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Kuo DP, Kuo PC, Chen YC, Kao YCJ, Lee CY, Chung HW, Chen CY. Machine learning-based segmentation of ischemic penumbra by using diffusion tensor metrics in a rat model. J Biomed Sci 2020; 27:80. [PMID: 32664906 PMCID: PMC7362663 DOI: 10.1186/s12929-020-00672-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2020] [Accepted: 07/09/2020] [Indexed: 01/01/2023] Open
Abstract
Background Recent trials have shown promise in intra-arterial thrombectomy after the first 6–24 h of stroke onset. Quick and precise identification of the salvageable tissue is essential for successful stroke management. In this study, we examined the feasibility of machine learning (ML) approaches for differentiating the ischemic penumbra (IP) from the infarct core (IC) by using diffusion tensor imaging (DTI)-derived metrics. Methods Fourteen male rats subjected to permanent middle cerebral artery occlusion (pMCAO) were included in this study. Using a 7 T magnetic resonance imaging, DTI metrics such as fractional anisotropy, pure anisotropy, diffusion magnitude, mean diffusivity (MD), axial diffusivity, and radial diffusivity were derived. The MD and relative cerebral blood flow maps were coregistered to define the IP and IC at 0.5 h after pMCAO. A 2-level classifier was proposed based on DTI-derived metrics to classify stroke hemispheres into the IP, IC, and normal tissue (NT). The classification performance was evaluated using leave-one-out cross validation. Results The IC and non-IC can be accurately segmented by the proposed 2-level classifier with an area under the receiver operating characteristic curve (AUC) between 0.99 and 1.00, and with accuracies between 96.3 and 96.7%. For the training dataset, the non-IC can be further classified into the IP and NT with an AUC between 0.96 and 0.98, and with accuracies between 95.0 and 95.9%. For the testing dataset, the classification accuracy for IC and non-IC was 96.0 ± 2.3% whereas for IP and NT, it was 80.1 ± 8.0%. Overall, we achieved the accuracy of 88.1 ± 6.7% for classifying three tissue subtypes (IP, IC, and NT) in the stroke hemisphere and the estimated lesion volumes were not significantly different from those of the ground truth (p = .56, .94, and .78, respectively). Conclusions Our method achieved comparable results to the conventional approach using perfusion–diffusion mismatch. We suggest that a single DTI sequence along with ML algorithms is capable of dichotomizing ischemic tissue into the IC and IP.
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Affiliation(s)
- Duen-Pang Kuo
- Department of Medical Imaging, Taipei Medical University Hospital, No.250, Wu-Hsing St, Taipei, 11031, Taiwan.,Department of Radiology, Taoyuan Armed Forces General Hospital, Taoyuan, Taiwan
| | - Po-Chih Kuo
- Institute for Medical Engineering and Science, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Yung-Chieh Chen
- Department of Medical Imaging, Taipei Medical University Hospital, No.250, Wu-Hsing St, Taipei, 11031, Taiwan
| | - Yu-Chieh Jill Kao
- Department of Biomedical Imaging and Radiological Sciences, National Yang-Ming University, No.155, Sec.2, Linong St, Taipei, 11221, Taiwan
| | - Ching-Yen Lee
- TMU Center for Big Data and Artificial Intelligence in Medical Imaging, Taipei Medical University Hospital, Taipei, Taiwan.,TMU Research Center for Artificial Intelligence in Medicine, Taipei Medical University Hospital, Taipei, Taiwan
| | - Hsiao-Wen Chung
- Graduate Institute of Biomedical Electrics and Bioinformatics, National Taiwan University, Taipei, Taiwan
| | - Cheng-Yu Chen
- Department of Medical Imaging, Taipei Medical University Hospital, No.250, Wu-Hsing St, Taipei, 11031, Taiwan. .,Department of Biomedical Imaging and Radiological Sciences, National Yang-Ming University, No.155, Sec.2, Linong St, Taipei, 11221, Taiwan. .,Department of Radiology, School of Medicine, College of Medicine, Taipei Medical University, No.250, Wu-Hsing St, Taipei, 11031, Taiwan. .,Radiogenomic Research Center, Taipei Medical University Hospital, No.250, Wu-Hsing St, Taipei, 11031, Taiwan. .,Center for Artificial Intelligence in Medicine, Taipei Medical University, No.250, Wu-Hsing St, Taipei, 11031, Taiwan. .,Department of Radiology, National Defense Medical Center, No.250, Wu-Hsing St, Taipei, 11031, Taiwan.
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Yi KS, Choi CH, Jung C, Lee Y, Jeon CY, Yeo HG, Ahn Y, Hwang J, Lee HJ, Cho J, Kwak B, Kwak KA, Lee SR, Cha SH. Which pathologic staining method can visualize the hyperacute infarction lesion identified by diffusion MRI?: A comparative experimental study. J Neurosci Methods 2020; 344:108838. [PMID: 32619586 DOI: 10.1016/j.jneumeth.2020.108838] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2020] [Revised: 06/29/2020] [Accepted: 06/29/2020] [Indexed: 10/24/2022]
Abstract
BACKGROUND The study aimed to establish a staining method that could delineate the macroscopic lesion boundary of a hyperacute infarction depicted by diffusion-weighted MRI (DWI) and to validate the infarction boundary by comparing different staining methods. NEW METHOD Thirteen rats with 1 -h middle cerebral artery (MCA) infarction were included. Five different staining methods (Hematoxylin and eosin (H&E), Nissl, 2,3,5-triphenyltetrazolium hydrochloride (TTC), microtubule associated protein 2 (MAP2), and terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) stains) were used to identify whether the hyperacute infarction could be histopathologically identified. Dice indices were compared to evaluate similarities in the lesion area ascertained by DWI and the staining methods. Through macroscopic lesion delineation, each region was subdivided into abnormal regions in all three stains (ROIA), abnormal in two stains (ROIB), and abnormal in only one (ROIC). Microscopic cellular changes were evaluated and graded according to each region. RESULTS Mean Dice indices of the H&E stain were significantly higher than those of the Nissl- and MAP2-stained specimens (0.83 ± 0.052, 0.58 ± 0.107, and 0.56 ± 0.059, respectively; p = 0.000). Grading scores for ROIs in the DWI abnormal lesions varied by region: ROIA exhibited the most severe damage [median (IQR), 3 (1)], followed respectively by ROIB [median (IQR), 2 (0)] and ROIC [median (IQR), 1 (0)] COMPARISON WITH EXISTING METHODS: H&E stain best reflects 1 h hyperacute DWI abnormal lesions. CONCLUSIONS H&E stain allowed for the macroscopic delineation of the 1 h DWI-abnormal lesions, while MAP2 and Nissl stains could only partially depict lesions.
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Affiliation(s)
- Kyung Sik Yi
- Department of Radiology, Chungbuk National University Hospital, Cheongju, Chungbuk, Republic of Korea
| | - Chi-Hoon Choi
- Department of Radiology, Chungbuk National University Hospital, Cheongju, Chungbuk, Republic of Korea
| | - Cheolkyu Jung
- Department of Radiology, Seoul National University Bundang Hospital, Seongnam, Gyeonggi-do, Republic of Korea
| | - Youngjeon Lee
- National Primate Research Center, Korea Research Institute of Bioscience and Biotechnology, Cheongju, Chungbuk, Republic of Korea
| | - Chang-Yeop Jeon
- National Primate Research Center, Korea Research Institute of Bioscience and Biotechnology, Cheongju, Chungbuk, Republic of Korea
| | - Hyun-Gu Yeo
- National Primate Research Center, Korea Research Institute of Bioscience and Biotechnology, Cheongju, Chungbuk, Republic of Korea
| | - Yujin Ahn
- National Primate Research Center, Korea Research Institute of Bioscience and Biotechnology, Cheongju, Chungbuk, Republic of Korea
| | - Jinwoo Hwang
- Clinical Science, Philips Healthcare, Seoul, Republic of Korea
| | - Hong Jun Lee
- Research Institute, eBiogen Inc., Seoul, Republic of Korea; College of Medicine and Medical Research Institute, Chungbuk National University, Cheongju, Chungbuk, Republic of Korea
| | - Janggeun Cho
- College of Medicine and Medical Research Institute, Chungbuk National University, Cheongju, Chungbuk, Republic of Korea
| | - Bitnarae Kwak
- College of Medicine and Medical Research Institute, Chungbuk National University, Cheongju, Chungbuk, Republic of Korea
| | - Kyung A Kwak
- College of Medicine and Medical Research Institute, Chungbuk National University, Cheongju, Chungbuk, Republic of Korea
| | - Sang-Rae Lee
- National Primate Research Center, Korea Research Institute of Bioscience and Biotechnology, Cheongju, Chungbuk, Republic of Korea.
| | - Sang-Hoon Cha
- Department of Radiology, Chungbuk National University Hospital, Cheongju, Chungbuk, Republic of Korea; College of Medicine and Medical Research Institute, Chungbuk National University, Cheongju, Chungbuk, Republic of Korea.
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Williams CJ, Foote A, Choi P. Pseudomonas meningoencephalitis masquerading as a stroke in a patient on tocilizumab. BMJ Case Rep 2019; 12:12/1/bcr-2018-227296. [PMID: 30696642 DOI: 10.1136/bcr-2018-227296] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
Abstract
A previously high-functioning woman presents with clinical and CT features of a subacute ischaemic stroke. Her medical history is relevant for refractory giant cell arteritis on long-term high-dose prednisolone and recent commencement of tocilizumab (interleukin-6 monoclonal antibody). The potential for stroke mimic is considered and a magnetic resonance brain scan is requested. She rapidly deteriorates within 24 hours of admission and unexpectantly dies. An autopsy reveals that she has bilateral pulmonary emboli with lower limb deep vein thrombosis and Pseudomonas meningoencephalitis with frank pus on the brain. We discuss the potential risks of immunosuppression and the role of imaging in the diagnosis of stroke.
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Affiliation(s)
| | | | - Philip Choi
- Box Hill Hospital, Box Hill, Victoria, Australia
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Wu Y, Hu L, Yang X, Wang X, Wan L, Hua X, Cheng J, Li Y. Intraluminal spindle-shaped-head suture induced occlusion of middle cerebral artery in the rats. Neurol Res 2017; 39:1028-1036. [PMID: 28936922 DOI: 10.1080/01616412.2017.1375661] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
OBJECTIVE This study aimed to introduce a modified animal model of middle cerebral arterial occlusion (MCAO) through placement of intraluminal spindle-shaped head suture by comparing the traditional MCAO model. METHODS A total of 60 male Spraque-Dawley (SD) rats were divided into two groups and MCAO was induced using spindle-shaped head suture or round head suture. The mortality, infarct volume, neurological function, success rate of the surgery, and stability of modeling were examined to evaluate the effectiveness of this model. RESULTS Our results showed the success rate was 90.0% in spindle-shaped head group and 83.3% in round head group showing no significant difference; spindle-shaped head achieved a better establishment of MCAO model as shown in neurological examination. The infarct volume was 31.99 ± 5.44% in spindle-shaped head group and was significantly higher than in round head group (24.59 ± 7.17%; p < 0.05), and the coefficient of variation of infarct volume in spindle-shaped head group was lower than in round head group. CONCLUSION Our findings indicate that the modified suture induces a more reproducible and stable ischemic stroke following MCAO in SD rats.
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Affiliation(s)
- Ye Wu
- a Department of Neurosurgery , Tongde Hospital of Zhejiang Province , Hangzhou , China
| | - Lan Hu
- b Department of Neurology , The First People's Hospital of Wujiang , Suzhou , China
| | - Xiaosheng Yang
- c Department of Neurosurgery , Xinhua Hospital, Shanghai Jiao Tong University School of Medicine , Shanghai , China
| | - Xuhui Wang
- c Department of Neurosurgery , Xinhua Hospital, Shanghai Jiao Tong University School of Medicine , Shanghai , China
| | - Liang Wan
- c Department of Neurosurgery , Xinhua Hospital, Shanghai Jiao Tong University School of Medicine , Shanghai , China
| | - Xuming Hua
- c Department of Neurosurgery , Xinhua Hospital, Shanghai Jiao Tong University School of Medicine , Shanghai , China
| | - Juan Cheng
- d Department of Ultrasound , Xinhua Hospital, Shanghai Jiao Tong University School of Medicine , Shanghai , China
| | - Yi Li
- c Department of Neurosurgery , Xinhua Hospital, Shanghai Jiao Tong University School of Medicine , Shanghai , China
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Muir KW, Macrae IM. Neuroimaging as a Selection Tool and Endpoint in Clinical and Pre-clinical Trials. Transl Stroke Res 2016; 7:368-77. [PMID: 27543177 PMCID: PMC5014902 DOI: 10.1007/s12975-016-0487-1] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2016] [Revised: 06/29/2016] [Accepted: 07/19/2016] [Indexed: 12/03/2022]
Abstract
Standard imaging in acute stroke enables the exclusion of non-stroke structural CNS lesions and cerebral haemorrhage from clinical and pre-clinical ischaemic stroke trials. In this review, the potential benefit of imaging (e.g., angiography and penumbral imaging) as a translational tool for trial recruitment and the use of imaging endpoints are discussed for both clinical and pre-clinical stroke research. The addition of advanced imaging to identify a “responder” population leads to reduced sample size for any given effect size in phase 2 trials and is a potentially cost-efficient means of testing interventions. In pre-clinical studies, technical failures (failed or incomplete vessel occlusion, cerebral haemorrhage) can be excluded early and continuous multimodal imaging of the animal from stroke onset is feasible. Pre- and post-intervention repeat scans provide real time assessment of the intervention over the first 4–6 h. Negative aspects of advanced imaging in animal studies include increased time under general anaesthesia, and, as in clinical studies, a delay in starting the intervention. In clinical phase 3 trial designs, the negative aspects of advanced imaging in patient selection include higher exclusion rates, slower recruitment, overestimated effect size and longer acquisition times. Imaging may identify biological effects with smaller sample size and at earlier time points, compared to standard clinical assessments, and can be adjusted for baseline parameters. Mechanistic insights can be obtained. Pre-clinically, multimodal imaging can non-invasively generate data on a range of parameters, allowing the animal to be recovered for subsequent behavioural testing and/or the brain taken for further molecular or histological analysis.
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Affiliation(s)
- Keith W Muir
- Institute of Neuroscience and Psychology, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, Scotland, UK
| | - I Mhairi Macrae
- Institute of Neuroscience and Psychology, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, Scotland, UK.
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Walberer M, Rueger MA. The macrosphere model-an embolic stroke model for studying the pathophysiology of focal cerebral ischemia in a translational approach. ANNALS OF TRANSLATIONAL MEDICINE 2015. [PMID: 26207251 DOI: 10.3978/j.issn.2305-5839.2015.04.02] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Abstract
The main challenge of stroke research is to translate promising experimental findings from the bench to the bedside. Many suggestions have been made how to achieve this goal, identifying the need for appropriate experimental animal models as one key issue. We here discuss the macrosphere model of focal cerebral ischemia in the rat, which closely resembles the pathophysiology of human stroke both in its acute and chronic phase. Key pathophysiological processes such as brain edema, cortical spreading depolarizations (CSD), neuroinflammation, and stem cell-mediated regeneration are observed in this stroke model, following characteristic temporo-spatial patterns. Non-invasive in vivo imaging allows studying the macrosphere model from the very onset of ischemia up to late remodeling processes in an intraindividual and longitudinal fashion. Such a design of pre-clinical stroke studies provides the basis for a successful translation into the clinic.
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Affiliation(s)
- Maureen Walberer
- 1 Department of Neurology, University Hospital of Cologne, Cologne, Germany ; 2 Max-Planck-Institute for Metabolism Research, Cologne, Germany ; 3 Animal Welfare Office, University of Cologne, Germany
| | - Maria Adele Rueger
- 1 Department of Neurology, University Hospital of Cologne, Cologne, Germany ; 2 Max-Planck-Institute for Metabolism Research, Cologne, Germany ; 3 Animal Welfare Office, University of Cologne, Germany
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Divani AA, Chow R, Sadeghi-Bazargani H, Murphy AJ, Nordberg JA, Tokarev JV, Hevesi M, Wang X, Zhu XH, Acompanado T, Edwards PA, Zhang Y, Chen W. Focal middle cerebral artery ischemia in rats via a transfemoral approach using a custom designed microwire. J Neurointerv Surg 2015; 8:608-14. [PMID: 25935923 DOI: 10.1136/neurintsurg-2014-011607] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2014] [Accepted: 04/15/2015] [Indexed: 11/03/2022]
Abstract
OBJECTIVES The aim of this study was to develop a reliable and repeatable method of inducing focal middle cerebral artery occlusion (MCAo) in rats without ligation of the external carotid artery (ECA), while reducing the risk of subarachnoid hemorrhage. METHODS We prototyped microwires with different diameters (0.0120 inch, 0.0115 inch, 0.0110 inch), materials, and construction methods (coil-on-core, extruded polymer jacket-on-core). Under fluoroscopic guidance and using femoral artery access, the microwires were navigated into the internal carotid artery of male Wistar rats (n=50, weight 376±64 g) to induce MCAo for 1 or 2 h. We performed neurological assessments at baseline, and at 3, 24, 72, and 168 h after MCAo. MRI measurements were performed on a 9.4 T scanner at 1 and 7 days post-injury. RESULTS The 0.0115 inch microwire with polymer jacket-on-core provided the most successful outcome. At 1 and 7 days post-injury, we observed similar infarction volumes for 1 and 2 h MCAo in the MRI study. Infarcted lesion volumes in both MCAo groups were significantly reduced at 7 days compared with 1 day post-injury. The trend in longitudinal changes for the scores of different neurological assessments was confirmed to be significant after the injury, but both groups showed a similar trend of neurological deficits over the course of the study. CONCLUSIONS We have developed a reliable and repeatable MCAo method in rats, allowing for precise occlusion of the MCA under direct fluoroscopic visualization without alteration of the cerebral hemodynamics associated with ECA ligation. The custom designed microwire can also be sized for targeted focal ischemia in larger animals.
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Affiliation(s)
- Afshin A Divani
- Department of Neurology, University of Minnesota, Minneapolis, Minnesota, USA Department of Neurological Surgery, University of Minnesota, Minneapolis, Minnesota, USA Department of Mechanical Engineering, University of Minnesota, Minneapolis, Minnesota, USA
| | - Ricky Chow
- Department of Mechanical Engineering, University of Minnesota, Minneapolis, Minnesota, USA Lake Region Medical, Chaska, Minnesota, USA
| | - Homayoun Sadeghi-Bazargani
- Neurosciences Research Center, Tabriz University of Medical Sciences, Iran Department of Public Health Sciences, Karolinska Institute, Stockholm, Sweden
| | - Amanda J Murphy
- Department of Neurology, University of Minnesota, Minneapolis, Minnesota, USA Medical School, University of Minnesota, Minneapolis, Minnesota, USA
| | - Jessica A Nordberg
- Department of Neurology, University of Minnesota, Minneapolis, Minnesota, USA
| | - Julian V Tokarev
- Department of Neurology, University of Minnesota, Minneapolis, Minnesota, USA Medical School, University of Minnesota, Minneapolis, Minnesota, USA
| | - Mario Hevesi
- Department of Neurology, University of Minnesota, Minneapolis, Minnesota, USA Medical School, University of Minnesota, Minneapolis, Minnesota, USA
| | - Xiao Wang
- Department of Radiology, Center for Magnetic Imaging Research, University of Minnesota, Minneapolis, Minnesota, USA
| | - Xiao-Hong Zhu
- Department of Radiology, Center for Magnetic Imaging Research, University of Minnesota, Minneapolis, Minnesota, USA
| | | | | | - Yi Zhang
- Department of Radiology, Center for Magnetic Imaging Research, University of Minnesota, Minneapolis, Minnesota, USA
| | - Wei Chen
- Department of Radiology, Center for Magnetic Imaging Research, University of Minnesota, Minneapolis, Minnesota, USA
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Dynamic perfusion and diffusion MRI of cortical spreading depolarization in photothrombotic ischemia. Neurobiol Dis 2014; 71:131-9. [PMID: 25066776 DOI: 10.1016/j.nbd.2014.07.005] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2014] [Revised: 06/15/2014] [Accepted: 07/16/2014] [Indexed: 11/21/2022] Open
Abstract
Cortical spreading depolarization (CSD) is known to exacerbate ischemic damage, as the number of CSDs correlates with the final infarct volumes and suppressing CSDs improves functional outcomes. To investigate the role of CSD in ischemic damage, we developed a novel rat model of photothrombotic ischemia using a miniature implantable optic fiber that allows lesion induction inside the magnetic resonance imaging (MRI) scanner. We were able to precisely control the location and the size of the ischemic lesion, and continuously monitor dynamic perfusion and diffusion MRI signal changes at high temporal resolution before, during and after the onset of focal ischemia. Our model showed that apparent diffusion coefficient (ADC) and cerebral blood flow (CBF) in the ischemic core dropped immediately after lesion onset by 20±6 and 41±23%, respectively, and continually declined over the next 5h. Meanwhile, CSDs were observed in all animals (n=36) and displayed either a transient decrease of ADC by 17±3% or an increase of CBF by 104±15%. All CSDs were initiated from the rim of the ischemic core, propagated outward, and confined to the ipsilesional cortex. Additionally, we demonstrated that by controlling the size of perfusion-diffusion mismatch (which approximates the penumbra) in our model, the number of CSDs correlated with the mismatch area rather than the final infarct volume. This study introduces a novel platform to study CSDs in real-time with high reproducibility using MRI.
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Oligogenesis and oligodendrocyte progenitor maturation vary in different brain regions and partially correlate with local angiogenesis after ischemic stroke. Transl Stroke Res 2013; 2:366-75. [PMID: 22022343 DOI: 10.1007/s12975-011-0078-0] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
Oligogenesis plays an important role in functional recovery after ischemic stroke. We tested the hypothesis that oligogenesis and the maturation of oligodendrocyte progenitor cells (OPCs) vary in different brain regions using a rat transient middle cerebral artery occlusion (tMCAO) model. Compared to Day 1, olig2(+) OPCs and oligodendrocytes (OLGs) increased in the peri-infarct basal ganglia (BG) 7 (44%) and 14 (61%) days after 2 hours of MCAO; OPCs (PDGFRα(+)) and OLGs (CC1(+)) increased in this region 14 days after tMCAO by 139% and 126%, respectively. Although the olig2(+) cells and OLGs did not increase significantly in the peri-infarct cortex (CTX), the OPCs increased in this region by 95% at Day 14 vs. Day 1 after tMCAO. The numbers of OPCs and OLGs remained low after an initial reduction at Day 1 in the peri-infarct corpus callosum (CC). Correlation analyses showed that the numbers of olig2(+) cells (r=0.73, P=0.03) and OLGs (r=0.74, P=0.02) correlated with local vessel density; however, the number of OPCs did not correlate with vessel density (r=0.43, P=0.24). Our data show that oligogenesis and the maturation of OPCs differ in various brain regions and the difference in regional angiogenic response is one of the potential reasons.
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Campbell BCV, Macrae IM. Translational Perspectives on Perfusion–Diffusion Mismatch in Ischemic Stroke. Int J Stroke 2013; 10:153-62. [DOI: 10.1111/ijs.12186] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Magnetic resonance imaging has tremendous potential to illuminate ischemic stroke pathophysiology and guide rational treatment decisions. Clinical applications to date have been largely limited to trials. However, recent analyses of the major clinical studies have led to refinements in selection criteria and improved understanding of the potential implications for the risk vs. benefit of thrombolytic therapy. In parallel, preclinical studies have provided complementary information on the evolution of stroke that is difficult to obtain in humans due to the requirement for continuous or repeated imaging and pathological verification. We review the clinical and preclinical advances that have led to perfusion–diffusion mismatch being applied in phase 3 randomized trials and, potentially, future routine clinical practice.
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Affiliation(s)
- Bruce C. V. Campbell
- Department of Medicine and Neurology, Melbourne Brain Centre at the Royal Melbourne Hospital, University of Melbourne, Victoria, Australia
| | - I. Mhairi Macrae
- Institute of Neuroscience and Psychology, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, UK
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Kim JH, Na DG, Chang KH, Song IC, Choi SH, Son KR, Kim KW, Sohn CH. Serial MR analysis of early permanent and transient ischemia in rats: diffusion tensor imaging and high b value diffusion weighted imaging. Korean J Radiol 2013; 14:307-15. [PMID: 23482695 PMCID: PMC3590345 DOI: 10.3348/kjr.2013.14.2.307] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2012] [Accepted: 09/04/2012] [Indexed: 11/15/2022] Open
Abstract
Objective To evaluate the temporal evolution and diagnostic values of the diffusion tensor imaging (DTI) and the high b value diffusion weighted imaging (DWI) in the early permanent and transient cerebral ischemia. Materials and Methods For permanent or 30-minute transient-ischemia induced 30 rats, DTI and DWIs at both high b (b = 3000 s/mm2) and standard b value (b = 1000 s/mm2) were obtained at the following conditions: at 15, 30, 45, 60 minutes after the occlusion of what for hyperacute permanent ischemia; at 1, 3, 5, 7, 9 hours after the occlusion for acute permanent ischemia; and at 15 minutes before reperfusion, 0.5, 2.5, and 24 hours after reperfusion for transient ischemia. The diffusion parameters and their ratios were obtained and compared between different b values, and among different time points and groups, respectively. Results For both b values, the apparent diffusion coefficient (ADC) ratio decreased for first three hours, and then slightly increased until 9 hours after the occlusion during a gradual continuous increase of DWI signal intensity (SI) ratio, with excellent correlation between ADC ratios and DWI SI ratios. The DWI showed a higher contrast ratio, but the ADC map showed a lower contrast ratio for permanent ischemia at high b value than at standard b value. Fractional anisotropy (FA) increased for 1 hour, then gradually decreased until 9 hours after the occlusion in permanent ischemia and showed transient normalization and secondary decay along with change in ADC in transient ischemia. Conclusion This study presents characteristic initial elevation and secondary decay of FA, higher contrast ratio of DWI, and lower contrast ratio of ADC map at high b value, in addition to the time evolutions of diffusion parameters in early permanent and transient ischemia.
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Affiliation(s)
- Ji-hoon Kim
- Department of Radiology, Seoul National University Hospital, Seoul 110-744, Korea
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Balasanyan MG, Yeritsyan EL, Topchyan AV, Karamyan ST, Galoyan AA. The cerebrovascular effects of PRP-1. NEUROCHEM J+ 2012. [DOI: 10.1134/s1819712412030038] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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Abstract
Stroke is a leading cause of death and adult morbidity worldwide. By defining stroke symptom onset by the time the patient was last known to be well, many patients whose onsets are unwitnessed are automatically ineligible for thrombolytic therapy. Advanced brain imaging may serve as a substitute witness to estimate stroke onset and duration in those patients who do not have a human witness. This article reviews and compares some of these imaging-based approaches to thrombolysis eligibility, which can potentially expand the use of thrombolytic therapy to a broader population of acute stroke patients.
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Affiliation(s)
- Ona Wu
- Department of Radiology, MGH/MIT/HMS Athinoula A. Martinos Center for Biomedical Imaging, MGH, 149 Thirteenth Street Suite 2301, Charlestown, MA 02129, USA.
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Affiliation(s)
- Dae-Yul Kim
- Department of Rehabilitation Medicine, Asan Medical Center, University of Ulsan College Medicine, Korea
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Characterization of gadolinium-based dynamic susceptibility contrast perfusion measurements in permanent and transient MCAO models with volumetric based validation by CASL. J Cereb Blood Flow Metab 2010; 30:336-42. [PMID: 19826434 PMCID: PMC2949116 DOI: 10.1038/jcbfm.2009.218] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Perfusion imaging is crucial in imaging of ischemic stroke to determine 'tissue at risk' for infarction. In this study we compared the volumetric quantification of the perfusion deficit in two rat middle-cerebral-artery occlusion (MCAO) models using two gadolinium-based contrast agents (P1152 (Guerbet) and Magnevist (Bayer-Schering, Pittsburgh, PA, USA)) as compared with our well established continuous arterial spin labeling (CASL) perfusion imaging technique. Animals underwent either permanent MCAO or transient MCAO with 80-min reperfusion. Imaging was performed at four different time points after MCAO. A region-of-interest (ROI) analysis of the subregions of the ischemic zone (core, penumbra, transient reversal (TR), and sustained reversal (SR)) using P1152 showed significant reduction in blood flow in the core and TR subregions relative to the penumbral and SR subregions while occluded. After reperfusion, a significant increase in blood flow was recorded at all time points after reperfusion in all regions except TR. From the ROI analysis the threshold for the penumbra was determined to be -62+/-11% and this value was subsequently used for quantification of the volumetric deficit. The ischemic volume as defined by dynamic susceptibility contrast (DSC), was only statistically different from the CASL-derived ischemic volume when using Magnevist at post-reperfusion time points.
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Sicard KM, Fisher M. Animal models of focal brain ischemia. EXPERIMENTAL & TRANSLATIONAL STROKE MEDICINE 2009; 1:7. [PMID: 20150985 PMCID: PMC2820445 DOI: 10.1186/2040-7378-1-7] [Citation(s) in RCA: 62] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 07/16/2009] [Accepted: 11/13/2009] [Indexed: 11/25/2022]
Abstract
Stroke is a leading cause of disability and death in many countries. Understanding the pathophysiology of ischemic injury and developing therapies is an important endeavor that requires much additional research. Animal stroke models provide an important mechanism for these activities. A large number of stroke models have been developed and are currently used in laboratories around the world. These models are overviewed as are approaches for measuring infarct size and functional outcome.
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Affiliation(s)
- Kenneth M Sicard
- Department of Neurology, University of Massachusetts Medical School, 55 Lake Avenue North, Worcester, MA 01453, USA
| | - Marc Fisher
- Department of Neurology, University of Massachusetts Medical School, 55 Lake Avenue North, Worcester, MA 01453, USA
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19
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Abstract
Ischemic stroke occurs most often in the territory of the middle cerebral artery (MCA) in humans. Since its description in rats more than two decades ago, the minimally invasive intraluminal suture occlusion of MCA is an increasingly used model of stroke in both rats and mice due to its ease of inducing ischemia and achieving reperfusion under well-controlled conditions. This method can be used under the guidance of laser-Doppler flowmetry to ascertain the magnitude of occlusion or reperfusion and to decrease the rate of subarachnoid hemorrhage. Ninety minutes of transient ischemia in the territory of MCA results in substantial and reproducible ischemic lesions in both the striatum and the cortex, with characteristics of lesion core and penumbra. Thus, this model is applicable to neuroprotective drug studies, including ischemic brain lesion evaluation (either in vivo with magnetic resonance imaging or post-mortem with brain tissue staining) and neurological status (motor deficits simply assessed by a six-point neurological score scale) as outcome parameters.
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Affiliation(s)
- Aysan Durukan
- Department of Neurology, Helsinki University Central Hospital, Helsinki, Finland
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Dave JR, Williams AJ, Yao C, Lu XCM, Tortella FC. Modeling cerebral ischemia in neuroproteomics. Methods Mol Biol 2009; 566:25-40. [PMID: 20058162 DOI: 10.1007/978-1-59745-562-6_2] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
Protein changes induced by traumatic or ischemic brain injury can serve as diagnostic markers as well as therapeutic targets for neuroprotection. The focus of this chapter is to provide a representative overview of preclinical brain injury and proteomics analysis protocols for evaluation and discovery of novel biomarkers. Detailed surgical procedures have been provided for inducing MCAo and implantation of chronic indwelling cannulas for drug delivery. Sample collection and tissue processing techniques for collection of blood, CSF, and brain are also described including standard biochemical methodology for the proteomic analysis of these tissues.The dynamics of proteomic analysis is a multistep process comprising sample preparation, separation, quantification, and identification of proteins. Our approach is to separate proteins first by two-dimensional gel electrophoresis according to charge and molecular mass. Proteins are then fragmented and analyzed using matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS). Identification of proteins can be achieved by comparing the mass-to-charge data to protein sequences in respective databases.
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Affiliation(s)
- Jitendra R Dave
- Department of Applied Neurobiology, Walter Reed Army Institute of Research, Silver Spring, MD, USA.
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Effectiveness of a new modified intraluminal suture for temporary middle cerebral artery occlusion in rats of various weight. J Neurosci Methods 2008; 173:225-34. [DOI: 10.1016/j.jneumeth.2008.06.018] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2008] [Revised: 05/12/2008] [Accepted: 06/10/2008] [Indexed: 11/20/2022]
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23
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Henninger N, Bouley J, Nelligan JM, Sicard KM, Fisher M. Normobaric hyperoxia delays perfusion/diffusion mismatch evolution, reduces infarct volume, and differentially affects neuronal cell death pathways after suture middle cerebral artery occlusion in rats. J Cereb Blood Flow Metab 2007; 27:1632-42. [PMID: 17311078 DOI: 10.1038/sj.jcbfm.9600463] [Citation(s) in RCA: 94] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Normobaric hyperoxia (NBO) has been shown to extend the reperfusion window after focal cerebral ischemia. Employing diffusion (DWI)- and perfusion (PWI)-weighted magnetic resonance imaging (MRI), the effect of NBO (100% started at 30 mins after middle cerebral artery occlusion (MCAO)) on the spatiotemporal evolution of ischemia during and after permanent (pMCAO) and transient suture middle cerebral artery occlusion (tMCAO) was investigated (experiment 3). In two additional experiments, time window (experiment 1) and cell death pathways (experiment 2) were investigated in the pMCAO model. In experiment 1, NBO treatment reduced infarct volume at 24 h after pMCAO by 10% when administered for 3 h (P>0.05) and by 44% when administered for 6 h (P<0.05). In experiment 2, NBO acutely (390 mins, P<0.05) reduced in situ end labeling (ISEL) positivity in the ipsilesional penumbra but increased contralesional necrotic as well as caspase-3-mediated apoptotic cell death. In experiment 3, CBF characteristics and CBF-derived lesion volumes did not differ between treated and untreated animals, whereas the apparent diffusion coefficient (ADC)-derived lesion volume essentially stopped progressing during NBO treatment, resulting in a persistent PWI/DWI mismatch that could be salvaged by delayed (3 h) reperfusion. In conclusion, NBO (1) acutely preserved the perfusion/diffusion mismatch without altering CBF, (2) significantly extended the time window for reperfusion, (3) induced lasting neuroprotection in permanent ischemia, and (4) although capable of reducing cell death in hypoperfused tissue it also induced cell death in otherwise unaffected areas. Our data suggest that NBO may represent a promising strategy for acute stroke treatment.
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Affiliation(s)
- Nils Henninger
- Department of Neurology, University of Massachusetts Medical School, Worcester, Massachusetts, USA.
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24
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Durukan A, Tatlisumak T. Acute ischemic stroke: overview of major experimental rodent models, pathophysiology, and therapy of focal cerebral ischemia. Pharmacol Biochem Behav 2007; 87:179-97. [PMID: 17521716 DOI: 10.1016/j.pbb.2007.04.015] [Citation(s) in RCA: 501] [Impact Index Per Article: 29.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/04/2006] [Revised: 04/16/2007] [Accepted: 04/19/2007] [Indexed: 12/22/2022]
Abstract
Ischemic stroke is a devastating disease with a complex pathophysiology. Animal modeling of ischemic stroke serves as an indispensable tool first to investigate mechanisms of ischemic cerebral injury, secondly to develop novel antiischemic regimens. Most of the stroke models are carried on rodents. Each model has its particular strengths and weaknesses. Mimicking all aspects of human stroke in one animal model is not possible since ischemic stroke is itself a very heterogeneous disorder. Experimental ischemic stroke models contribute to our understanding of the events occurring in ischemic and reperfused brain. Major approaches developed to treat acute ischemic stroke fall into two categories, thrombolysis and neuroprotection. Trials aimed to evaluate effectiveness of recombinant tissue-type plasminogen activator in longer time windows with finer selection of patients based on magnetic resonance imaging tools and trials of novel recanalization methods are ongoing. Despite the failure of most neuroprotective drugs during the last two decades, there are good chances to soon have effective neuroprotectives with the help of improved preclinical testing and clinical trial design. In this article, we focus on various rodent animal models, pathogenic mechanisms, and promising therapeutic approaches of ischemic stroke.
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Affiliation(s)
- Aysan Durukan
- Department of Neurology, Helsinki University Central Hospital, Biomedicum Helsinki, POB 700, Haartmaninkatu 8, 00290 Helsinki, Finland.
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25
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Sicard KM, Henninger N, Fisher M, Duong TQ, Ferris CF. Differential recovery of multimodal MRI and behavior after transient focal cerebral ischemia in rats. J Cereb Blood Flow Metab 2006; 26:1451-62. [PMID: 16538230 PMCID: PMC2962954 DOI: 10.1038/sj.jcbfm.9600299] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The association between recovery of brain function and behavior after transient cerebral ischemia in animals and humans is incompletely characterized. Quantitative diffusion- (DWI), perfusion- (PWI), T(2)-weighted (T(2)WI), and functional magnetic resonance imaging (fMRI) were performed before, during, and up to 1 day after 20-mins transient middle cerebral artery occlusion (tMCAO; n=6) or sham operation (n=6) in male Sprague-Dawley rats. Viability thresholds were employed to calculate diffusion, perfusion, and T(2) lesion volumes. Region of interest analysis was used to evaluate structural and functional MR signal changes within the sensorimotor network, which were then related to corresponding behavioral measures. Post-mortem 2,3,5-triphenyltetrazolium chloride (TTC) staining was performed 24 h after ischemia. Transient middle cerebral artery occlusion produced lesions on DWI and PWI, which fully recovered by 30 mins after reperfusion. Ipsilesional fMRI responses to hypercapnia and forepaw stimulation were significantly impaired after ischemia and did not fully normalize until 3 and 24 h after tMCAO, respectively. No abnormalities were observed on imaging or TTC at 24 h despite significant behavioral dysfunctions including contralesional forelimb impairment and ipsilesional neglect. No MRI, behavioral, or TTC anomalies were observed in sham-operated rats. There were no significant correlations between MRI parameters, behavior, and TTC in either group. Together, these results suggest that normal findings on diffusion, perfusion, and T(2) imaging shortly after transient ischemia may not indicate normal tissue status as indicated by fMRI and behavior, which may help explain the persistence of neurologic deficits in patients with normal conventional MRI after cerebral ischemia.
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Affiliation(s)
- Kenneth M Sicard
- Department of Psychiatry, Center for Comparative NeuroImaging, University of Massachusetts Medical School, Worcester, Massachusetts 01604, USA.
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26
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Shimamura N, Matchett G, Tsubokawa T, Ohkuma H, Zhang J. Comparison of silicon-coated nylon suture to plain nylon suture in the rat middle cerebral artery occlusion model. J Neurosci Methods 2006; 156:161-5. [PMID: 16569436 DOI: 10.1016/j.jneumeth.2006.02.017] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2005] [Revised: 02/08/2006] [Accepted: 02/20/2006] [Indexed: 12/17/2022]
Abstract
UNLABELLED A variety of intraluminal sutures have been used in the middle cerebral artery occlusion model (MCAO) of focal ischemia. In the present study we tested commercially available silicon-coated nylon suture in the MCAO model and compared the results to traditional monofilament nylon suture occlusion. Twelve Sprague-Dawley male rats were randomly divided two groups, MCAO with 4-0 nylon suture (Group N, n=6) and MCAO with silicone-coated 4-0 nylon suture (Group S, n=6). Rats were sacrificed 24 h after reperfusion. Assessment included mortality rates, neurological evaluation, and infarct volume. One rat died in each group from subarachanoid hemorrhage. Neurological evaluation demonstrated that Group S tended to have worse neurological outcomes than Group N, although this difference was not statistically significant. On TTC stain Group S had significantly larger infarct volumes than Group N. We conclude that the commercially available silicone-coated occlusion suture provides better occlusion of the middle cerebral artery than the traditional uncoated nylon suture. CLASSIFICATION Disease-related neuroscience (Section 6).
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Affiliation(s)
- Norihito Shimamura
- Department of Physiology and Pharmacology, Loma Linda University School of Medicine, Loma Linda, CA 92350, USA
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27
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Gerriets T, Stolz E, Walberer M, Müller C, Kluge A, Kaps M, Fisher M, Bachmann G. Middle cerebral artery occlusion during MR-imaging: investigation of the hyperacute phase of stroke using a new in-bore occlusion model in rats. ACTA ACUST UNITED AC 2004; 12:137-43. [PMID: 15013464 DOI: 10.1016/j.brainresprot.2003.08.006] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2003] [Revised: 08/04/2003] [Accepted: 08/21/2003] [Indexed: 11/15/2022]
Abstract
Magnetic resonance imaging (MRI) provides insights into the dynamics of focal cerebral ischemia. Usually, experimental stroke is induced outside the magnet bore, preventing investigators from acquiring pre-ischemic images for later pixel-by-pixel comparisons and from studying the earliest changes in the hyperacute phase of ischemia. Herein, we introduce a new and easy to apply in-bore occlusion protocol based on the intraarterial embolization of ceramic macrospheres. PE-50 tubing, filled with saline and six macrospheres (0.315-0.355 mm in diameter), was placed into the internal carotid artery (ICA) of anesthetized Sprague-Dawley rats. The animals were transferred into an MRI scanner (7.0 T) and baseline diffusion-weighted imaging (DWI) and T2-imaging was performed. Then the macrospheres were injected into the internal artery to occlude the MCA. Post-ischemic DWI and T2-imaging was started immediately thereafter. The apparent diffusion coefficient (ADC) (a marker for cytotoxic brain edema) and T2-relaxation time (a marker for vasogenic brain edema) were determined in the ischemic lesions and compared to the unaffected hemisphere. ADC significantly declined within the first 5-10 min after stroke onset. T2-relaxation time increased as early as at the first T2-imaging time-point (20-35 min after embolization). After 150 min of ischemia, the lesions covered 18.0 +/- 7.4% of the hemispheres. The model failed in one out of nine animals (11%). This model allows MR-imaging from the initial minutes after permanent middle cerebral artery (MCA) occlusion. It does not permit reperfusion. This technique might provide information about the pathophysiological processes in the hyperacute phase of stroke.
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Affiliation(s)
- Tibo Gerriets
- Department of Radiology-Experimental Neurology Research Group Kerckhoff Klinik Bad Nauheim, Germany.
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28
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Schwartz ED, Hackney DB. Diffusion-weighted MRI and the evaluation of spinal cord axonal integrity following injury and treatment. Exp Neurol 2003; 184:570-89. [PMID: 14769351 DOI: 10.1016/s0014-4886(03)00295-4] [Citation(s) in RCA: 74] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2003] [Revised: 05/14/2003] [Accepted: 05/28/2003] [Indexed: 11/19/2022]
Abstract
Diffusion-based magnetic resonance imaging (MRI) (DWI) has been shown experimentally to detect both injury and functionally significant neuroprotection of injured spinal cord white matter that would otherwise go undetected with conventional MRI techniques. The diffusion of water in the central nervous system (CNS) is thought to be affected by both its location (intracellular or extracellular), and by diffusion barriers formed by cell membranes and myelin sheaths. There is, however, controversy concerning how to obtain, interpret, and present DWI data. Computer simulations and MR microscopy have been helpful in resolving some of these issues, as well as determining exact histologic correlates to DWI findings.
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Affiliation(s)
- Eric D Schwartz
- Department of Radiology, Hospital of the University of Pennsylvania, 3400 Spruce Street, 1 Silverstein, Philadelphia, PA 19104, USA.
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29
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Leker RR, Constantini S. Experimental models in focal cerebral ischemia: are we there yet? ACTA NEUROCHIRURGICA. SUPPLEMENT 2003; 83:55-9. [PMID: 12442622 DOI: 10.1007/978-3-7091-6743-4_10] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/27/2023]
Abstract
Therapeutic options available for acute stroke management are sparse and inadequate. Therefore, new insights into stroke pathophysiology leading to new therapeutic targets are needed. In order to attain these goals, adequate animal models for cerebral ischemia are needed. In the following paper the authors will review the various animal models for stroke and emphasize their potential strengths and weaknesses.
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Affiliation(s)
- R R Leker
- Department of Neurology, Agnes Ginges Center for Human Neurogenetics, Hadassah University Hospital, Jerusalem, Israel
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30
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Riyamongkol P, Zhao W, Liu Y, Belayev L, Busto R, Ginsberg MD. Automated registration of laser Doppler perfusion images by an adaptive correlation approach: application to focal cerebral ischemia in the rat. J Neurosci Methods 2002; 122:79-90. [PMID: 12535767 DOI: 10.1016/s0165-0270(02)00294-7] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Hemodynamic changes are extremely important in analyzing responses from a brain subjected to a stimulus or treatment. The Laser Doppler technique has emerged as an important tool in neuroscience research. This non-invasive method scans a low-power laser beam in a raster pattern over a tissue surface to generate the time course of images in unit of relative flux changes. Laser Doppler imager (LDI) records cerebral perfusion not only in the temporal but also in the spatial domain. The traditional analysis of LD images has been focused on the region-of-interest (ROI) approach, in which the analytical accuracy in an experiment that necessitates a relative repositioning between the LDI and the scanned tissue area will be weakened due to the operator's subjective decision in data collecting. This report describes a robust image registration method designed to obviate this problem, which is based on the adaptive correlation approach. The assumption in mapping corresponding pixels in two images is to correlate the regions in which these pixels are centered. Based on this assumption, correlation coefficients are calculated between two regions by a method in which one region is moved around over the other in all possible combinations. To avoid ambiguity in distinguishing maximum correlation coefficients, an adaptive algorithm is adopted. Correspondences are then used to estimate the transformation by linear regression. We used a pair of phantom LD images to test this algorithm. A reliability test was also performed on each of the 15 sequential LD images derived from an actual experiment by imposing rotation and translation. The result shows that the calculated transformation parameters (rotation: theta =7.7+/-0.5 degrees; translation: Delta x =2.8+/-0.3, Deltaŷ=4.7+/-0.4) are very close to the prior-set parameters (rotation: theta=8 degrees; translation: Delta x=3, Delta y=5). This result indicates that this approach is a valuable adjunct to LD perfusion monitoring. An original sequence of LD images that recorded cerebral perfusion through a cranial window before, during and after middle cerebral artery occlusion (MCAo) is presented, together with the registered image sequence. Cerebral perfusion data acquired in a pixel-based manner from different anatomic locations of the registered LD image sequence are also presented over the whole time-course of the experiment.
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Affiliation(s)
- Panomkhawn Riyamongkol
- Department of Electrical and Computer Engineering, University of Miami College of Engineering, PO Box 248294, Coral Gables, FL 33124-0640, USA
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Yushmanov VE, Wang L, Liachenko S, Tang P, Xu Y. ADC characterization of region-specific response to cerebral perfusion deficit in rats by MRI at 9.4 T. Magn Reson Med 2002; 47:562-70. [PMID: 11870844 DOI: 10.1002/mrm.10103] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Region-specific cerebral blood flow (CBF) and apparent diffusion coefficient (ADC) of water in the rat brain were quantified in vivo by high-field MRI (9.4 T) for 6-7 h after middle cerebral artery occlusion (MCAO). Upon occlusion, average CBF fell from about 1.5-2 ml/g/min to below 0.5 ml/g/min in cortical areas and the amygdala, and below 0.2 ml/g/min in the caudate putamen. CBF in some of the homologous contralateral areas also decreased by 20-30%. Average ADC decreased from about 8 center dot 10(-4) to 5 center dot 10(-4) mm(2)/s in the caudate putamen and parietal cortex. Corresponding changes in ADC were lower in the frontal cortex and negligible in the piriform cortex, suggesting that the perfusion threshold for ADC decrease may be different for different brain regions in the same animal. The area of decreased ADC correlated well with the infarction area revealed by 2,3,5-triphenyltetrazolium chloride (TTC) staining of brain slices in vitro. A better understanding of the mechanisms linking ADC and CBF changes to ischemic cell disorders may prove useful in characterizing the degree of tissue damage, and in developing and evaluating treatment strategies.
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Affiliation(s)
- Victor E Yushmanov
- Department of Anesthesiology and Critical Care Medicine, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA
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32
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Carano RA, Li F, Irie K, Helmer KG, Silva MD, Fisher M, Sotak CH. Multispectral analysis of the temporal evolution of cerebral ischemia in the rat brain. J Magn Reson Imaging 2000; 12:842-58. [PMID: 11105022 DOI: 10.1002/1522-2586(200012)12:6<842::aid-jmri7>3.0.co;2-5] [Citation(s) in RCA: 67] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
A major difficulty in staging and predicting ischemic brain injury by magnetic resonance (MR) imaging is the time-varying nature of the MR parameters within the ischemic lesion. A new multispectral (MS) approach is described to characterize cerebral ischemia in a time-independent fashion. MS analysis of five MR parameters (mean diffusivity, diffusion anisotropy, T2, proton density, and perfusion) was employed to characterize the progression of ischemic lesion in the rat brain following 60 minutes of transient focal ischemia. k-Means (KM) and fuzzy c-means (FCM) classification methods were employed to define the acute and subacute ischemic lesion. KM produced an estimate of lesion volume that was highly correlated with postmortem infarct volume, independent of the age of the lesion. Overall classification rates for KM exceeded FCM at acute and subacute time points as follows: KM, 90.5%, 94.4%, and 95. 9%; FCM, 82.4%, 90.6%, and 82.6% (for 45 minutes, 180 minutes, and 24-120 hours post MCAO groups). MS analysis also offers a formal method of combining diffusion and perfusion parameters to provide an estimate of the ischemic penumbra (KM classification rate = 70.3%). J. Magn. Reson. Imaging 2000;12:842-858.
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Affiliation(s)
- R A Carano
- Department of Biomedical Engineering, Worcester Polytechnic Institute, Worcester, Massachusetts 01609, USA
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33
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Lythgoe MF, Thomas DL, Calamante F, Pell GS, King MD, Busza AL, Sotak CH, Williams SR, Ordidge RJ, Gadian DG. Acute changes in MRI diffusion, perfusion, T(1), and T(2) in a rat model of oligemia produced by partial occlusion of the middle cerebral artery. Magn Reson Med 2000; 44:706-12. [PMID: 11064405 DOI: 10.1002/1522-2594(200011)44:5<706::aid-mrm8>3.0.co;2-1] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Oligemic regions, in which the cerebral blood flow is reduced without impaired energy metabolism, have the potential to evolve toward infarction and remain a target for therapy. The aim of this study was to investigate this oligemic region using various MRI parameters in a rat model of focal oligemia. This model has been designed specifically for remote-controlled occlusion from outside an MRI scanner. Wistar rats underwent remote partial MCAO using an undersize 0.2 mm nylon monofilament with a bullet-shaped tip. Cerebral blood flow (CBF(ASL)), using an arterial spin labeling technique, the apparent diffusion coefficient of water (ADC), and the relaxation times T(1) and T(2) were acquired using an 8.5 T vertical magnet. Following occlusion there was a decrease in CBF(ASL) to 35 +/- 5% of baseline throughout the middle cerebral artery territory. During the entire period of the study there were no observed changes in the ADC. On occlusion, T(2) rapidly decreased in both cortex and basal ganglia and then normalized to the preocclusion values. T(1) values rapidly increased (within approximately 7 min) on occlusion. In conclusion, this study demonstrates the feasibility of partially occluding the middle cerebral artery to produce a large area of oligemia within the MRI scanner. In this region of oligemic flow we detect a rapid increase in T(1) and decrease in T(2). These changes occur before the onset of vasogenic edema. We attribute the acute change in T(2) to increased amounts of deoxyhemoglobin; the mechanisms underlying the change in T(1) require further investigation.
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Affiliation(s)
- M F Lythgoe
- Royal College of Surgeons Unit of Biophysics, Institute of Child Health, University College London, London, UK.
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Li F, Carano RA, Irie K, Sotak CH, Fisher M. Temporal evolution of average apparent diffusion coefficient threshold to define ischemic abnormalities in a rat permanent occlusion model. J Stroke Cerebrovasc Dis 2000. [DOI: 10.1016/s1052-3057(00)94357-x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
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Li F, Han SS, Tatlisumak T, Liu KF, Garcia JH, Sotak CH, Fisher M. Reversal of acute apparent diffusion coefficient abnormalities and delayed neuronal death following transient focal cerebral ischemia in rats. Ann Neurol 1999; 46:333-42. [PMID: 10482264 DOI: 10.1002/1531-8249(199909)46:3<333::aid-ana9>3.0.co;2-x] [Citation(s) in RCA: 114] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Twenty-two rats were subjected to 8, 15, 30, or 60 minutes of temporary middle cerebral artery occlusion (n = 5 per group) or sham occlusion (n = 2) in the magnetic resonance imaging unit. Diffusion-, perfusion-, and T2-weighted imaging were acquired before and during occlusion, and after reperfusion. A coregistration method was used to correlate the acute changes of the average apparent diffusion coefficient (ADCav) with the histology after 72 hours at the same topographic sites. The initially reduced ADCav values recovered completely in both the lateral caudoputamen and upper frontoparietal cortex in the 8-, 15-, and 30-minute groups, partially in the cortex, and not at all in the caudoputamen in the 60-minute group. The histology showed that the caudoputamen was either normal or had mild neuronal injury in the 8-minute group and invariably had some degree of neuronal death in the 15-, 30-, and 60-minute groups, whereas the cortex was either normal or had varying degrees of neuronal injury in all groups. No histological abnormalities were seen in the sham-operated rats. Our data suggest that acute ADCav reversal does not always predict tissue recovery from ischemic injury and that temporary focal ischemia for even 8-minute duration can cause delayed neuronal death that is more severe in the caudoputamen where the initial ADCav decline was greater than in the cortex.
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Affiliation(s)
- F Li
- Department of Neurology, UMass Memorial Health Care, Worcester, MA 01605, USA
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Fisher M, Albers GW. Applications of diffusion-perfusion magnetic resonance imaging in acute ischemic stroke. Neurology 1999; 52:1750-6. [PMID: 10371519 DOI: 10.1212/wnl.52.9.1750] [Citation(s) in RCA: 114] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
Diffusion-weighted imaging (DWI) and perfusion imaging (PI) are two new magnetic resonance technologies that are becoming increasingly available for evaluation of acute ischemic stroke patients. DWI provides information about the location of acute focal ischemic brain injury at early time points and PI can document the presence of disturbances in microcirculatory perfusion. DWI and PI are now being used in clinical practice and in clinical trials of potential acute stroke therapies to assess their utility. In the future, DWI and PI may aid in the development of effective acute stroke therapies and help identify which stroke patients are most likely to benefit from specific agents.
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Affiliation(s)
- M Fisher
- Department of Neurology, University of Massachusetts Medical School, Worcester, USA
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