralleled by an increase in isometric grip force and movement rate ( P < 0.05). Recovery was predicted by the area of moderately impaired perfusion indicated by the per-fusion mismatch volume ( r = 0.578, P < 0.001). Conclusions. In acute stroke, recovery of hand function is predicted by the volume of salvageable ischemic tissue, as determined by the perfusion mismatch.
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Affiliation(s)
- Patrick Weller
- Department of Neurology, University Hospital Düsseldorf, Düsseldorf, Germany
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19
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Abstract
Acute ischemic stroke is common and often treatable, but treatment requires reliable information on the state of the brain that may be provided by modern neuroimaging. Critical information includes: the presence of hemorrhage; the site of arterial occlusion; the size of the early infarct "core"; and the size of underperfused, potentially threatened brain parenchyma, commonly referred to as the "penumbra." In this chapter we review the major determinants of outcomes in ischemic stroke patients, and the clinical value of various advanced computed tomography and magnetic resonance imaging methods that may provide key physiologic information in these patients. The focus is on major strokes due to occlusions of large arteries of the anterior circulation, the most common cause of a severe stroke syndrome. The current evidence-based approach to imaging the acute stroke patient at the Massachusetts General Hospital is presented, which is applicable for all stroke types. We conclude with new information on time and stroke evolution that imaging has revealed, and how it may open the possibilities of treating many more patients.
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Affiliation(s)
- R Gilberto González
- Neuroradiology Division, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA.
| | - Lee H Schwamm
- Department of Neurology, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA
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20
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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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21
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Ozenne B, Cho TH, Mikkelsen IK, Hermier M, Ribe L, Thomalla G, Pedraza S, Baron JC, Roy P, Berthezène Y, Nighoghossian N, Østergaard L, Maucort-Boulch D. Evaluation of Early Reperfusion Criteria in Acute Ischemic Stroke. J Neuroimaging 2015; 25:952-8. [PMID: 25940773 DOI: 10.1111/jon.12255] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2014] [Revised: 03/26/2015] [Accepted: 03/27/2015] [Indexed: 11/26/2022] Open
Abstract
BACKGROUND AND PURPOSE Though still debated, early reperfusion is increasingly used as a biomarker for clinical outcome. However, the lack of a standard definition hinders the assessment of reperfusion therapies and study comparisons. The objective was to determine the optimal early reperfusion criteria that predicts clinical outcome in ischemic stroke. METHODS Early reperfusion was assessed voxel-wise in 57 patients within 6 hours of symptom onset. The performance of the time to peak (TTP), the mean transit time (MTT), and the time to maximum of residue function (Tmax ) at various delays thresholds in predicting the neurological response (based on the National Institutes of Health Stroke Scale) and the functional outcome (modified Rankin scale ≤1) at 1 month were compared. A receiver operating characteristics (ROC) analysis determined the optimal extent of reperfusion. A novel unsupervised classification of reperfusion using group-based trajectory modeling (GBTM) was evaluated. RESULTS MTT had a lower performance than TTP and Tmax in predicting the neurological response (P = .008 vs. TTP and P = .006 vs. Tmax ) or the functional outcome (P = .0006 vs. TTP; P = .002 vs. Tmax ). No delay threshold had a significantly higher predictive value than another. The optimal percentage of reperfusion was dependent on the outcome scale (P < .001). The GBTM-based classification of reperfusion was closely associated with the clinical outcome and had a similar accuracy compared to ROC-based classification. CONCLUSIONS TTP and Tmax should be preferred to MTT in defining early reperfusion. GBTM provided a clinically relevant reperfusion classification that does not require prespecified delay thresholds or clinical outcomes.
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Affiliation(s)
- Brice Ozenne
- Service de Biostatistique, Hospices Civils de Lyon, Lyon, France, Equipe Biostatistique Santé CNRS UMR 5558, Villeurbanne, France; Université Lyon I, Lyon, France
| | - Tae-Hee Cho
- Department of Stroke Medicine and Department of Neuroradiology, Université Lyon 1; CREATIS, CNRS UMR 5220-INSERM U1044, INSA-Lyon; Hospices Civils de Lyon, Lyon, France
| | - Irene Klaerke Mikkelsen
- Center of Functionally Integrative Neuroscience, Aarhus University, Aarhus, Denmark.,Department of Neurology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Marc Hermier
- Service de Biostatistique, Hospices Civils de Lyon, Lyon, France, Equipe Biostatistique Santé CNRS UMR 5558, Villeurbanne, France; Université Lyon I, Lyon, France
| | - Lars Ribe
- Department of Neurology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Götz Thomalla
- Department of Neurology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Salvador Pedraza
- Department of Radiology (IDI), Girona Biomedical Research Institute (IDIBGI), Hospital Universitari de Girona Dr Josep Trueta, Girona, Spain
| | - Jean-Claude Baron
- INSERM U894, Hôpital Sainte-Anne, Université Paris Descartes, Sorbonne Paris Cité, France
| | - Pascal Roy
- Service de Biostatistique, Hospices Civils de Lyon, Lyon, France, Equipe Biostatistique Santé CNRS UMR 5558, Villeurbanne, France; Université Lyon I, Lyon, France
| | - Yves Berthezène
- Department of Stroke Medicine and Department of Neuroradiology, Université Lyon 1; CREATIS, CNRS UMR 5220-INSERM U1044, INSA-Lyon; Hospices Civils de Lyon, Lyon, France
| | - Norbert Nighoghossian
- Department of Stroke Medicine and Department of Neuroradiology, Université Lyon 1; CREATIS, CNRS UMR 5220-INSERM U1044, INSA-Lyon; Hospices Civils de Lyon, Lyon, France
| | - Leif Østergaard
- Department of Neurology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Delphine Maucort-Boulch
- Service de Biostatistique, Hospices Civils de Lyon, Lyon, France, Equipe Biostatistique Santé CNRS UMR 5558, Villeurbanne, France; Université Lyon I, Lyon, France
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22
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Bauer S, Wagner M, Seiler A, Hattingen E, Deichmann R, Nöth U, Singer OC. Quantitative T2'-mapping in acute ischemic stroke. Stroke 2014; 45:3280-6. [PMID: 25278559 DOI: 10.1161/strokeaha.114.006530] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
BACKGROUND AND PURPOSE Quantitative T2'-mapping detects regional changes in the relation of oxygenated and deoxygenated haemoglobine and might reflect areas with increased oxygen extraction. T2'-mapping in conjunction with an elaborate algorithm for motion correction was performed in patients with acute large-vessel stroke, and quantitative T2'-values were determined within the diffusion-weighted imaging lesion and perfusion-restricted tissue. METHODS Eleven patients (median age, 71 years) with acute middle cerebral or internal carotid artery occlusion underwent MRI before scheduled endovascular treatment. MR-examination included diffusion- and perfusion-weighted imaging and quantitative, motion-corrected mapping of T2'. Time-to-peak maps were thresholded for different degrees of perfusion delays (eg, ≥0 s, ≥ 2s) when compared with a reference time-to-peak value from healthy contralateral tissue. Mean T2'-values in areas with reduced apparent diffusion coefficient and in areas with impaired perfusion were compared with T2'-values in corresponding contralateral areas. RESULTS Median time between symptom onset and MRI was 238 minutes. T2'-values were significantly reduced within the apparent diffusion coefficient -lesion when compared with contralateral healthy tissue (83 ms [67, 97] versus 97 ms [91, 111]; P<0.003). In perfusion-restricted tissue, T2'-values were also significantly lower when compared with contralateral healthy tissue (ie, for time to peak, ≥0 s 93 ms [86, 102] versus 104 [90, 110]; P=0.008) but were significantly higher than within the apparent diffusion coefficient lesion. The severity of the perfusion impairment had no influence on median T2'-values. CONCLUSIONS Motion-corrected T2'-mapping reveals significant and gradually declining values from healthy to perfusion-disturbed to apparent diffusion coefficient-restricted tissue. Current T2'-mapping can differentiate between the ischemic core and the perfusion-impaired areas but not on its own between penumbral and oligemic tissue.
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Affiliation(s)
- Sonja Bauer
- From the Department of Neurology (S.B., A.S., O.C.S.), Institute for Neuroradiology (M.W., E.H.); and Brain Imaging Center (R.D., U.N.), University Hospital Frankfurt, Goethe University, Frankfurt, Germany
| | - Marlies Wagner
- From the Department of Neurology (S.B., A.S., O.C.S.), Institute for Neuroradiology (M.W., E.H.); and Brain Imaging Center (R.D., U.N.), University Hospital Frankfurt, Goethe University, Frankfurt, Germany
| | - Alexander Seiler
- From the Department of Neurology (S.B., A.S., O.C.S.), Institute for Neuroradiology (M.W., E.H.); and Brain Imaging Center (R.D., U.N.), University Hospital Frankfurt, Goethe University, Frankfurt, Germany
| | - Elke Hattingen
- From the Department of Neurology (S.B., A.S., O.C.S.), Institute for Neuroradiology (M.W., E.H.); and Brain Imaging Center (R.D., U.N.), University Hospital Frankfurt, Goethe University, Frankfurt, Germany
| | - Ralf Deichmann
- From the Department of Neurology (S.B., A.S., O.C.S.), Institute for Neuroradiology (M.W., E.H.); and Brain Imaging Center (R.D., U.N.), University Hospital Frankfurt, Goethe University, Frankfurt, Germany
| | - Ulrike Nöth
- From the Department of Neurology (S.B., A.S., O.C.S.), Institute for Neuroradiology (M.W., E.H.); and Brain Imaging Center (R.D., U.N.), University Hospital Frankfurt, Goethe University, Frankfurt, Germany
| | - Oliver C Singer
- From the Department of Neurology (S.B., A.S., O.C.S.), Institute for Neuroradiology (M.W., E.H.); and Brain Imaging Center (R.D., U.N.), University Hospital Frankfurt, Goethe University, Frankfurt, Germany.
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Hirano T. Searching for Salvageable Brain: The Detection of Ischemic Penumbra Using Various Imaging Modalities? J Stroke Cerebrovasc Dis 2014; 23:795-8. [DOI: 10.1016/j.jstrokecerebrovasdis.2013.10.003] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2013] [Revised: 10/07/2013] [Accepted: 10/07/2013] [Indexed: 11/25/2022] Open
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Changes in brain tissue oxygenation after treatment of diffuse traumatic brain injury by erythropoietin. Crit Care Med 2013; 41:1316-24. [PMID: 23591210 DOI: 10.1097/ccm.0b013e31827ca64e] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
OBJECTIVES To investigate the effects of recombinant human erythropoietin on brain oxygenation in a model of diffuse traumatic brain injury. DESIGN Adult male Wistar rats. SETTING Neurosciences and physiology laboratories. INTERVENTIONS Thirty minutes after diffuse traumatic brain injury (impact-acceleration model), rats were intravenously administered with either a saline solution or a recombinant human erythropoietin (5000 IU/kg). A third group received no traumatic brain injury insult (sham-operated). MEASUREMENTS AND MAIN RESULTS Three series of experiments were conducted 2 hours after traumatic brain injury to investigate: 1) the effect of recombinant human erythropoietin on brain edema using diffusion-weighted magnetic resonance imaging and measurements of apparent diffusion coefficient (n = 11 rats per group); local brain oxygen saturation, mean transit time, and blood volume fraction were subsequently measured using a multiparametric magnetic resonance-based approach to estimate brain oxygenation and brain perfusion in the neocortex and caudoputamen; 2) the effect of recombinant human erythropoietin on brain tissue PO₂ in similar experiments (n = 5 rats per group); and 3) the cortical ultrastructural changes after treatment (n = 1 rat per group). Compared with the sham-operated group, traumatic brain injury saline rats showed a significant decrease in local brain oxygen saturation and in brain tissue PO₂ alongside brain edema formation and microvascular lumen collapse at H2. Treatment with recombinant human erythropoietin reversed all of these traumatic brain injury-induced changes. Brain perfusion (mean transit time and blood volume fraction) was comparable between the three groups of animals. CONCLUSION Our findings indicate that brain hypoxia can be related to microcirculatory derangements and cell edema without evidence of brain ischemia. These changes were reversed with post-traumatic administration of recombinant human erythropoietin, thus offering new perspectives in the use of this drug in brain injury.
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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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González RG, Copen WA, Schaefer PW, Lev MH, Pomerantz SR, Rapalino O, Chen JW, Hunter GJ, Romero JM, Buchbinder BR, Larvie M, Hirsch JA, Gupta R. The Massachusetts General Hospital acute stroke imaging algorithm: an experience and evidence based approach. J Neurointerv Surg 2013; 5 Suppl 1:i7-12. [PMID: 23493340 PMCID: PMC3623036 DOI: 10.1136/neurintsurg-2013-010715] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
The Massachusetts General Hospital Neuroradiology Division employed an experience and evidence based approach to develop a neuroimaging algorithm to best select patients with severe ischemic strokes caused by anterior circulation occlusions (ACOs) for intravenous tissue plasminogen activator and endovascular treatment. Methods found to be of value included the National Institutes of Health Stroke Scale (NIHSS), non-contrast CT, CT angiography (CTA) and diffusion MRI. Perfusion imaging by CT and MRI were found to be unnecessary for safe and effective triage of patients with severe ACOs. An algorithm was adopted that includes: non-contrast CT to identify hemorrhage and large hypodensity followed by CTA to identify the ACO; diffusion MRI to estimate the core infarct; and NIHSS in conjunction with diffusion data to estimate the clinical penumbra.
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Affiliation(s)
- Ramon Gilberto González
- Neuroradiology Division, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts 02114, USA.
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Rapid quantitative CBF and CMRO(2) measurements from a single PET scan with sequential administration of dual (15)O-labeled tracers. J Cereb Blood Flow Metab 2013; 33:440-8. [PMID: 23232945 PMCID: PMC3587817 DOI: 10.1038/jcbfm.2012.188] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Positron emission tomography (PET) with (15)O tracers provides essential information in patients with cerebral vascular disorders, such as cerebral blood flow (CBF), oxygen extraction fraction (OEF), and metabolic rate of oxygen (CMRO(2)). However, most of techniques require an additional C(15)O scan for compensating cerebral blood volume (CBV). We aimed to establish a technique to calculate all functional images only from a single dynamic PET scan, without losing accuracy or statistical certainties. The technique was an extension of previous dual-tracer autoradiography (DARG) approach, but based on the basis function method (DBFM), thus estimating all functional parametric images from a single session of dynamic scan acquired during the sequential administration of H(2)(15)O and (15)O(2). Validity was tested on six monkeys by comparing global OEF by PET with those by arteriovenous blood sampling, and tested feasibility on young healthy subjects. The mean DBFM-derived global OEF was 0.57±0.06 in monkeys, in an agreement with that by the arteriovenous method (0.54±0.06). Image quality was similar and no significant differences were seen from DARG; 3.57%±6.44% and 3.84%±3.42% for CBF, and -2.79%±11.2% and -6.68%±10.5% for CMRO(2). A simulation study demonstrated similar error propagation between DBFM and DARG. The DBFM method enables accurate assessment of CBF and CMRO(2) without additional CBV scan within significantly shortened examination period, in clinical settings.
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Baron JC, Jones T. Oxygen metabolism, oxygen extraction and positron emission tomography: Historical perspective and impact on basic and clinical neuroscience. Neuroimage 2012; 61:492-504. [DOI: 10.1016/j.neuroimage.2011.12.036] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2011] [Revised: 12/08/2011] [Accepted: 12/15/2011] [Indexed: 10/14/2022] Open
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Spratt NJ, Donnan GA, McLeod DD, Howells DW. 'Salvaged' stroke ischaemic penumbra shows significant injury: studies with the hypoxia tracer FMISO. J Cereb Blood Flow Metab 2011; 31:934-43. [PMID: 20877386 PMCID: PMC3063627 DOI: 10.1038/jcbfm.2010.174] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
The degree of cellular injury within the stroke ischaemic penumbra is controversial. Clinical and experimental studies using the hypoxia tracer fluoromisonidazole (FMISO) have shown retention of this tracer in the penumbra, but cellular outcome has not been well characterised. We hypothesised that macroscopically intact FMISO-retaining penumbral tissues would show evidence of microscopic injury, and that no FMISO retention would be seen in the infarct core. To determine the distribution of FMISO retention, a tritium-labelled tracer (hydrogen-3 FMISO ([(3)H]FMISO)) was administered 5 minutes after induction of 2-hour temporary middle cerebral artery occlusion. Coregistered brain histology and autoradiography at 24 hours revealed marked retention of FMISO within the infarct. However, 48% of the FMISO-retaining tissue was not infarcted. Within this noninfarcted tissue, only 27% (17 of 64) of sampled regions showed no evidence of neuronal loss, whereas 44% (28 of 64) showed injury to >50% of neurons within the sample. To determine whether FMISO retention occurred after the tissue was already committed to infarction, FMISO was administered 4 to 6 hours after the onset of permanent vessel occlusion. Intense FMISO retention was consistently seen throughout the infarct core. In conclusion, FMISO retention occurs both within the ischaemic penumbra and within the early infarct core. Most penumbral tissues show evidence of selective cellular injury.
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Affiliation(s)
- Neil J Spratt
- Hunter Medical Research Institute and University of Newcastle School of Biomedical Sciences and Pharmacy, Callaghan, New South Wales, Australia.
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Shichita T, Muto G, Yoshimura A. T lymphocyte function in the delayed phase of ischemic brain injury. Inflamm Regen 2011. [DOI: 10.2492/inflammregen.31.102] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
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Ma L, Gao PY, Hu QM, Lin Y, Jing LN, Xue J, Wang XC, Chen ZJ, Wang YL, Liao XL, Liu ML, Chen WJ. Prediction of infarct core and salvageable ischemic tissue volumes by analyzing apparent diffusion coefficient without intravenous contrast material. Acad Radiol 2010; 17:1506-17. [PMID: 21056849 DOI: 10.1016/j.acra.2010.07.010] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2010] [Revised: 07/23/2010] [Accepted: 07/26/2010] [Indexed: 10/18/2022]
Abstract
RATIONALE AND OBJECTIVES To investigate whether baseline apparent diffusion coefficient (ADC) maps can be employed to predict both infarct core and salvageable ischemic tissue volumes in acute ischemic stroke. MATERIALS AND METHODS An automated image analysis system based on baseline ADC maps was tested against 30 patients with acute ischemic stroke of anterior circulation to predict both infarct core and salvageable ischemic tissue volumes. The predicted infarct core and predicted salvageable ischemic tissue were quantitatively and qualitatively compared with follow-up imaging data in recanalization and no recanalization groups, respectively. Direct comparisons with perfusion- and diffusion- weighted magnetic resonance imaging measures were also made. Wilcoxon signed-rank test, Spearman rank correlation, and Bland-Altman plots were performed. RESULTS In the recanalization group, the predicted infarct core volume was significantly correlated with the final infarct volume (r = 0. 868, P < .001). In the no recanalization group, the predicted final infarct volume (sum of the predicted infarct core and salvageable ischemic tissue volumes), as well as the predicted salvageable ischemic tissue volume, was also significantly correlated with the true final infarct volume (r = 0.955, P < .001) and infarct growth (r = 0.918, P < .001), respectively. The volumes of perfusion-diffusion mismatch were significantly larger than those of infarct growth and predicted salvageable ischemic tissue. Good agreement between predicted and true final infarct lesions was visualized by Bland-Altman plots in two groups. Direct visual comparative analysis revealed good qualitative agreement between the true final infarct and predicted lesions in 21 patients. CONCLUSION The proposed ADC based approach may be a feasible and practical tool to predict the volumes of infarct core and salvageable ischemic tissue without intravenous contrast media-enhanced perfusion-weighted imaging at baseline.
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Abstract
Investigation of the interplay between the cerebral circulation and brain cellular function is fundamental to understanding both the pathophysiology and treatment of stroke. Currently, PET is the only technique that provides accurate, quantitative in vivo regional measurements of both cerebral circulation and cellular metabolism in human subjects. We review normal human cerebral blood flow and metabolism and human PET studies of ischemic stroke, carotid artery disease, vascular dementia, intracerebral hemorrhage and aneurysmal subarachnoid hemorrhage and discuss how these studies have added to our understanding of the pathophysiology of human cerebrovascular disease.
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Affiliation(s)
- William J. Powers
- Department of Neurology, University of North Carolina School of Medicine, Chapel Hill, NC
| | - Allyson R. Zazulia
- Departments of Neurology and Radiology, Washington University School of Medicine, St. Louis, MO
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Liu S, Levine SR, Winn HR. Targeting ischemic penumbra: part I - from pathophysiology to therapeutic strategy. ACTA ACUST UNITED AC 2010; 3:47-55. [PMID: 20607107 DOI: 10.6030/1939-067x-3.1.47] [Citation(s) in RCA: 86] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Penumbra is the viable tissue around the irreversibly damaged ischemic core. The purpose of acute stroke treatment is to salvage penumbral tissue and to improve brain function. However, the majority of acute stroke patients who have treatable penumbra are left untreated. Therefore, developing an effective non-recanalizational therapeutics, such as neuroprotective agents, has significant clinical applications. Part I of this serial review on "targeting penumbra" puts special emphases on penumbral pathophysiology and the development of therapeutic strategies. Bioenergetic intervention by massive metabolic suppression and direct energy delivery would be a promising future direction. An effective drug delivery system for this purpose should be able to penetrate BBB and achieve high local tissue drug levels while non-ischemic region being largely unaffected. Selective drug delivery to ischemic stroke penumbra is feasible and deserves intensive research.
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Affiliation(s)
- Shimin Liu
- Department of Neurology, Mount Sinai School of Medicine, NYU
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Latchaw RE, Alberts MJ, Lev MH, Connors JJ, Harbaugh RE, Higashida RT, Hobson R, Kidwell CS, Koroshetz WJ, Mathews V, Villablanca P, Warach S, Walters B. Recommendations for imaging of acute ischemic stroke: a scientific statement from the American Heart Association. Stroke 2009; 40:3646-78. [PMID: 19797189 DOI: 10.1161/strokeaha.108.192616] [Citation(s) in RCA: 291] [Impact Index Per Article: 19.4] [Reference Citation Analysis] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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Pivotal role of cerebral interleukin-17–producing γδT cells in the delayed phase of ischemic brain injury. Nat Med 2009; 15:946-50. [DOI: 10.1038/nm.1999] [Citation(s) in RCA: 624] [Impact Index Per Article: 41.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2008] [Accepted: 06/18/2009] [Indexed: 12/11/2022]
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Cho TH, Pialat JB, Hermier M, Derex L, Nighoghossian N. Risonanza magnetica multimodale nel trattamento in urgenza degli ictus cerebrali ischemici. Neurologia 2009. [DOI: 10.1016/s1634-7072(09)70512-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022] Open
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Takasawa M, Jones PS, Guadagno JV, Christensen S, Fryer TD, Harding S, Gillard JH, Williams GB, Aigbirhio FI, Warburton EA, Østergaard L, Baron JC. How reliable is perfusion MR in acute stroke? Validation and determination of the penumbra threshold against quantitative PET. Stroke 2008; 39:870-7. [PMID: 18258831 DOI: 10.1161/strokeaha.107.500090] [Citation(s) in RCA: 166] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
BACKGROUND AND PURPOSE Perfusion magnetic resonance imaging (pMR) is increasingly used in acute stroke, but its physiologic significance is still debated. A reasonably good correlation between pMR and positron emission tomography (PET) has been reported in normal subjects and chronic cerebrovascular disease, but corresponding validation in acute stroke is still lacking. METHODS We compared the cerebral blood flow (CBF), cerebral blood volume, and mean transit time (MTT) maps generated by pMR (deconvolution method) and PET ((15)O steady-state method) in 5 patients studied back-to-back with the 2 modalities at a mean of 16 hours (range, 7 to 21 hours) after stroke onset. We also determined the penumbra thresholds for pMR-derived MTT, time to peak (TTP), and Tmax against the previously validated probabilistic PET penumbra thresholds. RESULTS In all patients, the PET and pMR relative distribution images were remarkably similar, especially for CBF and MTT. Within-patient correlations between pMR and PET were strong for absolute CBF (average r(2)=0.45) and good for MTT (r(2)=0.35) but less robust for cerebral blood volume (r(2)=0.24). However, pMR overestimated absolute CBF and underestimated MTT, with substantial variability in individual slopes. Removing individual differences by normalization to the mean resulted in much stronger between-patient correlations. Penumbra thresholds of approximately 6, 4.8, and 5.5 seconds were obtained for MTT delay, TTP delay, and Tmax, respectively. CONCLUSIONS Although derived from a small sample studied relatively late after stroke onset, our data show that pMR tends to overestimate absolute CBF and underestimate MTT, but the relative distribution of the perfusion variables was remarkably similar between pMR and PET. pMR appears sufficiently reliable for clinical purposes and affords reliable detection of the penumbra from normalized time-based thresholds.
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Affiliation(s)
- Masashi Takasawa
- Department of Clinical Neurosciences, University of Cambridge, Cambridge, England
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Abstract
PURPOSE OF REVIEW MRI is increasingly used as the primary imaging modality in acute stroke, since it allows treatment based on individual pathophysiology rather than strict time windows. RECENT FINDINGS PET studies have confirmed that regions with disturbed diffusion frequently indicate irreversible tissue damage, although they may in part be viable. The mismatch between a larger perfusion deficit and a smaller diffusion abnormality contains both critically hypoperfused regions as well as oligemic regions. Although mismatch is thus not perfect, recent prospective trials have convincingly shown that mismatch patients treated with revascularization therapies benefit from reperfusion, while patients without mismatch do not. This is particularly important for patients presenting beyond the first three hours. In addition, several studies have investigated MRI as a tool to assess the risk of thrombolytic treatment. Parameters reflecting severe ischemia, blood-brain barrier damage and preexisting small-vessel disease emerge as risk factors for intracerebral hemorrhage, while microbleeds are not clearly associated with an increased risk. SUMMARY Based on data from prospective trials, the mismatch concept is an acceptable method to identify patients who benefit from recanalization therapies. The concept, however, still needs to be further improved and standard definitions are required before widespread use can be recommended.
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Naidech AM, Jovanovic B, Wartenberg KE, Parra A, Ostapkovich N, Connolly ES, Mayer SA, Commichau C. Higher hemoglobin is associated with improved outcome after subarachnoid hemorrhage. Crit Care Med 2007; 35:2383-9. [PMID: 17717494 DOI: 10.1097/01.ccm.0000284516.17580.2c] [Citation(s) in RCA: 118] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
OBJECTIVE There are few data regarding anemia and transfusion after subarachnoid hemorrhage (SAH). We addressed the hypothesis that higher hemoglobin (HGB) levels are associated with less death and disability after SAH. DESIGN Prospective registry with automated data retrieval. PATIENTS Six hundred eleven patients enrolled in the Columbia University SAH Outcomes Project between August 1996 and June 2002. SETTING Neurologic intensive care unit. INTERVENTIONS Patients were treated according to standard management protocols. MEASUREMENTS AND MAIN RESULTS We electronically retrieved all HGB readings during the acute hospital stay for 611 consecutively admitted SAH patients. Outcomes were measured with the modified Rankin Scale at 14 days or discharge, and at 3 months. Patients who were independent (modified Rankin Scale, 0-3) at discharge or 14 days had higher mean (11.7 +/- 1.5 vs. 10.9 +/- 1.2, p < .001) and nadir (9.9 +/- 2.1 vs. 8.6 +/- 1.8, p < .001) HGB, and had higher HGB values every day in the hospital. There were similar results when patients were stratified by mortality. Higher HGB was associated with reduced risk of poor outcome (modified Rankin Scale, 4-6) at 14 days/discharge and 3 months after correcting for Hunt and Hess grade, age, history of diabetes, and cerebral infarction. Length of stay and HGB interacted such that lower HGB has a more pronounced effect with length of stay > 14 days. CONCLUSIONS Higher HGB values are associated with improved outcomes after SAH at 14 days/discharge and 3 months. In contrast to general critical care patients, SAH patients may benefit from higher HGB. Determination of the optimal goal HGB after SAH will require separate prospective research.
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Konstas AA, Neimark MA, Laine AF, Pile-Spellman J. A theoretical model of selective cooling using intracarotid cold saline infusion in the human brain. J Appl Physiol (1985) 2007; 102:1329-40. [PMID: 17170208 DOI: 10.1152/japplphysiol.00805.2006] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
A three-dimensional mathematical model was developed to examine the transient and steady-state temperature distribution in the human brain during selective brain cooling (SBC) by unilateral intracarotid freezing-cold saline infusion. To determine the combined effect of hemodilution and hypothermia from the cold saline infusion, data from studies investigating the effect of these two parameters on cerebral blood flow (CBF) were pooled, and an analytic expression describing the combined effect of the two factors was derived. The Pennes bioheat equation used the thermal properties of the different cranial layers and the effect of cold saline infusion on CBF to propagate the evolution of brain temperature. A healthy brain and a brain with stroke (ischemic core and penumbra) were modeled. CBF and metabolic rate data were reduced to simulate the core and penumbra. Simulations using different saline flow rates were performed. The results suggested that a flow rate of 30 ml/min is sufficient to induce moderate hypothermia within 10 min in the ipsilateral hemisphere. The brain with stroke cooled to lower temperatures than the healthy brain, mainly because the stroke limited the total intracarotid blood flow. Gray matter cooled twice as fast as white matter. The continuously falling hematocrit was the main time-limiting factor, restricting the SBC to a maximum of 3 h. The study demonstrated that SBC by intracarotid saline infusion is feasible in humans and may be the fastest method of hypothermia induction.
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Karaszewski B, Wardlaw JM, Marshall I, Cvoro V, Wartolowska K, Haga K, Armitage PA, Bastin ME, Dennis MS. Measurement of brain temperature with magnetic resonance spectroscopy in acute ischemic stroke. Ann Neurol 2006; 60:438-46. [PMID: 16972284 DOI: 10.1002/ana.20957] [Citation(s) in RCA: 76] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
OBJECTIVE Pyrexia is associated with poor outcome after stroke, but the temperature changes in the brain after stroke are poorly understood. We used magnetic resonance spectroscopic imaging (water-to-N-acetylaspartate frequency shift) to measure cerebral temperature noninvasively in stroke patients. METHODS We performed magnetic resonance diffusion, perfusion (diffusion- and perfusion-weighted imaging), and magnetic resonance spectroscopic imaging, compared temperatures in tissues as defined by the diffusion-weighted imaging appearance (definitely abnormal, possibly abnormal and immediately adjacent normal-appearing brain, and normal brain), and tested associations with lesion and patient characteristics. RESULTS Among 40 patients, temperature was higher in possibly abnormal (37.63 degrees C) than in definitely abnormal tissue (37.30 degrees C; p < 0.001) or in normal-appearing brain (ipsilateral, 37.16 degrees C; contralateral, 37.22 degrees C; both p < 0.001). Ischemic lesion temperature increased before normal brain temperature. Higher temperatures occurred in lesions that were large, had diffusion/perfusion-weighted imaging mismatch, had reduced cerebral blood flow, and in clinically severe strokes. Only 1 of 25 patients with ischemic lesion temperature greater than 37.5 degrees C was pyrexial. INTERPRETATION Temperature is elevated in acutely ischemic brain. More work is required to determine whether raised temperature results from ischemic metabolic reactions, impaired heat exchange from reduced cerebral blood flow, or early inflammatory cell activity (or a combination of these), but magnetic resonance spectroscopic imaging could be used in studies of temperature after brain injury and to monitor interventions.
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Affiliation(s)
- Bartosz Karaszewski
- Department of Neurology of Adults, Medical University of Gdansk, Gdansk, Poland
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Abstract
PURPOSE OF REVIEW To review the techniques for imaging cerebral blood flow and metabolism following injury to the brain. RECENT FINDINGS Xenon enhanced computerized tomography (Xenon CT), CT perfusion and single photon emission CT provide measurements of cerebral perfusion, while positron emission tomography (PET), and magnetic resonance imaging and spectroscopy (MRI and MRS) are able to assess both perfusion and cerebral metabolism. Xenon CT and CT perfusion are readily available and have proved useful in a variety of causes of brain injury. PET is an extremely useful research tool for defining cerebral physiology, but is limited in its availability. Despite the continuing development of MRI and MRS imaging, the scanning environment remains hostile for critically ill patients, and further research is required before the techniques become generally available. SUMMARY Imaging of cerebral blood flow and metabolism has been shown to be useful following a variety of causes of brain injury, as it can help to define the cause and extent of injury, identify appropriate treatments and predict outcome. Imaging based on CT techniques (Xenon CT and CT perfusion) can be implemented easily in most hospital centres, and are able to provide quantitative perfusion data in addition to structural images.
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Affiliation(s)
- Jonathan P Coles
- University Department of Anaesthesia, Addenbrooke's Hospital, Cambridge, UK.
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Guadagno JV, Jones PS, Fryer TD, Barret O, Aigbirhio FI, Carpenter TA, Price CJ, Gillard JH, Warburton EA, Baron JC. Local Relationships Between Restricted Water Diffusion and Oxygen Consumption in the Ischemic Human Brain. Stroke 2006; 37:1741-8. [PMID: 16763173 DOI: 10.1161/01.str.0000232437.00621.86] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
BACKGROUND AND PURPOSE MR is widely used to depict still ischemic but viable tissue in acute stroke. However, the relationship between the apparent diffusion coefficient (ADC) and energy failure from reduced oxygen supply are unknown in man. METHODS Acute carotid-territory stroke patients were studied prospectively with both diffusion tensor-imaging and back-to-back steady-state 15O-PET. Substantial numbers of voxels with oxygen extraction fraction >0.70 (ie, significant ongoing hypoxia) were identified in 3 patients (imaged at 7, 16 and 21 hours after stroke onset). In this voxel population, the quantitative relationships between the ADC and cerebral metabolic rate of oxygen (CMRO2), and ADC and cerebral blood flow (CBF), were assessed. RESULTS The ADC remained essentially unchanged until CBF reached values approximately 20 mls/100g per min, beyond which it declined linearly. In contrast, except when severely reduced, the ADC was a poorer predictor of CMRO2. For both CBF and CMRO2, however, the relationship with ADC became steeper with longer times since onset, ie, the same ADC reflected lower perfusion and CMRO2 with elapsed time. CONCLUSIONS Despite the small sample and late times from stroke onset, the findings indicate that the degree of restricted water diffusion reliably reflects the severity of oxygen deprivation below the penumbral threshold but is less strongly related to metabolic disruption, which may explain why the ADC does not reliably predict tissue outcome. However, the same degree of diffusion restriction may correspond to greater severity of tissue disruption with elapsing time, which has relevance for stroke therapy. Time elapsed since stroke onset should be taken into account when interpreting ADC declines and in voxel-based infarct prediction models.
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