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Koukalova L, Chmelova M, Amlerova Z, Vargova L. Out of the core: the impact of focal ischemia in regions beyond the penumbra. Front Cell Neurosci 2024; 18:1336886. [PMID: 38504666 PMCID: PMC10948541 DOI: 10.3389/fncel.2024.1336886] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2023] [Accepted: 02/08/2024] [Indexed: 03/21/2024] Open
Abstract
The changes in the necrotic core and the penumbra following induction of focal ischemia have been the focus of attention for some time. However, evidence shows, that ischemic injury is not confined to the primarily affected structures and may influence the remote areas as well. Yet many studies fail to probe into the structures beyond the penumbra, and possibly do not even find any significant results due to their short-term design, as secondary damage occurs later. This slower reaction can be perceived as a therapeutic opportunity, in contrast to the ischemic core defined as irreversibly damaged tissue, where the window for salvation is comparatively short. The pathologies in remote structures occur relatively frequently and are clearly linked to the post-stroke neurological outcome. In order to develop efficient therapies, a deeper understanding of what exactly happens in the exo-focal regions is necessary. The mechanisms of glia contribution to the ischemic damage in core/penumbra are relatively well described and include impaired ion homeostasis, excessive cell swelling, glutamate excitotoxic mechanism, release of pro-inflammatory cytokines and phagocytosis or damage propagation via astrocytic syncytia. However, little is known about glia involvement in post-ischemic processes in remote areas. In this literature review, we discuss the definitions of the terms "ischemic core", "penumbra" and "remote areas." Furthermore, we present evidence showing the array of structural and functional changes in the more remote regions from the primary site of focal ischemia, with a special focus on glia and the extracellular matrix. The collected information is compared with the processes commonly occurring in the ischemic core or in the penumbra. Moreover, the possible causes of this phenomenon and the approaches for investigation are described, and finally, we evaluate the efficacy of therapies, which have been studied for their anti-ischemic effect in remote areas in recent years.
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Affiliation(s)
- Ludmila Koukalova
- Department of Neuroscience, Second Faculty of Medicine, Charles University, Prague, Czechia
| | - Martina Chmelova
- Department of Neuroscience, Second Faculty of Medicine, Charles University, Prague, Czechia
- Department of Cellular Neurophysiology, Institute of Experimental Medicine of the Czech Academy of Sciences, Prague, Czechia
| | - Zuzana Amlerova
- Department of Neuroscience, Second Faculty of Medicine, Charles University, Prague, Czechia
| | - Lydia Vargova
- Department of Neuroscience, Second Faculty of Medicine, Charles University, Prague, Czechia
- Department of Cellular Neurophysiology, Institute of Experimental Medicine of the Czech Academy of Sciences, Prague, Czechia
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2
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Astrakas LG, Li S, Elbach S, Tzika AA. The Severity of Sensorimotor Tracts Degeneration May Predict Motor Performance in Chronic Stroke Patients, While Brain Structural Network Dysfunction May Not. Front Neurol 2022; 13:813763. [PMID: 35432180 PMCID: PMC9008887 DOI: 10.3389/fneur.2022.813763] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2021] [Accepted: 03/11/2022] [Indexed: 11/13/2022] Open
Abstract
Although the relationship between corticospinal tract (CST) fiber degeneration and motor outcome after stroke has been established, the relationship of sensorimotor cortical areas with CST fibers has not been clarified. Also limited research has been conducted on how abnormalities in brain structural networks are related to motor recovery. To address these gaps in knowledge, we conducted a diffusion tensor imaging (DTI) study with 12 chronic stroke patients (CSPs) and 12 age-matched healthy controls (HCs). We compared fractional anisotropy (FA) and mean diffusivity (MD) in 60 CST segments using the probabilistic sensorimotor area tract template (SMATT). Least Absolute Shrinkage and Selection Operator (LASSO) regressions were used to select independent predictors of Fugl-Meyer upper extremity (FM-UE) scores among FA and MD values of SMATT regions. The Graph Theoretical Network Analysis Toolbox was used to assess the structural network of each subject's brain. Global and nodal metrics were calculated, compared between the groups, and correlated with FM-UE scores. Mann–Whitney U-tests revealed reduced FA values in CSPs, compared to HCs, in many ipsilesional SMATT regions and in two contralesional regions. Mean FA value of the left (L.) primary motor cortex (M1)/supplementary motor area (SMA) region was predictive of FM-UE score (P = 0.004). Mean MD values for the L. M1/ventral premotor cortex (PMv) region (P = 0.001) and L. PMv/SMA region (P = 0.001) were found to be significant predictors of FM-UE scores. Network efficiency was the only global metric found to be reduced in CSPs (P = 0.006 vs. HCs). Nodal efficiency of the L. hippocampus, L. parahippocampal gyrus, L. fusiform gyrus (P = 0.001), and nodal local efficiency of the L. supramarginal gyrus (P < 0.001) were reduced in CSPs relative to HCs. No graph metric was associated with FM-UE scores. In conclusion, the integrity of CSTs connected to M1, SMA, and PMv were shown to be independent predictors of motor performance in CSPs, while stroke-induced topological changes in the brain's structural connectome may not be. A sensorimotor cortex-specific tract template can refine CST degeneration data and the relationship of CST degeneration with motor performance.
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Affiliation(s)
- Loukas G. Astrakas
- Department of Medical Physics, Faculty of Medicine, University of Ioannina, Ioannina, Greece
| | - Shasha Li
- Department of Radiology, Athinoula A. Martinos Center of Biomedical Imaging, Massachusetts General Hospital, Harvard Medical School, Boston, MA, United States
- NMR Surgical Laboratory, Department of Surgery, Massachusetts General Hospital, Harvard Medical School, Boston, MA, United States
| | - Sabrina Elbach
- Department of Radiology, Athinoula A. Martinos Center of Biomedical Imaging, Massachusetts General Hospital, Harvard Medical School, Boston, MA, United States
- NMR Surgical Laboratory, Department of Surgery, Massachusetts General Hospital, Harvard Medical School, Boston, MA, United States
| | - A. Aria Tzika
- Department of Radiology, Athinoula A. Martinos Center of Biomedical Imaging, Massachusetts General Hospital, Harvard Medical School, Boston, MA, United States
- NMR Surgical Laboratory, Department of Surgery, Massachusetts General Hospital, Harvard Medical School, Boston, MA, United States
- *Correspondence: A. Aria Tzika
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3
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A pilot [ 11C]PBR28 PET/MRI study of neuroinflammation and neurodegeneration in chronic stroke patients. Brain Behav Immun Health 2021; 17:100336. [PMID: 34589819 PMCID: PMC8474408 DOI: 10.1016/j.bbih.2021.100336] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2021] [Revised: 08/18/2021] [Accepted: 08/21/2021] [Indexed: 11/24/2022] Open
Abstract
Neuroinflammation occurs in response to acute ischemic stroke, and has been speculated to underlie secondary poststroke pathologies, such as depression, that often develop over time poststroke. However, no study has examined whether neuroinflammation is present in chronic stroke patients (e.g., ≥ 1 year poststroke). This study tested whether neuroinflammation is present in chronic stroke patients, and is associated with neurodegeneration, using [11C]PBR28 PET and diffusion MRI. Eight patients with middle cerebral artery (MCA) ischemic stroke incurred 1–3 years prior and 16 healthy controls underwent [11C]PBR28 PET to measure glial activation and diffusion MRI to measure microstructural integrity by mean diffusivity (MD) and fractional anisotropy (FA) using an integrated PET/MRI scanner. Group differences in [11C]PBR28 binding, MD and FA were analyzed voxelwise across the whole brain excluding the infarct zone defined as voxels containing the infarct in any patient. Compared to controls, patients showed elevations in [11C]PBR28 binding in several brain regions outside the infarct zone, including regions with presumed direct neuroanatomical connections to the infarct (e.g., ipsilesional internal capsule and thalamus) and those without known direct connections (e.g., contralesional thalamus and cingulate gyrus). Patients also showed widespread elevations in MD, with a subset of these regions having reduced FA. In patients, MD was more elevated in regions with co-localized elevations in [11C]PBR28 binding than in contralateral regions without elevations in [11C]PBR28 binding. This pilot study supports the presence of extensive glial activation along with widespread loss in microstructural integrity in non-infarcted tissue in a cohort of patients with chronic MCA stroke. The loss in microstructural integrity was greater in regions with co-localized glial activation. It is possible that stroke risk factors (e.g., hypertension) contributed to these tissue changes in patients. Chronic neuroinflammation speculated to underlie secondary poststroke pathologies such as depression. Measured neuroinflammation in chronic stroke patients using [11C]PBR28 PET. First study showing extensive neuroinflammation in non-infarcted tissue in chronic stroke patients.
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Xia C, Zhou J, Lu C, Wang Y, Tang T, Cai Y, Ju S. Characterizing Diaschisis-Related Thalamic Perfusion and Diffusion After Middle Cerebral Artery Infarction. Stroke 2021; 52:2319-2327. [PMID: 33971741 DOI: 10.1161/strokeaha.120.032464] [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] [Indexed: 11/16/2022]
Abstract
[Figure: see text].
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Affiliation(s)
- Cong Xia
- Jiangsu Key Laboratory of Molecular and Functional Imaging, Department of Radiology, Zhongda Hospital, Medical School of Southeast University, Nanjing, China
| | - Jiaying Zhou
- Jiangsu Key Laboratory of Molecular and Functional Imaging, Department of Radiology, Zhongda Hospital, Medical School of Southeast University, Nanjing, China
| | - Chunqiang Lu
- Jiangsu Key Laboratory of Molecular and Functional Imaging, Department of Radiology, Zhongda Hospital, Medical School of Southeast University, Nanjing, China
| | - Yuancheng Wang
- Jiangsu Key Laboratory of Molecular and Functional Imaging, Department of Radiology, Zhongda Hospital, Medical School of Southeast University, Nanjing, China
| | - Tianyu Tang
- Jiangsu Key Laboratory of Molecular and Functional Imaging, Department of Radiology, Zhongda Hospital, Medical School of Southeast University, Nanjing, China
| | - Yu Cai
- Jiangsu Key Laboratory of Molecular and Functional Imaging, Department of Radiology, Zhongda Hospital, Medical School of Southeast University, Nanjing, China
| | - Shenghong Ju
- Jiangsu Key Laboratory of Molecular and Functional Imaging, Department of Radiology, Zhongda Hospital, Medical School of Southeast University, Nanjing, China
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Zolkefley MKI, Firwana YMS, Hatta HZM, Rowbin C, Nassir CMNCM, Hanafi MH, Abdullah MS, Mustapha M. An overview of fractional anisotropy as a reliable quantitative measurement for the corticospinal tract (CST) integrity in correlation with a Fugl-Meyer assessment in stroke rehabilitation. J Phys Ther Sci 2021; 33:75-83. [PMID: 33519079 PMCID: PMC7829559 DOI: 10.1589/jpts.33.75] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2020] [Accepted: 10/25/2020] [Indexed: 11/24/2022] Open
Abstract
[Purpose] Understanding the essential mechanisms in post-stroke recovery not only
provides important basic insights into brain function and plasticity but can also guide
the development of new therapeutic approaches for stroke patients. This review aims to
give an overview of how various variables of Magnetic Resonance-Diffusion Tensor Imaging
(MR-DTI) metrics of fractional anisotropy (FA) can be used as a reliable quantitative
measurement and indicator of corticospinal tract (CST) changes, particularly in relation
to functional motor outcome correlation with a Fugl-Meyer assessment in stroke
rehabilitation. [Methods] PubMed electronic database was searched for the relevant
literature, using key words of diffusion tensor imaging (dti), corticospinal tract, and
stroke. [Results] We reviewed the role of FA in monitoring CST remodeling and its role of
predicting motor recovery after stroke. We also discussed the mechanism of CST remodeling
and its modulation from the value of FA and FMA-UE. [Conclusion] Heterogeneity of
post-stroke brain disorganization and motor impairment is a recognized challenge in the
development of accurate indicators of CST integrity. DTI-based FA measurements offer a
reliable and evidence-based indicator for CST integrity that would aid in predicting motor
recovery within the context of stroke rehabilitation.
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Affiliation(s)
- Mohd Khairul Izamil Zolkefley
- Department of Neurosciences, School of Medical Sciences, Universiti Sains Malaysia: 16150 Kubang Kerian, Kelantan, Malaysia
| | - Younis M S Firwana
- Department of Neurosciences, School of Medical Sciences, Universiti Sains Malaysia: 16150 Kubang Kerian, Kelantan, Malaysia
| | - Hasnettty Zuria Mohamed Hatta
- Department of Neurosciences, School of Medical Sciences, Universiti Sains Malaysia: 16150 Kubang Kerian, Kelantan, Malaysia.,Rehabilitation Unit, Hospital Universiti Sains Malaysia, Universiti Sains Malaysia, Malaysia
| | - Christina Rowbin
- Department of Neurosciences, School of Medical Sciences, Universiti Sains Malaysia: 16150 Kubang Kerian, Kelantan, Malaysia.,Rehabilitation Unit, Hospital Universiti Sains Malaysia, Universiti Sains Malaysia, Malaysia
| | | | - Muhammad Hafiz Hanafi
- Department of Neurosciences, School of Medical Sciences, Universiti Sains Malaysia: 16150 Kubang Kerian, Kelantan, Malaysia.,Rehabilitation Unit, Hospital Universiti Sains Malaysia, Universiti Sains Malaysia, Malaysia
| | - Mohd Shafie Abdullah
- Department of Radiology, School of Medical Sciences, Universiti Sains Malaysia, Malaysia
| | - Muzaimi Mustapha
- Department of Neurosciences, School of Medical Sciences, Universiti Sains Malaysia: 16150 Kubang Kerian, Kelantan, Malaysia
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Brodtmann A, Khlif MS, Egorova N, Veldsman M, Bird LJ, Werden E. Dynamic Regional Brain Atrophy Rates in the First Year After Ischemic Stroke. Stroke 2020; 51:e183-e192. [PMID: 32772680 DOI: 10.1161/strokeaha.120.030256] [Citation(s) in RCA: 46] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
BACKGROUND AND PURPOSE Brain atrophy can be regarded as an end-organ effect of cumulative cardiovascular risk factors. Accelerated brain atrophy is described following ischemic stroke, but it is not known whether atrophy rates vary over the poststroke period. Examining rates of brain atrophy allows the identification of potential therapeutic windows for interventions to prevent poststroke brain atrophy. METHODS We charted total and regional brain volume and cortical thickness trajectories, comparing atrophy rates over 2 time periods in the first year after ischemic stroke: within 3 months (early period) and between 3 and 12 months (later period). Patients with first-ever or recurrent ischemic stroke were recruited from 3 Melbourne hospitals at 1 of 2 poststroke time points: within 6 weeks (baseline) or 3 months. Whole-brain 3T magnetic resonance imaging was performed at 3 time points: baseline, 3 months, and 12 months. Eighty-six stroke participants completed testing at baseline; 125 at 3 months (76 baseline follow-up plus 49 delayed recruitment); and 113 participants at 12 months. Their data were compared with 40 healthy control participants with identical testing. We examined 5 brain measures: hippocampal volume, thalamic volume, total brain and hemispheric brain volume, and cortical thickness. We tested whether brain atrophy rates differed between time points and groups. A linear mixed-effect model was used to compare brain structural changes, including age, sex, years of education, a composite cerebrovascular risk factor score, and total intracranial volume as covariates. RESULTS Atrophy rates were greater in stroke than control participants. Ipsilesional hemispheric, hippocampal, and thalamic atrophy rates were 2 to 4 times greater in the early versus later period. CONCLUSIONS Regional atrophy rates vary over the first year after stroke. Rapid brain volume loss in the first 3 months after stroke may represent a potential window for intervention. Registration: URL: https://www.clinicaltrials.gov. Unique identifier: NCT02205424.
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Affiliation(s)
- Amy Brodtmann
- The Florey Institute of Neuroscience and Mental Health (A.B., M.S.K., N.E., M.V., L.J.B., E.W.), University of Melbourne, Australia.,Melbourne Dementia Research Centre, Florey Institute (A.B., N.E., E.W.), University of Melbourne, Australia.,Eastern Cognitive Disorders Clinic, Eastern Health, Monash University, Australia (A.B.).,Department of Neurology, Austin Health, Melbourne, Australia (A.B.)
| | - Mohamed Salah Khlif
- The Florey Institute of Neuroscience and Mental Health (A.B., M.S.K., N.E., M.V., L.J.B., E.W.), University of Melbourne, Australia
| | - Natalia Egorova
- The Florey Institute of Neuroscience and Mental Health (A.B., M.S.K., N.E., M.V., L.J.B., E.W.), University of Melbourne, Australia.,Melbourne Dementia Research Centre, Florey Institute (A.B., N.E., E.W.), University of Melbourne, Australia.,Melbourne School of Psychological Sciences (N.E.), University of Melbourne, Australia
| | - Michele Veldsman
- The Florey Institute of Neuroscience and Mental Health (A.B., M.S.K., N.E., M.V., L.J.B., E.W.), University of Melbourne, Australia
| | - Laura J Bird
- The Florey Institute of Neuroscience and Mental Health (A.B., M.S.K., N.E., M.V., L.J.B., E.W.), University of Melbourne, Australia
| | - Emilio Werden
- The Florey Institute of Neuroscience and Mental Health (A.B., M.S.K., N.E., M.V., L.J.B., E.W.), University of Melbourne, Australia.,Melbourne Dementia Research Centre, Florey Institute (A.B., N.E., E.W.), University of Melbourne, Australia
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7
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Datta A, Sarmah D, Kalia K, Borah A, Wang X, Dave KR, Yavagal DR, Bhattacharya P. Advances in Studies on Stroke-Induced Secondary Neurodegeneration (SND) and Its Treatment. Curr Top Med Chem 2020; 20:1154-1168. [DOI: 10.2174/1568026620666200416090820] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2020] [Revised: 03/13/2020] [Accepted: 03/13/2020] [Indexed: 12/23/2022]
Abstract
Background:
The occurrence of secondary neurodegeneration has exclusively been observed
after the first incidence of stroke. In humans and rodents, post-stroke secondary neurodegeneration
(SND) is an inevitable event that can lead to progressive neuronal loss at a region distant to initial infarct.
SND can lead to cognitive and motor function impairment, finally causing dementia. The exact
pathophysiology of the event is yet to be explored. It is seen that the thalami, in particular, are susceptible
to cause SND. The reason behind this is because the thalamus functioning as the relay center and is
positioned as an interlocked structure with direct synaptic signaling connection with the cortex. As SND
proceeds, accumulation of misfolded proteins and microglial activation are seen in the thalamus. This
leads to increased neuronal loss and worsening of functional and cognitive impairment.
Objective:
There is a necessity of specific interventions to prevent post-stroke SND, which are not properly
investigated to date owing to sparsely reproducible pre-clinical and clinical data. The basis of this
review is to investigate about post-stroke SND and its updated treatment approaches carefully.
Methods:
Our article presents a detailed survey of advances in studies on stroke-induced secondary neurodegeneration
(SND) and its treatment.
Results:
This article aims to put forward the pathophysiology of SND. We have also tabulated the latest
treatment approaches along with different neuroimaging systems that will be helpful for future reference
to explore.
Conclusion:
In this article, we have reviewed the available reports on SND pathophysiology, detection
techniques, and possible treatment modalities that have not been attempted to date.
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Affiliation(s)
- Aishika Datta
- Department of Pharmacology and Toxicology, National Institute of Pharmaceutical Education and Research (NIPER), Ahmedabad, Gandhinagar, Gujarat, India
| | - Deepaneeta Sarmah
- Department of Pharmacology and Toxicology, National Institute of Pharmaceutical Education and Research (NIPER), Ahmedabad, Gandhinagar, Gujarat, India
| | - Kiran Kalia
- Department of Pharmacology and Toxicology, National Institute of Pharmaceutical Education and Research (NIPER), Ahmedabad, Gandhinagar, Gujarat, India
| | - Anupom Borah
- Cellular and Molecular Neurobiology Laboratory, Department of Life Science and Bioinformatics, Assam University, Silchar, Assam, India
| | - Xin Wang
- Department of Neurosurgery, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, United States
| | - Kunjan R. Dave
- Department of Neurology, University of Miami Miller School of Medicine, Miami, FL, United States
| | - Dileep R. Yavagal
- Department of Neurology and Neurosurgery, University of Miami Miller School of Medicine, Miami, FL, United States
| | - Pallab Bhattacharya
- Department of Pharmacology and Toxicology, National Institute of Pharmaceutical Education and Research (NIPER), Ahmedabad, Gandhinagar, Gujarat, India
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8
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Anttila JE, Pöyhönen S, Airavaara M. Secondary Pathology of the Thalamus after Focal Cortical Stroke in Rats is not Associated with Thermal or Mechanical Hypersensitivity and is Not Alleviated by Intra-Thalamic Post-Stroke Delivery of Recombinant CDNF or MANF. Cell Transplant 2019; 28:425-438. [PMID: 31037983 PMCID: PMC6628565 DOI: 10.1177/0963689719837915] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
A stroke affecting the somatosensory pathway can trigger central post-stroke pain
syndrome (CPSP). The symptoms often include hyperalgesia, which has also been described in
rodents after the direct damage of the thalamus. Previous studies have shown that
hemorrhagic stroke or ischemia caused by vasoconstriction in the thalamus induces
increased pain sensitivity. We investigated whether inducing secondary damage in the
thalamus by a cortical stroke causes similar pain hypersensitivity as has previously been
reported with direct ischemic injury. We induced a focal cortical ischemia-reperfusion
injury in male rats, quantified the amount of secondary neurodegeneration in the thalamus,
and measured whether the thalamic neurodegeneration is associated with thermal or
mechanical hypersensitivity. After one month, we observed extensive neuronal degeneration
and found approximately 40% decrease in the number of NeuN+ cells in the ipsilateral
thalamus. At the same time, there was a massive accumulation—a 30-fold increase—of
phagocytic cells in the ipsilateral thalamus. However, despite the evident damage in the
thalamus, we did not observe thermal or mechanical sensitization. Thus, thalamic
neurodegeneration after cortical ischemia-reperfusion does not induce CPSP-like symptoms
in rats, and these results suggest that direct ischemic damage is needed for CPSP
induction. Despite not observing hyperalgesia, we investigated whether administration of
cerebral dopamine neurotrophic factor (CDNF) and mesencephalic astrocyte-derived
neurotrophic factor (MANF) into the ipsilateral thalamus would reduce the secondary
damage. We gave a single injection (10 µg) of recombinant CDNF or MANF protein into the
thalamus at 7 days post-stroke. Both CDNF and MANF treatment promoted the functional
recovery but had no effect on the neuronal loss or the amount of phagocytic cells in the
thalamus.
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Affiliation(s)
- Jenni E. Anttila
- Institute of Biotechnology, HiLIFE, University of Helsinki, Helsinki,
Finland
| | - Suvi Pöyhönen
- Institute of Biotechnology, HiLIFE, University of Helsinki, Helsinki,
Finland
| | - Mikko Airavaara
- Institute of Biotechnology, HiLIFE, University of Helsinki, Helsinki,
Finland
- Mikko Airavaara, Institute of Biotechnology, HiLIFE,
University of Helsinki, P.O. Box 56, Helsinki 00014, Finland.
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9
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Wu Z, Hu J, Du F, Zhou X, Xiang Q, Miao F. Long-Term Changes of Diffusion Tensor Imaging and Behavioural Status after Acupuncture Treatment in Rats with Transient Focal Cerebral Ischaemia. Acupunct Med 2018; 30:331-8. [PMID: 23074236 DOI: 10.1136/acupmed-2012-010172] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
Background The effect of acupuncture treatment in cerebral ischaemia is controversial. A study was undertaken to assess its effects in rats with transient middle cerebral artery occlusion (tMCAO) and discuss its mechanisms. Methods 21 Sprague–Dawley rats were divided into three groups. Group 1 underwent tMCAO and subsequently received acupuncture treatment, Group 2 underwent tMCAO without treatment and Group 3 only underwent sham operation. The evolution of diffusion tensor imaging (DTI) features in ischaemic lesions from acute to chronic periods was assessed and the correlations with behavioural tests and histopathological changes were examined. Results tMCAO rats displayed side-specific sensorimotor deficits after occlusion. Behavioural scores of rats in group 1 reduced gradually with acupuncture treatment. No significant difference in lesion size on T2-weighted imaging was found between the two tMCAO groups. Relative apparent diffusion coefficient (rADC) and relative fractional anisotropy (rFA) values in the centre and at the edge of the ischaemic lesions reduced at first and then increased to varying degrees. Only changes in the rFA value at the edge of the ischaemic lesions were significantly different between the two tMCAO groups. A more significant increase in growth-associated protein B-50 and synaptophysin protein expression was found in group 1 than in the other groups. No significant correlations were found between behavioural scores, DTI appearances and immunohistochemical results. Conclusions The acupuncture points applied were effective, and improving neuronal regeneration may have a role in the mechanism of acupuncture treatment of post-stroke paralysis of the limbs in rats. MRI, particularly the fractional anisotropy value of DTI, is an appropriate parameter to evaluate the recovery status.
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Affiliation(s)
- Zhiyuan Wu
- Department of Radiology, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, People's Republic of China
| | - Jinqing Hu
- Department of Neurosurgery, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, People's Republic of China
| | - Fang Du
- Department of Neurosurgery, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, People's Republic of China
| | - Xiaoyan Zhou
- Department of Rheumatology, Renji Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, People's Republic of China
| | - Qiongyao Xiang
- Department of Pathology, Cancer Hospital, Fudan University, Shanghai, People's Republic of China
| | - Fei Miao
- Department of Radiology, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, People's Republic of China
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10
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Van Kaam R, van Putten M, Vermeer S, Hofmeijer J. Contralesional Brain Activity in Acute Ischemic Stroke. Cerebrovasc Dis 2018; 45:85-92. [DOI: 10.1159/000486535] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2017] [Accepted: 12/20/2017] [Indexed: 11/19/2022] Open
Abstract
Background: The noninjured, contralateral hemisphere is increasingly acknowledged in the process of recovery from acute ischemic stroke. We estimated the value of conventional electroencephalography (EEG) recordings for identifying contralateral hemisphere involvement in relation to functional recovery. Methods: We analyzed 2-min epochs from 21 electrode EEG registrations of 18 patients with acute hemispheric ischemic stroke and compared with 18 age-matched controls. Outcome was dichotomized as good (modified Rankin Scale [mRS] 0–2) or poor (mRS 3–5 or death) at 3 months. Effects of the infarct on the ipsi-and contralateral hemispheres were analyzed by the delta/alpha ratio (DAR) and 2 measures of functional connectivity (magnitude squared coherence [MSC] and weighted phase lag index [WPLI]). Results: DAR was higher in patients than in controls, both in the ipsilateral and in the contralateral hemisphere (median 4.5 ± 6.7 ipsilateral and 2.4 ± 2.0 contralateral vs. 0.5 ± 0.5 in the control group, p < 0.001), indicating robust EEG changes in both lesioned and non-lesioned hemisphere. MSC and WPLI in the alpha and beta frequency bands were lower in patients than in controls in both hemispheres, indicating clear disturbances of functional connectivity (p < 0.05). In the poor outcome group, contralateral MSC and WPLI were lower than in the good outcome group, although these differences did not reach statistical significance. Conclusions: Short conventional EEG measurements show robust changes of brain activity and functional connectivity in both ipsilateral and contralateral hemispheres of patients with acute ischemic stroke. Changes of remote functional connectivity tend to interact with functional recovery. Future studies should estimate predictive values for individual patients and interactions with plasticity enhancing treatments.
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11
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Comprehensive analysis of early fractional anisotropy changes in acute ischemic stroke. PLoS One 2017; 12:e0188318. [PMID: 29190762 PMCID: PMC5708650 DOI: 10.1371/journal.pone.0188318] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2017] [Accepted: 11/03/2017] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND AND PURPOSE Cerebral ischemia leads to a rapid decrease of the apparent diffusion coefficient. For fractional anisotropy both increase and decrease have been reported in acute ischemic stroke. Aim of this study was to characterize early water diffusion changes in a homogenous group of acute stroke patients and to clarify the issue of early fractional anisotropy changes and their relation to time from symptom onset. METHODS MRI data of patients with acute ischemic stroke examined by diffusion tensor imaging within 8h after symptom were analyzed. We calculated fractional anisotropy, eigenvalues and the isotropic and anisotropic components of the diffusion tensor. The values were calculated as ratios between the ischemic lesion and a mirror region in the unaffected side and correlated with clinical parameters. RESULTS We included 63 patients: 49% female, mean age 69 ± 14 years, median NIHSS on admission 9 (IQR 4-14). For the whole sample, mean fractional anisotropy was increased (ratio: 1.083 ± 0.168), while all other diffusion parameters were decreased. Both the isotropic and anisotropic component of the diffusion tensor were decreased with a more pronounced decrease of the isotropic component (ratios: isotropic = 0.730 ± 0.106, anisotropic = 0.788 ± 0.127; p<0.001). There was no correlation of fractional anisotropy with time from symptom onset. Looking at individual patients, fractional anisotropy was increased in 70%. There were no differences in clinical characteristics between patients with increased and decreased fractional anisotropy. CONCLUSION Fractional anisotropy increase in acute stroke results from a more pronounced decrease of the isotropic diffusion component and is not related to time from symptom onset. Thus, fractional anisotropy is not helpful as a surrogate marker of lesion age in the very first hours of stroke.
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Cadasil. Neurologia 2017. [DOI: 10.1016/s1634-7072(17)85562-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
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Schulz R, Park E, Lee J, Chang WH, Lee A, Kim YH, Hummel FC. Synergistic but independent: The role of corticospinal and alternate motor fibers for residual motor output after stroke. NEUROIMAGE-CLINICAL 2017; 15:118-124. [PMID: 28516034 PMCID: PMC5426012 DOI: 10.1016/j.nicl.2017.04.016] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/14/2016] [Revised: 04/13/2017] [Accepted: 04/17/2017] [Indexed: 11/25/2022]
Abstract
Background Brain imaging has shown that not only the cortico-spinal tract (CST), but also alternate corticofugal motor fibers (aMF), such as the cortico-rubro-spinal and cortico-reticulo-spinal tract, influence residual motor output after stroke. So far, studies mainly have investigated each tract separately. A combined analysis of CST and aMF with assessment of their interactive role, i.e., that structural integrity of one tract influences the functional role of the structural integrity of the other, is pending. Methods 39 late subacute stroke patients (aged 59.4 ± 12.0 years, 100 ± 11 days after stroke) were included. Probabilistic tractography was used to reconstruct CST and aMF. Fractional anisotropy (FA) was calculated as a measure of microstructural integrity. Multiple-linear-regression analysis was used to associate tract-related FA with residual motor output and to determine interactions between CST and aMF. Results Both CST (coefficient = 3.93, p < 0.0001) and aMF (coefficient = − 4.43, p = 0.003) of the affected hemisphere significantly contributed to residual motor output. An interaction of their impacts with a consecutive influence on motor output was not detected (p = 0.882). Thus, these data suggest that aMF and CST explain residual motor output in stroke patients in a synergistic, but mainly independent manner. Conclusions The structural states of the CST and also – to a smaller degree – of the aMF correlate with residual motor output in late subacute stroke patients. Based on this statistical modeling with all inherent limitations, the novel finding of an absence of a significant interaction between both tracts in regard of their functional role, suggests that both corticofugal pathways act synergistically but largely independently. These findings add to the understanding of the functional role of different corticofugal motor fibers and their interactions for motor output after stroke. Cortico-spinal tract (CST) integrity is associated with motor function after stroke. Alternate descending motor tracts (aMF) may also contribute to motor outcome. A combined analysis is needed to assess possible interdependencies and interactions. CST and aMF influence motor outcome synergistically but large independently.
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Affiliation(s)
- Robert Schulz
- Dept. of Neurology, University Medical Center Hamburg-Eppendorf, Germany
| | - Eunhee Park
- Dept. of Physical and Rehabilitation Medicine, Center for Prevention and Rehabilitation, Heart Vascular and Stroke Institute, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Republic of Korea
| | - Jungsoo Lee
- Dept. of Physical and Rehabilitation Medicine, Center for Prevention and Rehabilitation, Heart Vascular and Stroke Institute, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Republic of Korea
| | - Won Hyuk Chang
- Dept. of Physical and Rehabilitation Medicine, Center for Prevention and Rehabilitation, Heart Vascular and Stroke Institute, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Republic of Korea
| | - Ahee Lee
- Samsung Advanced Institute for Health Science and Technology, Sungkyunkwan University, Seoul, Republic of Korea
| | - Yun-Hee Kim
- Dept. of Physical and Rehabilitation Medicine, Center for Prevention and Rehabilitation, Heart Vascular and Stroke Institute, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Republic of Korea; Samsung Advanced Institute for Health Science and Technology, Sungkyunkwan University, Seoul, Republic of Korea.
| | - Friedhelm C Hummel
- Defitech Chair Clinical Neuroengineering, Swiss Federal Institute of Technology (EPFL), Geneva, Switzerland; Defitech Chair Clinical Neuroengineering, Swiss Federal Institute of Technology (EPFL Valais), Clinique Romande de Reeducation (CRR), Sion, Switzerland; Clinical Neuroscience, Medical School, University of Geneva, Geneva, Switzerland.
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Kooi Ong L, Rohan Walker F, Nilsson M. Is Stroke a Neurodegenerative Condition? A Critical Review of Secondary Neurodegeneration and Amyloid-beta Accumulation after Stroke. AIMS MEDICAL SCIENCE 2017. [DOI: 10.3934/medsci.2017.1.1] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
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15
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Kim BR, Moon WJ, Kim H, Jung E, Lee J. Association of Dysphagia With Supratentorial Lesions in Patients With Middle Cerebral Artery Stroke. Ann Rehabil Med 2016; 40:637-46. [PMID: 27606270 PMCID: PMC5012975 DOI: 10.5535/arm.2016.40.4.637] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2015] [Accepted: 12/16/2015] [Indexed: 11/11/2022] Open
Abstract
Objective To determine the supratentorial area associated with poststroke dysphagia, we assessed the diffusion tensor images (DTI) in subacute stroke patients with supratentorial lesions. Methods We included 31 patients with a first episode of infarction in the middle cerebral artery territory. Each subject underwent brain DTI as well as a videofluoroscopic swallowing study (VFSS) and patients divided were into the dysphagia and non-dysphagia groups. Clinical dysphagia scale (CDS) scores were compared between the two groups. The corticospinal tract volume (TV), fractional anisotropy (FA) and apparent diffusion coefficient (ADC) values were calculated for 11 regions of interest in the supratentorial area—primary motor cortex, primary somatosensory cortex, supplementary motor cortex, anterior cingulate cortex, orbitofrontal cortex, parieto-occipital cortex, insular cortex, posterior limb of the internal capsule, thalamus, and basal ganglia (putamen and caudate nucleus). DTI parameters were compared between the two groups. Results Among the 31 subjects, 17 were diagnosed with dysphagia by VFSS. Mean TVs were similar across the two groups. Significant inter-group differences were observed in two DTI values: the FA value in the contra-lesional primary motor cortex and the ADC value in the bilateral posterior limbs of the internal capsule (all p<0.05). Conclusion The FA value in the primary motor cortex on the contra-lesional side and the ADC value in the bilateral PLIC can be associated with dysphagia in middle cerebral artery stroke.
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Affiliation(s)
- Bo-Ram Kim
- Department of Rehabilitation Medicine, Konkuk University School of Medicine & Konkuk University Medical Center, Seoul, Korea
| | - Won-Jin Moon
- Department of Radiology, Konkuk University School of Medicine & Konkuk University Medical Center, Seoul, Korea
| | - Hyuntae Kim
- Department of Rehabilitation Medicine, Konkuk University School of Medicine & Konkuk University Medical Center, Seoul, Korea
| | - Eunhwa Jung
- Department of Rehabilitation Medicine, Konkuk University School of Medicine & Konkuk University Medical Center, Seoul, Korea
| | - Jongmin Lee
- Department of Rehabilitation Medicine, Konkuk University School of Medicine & Konkuk University Medical Center, Seoul, Korea
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Brusini L, Obertino S, Galazzo IB, Zucchelli M, Krueger G, Granziera C, Menegaz G. Ensemble average propagator-based detection of microstructural alterations after stroke. Int J Comput Assist Radiol Surg 2016; 11:1585-97. [DOI: 10.1007/s11548-016-1442-z] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2016] [Accepted: 06/02/2016] [Indexed: 11/28/2022]
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17
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Potter-Baker KA, Varnerin NM, Cunningham DA, Roelle SM, Sankarasubramanian V, Bonnett CE, Machado AG, Conforto AB, Sakaie K, Plow EB. Influence of Corticospinal Tracts from Higher Order Motor Cortices on Recruitment Curve Properties in Stroke. Front Neurosci 2016; 10:79. [PMID: 27013942 PMCID: PMC4781847 DOI: 10.3389/fnins.2016.00079] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2015] [Accepted: 02/18/2016] [Indexed: 12/17/2022] Open
Abstract
BACKGROUND Recruitment curves (RCs) acquired using transcranial magnetic stimulation are commonly used in stroke to study physiologic functioning of corticospinal tracts (CST) from M1. However, it is unclear whether CSTs from higher motor cortices contribute as well. OBJECTIVE To explore whether integrity of CST from higher motor areas, besides M1, relates to CST functioning captured using RCs. METHODS RCs were acquired for a paretic hand muscle in patients with chronic stroke. Metrics describing gain and overall output of CST were collected. CST integrity was defined by diffusion tensor imaging. For CST emerging from M1 and higher motor areas, integrity (fractional anisotropy) was evaluated in the region of the posterior limb of the internal capsule, the length of CST and in the region of the stroke lesion. RESULTS We found that output and gain of RC was related to integrity along the length of CST emerging from higher motor cortices but not the M1. CONCLUSIONS Our results suggest that RC parameters in chronic stroke infer function primarily of CST descending from the higher motor areas but not M1. RCs may thus serve as a simple, in-expensive means to assess re-mapping of alternate areas that is generally studied with resource-intensive neuroimaging in stroke.
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Affiliation(s)
- Kelsey A Potter-Baker
- Department of Biomedical Engineering, Lerner Research Institute, Cleveland Clinic Foundation Cleveland, OH, USA
| | - Nicole M Varnerin
- Department of Biomedical Engineering, Lerner Research Institute, Cleveland Clinic Foundation Cleveland, OH, USA
| | - David A Cunningham
- Department of Biomedical Engineering, Lerner Research Institute, Cleveland Clinic FoundationCleveland, OH, USA; School of Biomedical Sciences, Department of Neuroscience, Kent State UniversityKent, OH, USA
| | - Sarah M Roelle
- Department of Biomedical Engineering, Lerner Research Institute, Cleveland Clinic Foundation Cleveland, OH, USA
| | | | - Corin E Bonnett
- Department of Biomedical Engineering, Lerner Research Institute, Cleveland Clinic Foundation Cleveland, OH, USA
| | - Andre G Machado
- Center for Neurological Restoration, Neurosurgery, Neurological Institute, Cleveland Clinic Foundation Cleveland, OH, USA
| | - Adriana B Conforto
- Neurology Clinical Division, Neurology Department, Clinics Hospital, São Paulo UniversitySão Paulo, Brazil; Hospital Israelita Albert EinsteinSão Paulo, Brazil
| | - Ken Sakaie
- Department of Diagnostic Radiology, Imaging Institute, Cleveland Clinic Foundation Cleveland, OH, USA
| | - Ela B Plow
- Department of Biomedical Engineering, Lerner Research Institute, Cleveland Clinic FoundationCleveland, OH, USA; Center for Neurological Restoration, Neurosurgery, Neurological Institute, Cleveland Clinic FoundationCleveland, OH, USA; Department of Physical Medicine and Rehabilitation, Neurological Institute, Cleveland Clinic FoundationCleveland, OH, USA
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Ota M, Sato N, Okamoto T, Noda T, Araki M, Yamamura T, Kunugi H. Neuromyelitis optica spectrum disorder and multiple sclerosis: Differentiation by a multimodal approach. Mult Scler Relat Disord 2015; 4:515-20. [DOI: 10.1016/j.msard.2015.08.006] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2015] [Revised: 07/28/2015] [Accepted: 08/17/2015] [Indexed: 11/26/2022]
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Jones KA, Zouikr I, Patience M, Clarkson AN, Isgaard J, Johnson SJ, Spratt N, Nilsson M, Walker FR. Chronic stress exacerbates neuronal loss associated with secondary neurodegeneration and suppresses microglial-like cells following focal motor cortex ischemia in the mouse. Brain Behav Immun 2015; 48:57-67. [PMID: 25749481 DOI: 10.1016/j.bbi.2015.02.014] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/31/2014] [Revised: 02/06/2015] [Accepted: 02/16/2015] [Indexed: 12/26/2022] Open
Abstract
Post-stroke patients describe suffering from persistent and unremitting levels of distress. Using an experimental model of focal cortical ischemia in adult male C57BL/6 mice, we examined whether exposure to chronic stress could modify the development of secondary thalamic neurodegeneration (STND), which is commonly reported to be associated with impaired functional recovery. We were particularly focused on the modulatory role of microglia-like cells, as several clinical studies have linked microglial activation to the development of STND. One month following the induction of cortical ischemia we identified that numbers of microglial-like cells, as well as putative markers of microglial structural reorganization (Iba-1), complement processing (CD11b), phagocytosis (CD68), and antigen presentation (MHC-II) were all significantly elevated in response to occlusion. We further identified that these changes co-occurred with a decrease in the numbers of mature neurons within the thalamus. Occluded animals that were also exposed to chronic stress exhibited significantly lower levels of Iba-1 positive cells and a reduced expression of Iba-1 and CD11b compared to the 'occlusion-alone' group. Interestingly, the dampened expression of microglial/monocyte markers observed in stressed animals was associated with significant additional loss of neurons. These findings indicate that the process of STND can be negatively modified, potentially in a microglial dependent manner, by exposure to chronic stress.
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Affiliation(s)
- Kimberley A Jones
- School of Biomedical Sciences and Pharmacy, University of Newcastle, Callaghan, NSW, Australia; Centre for Translational Neuroscience and Mental Health Research, Australia; Hunter Medical Research Institute, Newcastle, NSW, Australia
| | - Ihssane Zouikr
- School of Biomedical Sciences and Pharmacy, University of Newcastle, Callaghan, NSW, Australia; Centre for Translational Neuroscience and Mental Health Research, Australia; Hunter Medical Research Institute, Newcastle, NSW, Australia
| | - Madeleine Patience
- School of Biomedical Sciences and Pharmacy, University of Newcastle, Callaghan, NSW, Australia; Centre for Translational Neuroscience and Mental Health Research, Australia; Hunter Medical Research Institute, Newcastle, NSW, Australia
| | - Andrew N Clarkson
- Department of Anatomy and the Brain Health Research Center, Dunedin 9054, New Zealand; Centre for Translational Physiology, University of Otago Wellington, Dunedin 9054, New Zealand; Department of Psychology, University of Otago, Dunedin 9054, New Zealand
| | - Jörgen Isgaard
- University of Newcastle, Australia; Laboratory of Experimental Endocrinology, Department of Internal Medicine, Sahlgrenska Academy at the University of Gothenburg, SE-413 45 Gothenburg, Sweden
| | - Sarah J Johnson
- School of Electrical Engineering and Computer Science, University of Newcastle, Callaghan, NSW, Australia
| | - Neil Spratt
- School of Biomedical Sciences and Pharmacy, University of Newcastle, Callaghan, NSW, Australia; Centre for Translational Neuroscience and Mental Health Research, Australia; Hunter Medical Research Institute, Newcastle, NSW, Australia
| | - Michael Nilsson
- University of Newcastle, Australia; Hunter Medical Research Institute, Newcastle, NSW, Australia
| | - Frederick R Walker
- School of Biomedical Sciences and Pharmacy, University of Newcastle, Callaghan, NSW, Australia; Centre for Translational Neuroscience and Mental Health Research, Australia; Hunter Medical Research Institute, Newcastle, NSW, Australia.
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Diffusion tensor imaging in hemorrhagic stroke. Exp Neurol 2015; 272:88-96. [PMID: 26015333 DOI: 10.1016/j.expneurol.2015.05.011] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2015] [Revised: 04/13/2015] [Accepted: 05/07/2015] [Indexed: 12/21/2022]
Abstract
Diffusion tensor imaging (DTI) has evolved considerably over the last decade to now be knocking on the doors of wider clinical applications. There have been several efforts over the last decade to seek valuable and reliable application of DTI in different neurological disorders. The role of DTI in predicting outcomes in patients with brain tumors has been extensively studied and has become a fairly established clinical tool in this scenario. More recently DTI has been applied in mild traumatic brain injury to predict clinical outcomes based on DTI of the white matter tracts. The resolution of white matter fiber tractography based on DTI has improved over the years with increased magnet strength and better tractography post-processing. The role of DTI in hemorrhagic stroke has been studied preliminarily in the scientific literature. There is some evidence that DTI may be efficacious in predicting outcomes of motor function in animal models of intracranial hemorrhage. Only a handful of studies of DTI have been performed in subarachnoid hemorrhage or intraventricular hemorrhage scenarios. In this manuscript we will review the evolution of DTI, the existing evidence for its role in hemorrhagic stroke and discuss possible application of this non-invasive evaluation technique of human cerebral white matter tracts in the future.
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21
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Lunven M, Thiebaut De Schotten M, Bourlon C, Duret C, Migliaccio R, Rode G, Bartolomeo P. White matter lesional predictors of chronic visual neglect: a longitudinal study. ACTA ACUST UNITED AC 2015; 138:746-60. [PMID: 25609686 DOI: 10.1093/brain/awu389] [Citation(s) in RCA: 159] [Impact Index Per Article: 17.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Chronic visual neglect prevents brain-damaged patients from returning to an independent and active life. Detecting predictors of persistent neglect as early as possible after the stroke is therefore crucial to plan the relevant interventions. Neglect signs do not only depend on focal brain lesions, but also on dysfunction of large-scale brain networks connected by white matter bundles. We explored the relationship between markers of axonal degeneration occurring after the stroke and visual neglect chronicity. A group of 45 patients with unilateral strokes in the right hemisphere underwent cognitive testing for neglect twice, first at the subacute phase (<3 months after onset) and then at the chronic phase (>1 year). For each patient, magnetic resonance imaging including diffusion sequences was performed at least 4 months after the stroke. After masking each patient's lesion, we used tract-based spatial statistics to obtain a voxel-wise statistical analysis of the fractional anisotropy data. Twenty-seven patients had signs of visual neglect at initial testing. Only 10 of these patients had recovered from neglect at follow-up. When compared with patients without neglect, the group including all subacute neglect patients had decreased fractional anisotropy in the second (II) and third (III) branches of the right superior longitudinal fasciculus, as well as in the splenium of the corpus callosum. The subgroup of chronic patients showed reduced fractional anisotropy in a portion the splenium, the forceps major, which provides interhemispheric communication between regions of the occipital lobe and of the superior parietal lobules. The severity of neglect correlated with fractional anisotropy values in superior longitudinal fasciculus II/III for subacute patients and in its caudal portion for chronic patients. Our results confirm a key role of fronto-parietal disconnection in the emergence and chronic persistence of neglect, and demonstrate an implication of caudal interhemispheric disconnection in chronic neglect. Splenial disconnection may prevent fronto-parietal networks in the left hemisphere from resolving the activity imbalance with their right hemisphere counterparts, thus leading to persistent neglect.
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Affiliation(s)
- Marine Lunven
- 1 INSERM U 1127, CNRS UMR 7225, Sorbonne Universités, and Université Pierre et Marie Curie-Paris 6, UMR S 1127, Institut du Cerveau et de la Moelle épinière (ICM), F-75013 Paris, France 2 Service de Médecine Physique et Réadaptation, Unité de Rééducation Neurologique CRF 'Les Trois Soleils' Boissise le Roi, France 3 Inserm UMR_S 1028, CNRS UMR 5292, ImpAct, centre des neurosciences de Lyon, université Lyon-1, 16, avenue Lépine 69676 Bron, France
| | - Michel Thiebaut De Schotten
- 1 INSERM U 1127, CNRS UMR 7225, Sorbonne Universités, and Université Pierre et Marie Curie-Paris 6, UMR S 1127, Institut du Cerveau et de la Moelle épinière (ICM), F-75013 Paris, France 4 Natbrainlab, Department of Forensic and Neurodevelopmental Sciences, Institute of Psychiatry, King's College London, UK
| | - Clémence Bourlon
- 2 Service de Médecine Physique et Réadaptation, Unité de Rééducation Neurologique CRF 'Les Trois Soleils' Boissise le Roi, France
| | - Christophe Duret
- 2 Service de Médecine Physique et Réadaptation, Unité de Rééducation Neurologique CRF 'Les Trois Soleils' Boissise le Roi, France
| | - Raffaella Migliaccio
- 1 INSERM U 1127, CNRS UMR 7225, Sorbonne Universités, and Université Pierre et Marie Curie-Paris 6, UMR S 1127, Institut du Cerveau et de la Moelle épinière (ICM), F-75013 Paris, France 5 AP-HP, Department of Neurology, IFR 70, Salpêtrière Hospital, Paris, France
| | - Gilles Rode
- 3 Inserm UMR_S 1028, CNRS UMR 5292, ImpAct, centre des neurosciences de Lyon, université Lyon-1, 16, avenue Lépine 69676 Bron, France 6 Service de médecine physique et réadaptation neurologique, hospital Henry-Gabrielle, hospice civils de Lyon, 20, route de Vourles, Saint-Genis-Laval, France
| | - Paolo Bartolomeo
- 1 INSERM U 1127, CNRS UMR 7225, Sorbonne Universités, and Université Pierre et Marie Curie-Paris 6, UMR S 1127, Institut du Cerveau et de la Moelle épinière (ICM), F-75013 Paris, France 5 AP-HP, Department of Neurology, IFR 70, Salpêtrière Hospital, Paris, France 7 Department of Psychology, Catholic University, Milan, Italy
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Sikiö M, Kölhi P, Ryymin P, Eskola HJ, Dastidar P. MRI Texture Analysis and Diffusion Tensor Imaging in Chronic Right Hemisphere Ischemic Stroke. J Neuroimaging 2014; 25:614-9. [PMID: 25482992 DOI: 10.1111/jon.12185] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2014] [Revised: 07/30/2014] [Accepted: 08/16/2014] [Indexed: 11/26/2022] Open
Abstract
BACKGROUND AND PURPOSE Diffusion tensor imaging (DTI) is shown to reveal changes caused by cerebral infarction. The aim of this study is to reveal those changes also in the conventional magnetic resonance (MR) images using a quantitative image analysis method, texture analysis (TA). METHODS Thirty patients who had suffered their first ever infarction located on the right hemisphere underwent DTI and conventional MRI studies in the chronic phase. DTI parameters fractional anisotropy and mean diffusivity, as well as four second-order texture parameters were calculated. Interhemispheric differences and correlations between DTI and TA parameters were evaluated. RESULTS Our DTI findings supported earlier studies as fractional anisotropy values were lowered and mean diffusivity values elevated in the lesion site, and ipsilateral cerebral peduncle, thalamus, and centrum semiovale compared to the unaffected side. Textural homogeneity parameters showed lower and complexity parameters higher values in the lesion site and ipsilateral centrum semiovale compared to the contralateral hemisphere. Correlation between the two methods was found in ipsilateral mesencephalon. CONCLUSIONS In addition to DTI method, TA could assist in revealing the changes caused by infarction, also outside the lesion site. Damaged areas were found more heterogeneous and random in texture compared to unaffected sites.
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Affiliation(s)
- Minna Sikiö
- Department of Radiology, Medical Imaging Center and Hospital Pharmacy, Tampere University Hospital, Tampere, Finland.,Department of Electronics and Communications Engineering, Tampere University of Technology, Tampere, Finland
| | - Paula Kölhi
- Department of Radiology, Medical Imaging Center and Hospital Pharmacy, Tampere University Hospital, Tampere, Finland.,Department of Electronics and Communications Engineering, Tampere University of Technology, Tampere, Finland
| | - Pertti Ryymin
- Department of Radiology, Medical Imaging Center and Hospital Pharmacy, Tampere University Hospital, Tampere, Finland
| | - Hannu J Eskola
- Department of Radiology, Medical Imaging Center and Hospital Pharmacy, Tampere University Hospital, Tampere, Finland.,Department of Electronics and Communications Engineering, Tampere University of Technology, Tampere, Finland
| | - Prasun Dastidar
- Department of Radiology, Medical Imaging Center and Hospital Pharmacy, Tampere University Hospital, Tampere, Finland.,Medical School, University of Tampere, Tampere, Finland
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Dacosta-Aguayo R, Graña M, Fernández-Andújar M, López-Cancio E, Cáceres C, Bargalló N, Barrios M, Clemente I, Monserrat PT, Sas MA, Dávalos A, Auer T, Mataró M. Structural integrity of the contralesional hemisphere predicts cognitive impairment in ischemic stroke at three months. PLoS One 2014; 9:e86119. [PMID: 24475078 PMCID: PMC3901679 DOI: 10.1371/journal.pone.0086119] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2013] [Accepted: 12/10/2013] [Indexed: 02/06/2023] Open
Abstract
After stroke, white matter integrity can be affected both locally and distally to the primary lesion location. It has been shown that tract disruption in mirror's regions of the contralateral hemisphere is associated with degree of functional impairment. Fourteen patients suffering right hemispheric focal stroke (S) and eighteen healthy controls (HC) underwent Diffusion Weighted Imaging (DWI) and neuropsychological assessment. The stroke patient group was divided into poor (SP; n = 8) and good (SG; n = 6) cognitive recovery groups according to their cognitive improvement from the acute phase (72 hours after stroke) to the subacute phase (3 months post-stroke). Whole-brain DWI data analysis was performed by computing Diffusion Tensor Imaging (DTI) followed by Tract Based Spatial Statistics (TBSS). Assessment of effects was obtained computing the correlation of the projections on TBSS skeleton of Fractional Anisotropy (FA) and Radial Diffusivity (RD) with cognitive test results. Significant decrease of FA was found only in right brain anatomical areas for the S group when compared to the HC group. Analyzed separately, stroke patients with poor cognitive recovery showed additional significant FA decrease in several left hemisphere regions; whereas SG patients showed significant decrease only in the left genu of corpus callosum when compared to the HC. For the SG group, whole brain analysis revealed significant correlation between the performance in the Semantic Fluency test and the FA in the right hemisphere as well as between the performance in the Grooved Pegboard Test (GPT) and the Trail Making Test-part A and the FA in the left hemisphere. For the SP group, correlation analysis revealed significant correlation between the performance in the GPT and the FA in the right hemisphere.
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Affiliation(s)
- Rosalia Dacosta-Aguayo
- Group of Computational Intelligence, University of the Basque Country UPV/EHU, San Sebastian, Spain
| | - Manuel Graña
- Group of Computational Intelligence, University of the Basque Country UPV/EHU, San Sebastian, Spain
| | - Marina Fernández-Andújar
- Department of Psychiatry and Clinical Psychobiology, University of Barcelona, Barcelona, Spain
- Institute for Brain, Cognition and Behaviour (IR3C), Barcelona, Spain
| | - Elena López-Cancio
- Department of Neurosciences, Hospital Germans Trias i Pujol, Universitat Autònoma de Barcelona, Barcelona, Spain
| | - Cynthia Cáceres
- Department of Neurosciences, Hospital Germans Trias i Pujol, Universitat Autònoma de Barcelona, Barcelona, Spain
| | - Núria Bargalló
- Diagnostic Center for Image, Clinic Hospital, Barcelona, Spain
- Imatge Platform of IDIBAPS, Barcelona, Spain
| | - Maite Barrios
- Department of Methodology of Behavioral Sciences, University of Barcelona, Spain
| | - Immaculada Clemente
- Department of Psychiatry and Clinical Psychobiology, University of Barcelona, Barcelona, Spain
- Institute for Brain, Cognition and Behaviour (IR3C), Barcelona, Spain
| | - Pere Toran Monserrat
- Primary Healthcare Research Support Unit Metropolitana Nord, Institut Universitari d’Investigació en Atenció Primària (−IDIAP) Jordi Gol, Santa Coloma de Gramenet, Spain
| | - Maite Alzamora Sas
- Primary Healthcare Research Support Unit Metropolitana Nord, Institut Universitari d’Investigació en Atenció Primària (−IDIAP) Jordi Gol, Santa Coloma de Gramenet, Spain
| | - Antoni Dávalos
- Department of Neurosciences, Hospital Germans Trias i Pujol, Universitat Autònoma de Barcelona, Barcelona, Spain
| | - Tibor Auer
- MRC Cognition and Brain Sciences Unit, Cambridge, England
| | - Maria Mataró
- Department of Psychiatry and Clinical Psychobiology, University of Barcelona, Barcelona, Spain
- Institute for Brain, Cognition and Behaviour (IR3C), Barcelona, Spain
- * E-mail:
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Viscomi MT, Molinari M. Remote neurodegeneration: multiple actors for one play. Mol Neurobiol 2014; 50:368-89. [PMID: 24442481 DOI: 10.1007/s12035-013-8629-x] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2013] [Accepted: 12/24/2013] [Indexed: 12/19/2022]
Abstract
Remote neurodegeneration significantly influences the clinical outcome in many central nervous system (CNS) pathologies, such as stroke, multiple sclerosis, and traumatic brain and spinal cord injuries. Because these processes develop days or months after injury, they are accompanied by a therapeutic window of opportunity. The complexity and clinical significance of remote damage is prompting many groups to examine the factors of remote degeneration. This research is providing insights into key unanswered questions, opening new avenues for innovative neuroprotective therapies. In this review, we evaluate data from various remote degeneration models to describe the complexity of the systems that are involved and the importance of their interactions in reducing damage and promoting recovery after brain lesions. Specifically, we recapitulate the current data on remote neuronal degeneration, focusing on molecular and cellular events, as studied in stroke and brain and spinal cord injury models. Remote damage is a multifactorial phenomenon in which many components become active in specific time frames. Days, weeks, or months after injury onset, the interplay between key effectors differentially affects neuronal survival and functional outcomes. In particular, we discuss apoptosis, inflammation, oxidative damage, and autophagy-all of which mediate remote degeneration at specific times. We also review current findings on the pharmacological manipulation of remote degeneration mechanisms in reducing damage and sustaining outcomes. These novel treatments differ from those that have been proposed to limit primary lesion site damage, representing new perspectives on neuroprotection.
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Affiliation(s)
- Maria Teresa Viscomi
- Experimental Neurorehabilitation Laboratory, Santa Lucia Foundation I.R.C.C.S., Via del Fosso di Fiorano 65, 00143, Rome, Italy,
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Selective neuronal loss in ischemic stroke and cerebrovascular disease. J Cereb Blood Flow Metab 2014; 34:2-18. [PMID: 24192635 PMCID: PMC3887360 DOI: 10.1038/jcbfm.2013.188] [Citation(s) in RCA: 169] [Impact Index Per Article: 16.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/07/2013] [Revised: 10/15/2013] [Accepted: 10/17/2013] [Indexed: 01/23/2023]
Abstract
As a sequel of brain ischemia, selective neuronal loss (SNL)-as opposed to pannecrosis (i.e. infarction)-is attracting growing interest, particularly because it is now detectable in vivo. In acute stroke, SNL may affect the salvaged penumbra and hamper functional recovery following reperfusion. Rodent occlusion models can generate SNL predominantly in the striatum or cortex, showing that it can affect behavior for weeks despite normal magnetic resonance imaging. In humans, SNL in the salvaged penumbra has been documented in vivo mainly using positron emission tomography and (11)C-flumazenil, a neuronal tracer validated against immunohistochemistry in rodent stroke models. Cortical SNL has also been documented using this approach in chronic carotid disease in association with misery perfusion and behavioral deficits, suggesting that it can result from chronic or unstable hemodynamic compromise. Given these consequences, SNL may constitute a novel therapeutic target. Selective neuronal loss may also develop at sites remote from infarcts, representing secondary 'exofocal' phenomena akin to degeneration, potentially related to poststroke behavioral or mood impairments again amenable to therapy. Further work should aim to better characterize the time course, behavioral consequences-including the impact on neurological recovery and contribution to vascular cognitive impairment-association with possible causal processes such as microglial activation, and preventability of SNL.
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Chao LL, Decarli C, Kriger S, Truran D, Zhang Y, Laxamana J, Villeneuve S, Jagust WJ, Sanossian N, Mack WJ, Chui HC, Weiner MW. Associations between white matter hyperintensities and β amyloid on integrity of projection, association, and limbic fiber tracts measured with diffusion tensor MRI. PLoS One 2013; 8:e65175. [PMID: 23762308 PMCID: PMC3675157 DOI: 10.1371/journal.pone.0065175] [Citation(s) in RCA: 66] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2013] [Accepted: 04/23/2013] [Indexed: 01/08/2023] Open
Abstract
The goal of this study was to assess the relationship between Aβ deposition and white matter pathology (i.e., white matter hyperintensities, WMH) on microstructural integrity of the white matter. Fifty-seven participants (mean age: 78±7 years) from an ongoing multi-site research program who spanned the spectrum of normal to mild cognitive impairment (Clinical dementia rating 0–0.5) and low to high risk factors for arteriosclerosis and WMH pathology (defined as WMH volume >0.5% total intracranial volume) were assessed with positron emission tomography (PET) with Pittsburg compound B (PiB) and magnetic resonance and diffusion tensor imaging (DTI). Multivariate analysis of covariance were used to investigate the relationship between Aβ deposition and WMH pathology on fractional anisotropy (FA) from 9 tracts of interest (i.e., corona radiata, internal capsule, cingulum, parahippocampal white matter, corpus callosum, superior longitudinal, superior and inferior front-occipital fasciculi, and fornix). WMH pathology was associated with reduced FA in projection (i.e., internal capsule and corona radiate) and association (i.e., superior longitudinal, superior and inferior fronto-occipital fasciculi) fiber tracts. Aβ deposition (i.e., PiB positivity) was associated with reduced FA in the fornix and splenium of the corpus callosum. There were interactions between PiB and WMH pathology in the internal capsule and parahippocampal white matter, where Aβ deposition reduced FA more among subjects with WMH pathology than those without. However, accounting for apoE ε4 genotype rendered these interactions insignificant. Although this finding suggests that apoE4 may increase amyloid deposition, both in the parenchyma (resulting in PiB positivity) and in blood vessels (resulting in amyloid angiopathy and WMH pathology), and that these two factors together may be associated with compromised white matter microstructural integrity in multiple brain regions, additional studies with a longitudinal design will be necessary to resolve this issue.
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Affiliation(s)
- Linda L Chao
- Department of Radiology & Biomedical Imaging, University of California San Francisco, San Francisco, California, United States of America. linda.chao @ucsf.edu
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Meng X, Jun C, Wang Q, Zhang X, Li Z, Li Q, Hou J, Zeng Q, Wang Q, Ma X. High b-value diffusion tensor imaging of the remote white matter and white matter of obstructive unilateral cerebral arterial regions. Clin Radiol 2013; 68:815-22. [PMID: 23623577 DOI: 10.1016/j.crad.2013.03.009] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2012] [Revised: 03/08/2013] [Accepted: 03/14/2013] [Indexed: 12/13/2022]
Abstract
AIM To assess diffusion changes in the remote white matter and areas of white matter with cerebral artery obstruction without magnetic resonance imaging (MRI) evidence of brain parenchymal abnormalities using high b-value diffusion tensor imaging (DTI). MATERIALS AND METHODS A total of 34 patients with severe unilateral stenosis (≥75%) or occlusion of the middle cerebral artery (MCA) without abnormal brain parenchymal signals at MRI underwent DTI with a b value of 2200 s/mm(2) at 3 T. Fractional anisotropy (FA), apparent diffusion coefficient (ADC), axial diffusivity (eigenvalue λ₁) and radial diffusivity (eigenvalue λ₂₃) were measured at the bilateral corona radiata, anterior and posterior limbs of the internal capsule, cerebral peduncle, and pons. RESULTS The mean FA was significantly lower at the ipsilateral corona radiata and anterior and posterior limbs of the internal capsule than at the contralateral corona radiata and anterior and posterior limbs of the internal capsule (p < 0.05). The mean ADC, λ₁ and λ₂₃ were significantly higher at the ipsilateral corona radiata than at the contralateral corona radiata (p < 0.01). The mean λ₂₃ were significantly higher at the ipsilateral anterior and posterior limb of the internal capsule than at the contralateral anterior and posterior limb of the internal capsule (p < 0.05). The mean ADC, λ₁ and λ₂ ₃were not significantly different between the ipsilateral cerebral peduncle and pons. CONCLUSIONS High b-value DTI could sensitively reveal diffusion changes in white matter in regions of cerebral artery obstruction without abnormal anisotropy and diffusivity of the remote white matter of patients with severe MCA stenosis or occlusion without MRI evidence of brain parenchymal abnormalities.
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Affiliation(s)
- X Meng
- Department of Radiology, Qi Lu Hospital of Shandong University, Jinan, China
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28
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Abnormalities of cerebral blood flow in multiple sclerosis: a pseudocontinuous arterial spin labeling MRI study. Magn Reson Imaging 2013; 31:990-5. [PMID: 23582984 DOI: 10.1016/j.mri.2013.03.016] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2012] [Revised: 01/30/2013] [Accepted: 03/09/2013] [Indexed: 11/22/2022]
Abstract
Arterial spin labeling (ASL) is a noninvasive technique that can measure cerebral blood flow (CBF). To our knowledge, there is no study that examined regional CBF of multiple sclerosis (MS) patients by using this technique. The present study assessed the relationship between clinical presentations and functional imaging data in MS using pseudocontinuous arterial spin labeling (pCASL). Twenty-seven patients with MS and 24 healthy volunteers underwent magnetic resonance imaging and pCASL to assess CBF. Differences in CBF between the two groups and the relationships of CBF values with the T2-hyperintense volume were evaluated. Compared to the healthy volunteers, reduced CBF was found in the bilateral thalami and right frontal region of the MS patients. The volume of the T2-hyperintense lesion was negatively correlated with regional CBF in some areas, such as both thalami. Our results suggest that demyelinated lesions in MS mainly have a remote effect on the thalamus and that the measurement of CBF using ASL could be an objective marker for monitoring disease activity in MS.
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Rüber T, Schlaug G, Lindenberg R. Compensatory role of the cortico-rubro-spinal tract in motor recovery after stroke. Neurology 2012; 79:515-22. [PMID: 22843266 DOI: 10.1212/wnl.0b013e31826356e8] [Citation(s) in RCA: 87] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
OBJECTIVES Studies on nonhuman primates have demonstrated that the cortico-rubro-spinal system can compensate for damage to the pyramidal tract (PT). In humans, so-called alternate motor fibers (aMF), which may comprise the cortico-rubro-spinal tract, have been suggested to play a similar role in motor recovery after stroke. Using diffusion tensor imaging, we examined PT and aMF in the context of human motor recovery by relating their microstructural properties to functional outcome in chronic stroke patients. METHODS PT and aMF were reconstructed based on their origins in primary motor, dorsal premotor, and supplementary motor cortices in 18 patients and 10 healthy controls. The patients' degree of motor recovery was assessed using the Wolf Motor Function Test (WMFT). RESULTS Compared to controls, fractional anisotropy (FA) was lower along ipsilesional PT and aMF in chronic stroke patients, but clusters of higher FA were found bilaterally in aMF within the vicinity of the red nuclei. FA along ipsilesional PT and aMF and within the red nuclei correlated significantly with WMFT scores. Probabilistic connectivity of aMF originating from ipsilesional primary motor cortex was higher in patients, whereas the ipsilesional PT exhibited lower connectivity compared to controls. CONCLUSIONS The strong correlations observed between microstructural properties of bilateral red nuclei and the level of motor function in chronic stroke patients indicate possible remodeling during recovery. Our results shed light on the role of different corticofugal motor tracts, and highlight a compensatory function of the cortico-rubro-spinal system which may be used as a target in future restorative treatments.
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Affiliation(s)
- Theodor Rüber
- Department of Neurology, Beth Israel Deaconess Medical Center/Harvard Medical School, Boston, MA, USA.
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Zhang J, Zhang Y, Xing S, Liang Z, Zeng J. Secondary neurodegeneration in remote regions after focal cerebral infarction: a new target for stroke management? Stroke 2012; 43:1700-5. [PMID: 22492515 DOI: 10.1161/strokeaha.111.632448] [Citation(s) in RCA: 159] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Affiliation(s)
- Jian Zhang
- Department of Neurology and Stroke Center, The First Affiliated Hospital, Sun Yat-Sen University, No. 58 Zhongshan Road 2, Guangzhou 510080, China
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Li D, Hodge J, Wei XC, Kirton A. Reduced ipsilesional cortical volumes in fetal periventricular venous infarction. Stroke 2012; 43:1404-7. [PMID: 22282891 DOI: 10.1161/strokeaha.111.645077] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
BACKGROUND AND PURPOSE Perinatal stroke causes most term-born hemiplegic cerebral palsy. Many suffer additional sequelae. Periventricular venous infarction (PVI) is a common fetal stroke in which isolated subcortical injury may cause only motor deficits. However, cognitive, language, and behavioral deficits also occur. We hypothesized that ipsilesional cortical gray matter volumes are reduced in PVI. METHODS Children (12 months to 18 years) with MRI-confirmed PVI were identified through the Alberta Perinatal Stroke Project. We developed an MRI method to quantify sectional gray (GM) and white matter (WM) volumes from lesioned and unlesioned (control) hemispheres (OsiriX software). Differences in cortical GM and WM volumes were compared between hemispheres in preselected regions "above" the lesion (middle) and anterior and posterior to this. Outcomes dichotomized for "cortical dysfunction" (cognitive, behavioral, language) and motor deficit severity (Pediatric Stroke Outcome Measure) were compared with GM volumes. RESULTS Twenty-two children (81% boys; median age, 8 years) were included. Methods demonstrated high intrarater and inter-rater reliabilities (ρ=0.988, ρ=0.943) and minimal observer bias. Ipsilesional GM volume was significantly reduced in the middle (P=0.007) and posterior (P=0.03) regions. Middle ipsilesional WM volumes were reduced (P<0.001). The degree of GM reduction was not associated with cortical dysfunction or severity of motor deficit. CONCLUSIONS Ipsilesional GM volume is diminished in PVI. Speculative mechanisms include retrograde neuronal degeneration and disrupted migration. Neuropsychological testing of larger samples is required to determine clinical significance.
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Affiliation(s)
- Damon Li
- Alberta Children's Hospital, Calgary, Canada
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32
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Nordvik JE, Schanke AK, Walhovd K, Fjell A, Grydeland H, Landrø NI. Exploring the relationship between white matter microstructure and working memory functioning following stroke: a single case study of computerized cognitive training. Neurocase 2012; 18:139-51. [PMID: 21780988 DOI: 10.1080/13554794.2011.568501] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Cognitive impairment is a well-known consequence of acquired brain injuries, including stroke. Computerized cognitive training (CCT) is a rehabilitation approach intended to enhance cognitive functioning. It is unclear whether CCT leads to generalized cognitive improvements in daily life functioning, or if the subjects improve performance only on the exercises involved in the training. The current study explores whether fractional anisotropy (FA), a measure of white matter microstructure, may serve as an indirect biological indicator of enhanced neuropsychological functioning, particularly working memory, following CCT. The findings suggest a possible relationship between changes in FA measures and working memory.
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Affiliation(s)
- Jan E Nordvik
- Centre for the Study of Human Cognition, Department of Psychology, University of Oslo, Norway.
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Cykowski MD, Lancaster JL, Fox PT. A method to enhance the sensitivity of DTI analyses to group differences: a validation study with comparison to voxelwise analyses. Psychiatry Res 2011; 193:191-8. [PMID: 21764564 PMCID: PMC3156862 DOI: 10.1016/j.pscychresns.2011.03.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/05/2010] [Revised: 01/25/2011] [Accepted: 03/17/2011] [Indexed: 11/18/2022]
Abstract
Studies of white matter (WM) abnormalities in psychiatric and neurological disorders often use the analysis package Tract-Based Spatial Statistics (TBSS). However, with small samples and/or subtle effects, a study using the standard TBSS approach can be underpowered. For such cases, a new method is presented that summarizes global differences between TBSS-derived fractional anisotropy (FA) images with a single paired t-statistic, estimating the degrees of freedom using spatial autocorrelation. The sensitivity of the method is demonstrated by using well-known aging effects on FA as a proxy for disease effects. Sixty healthy subjects were divided equally into younger- (YA), middle- (MA), and older-aged (OA) groups and significant global differences were demonstrated in the YA versus OA (all N ≥ 4, FA difference≈0.023), MA versus OA (all N≥4, FA difference≈0.017), and YA versus MA (FA difference≈0.005 at N=20) comparisons. In contrast, no significant difference could be detected in the YA versus MA comparison using voxelwise TBSS analysis with the full sample (N=20 per group). This method should facilitate localizing analyses in the direction of a proven group difference while providing clinically relevant information about pathophysiologic processes globally affecting WM.
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Borich MR, Wadden KP, Boyd LA. Establishing the reproducibility of two approaches to quantify white matter tract integrity in stroke. Neuroimage 2011; 59:2393-400. [PMID: 21945470 DOI: 10.1016/j.neuroimage.2011.09.009] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2011] [Revised: 08/17/2011] [Accepted: 09/02/2011] [Indexed: 10/17/2022] Open
Abstract
Diffusion tensor imaging can provide unique and detailed information about white matter anatomy following stroke. Fiber tract reconstruction using tract-based techniques and cross-sectional region of interest delineation are two common approaches to quantify white matter integrity. After stroke, white matter tract integrity can be affected both locally and distally to the primary lesion location. It has been shown that tract disruption is associated with degree of functional impairment and response to skill training in participants with stroke. However, the reliability and validity of these approaches has not been systematically evaluated nor have the two approaches been directly compared in individuals with chronic stroke. Ten well-recovered individuals with chronic, right-sided, ischemic stroke in the sub-cortex and ten age-, gender- and handedness-matched healthy participants were studied. Semi-automated tractography of the ipsi- and contralesional corticospinal tract and cross-sectional region of interest drawing of the posterior limb of the internal capsule were performed bilaterally. Fractional anisotropy (FA) values and the hemispheric asymmetry in FA were the primary measures of tract integrity. Two raters performed each analysis method twice to evaluate inter- and intra-rater reliability. Participants with stroke were compared to healthy individuals to determine validity of each analysis approach. Correlational analyses were conducted to examine the relationships between the two approaches and the association between approaches and upper extremity motor impairment. Both analyses methods generally demonstrated good to excellent intra- and inter-rater reliability in each group (p<0.05). Stroke participants demonstrated lower mean FA values in both ipsi- and contralesional tract integrity, and larger FA hemispheric asymmetry as compared with healthy individuals (p<0.05). Comparison between the analysis approaches revealed significant associations between approaches across both groups and within each group (p<0.05). In stroke, individual tract integrity was not correlated between approaches for ipsilesional (r=0.26) or contralesional (0.15) tracts, nor was FA hemispheric asymmetry (r=0.18). Additionally, contralesional mean FA quantified with the cross-sectional approach correlated with upper extremity motor impairment (r=0.69). Importantly, this study is the first to systematically characterize the reliability of tract-based and cross-sectional DTI analysis approaches in well-recovered individuals with chronic stroke and matched healthy participants. Results suggest both tract-based and cross-sectional approaches to evaluate white matter tract integrity are reliable, can differentiate between groups of stroke and healthy participants, and are associated with one another. However, only mean FA values for the contralesional side derived using the cross-sectional approach were related to upper extremity impairment. Our findings suggest that each approach provides complimentary rather than redundant information regarding integrity and support the use of both approaches in combination in future investigations in well-recovered individuals with stroke.
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Affiliation(s)
- Michael R Borich
- University of British Columbia, Faculty of Medicine, Department of Physical Therapy, 212-2177 Wesbrook Mall, Vancouver, British Columbia, Canada V6T 1Z3.
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Jason E, Dastidar P, Kalliokoski A, Luukkaala T, Soimakallio S. Diffusion Tensor Imaging of Chronic Right Cerebral Hemisphere Infarctions. J Neuroimaging 2010; 21:325-31. [DOI: 10.1111/j.1552-6569.2010.00513.x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
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Rossi ME, Jason E, Marchesotti S, Dastidar P, Ollikainen J, Soimakallio S. Diffusion tensor imaging correlates with lesion volume in cerebral hemisphere infarctions. BMC Med Imaging 2010; 10:21. [PMID: 20849612 PMCID: PMC2954947 DOI: 10.1186/1471-2342-10-21] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2010] [Accepted: 09/17/2010] [Indexed: 11/10/2022] Open
Abstract
Background Both a large lesion volume and abnormalities in diffusion tensor imaging are independently associated with a poor prognosis after cerebral infarctions. Therefore, we assume that they are associated. This study assessed the associations between lesion volumes and diffusion tensor imaging in patients with a right-sided cerebral infarction. Methods The lesion volumes of 33 patients (age 65.9 ± 8.7, 26 males and 7 females) were imaged using computed tomography (CT) in the acute phase (within 3-4 hours) and magnetic resonance imaging (MRI) in the chronic phase (follow-up at 12 months, with a range of 8-27 months). The chronic-phase fractional anisotropy (FA) and mean diffusivity (MD) values were measured at the site of the infarct and selected white matter tracts. Neurological tests in both the acute and chronic phases, and DTI lateralization were assessed with the Wilcoxon signed-rank test. The effects of thrombolytic therapy (n = 10) were assessed with the Mann-Whitney U test. The correlations between the measured parameters were analysed with Spearman's rho correlation. Bonferroni post-hoc correction was used to compensate for the familywise error rate in multiple comparisons. Results Several MD values in the right hemisphere correlated positively and FA values negatively with the lesion volumes. These correlations included both lesion area and healthy tissue. The results of the mini-mental state examination and the National Institutes of Health Stroke Scale also correlated with the lesion volume. Conclusions A larger infarct volume is associated with more pronounced tissue modifications in the chronic stage as observed with the MD and FA alterations.
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Affiliation(s)
- Maija E Rossi
- Department of Radiology, Tampere University Hospital, Medical Imaging Centre, Tampere, Finland.
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37
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Use of magnetic resonance imaging to predict outcome after stroke: a review of experimental and clinical evidence. J Cereb Blood Flow Metab 2010; 30:703-17. [PMID: 20087362 PMCID: PMC2949172 DOI: 10.1038/jcbfm.2010.5] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Despite promising results in preclinical stroke research, translation of experimental data into clinical therapy has been difficult. One reason is the heterogeneity of the disease with outcomes ranging from complete recovery to continued decline. A successful treatment in one situation may be ineffective, or even harmful, in another. To overcome this, treatment must be tailored according to the individual based on identification of the risk of damage and estimation of potential recovery. Neuroimaging, particularly magnetic resonance imaging (MRI), could be the tool for a rapid comprehensive assessment in acute stroke with the potential to guide treatment decisions for a better clinical outcome. This review describes current MRI techniques used to characterize stroke in a preclinical research setting, as well as in the clinic. Furthermore, we will discuss current developments and the future potential of neuroimaging for stroke outcome prediction.
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Chin Y, Sato Y, Mase M, Kato T, Herculano B, Sekino M, Ohsaki H, Ageyama N, Ono F, Terao K, Yoshikawa Y, Hisatsune T. Transient decrease in cerebral motor pathway fractional anisotropy after focal ischemic stroke in monkey. Neurosci Res 2010; 66:406-11. [PMID: 20117152 DOI: 10.1016/j.neures.2010.01.001] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2009] [Revised: 12/22/2009] [Accepted: 01/05/2010] [Indexed: 11/17/2022]
Abstract
In this study, diffusion tensor MRI was used to examine the restoration of the cerebral white matter of macaque monkeys after unilateral cerebral multiple microinfarctions. Post-stroke, the monkeys showed deficits in several neurological functions, including motor functions, but most of the deficits resolved within 6 weeks. Very interestingly, the fractional anisotropy (a value determined by diffusion tensor MRI), of the monkeys' affected motor pathways dropped transiently, indicating a damage in the neural tracts. However, it returned to normal levels within 6 weeks after the stroke, concomitant with the gradual recovery of motor functions at subacute phase.
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Affiliation(s)
- Yo Chin
- Department of Integrated Biosciences, The University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8562, Japan
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Schaechter JD, Fricker ZP, Perdue KL, Helmer KG, Vangel MG, Greve DN, Makris N. Microstructural status of ipsilesional and contralesional corticospinal tract correlates with motor skill in chronic stroke patients. Hum Brain Mapp 2010; 30:3461-74. [PMID: 19370766 DOI: 10.1002/hbm.20770] [Citation(s) in RCA: 219] [Impact Index Per Article: 15.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Greater loss in structural integrity of the ipsilesional corticospinal tract (CST) is associated with poorer motor outcome in patients with hemiparetic stroke. Animal models of stroke have demonstrated that structural remodeling of white matter in the ipsilesional and contralesional hemispheres is associated with improved motor recovery. Accordingly, motor recovery in patients with stroke may relate to the relative strength of CST degeneration and remodeling. This study examined the relationship between microstructural status of brain white matter tracts, indexed by the fractional anisotropy (FA) metric derived from diffusion tensor imaging (DTI) data, and motor skill of the stroke-affected hand in patients with chronic stroke. Voxelwise analysis revealed that motor skill significantly and positively correlated with FA of the ipsilesional and contralesional CST in the patients. Additional voxelwise analyses showed that patients with poorer motor skill had reduced FA of bilateral CST compared to normal control subjects, whereas patients with better motor skill had elevated FA of bilateral CST compared to controls. These findings were confirmed using a DTI-tractography method applied to the CST in both hemispheres. The results of this study suggest that the level of motor skill recovery achieved in patients with hemiparetic stroke relates to microstructural status of the CST in both the ipsilesional and contralesional hemispheres, which may reflect the net effect of degeneration and remodeling of bilateral CST.
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Affiliation(s)
- Judith D Schaechter
- MGH/MIT/HMS Athinoula A. Martinos Center for Biomedical Imaging, Charlestown, Massachusetts 02129, USA.
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Kusano Y, Seguchi T, Horiuchi T, Kakizawa Y, Kobayashi T, Tanaka Y, Seguchi K, Hongo K. Prediction of functional outcome in acute cerebral hemorrhage using diffusion tensor imaging at 3T: a prospective study. AJNR Am J Neuroradiol 2009; 30:1561-5. [PMID: 19556354 DOI: 10.3174/ajnr.a1639] [Citation(s) in RCA: 71] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
BACKGROUND AND PURPOSE Early evaluation of the pyramidal tract is a prerequisite in patients with intracerebral hemorrhage (ICH) in order to decide the optimal treatment or to assess appropriate rehabilitation. The aim of this study was to evaluate and predict the neuromotor and functional outcome of an ICH by using diffusion tensor imaging (DTI) in the acute phase. MATERIALS AND METHODS Eighteen patients with a hemiparetic supratentorial ICH were prospectively studied with DTI within 2 days after onset. A region-of-interest-based analysis was performed for the fractional anisotropy (FA) of the pyramidal tract in the cerebral peduncles. The degree of paresis was assessed at day 0 and day 28 by paresis grading (PG). The functional outcome was evaluated by the modified Rankin Scale (mRS). RESULTS The FA in the affected side was significantly lower compared with that of the unaffected side (P = .001) with the mean diffusivity remaining unchanged (P = .50). The ratio of the FA (rFA) in the affected side to the unaffected side was significantly correlated with the PG at day 0 and 28 and the mRS score at day 28 (P = .002, r = -0.674; P < .001, r = -0.767; and P = .002, r = -0.676). The rFA for the good and poor outcomes based on the PG was significantly different (P < .001). The cutoff point of the rFA for the good and poor outcomes was set at 0.85 (sensitivity, 100%, specificity, 100%). CONCLUSIONS We conclude that DTI can evaluate the motor deficit quantitatively and may predict the functional outcome in patients with an ICH who were scanned within 2 days after the ICH onset.
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Affiliation(s)
- Y Kusano
- Department of Neurosurgery, Shinshu University School of Medicine, Asahi 3-1-1, Matsumoto, Japan.
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Jouvent E, Viswanathan A, Chabriat H. Cerebral Atrophy in Cerebrovascular Disorders. J Neuroimaging 2009; 20:213-8. [DOI: 10.1111/j.1552-6569.2009.00370.x] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
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Mori N, Miki Y, Fushimi Y, Kikuta KI, Urayama SI, Okada T, Fukuyama H, Hashimoto N, Togashi K. Cerebral infarction associated with moyamoya disease: histogram-based quantitative analysis of diffusion tensor imaging -- a preliminary study. Magn Reson Imaging 2008; 26:835-40. [PMID: 18467061 DOI: 10.1016/j.mri.2008.01.036] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2007] [Revised: 12/16/2007] [Accepted: 01/22/2008] [Indexed: 11/26/2022]
Abstract
Moyamoya disease (MMD) is a rare disorder of unknown etiology in which terminal portions of the internal carotid arteries become steno-occlusive, with fine collateral "moyamoya vessels" formed secondarily, resulting in serial ischemic strokes throughout its clinical course. Whole-brain histogram (WBH) of diffusion tensor imaging (WBH-DTI) is an analytical tool whose feasibility has been ascertained in various pathologies. To elucidate whether WBH-DTI could detect any difference between ischemic MMD and normal controls, we examined 27 consecutive MMD patients without hemorrhage and 48 normal controls in this prospective study using a 3.0-T magnetic resonance scanner. WBHs of fractional anisotropy (FA) (WBH-FA) and mean diffusivity (MD) (WBH-MD) were compared among three groups: Group 1, MMD patients with infarct (n=15); Group 2, MMD patients without infarct (n=12); and Group 3, normal controls (n=48). Group 1 showed significantly higher peak height and significantly lower mean value on WBH-FA, as well as significantly lower peak height and significantly higher mean value on WBH-MD, compared with Groups 2 and 3. No significant difference was seen in parameters at either WBH-FA or WBH-MD between Groups 2 and 3. These results might reflect the pathological severity of each group, and WBH-DTI could feasibly detect differences between ischemic MMD with infarction and MMD without infarction and normal controls.
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Affiliation(s)
- Nobuyuki Mori
- Department of Diagnostic Imaging and Nuclear Medicine, Kyoto University Graduate School of Medicine, Sakyo-ku, Kyoto, Kyoto 606-8507, Japan
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Bhagat YA, Hussain MS, Stobbe RW, Butcher KS, Emery DJ, Shuaib A, Siddiqui MM, Maheshwari P, Al-Hussain F, Beaulieu C. Elevations of diffusion anisotropy are associated with hyper-acute stroke: a serial imaging study. Magn Reson Imaging 2008; 26:683-93. [PMID: 18440747 DOI: 10.1016/j.mri.2008.01.015] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2007] [Revised: 01/10/2008] [Accepted: 01/28/2008] [Indexed: 10/22/2022]
Abstract
Diffusion tensor imaging (DTI) studies of human ischemic stroke within 24 h of symptom onset have reported variable findings of changes in diffusion anisotropy. Serial DTI within 24 h may clarify these heterogeneous results. We characterized longitudinal changes of diffusion anisotropy by analyzing discrete ischemic white matter (WM) and gray matter (GM) regions during the hyperacute (2.5-7 h) and acute (21.5-29 h) scanning phases of ischemic stroke onset in 13 patients. Mean diffusivity (MD), fractional anisotropy (FA) and T2-weighted signal intensity were measured for deep and subcortical WM and deep and cortical GM areas in lesions outlined by a > or =30% decrease in MD. Average reductions of approximately 40% in relative (r) MD were observed in all four brain regions during both the hyperacute and acute phases post stroke. Overall, 9 of 13 patients within 7 h post symptom onset showed elevated FA in at least one of the four tissues, and within the same cohort, 11 of 13 patients showed reduced FA in at least one of the ischemic WM and GM regions at 21.5-29 h after stroke. The fractional anisotropy in the lesion relative to the contralateral side (rFA, mean+/-S.D.) was significantly elevated in some patients in the deep WM (1.10+/-0.11, n=4), subcortical WM (1.13+/-0.14, n=4), deep GM (1.07+/-0.06, n=1) and cortical GM (1.22+/-0.13, n=5) hyperacutely (< or =7 h); however, reductions of rFA at approximately 24 h post stroke were more consistent (rFA= 0.85+/-0.12).
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Affiliation(s)
- Yusuf A Bhagat
- Department of Biomedical Engineering, University of Alberta, 1098 Research Transition Facility, Edmonton, Alberta, Canada T6G 2V2
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Axer H, Grässel D, Brämer D, Fitzek S, Kaiser WA, Witte OW, Fitzek C. Time course of diffusion imaging in acute brainstem infarcts. J Magn Reson Imaging 2008; 26:905-12. [PMID: 17896361 DOI: 10.1002/jmri.21088] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
PURPOSE To study the time course of diffusion imaging at the lesion site in brainstem infarcts. MATERIALS AND METHODS Sequential MR scans were acquired from 24 patients with brainstem infarcts. Diffusion-weighted images (DWI), T(2)-weighted images (T(2)w), maps of apparent diffusion coefficient, and maps of fractional anisotropy were generated from each MR scan. A trend function was fitted to these measurements to model an objective, general time course of the studied parameters. RESULTS Apparent diffusion coefficient (ADC) continuously decreased over time until a transition time around 45 hours; afterwards a continuous increase took place. After the 14th day ADC reached values similar to the ADC of the intact contralateral side (pseudonormalization) and then further increased. Fractional anisotropy (FA) decreased continuously over 3 to 6 months. CONCLUSION Times of transition and pseudonormalization of ADC were longer than described for territorial hemispheric infarcts and describe the acute to subacute phase of brainstem ischemia. In contrast, the continuous decline of FA over 3 to 6 months indicates a chronic process of change of histological structures in brainstem ischemia, and may be regarded as an indicator of the chronic phase.
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Affiliation(s)
- Hubertus Axer
- Department of Neurology, Friedrich-Schiller-University Jena, Jena, Germany.
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Abstract
Further evidence of diffusion tensor imaging contribution in the characterisation of retrograde and anterograde degeneration after stroke
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Lindberg PG, Skejø PHB, Rounis E, Nagy Z, Schmitz C, Wernegren H, Bring A, Engardt M, Forssberg H, Borg J. Wallerian Degeneration of the Corticofugal Tracts in Chronic Stroke: A Pilot Study Relating Diffusion Tensor Imaging, Transcranial Magnetic Stimulation, and Hand Function. Neurorehabil Neural Repair 2007; 21:551-60. [PMID: 17507645 DOI: 10.1177/1545968307301886] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Objective. This study tested the hypothesis that degeneration of the corticofugal tracts (CFTs) is related to poor functional outcome in the upper limb after stroke. Methods. The authors used diffusion tensor imaging to determine the degree of white matter integrity of the CFT (FAAH/UH) in chronic stroke patients and controls. The functional integrity of the corticospinal pathway was examined using transcranial magnetic stimulation. Recruitment curves and silent period duration were measured. The relationship between FA AH/UH and functional outcome of the upper limb was also assessed using a battery of upper limb function tests. Results. In patients, FA AH/UH correlated positively with the slope of recruitment curves (RC AH/UH) and grip strength. FAAH/UH also correlated negatively with the silent period duration (SPAH/UH). According to the FA AH/UH, patients were also classified into groups with minimal or extensive Wallerian degeneration (WD). Patients with more extensive WD had poorer grip strength, dexterity, and range of movement. Conclusions. The authors' results suggest that structural and functional integrity of the CFT is essential to maintain function of the upper limb after stroke.
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Affiliation(s)
- Påvel G Lindberg
- Department of Neuroscience, Uppsala University Hospital, Uppsala, Sweden.
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Bhagat YA, Emery DJ, Shuaib A, Sher F, Rizvi NH, Akhtar N, Clare TL, Leatherdale T, Beaulieu C. The relationship between diffusion anisotropy and time of onset after stroke. J Cereb Blood Flow Metab 2006; 26:1442-50. [PMID: 16552424 DOI: 10.1038/sj.jcbfm.9600294] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
Diffusion anisotropy changes in stroke lesions less than 24 h after onset have been reported to be elevated, decreased, or both. To address these mixed findings, we sought to characterize temporal changes of diffusion anisotropy by analyzing anatomically distinct ischemic white matter (WM) regions at 3 time phases within the first 34 h of ischemic stroke onset in 26 stroke patients (2 to 5 h, N=7; 7 to 14 h, N=11; 18 to 34 h, N=8). Mean diffusivity (Trace/3 apparent diffusion coefficient (ADC)), fractional anisotropy (FA), and T2-weighted signal intensity were measured for major and subcortical WM in lesions defined by a >or=30% drop in Trace/3 ADC. Major WM tract lesions with mean decreases of approximately 40% in relative (r) Trace/3 ADC showed an increased rFA of 1.11+/-0.18 (P<0.01) during the hyperacute phase (2 to 5 h), whereas rFA declined to 0.90+/-0.20 (P<0.01) and 0.88+/-0.12 (P<0.01) in the acute (7 to 14 h) and subacute (18 to 34 h) phases, respectively. Of those patients with lesions in major WM, 4 of 8 patients <or=7 h showed elevated rFA as opposed to none of the remaining 13 patients after 7 h. A greater proportion of the evaluated WM regions-of-interest (ROI) in the hyperacute phase revealed increases in rFA (60%), whereas conversely large proportions of ROIs (55% and 59%) in the acute and subacute phases showed reduced rFA. Similar anisotropy changes were noted in subcortical WM regions in the gyri.
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Affiliation(s)
- Yusuf A Bhagat
- Department of Biomedical Engineering, University of Alberta, Edmonton, Alberta, Canada
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Abstract
PURPOSE OF REVIEW Diffusion tractography uses non-invasive brain imaging data to trace fibre bundles in the human brain in vivo. This raises immediate possibilities for clinical application but responsible use of this approach requires careful consideration of the scope and limitations of the technique. RECENT FINDINGS To illustrate the potential for tractography to provide new information in clinical neuroscience we review recent studies in three broad areas: use of tractography for quantitative comparisons of specific white matter pathways in disease; evidence from tractography for the presence of qualitatively different pathways in congenital disorders or following recovery; use of tractography to gain insights into normal brain anatomy that can aid our understanding of the consequences of localised pathology, or guide interventions. SUMMARY Diffusion tractography opens exciting new possibilities for exploring features of brain anatomy that previously were not visible to us in vivo.
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Affiliation(s)
- Heidi Johansen-Berg
- Centre for Functional Magnetic Resonance Imaging of the Brain, University of Oxford, John Radcliffe Hospital, Oxford, UK
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Abstract
Diffusion tensor imaging (DTI) permits the quantitative evaluation of white matter pathology using measures of diffusion anisotropy. Fiber tractography based on DTI can reveal the three-dimensional white matter connectivity of the human brain. DTI fiber tractography is used to localize stroke lesions in relation to functionally important pathways and to assess wallerian degeneration, which may allow more accurate prognosis of long-term recovery or disability. DTI also improves the evaluation of hypoxic-ischemic injury to the developing brain of newborns and infants. DTI and fiber tractography may prove useful in elucidating alterations in brain connectivity resulting from neuroplasticity after stroke.
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Affiliation(s)
- Pratik Mukherjee
- Neuroradiology Section, Department of Radiology, University of California at San Francisco, CA 94143-0628, USA.
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