Dissertations / Theses on the topic 'Cerebrovascular disease – Spectroscoping imaging'
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1
Ross, Amy Psychiatry Faculty of Medicine UNSW. "Longitudinal study of cognitive and functional brain changes in ageing and cerebrovascular disease, using proton magnetic resonance spectroscopy." Awarded by:University of New South Wales. School of Psychiatry, 2005. http://handle.unsw.edu.au/1959.4/27329.
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The neurophysiological basis of cognition changes with age is relatively unexplained, with most studies reporting weak relationships between cognition and measures of brain function, such as event related potentials, brain size and cerebral blood flow. Proton magnetic resonance spectroscopy (1H-MRS) is an in vivo method used to detect metabolites within the brain that are relevant to certain brain processes. Recent studies have shown that these metabolites, in particular N-acetyl aspartate (NAA), which is associated with neuronal viability, correlate with performance on neuropsychological tests or other measures of cognitive function in patients with a variety of cognitive disorders associated with ageing and in normal ageing subjects. We have studied the relationship between metabolites and cognitive function in elderly patients 3 months and 3 years after a stroke or transient ischemic attack (TIA) and in an ageing comparison group. Metabolites were no different between stroke/TIA patients and elderly controls, however, there were significant metabolite differences between stroke/TIA patients with cognitive impairment (Vascular Cognitive Impairment and Vascular Dementia) and those without. Frontal measures of NAA and NAA/Cr predicted cognitive decline over 12 months and 3 years in stroke/TIA patients and elderly controls, and these measures were superior predictors than structural MRI measures. Longitudinal stability of metabolites in ageing over 3 years was associated with stability of cognitive function. The results indicate that 1H-MRS is a useful tool in differentiating stroke/TIA patients with and without cognitive impairment, with possibly superior predictive ability than structural MRI for assessing future cognitive decline. The changes in 1H-MRS that occur with ageing and cognitive decline have implications for the neurophysiological mechanisms and processes that are occurring in the brain, as well as application to clinical diagnosis, the early detection of pathology and the examination of longitudinal change.
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Gan, Rui. "Robust multimodal medical image registration and statistical cerebrovascular segmentation /." View abstract or full-text, 2006. http://library.ust.hk/cgi/db/thesis.pl?COMP%202006%20GAN.
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Evans, Nicholas Richard. "Multimodal imaging of inflammation at the neurovascular interface in cerebrovascular disease." Thesis, University of Cambridge, 2018. https://www.repository.cam.ac.uk/handle/1810/275947.
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A carotid atherosclerotic plaque represents a nidus of inflammation mere centimetres below the blood-brain barrier. This inflammation, along with associated regions of microcalcification, are histopathological features of atheroma at risk of rupture (so-called “vulnerable plaques”) that trigger thromboembolic stroke. While conventional clinical imaging simply measures the degree of vessel stenosis, it is a crude measure that reveals little of the metabolic processes affecting plaque vulnerability. Our research demonstrates the utility of positron emission tomography (PET) using 18F-fluorodeoxyglucose (FDG) and 18F-sodium fluoride (NaF), measuring inflammation and microcalcification respectively, to identify culprit carotid atheroma in vivo, and establish how these processes influence plaque vulnerability. Furthermore, for stroke care it is the downstream thromboembolic effects upon the brain that are key. While proinflammatory conditions may increase the risk of stroke, the relationship between atheroma inflammation and the peri-infarct inflammatory response following a stroke remains poorly defined. Our work demonstrates how inflammatory activity in symptomatic carotid atheroma, measured using PET, influences both chronic small vessel disease and the evolution of lesion volume in the post-stroke period. Using metabolic imaging we can both identify vulnerable atheroma in vivo and demonstrate how these processes affect infarct evolution. We show that whilst inflammation is a generalised process, microcalcification is a focal process that may represent a point of maximum vulnerability. These results also reveal the complexity of the atheroma-brain interaction that may simultaneously trigger events while also influencing stroke evolution in the early recovery period. This has important implications for understanding pathophysiology of both atherosclerosis and stroke evolution, advancing drug-discovery, and potential clinical applications to minimise the impact from this devastating disease.
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Zolgharni, Massoud. "Magnetic induction tomography for imaging cerebral stroke." Thesis, Swansea University, 2010. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.678669.
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Mullins, Paul Gerald Mark. "Magnetic resonance imaging in the study of animal models of cerebral ischaemia /." [St. Lucia, Qld.], 2001. http://www.library.uq.edu.au/pdfserve.php?image=thesisabs/absthe16186.pdf.
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Fernández-Andújar, Marina. "Neuroimaging correlates of cognitive functioning in cerebrovascular disease." Doctoral thesis, Universitat de Barcelona, 2014. http://hdl.handle.net/10803/290852.
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Cerebrovascular diseases (CD) are the third most common cause of death and the leading cause of disability in adults in developed countries (Carmichael, 2012; World Health Organization, 2004). Specifically, ischemic stroke and white matter lesions (WML) often result in multiple neurological, cognitive impairment and behavioral and emotional disorders (Gorelick et al., 2011; Troncoso et al., 2008). Strokes are responsible for damage in the core of the ischemic lesion but may also cause alterations in remote areas from the primary ischemic lesion. The thalamus is a key structure in the cortico-subcortical circuits (Alexander et al., 1986; Byne et al., 2009) and is involved in multiple cognitive functions (Herrero et al., 2002; Sherman, 2005) especially in functions executive, one of the most affected cognitive domains after suffering a stroke. Although it is known that the cortico- subcortical circuits are involved in cognitive functions, to date their neuroimage correlates are unknown. The overall objective of this thesis was to study the effects of a disruption in the cortico-subcortical circuits, due to a direct or remote damage, in executive functions. For the study of remote thalamic abnormalities we use the technique of diffusion tensor image (DTI) for both ischemic stroke and WML. Moreover, due to attention and cognitive inhibition are one of the most important functions of executive domain, we studied the relationship between a specific white matter (WM) tract -called Front aslant Tract (FAT)- and these functions. The study results showed that remote thalamic microstructural abnormalities secondary to a cerebrovascular lesion can occur in both ipsilateral and contralateral thalamus, in healthy subjects with WML and in patients with cerebral ischemic stroke. These thalamic abnormalities may be related to a disruption in the cortico-subcortical circuits associated with executive dysfunction. In addition, the right FAT is involved in attention and response inhibition functions in community-dwelling subjects and participants with ischemic stroke. In conclusion, the results obtained in this thesis suggest that stroke can affect the cortico-subcortical circuits through thalamic microstructural abnormalities and these could be related to cognitive dysfunction. Finally, the novel technique of DTI can play an important role in understanding the cognitive functioning in both ischemic stroke and WML.Los accidentes cerebrovasculares (ACV) son la tercera causa más común de muerte y la causa principal de discapacidad en adultos en los países desarrollados (Carmichael, 2012; Organización Mundial de la Salud, 2004). Concretamente, el ictus isquémico y las lesiones de sustancia blanca (LSB) frecuentemente dan lugar a múltiples secuelas neurológicas, deterioro cognitivo y alteraciones conductuales y emocionales (Gorelick et al., 2011; Troncoso et al., 2008). Los ACV son responsables de daño en la zona primaria de la lesión isquémica pero también pueden producir alteraciones en áreas remotas a ésta. El tálamo es una estructura clave en los circuitos cortico-subcorticales (Alexander et al., 1986; Byne et al., 2009) y está involucrado en múltiples funciones cognitivas (Herrero et al., 2002; Sherman, 2005) especialmente en las funciones ejecutivas, uno de los dominios cognitivos más afectados después de sufrir un ACV. Aunque se sabe que los circuitos cortico-subcorticales están implicados en las funciones cognitivas, hasta la fecha sus correlatos de neuroimagen se desconocen. El objetivo general de esta tesis ha sido estudiar los efectos de una interrupción en los circuitos cortico-subcorticales debido a una lesión directa o remota en las funciones ejecutivas. Para el estudio de las anomalías talámicas remotas usamos la técnica de la Imagen por Tensor de Difusión (ITD), tanto para el ictus isquémico como para las LSB. Además, dado que la atención y la inhibición cognitiva son una de las funciones más importantes de las funciones ejecutivas, estudiamos la relación entre un tracto de sustancia blanca (SB) -llamado Frontal Aslant Tract (FAT)- y estas funciones. Los resultados de los estudios mostraron que anomalías secundarias microestructurales talámicas remotas a la lesión cerebrovascular pueden ocurrir tanto en el tálamo ipsilateral como en el tálamo contralateral, en sujetos sanos con LSB y en pacientes con un ictus cerebral isquémico. Estas anomalías talámicas pueden estar relacionadas con una disrupción en los circuitos cortico-subcorticales asociado con disfunción ejecutiva. Además, en sujetos de la comunidad y con un ictus isquémico, el FAT derecho está implicado en atención e inhibición de respuesta. En conclusión, los resultados obtenidos en la presente tesis doctoral sugieren que los ACV puede afectar los circuitos cortico-subcortical a través de anomalías microstructurales talámicas y éstas podrían estar relacionadas con la disfunción cognitiva. Finalmente, la novedosa técnica de la ITD puede tener un papel relevante en el conocimiento del funcionamiento cognitivo tanto en el ictus isquémico como en las LSB.
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Madai, Vince István [Verfasser]. "Improvements of Magnetic Resonance Imaging techniques for clinical diagnosis in cerebrovascular disease / Vince Istvan Madai." Berlin : Medizinische Fakultät Charité - Universitätsmedizin Berlin, 2017. http://d-nb.info/1148425284/34.
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Madai, Vince Istvan [Verfasser]. "Improvements of Magnetic Resonance Imaging techniques for clinical diagnosis in cerebrovascular disease / Vince Istvan Madai." Berlin : Medizinische Fakultät Charité - Universitätsmedizin Berlin, 2017. http://d-nb.info/1148425284/34.
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Brevard, Mathew E. "Developing compatible techniques for magnetic resonance imaging of stroke pathophysiology." Link to electronic thesis, 2002. http://www.wpi.edu/Pubs/ETD/Available/etd-0107103-173954.
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Fox, Timothy H. "Evaluation of a method for identifying finite resolution effects in single photon emission computed tomographic (SPECT) imaging of the cerebral cortex." Thesis, Georgia Institute of Technology, 1992. http://hdl.handle.net/1853/17067.
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Li, Geng, and 李耕. "Brain activations on functional magnetic resonance imaging during acupuncture and/or physiological tasks in healthy volunteers andstable stroke patients." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2003. http://hub.hku.hk/bib/B29157511.
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Salarirad, Sima. "The contributions of imaging biomarkers of subclinical cerebrovascular disease and Alzheimer's pathology to cognition in normal ageing." Thesis, University of Aberdeen, 2011. http://digitool.abdn.ac.uk:80/webclient/DeliveryManager?pid=211291.
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This thesis aimed to investigate the individual and combined effects of brain magnetic resonance imaging (MRI) markers of the two commonest age-related brain pathologies associated with dementia on longitudinal cognitive ability in normal ageing. Participants were 106 members of the Aberdeen 1921 Birth Cohort (ABC21), for whom childhood intelligence and serial measures of cognitive ability age 78-81 were available. Cerebrovascular disease was measured as white matter hyperintensities (WMH) at baseline (age 78-79) and over two successive time points; age 79-80 years and age 80-81 years using a visual scoring method. All participants had some WMH and these were most abundant in the frontal lobes. WMH increased in burden on followup and the greatest increase was seen in the parietal lobes, even allowing for participant drop-out, which was greater in those with more WMH at baseline. The effect of WMH on cognitive ability showed significant negative cross-sectional associations but there was no relationship between increase in WMH burden and longitudinal cognitive decline, either using linear regression analyses or latent growth curve modelling. Both WMH and childhood intelligence contribute significantly to late life fluid cognitive ability, but not to the trajectory of age-related change in fluid intelligence. Age was the strongest predictor of the cognitive trajectory from 78 to 81 years, even within the narrow age range of the ABC21 sample. Combined analysis of the influence of whole brain volume and WMH showed that the main predictor of dementia and death over 7 years follow-up of ABC21 was reduced viii brain fraction (< 73% of total brain volume normalised to intra-cranial volume). While WMH contributed to a diagnosis of dementia, they did not predict mortality. Comparison of manual and automated methods of hippocampal segmentation demonstrated that the automated method (FreeSurfer) systematically over-estimated volumes compared with a manual method (MRIcro) but that both methods were correlated. There were significant positive relationships between hippocampal volume and a variety of cognitive abilities, but these relationships were most significant for the left hippocampus. A final model of the influence of WMH (as a measure of cerebrovascular disease) and hippocampal volume (as a measure of Alzheimer‘s pathology) on lifelong cognitive change from age 11 to age 78 showed that both WMH and hippocampal volume had negative effects on late life fluid intelligence but that only the effect of hippocampal volume was significant. The conclusions of this work are that WMH are age-related and while they have a negative association with fluid intelligence, the main predictor of lifelong cognitive decline is hippocampal volume, an imaging marker of Alzheimer‘s pathology. The flowchart in next page is demonstrated a schematic summary of the thesis.
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Schulz, Ursula Gabriele Renate. "Risk factors for specific subtypes of ischaemic stroke." Thesis, University of Oxford, 2004. http://ora.ox.ac.uk/objects/uuid:43200f6f-abe0-4b1e-84a2-31df49707b6f.
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Ischaemic stroke is a complex disorder with many different aetiologies, but previous studies of stroke often did not differentiate aetiological subtypes of ischaemic stroke. However, different stroke subtypes may have different risk factors, and to target preventive treatments more effectively, we need to understand these associations. I studied the association of established vascular risk factors with different aetiological stroke subtypes in population-based cohorts of stroke patients. I studied Diffusion Weighted Magnetic Resonance Imaging (DWI) in patients with subacute minor stroke and TIA to determine whether DWI may be a useful addition to the management of such patients, and whether it may be a useful tool in future epidemiological studies of stroke. To determine whether carotid anatomy may be a risk factor for large vessel atheroma I studied angiographical data from the European Carotid Surgery Trial. My main findings are that the prevalence of risk factors differs between stroke subtypes. It also differs between hospitalised and non-hospitalised patients, highlighting that risk factor studies should be performed in population-based cohorts. Analysis of family history data suggests that future genetic studies may best be targeted at non-cardioembolic stroke and at younger patients, and that genetic studies of hypertension may help to unravel some of the genetic factors contributing to stroke risk. DWI is sensitive in subacute minor stroke, and inter- and intra-observer reproducibility are high. DWI frequently adds useful information and may influence patient management. More widespread use of DWI in patients with subacute stroke and TIA should be considered, and DWI may also be a useful tool in future epidemiological studies of stroke. Carotid anatomy varies considerably between individuals, is very asymmetrical within individuals, and it differs between men and women. These findings may partly explain differences in plaque development between individuals, asymmetrical plaque formation within individuals, and sex differences in the distribution of carotid plaque and in the prevalence of carotid atheroma in the general population. Carotid anatomy may be a risk factor for local plaque development. Although not amenable to treatment, knowing which anatomical configuration is associated with atheroma formation could help to identify high-risk individuals in whom other risk factors should be treated aggressively.
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Bennett, David G. "Osmotic- and stroke-induced blood-brain barrier disruption detected by manganese-enhanced magnetic resonance imaging." Link to electronic thesis, 2007. http://www.wpi.edu/Pubs/ETD/Available/etd-081707-080430/.
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Brevard, Mathew E. "Developing Compatible Techniques for Magnetic Resonance Imaging of Stroke Pathophysiology." Digital WPI, 2001. https://digitalcommons.wpi.edu/etd-theses/20.
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Stroke is the most prevalent neurological disease facing our nation today. Treatments, however, are few and insufficient at reducing the impact of this neurological condition. Experimental animal models are important to improving our understanding of stroke, and for developing new therapies to counter the pathology of stroke. Magnetic Resonance Imaging is the leading tool for the non-invasive investigation of stroke pathophysiology. While most MRI work in animals is conducted under anesthesia, anesthesia has profound effects on cerebral circulation and metabolism, and can affect stroke outcome. Several novel methods were combined with MRI compatible physiologic monitoring equipment to conduct stroke studies in conscious animals. Stress was studied as a factor in these studies and conditioning was utilized to reduce the impact of stress on the animals' physiology. Models of both occlusive and hemorrhagic strokes were successfully implemented within the MRI apparatus. Lastly, experiments using a macrosphere model showed evidence of a pathophysiologic difference between awake and anesthetized animals that undergo stroke.
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Chen, Xiaohua Psychiatry Faculty of Medicine UNSW. "Vascular risk factors and brain structure in healthy middle-aged adults: a series of studies using high resolution MRI." Awarded by:University of New South Wales. Psychiatry, 2007. http://handle.unsw.edu.au/1959.4/31545.
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A number of chronic disease and behavioural factors are recognised to increase the risk of cardiovascular and cerebrovascular diseases. These putative ???vascular??? risk factors have increasingly been recognised to increase the risk of cognitive impairment in the absence of clinically manifest ischemic events. Their relationship to structural brain changes has received limited attention. In this dissertation, I used high resolution magnetic resonance image (MRI) to examine two structural features of the brain, regional gray matter (GM) volumes and silent lacunar infarcts, and determined their association with vascular risk factors. I related these to cognitive function in both cross-sectional and longitudinal studies. The work was based on the data of three waves in two healthy cohorts drawn from the PATH Through Life Study, which is a population-based longitudinal study of ageing comprising 3 cohorts aged 20-24, 40-44, and 60-64 years, with about 2500 participants in each cohort. Random subsamples of Wave 1 of the cohort aged 60-64 years (N = 478) and Wave 2 of the 40+ cohort (aged 44-48 years) (N = 411) were examined cross-sectionally for the MRI sub-study. The MRI cohort aged 60-64 years was re-examined 4 years later in Wave 2. These studies showed that vascular risk factors are associated with lower regional GM volumes and this association varies at different ages. In adults aged 44-48 years, individual risk factors did not show a significant relationship with GM volumes, but the Framingham risk score was associated with less GM volumes in a number of brain regions, suggesting an additive effect of the risk factors. In the 60+ cohort, hypertension was independently associated with less regional GM volumes in bilateral medial frontal, right superior frontal, left superior temporal and precentral gyri. The same cohort, when examined in Wave 2, showed the negative association of hypertension with gray matter volumes to be more widespread. These associations were observed in men but not in women in either wave. Sex dimorphism was observed in the younger cohort as well, with greater GM volumes in temporal and occipital cortices, midbrain and cerebellum in men, while less GM volumes in cingulate and parietal cortices in comparison with women. Lacunar infarcts were present in 7.8 % of the 60+ cohort, and asymptomatic new lacunar lesions developed in 0.4 % per year in this group. The prevalence of lacunar infarcts was correlated with hypertension and a steeper decline in mental speed. These series of studies indicate the relationship of vascular risk factors with changes in brain structure and cognitive function in healthy middle-aged adults. It is suggested that modifying these vascular risk factors may protect the brain from silent lesions and cognitive impairment, and that intervention should begin early in life to have a major impact.
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Karl, Jenni M., and University of Lethbridge Faculty of Arts and Science. "Thinning, movement, and volume loss of residual cortical tissue occurs after stroke in the adult rat as identified by histological and magnetic resonance imaging analysis." Thesis, Lethbridge, Alta. : University of Lethbridge, Dept. of Neuroscience, 2010, 2010. http://hdl.handle.net/10133/2566.
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Plasticity of residual cortical tissue has been identified as an important mediator of
functional post-stroke recovery. After neonatal stroke the thickness of residual tissue can
change, the tissue can move, and tissue can fill in the stroke core. Nevertheless, the
majority of preclinical stroke research utilizes adult rats. Thus, the purpose of the present
thesis was to systematically document such gross morphological changes in peri-infarct
tissue after stroke in the adult rat. Morphological changes were assessed in pial strip
devascularization, photothrombotic occlusion, and middle cerebral artery occlusion
models of stroke using histological and magnetic resonance imaging. Decreases in
cortical thickness, volume, and neural density were found to extend far beyond the stroke
infarct and included the sensorimotor regions of the intact hemisphere. Movement of
residual tissue towards the infarct was observed and confirmed using anatomical markers placed in intact cortical tissue at the time of stroke induction. I conclude that the
extensive time-dependent morphological changes that occur in residual cortical tissue
must be considered when evaluating plasticity-related cortical changes associated with
post-stroke recovery of function.ix, 162 leaves : ill. ; 28 cm
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Henning, Erica C. "NMR Characterization of Pathological Disease States Monitoring Response to Single-Dose Radiotherapy in a RIF-1 Tumor Model and the Role of Spreading Depression in the Evolution of Ischemic Stroke." Link to electronic thesis, 2005. http://www.wpi.edu/Pubs/ETD/Available/etd-042205-130831/.
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Dissertation (Ph.D.) -- Worcester Polytechnic Institute and University of Massachusetts Medical School.Keywords: multispectral analysis ; RIF-1; spreading depression; diffusion; MEMRI; stroke. Includes bibliographical references (p. 229-232).
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Ojha, Navdeep. "Imaging of tissue injury-repair addressing the significance of oxygen and its derivatives." Columbus, Ohio : Ohio State University, 2007. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=osu1196204993.
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McConnell, Flora A. Kennedy. "Quantifying collateral flow pathways in the brain." Thesis, University of Oxford, 2017. http://ora.ox.ac.uk/objects/uuid:2a0142ed-6161-4294-abd4-acd377ba6fed.
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Ischaemic stroke is a major cause of death and disability worldwide. Cerebral autoregulation, which can be impaired during acute stroke, and collateral flow to brain tissue through the circle of Willis, both play a role in preventing tissue infarction. The configuration of the arterial circle varies between individuals. Thus, personalised modelling of the cerebral arterial network, to determine the potential for collateral flow, can be of significant value in the clinical context of stroke. The interaction between autoregulation and collateral flow remains poorly understood. In this study, steady-state physiological models of the cerebral arterial network, including several common variants of the circle of Willis, were coupled to a spatially variable mathematical representation of cerebral autoregulation. The resulting model was used to simulate various arterial occlusions, as well as bilateral and unilateral impairment of autoregulation, in each structural variant. The work identified few circle of Willis variants that present either particularly high-risk or particularly low-risk of cerebral ischaemia. Instead it was found that most variants are dependent upon the bilateral function of autoregulation to facilitate collateral flow and preserve cerebral blood flows. When autoregulation was impaired unilaterally, downstream of an occlusion, blood flows in the contralateral hemisphere were preserved at the expense of the ipsilateral tissue at risk. Arterial network models have in the past been personalised using structural, rather than functional, angiography measurements. This thesis presents a novel model-based method for absolute blood volume flow rate quantification in short arterial segments using dynamic magnetic resonance angiography data. The work also investigated the additional information that can be obtained from such functional angiography. The flow quantification technique was found to accurately estimate flows in shorter arterial segments than an existing technique. However, improvements to noise performance, and strategies for rejection of contaminating signals from overlapping vessels within the imaging plane, are required before the technique can be applied to personalised cerebral arterial network modelling.
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Msayib, Yunus. "Quantifying impaired metabolism following acute ischaemic stroke using chemical exchange saturation transfer magnetic resonance imaging." Thesis, University of Oxford, 2017. http://ora.ox.ac.uk/objects/uuid:a98323ce-5998-436d-bca4-09df549cf191.
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In ischaemic stroke a disruption of cerebral blood flow leads to impaired metabolism and the formation of an ischaemic penumbra in which tissue at risk of infarction is sought for clinical intervention. In stroke trials, therapeutic intervention has largely been based on perfusion-weighted measures, but these have not been shown to be good predictors of tissue outcome. The aim of this thesis was to develop analysis techniques for magnetic resonance imaging (MRI) of chemical exchange saturation transfer (CEST) in order to quantify metabolic signals associated with tissue fate in patients with acute ischaemic stroke. This included addressing robustness for clinical application, and developing quantitative tools that allow exploration of the in-vivo complexity. Tissue-level analyses were performed on a dataset of 12 patients who had been admitted to the John Radcliffe Hospital in Oxford with acute ischaemic stroke and recruited into a clinical imaging study. Further characterisation of signals was performed on stroke models and tissue phantoms. A comparative study of CEST analysis techniques established a model-based approach, Bloch-McConnell model analysis, as the most robust for measuring pH-weighted signals in a clinical setting. Repeatability was improved by isolating non-CEST effects which attenuate signals of interest. The Bloch-McConnell model was developed further to explore whether more biologically-precise quantification of CEST effects was both possible and necessary. The additional model complexity, whilst more reflective of tissue biology, diminished contrast that distinguishes tissue fate, implying the biology is more complex than pH alone. The same model complexity could be used reveal signal patterns associated with tissue outcome that were otherwise obscured by competing CEST processes when observed through simpler models. Improved quantification techniques were demonstrated which were sufficiently robust to be used on clinical data, but also provided insight into the different biological processes at work in ischaemic tissue in the early stages of the disease. The complex array of competing processes in pathological tissue has underscored a need for analysis tools adequate for investigating these effects in the context of human imaging. The trends herein identified at the tissue level support the use of quantitative CEST MRI analysis as a clinical metabolic imaging tool in the investigation of ischaemic stroke.
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Nelson, Merlisa Claudia. "Ultrasound evaluation of the extracranial cerebrospinal venous system and carotid arteries in patients with multiple sclerosis." Thesis, Cape Peninsula University of Technology, 2013. http://hdl.handle.net/20.500.11838/1565.
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Thesis submitted in fulfilment of the requirements for the degree
Master of Technology: Radiography
in the Faculty of Health and Wellness Sciences
at the Cape Peninsula University of Technology
Supervisor: Ms. Ferial Isaacs
Co-supervisor: Prof. Susan J. Van Rensburg
Bellville
September 2013Multiple Sclerosis (MS) is characterised by demyelination within the central nervous system (CNS), which may result in neurological disabilities over time, causing considerable hardship to patients and their families, in addition to being costly to treat. Recent studies have linked MS to impaired cerebral blood flow, called chronic cerebrospinal venous insufficiency (CCSVI). Anecdotal evidence has suggested that surgical correction thereof results in improvement of symptoms experienced by MS patients. To my knowledge, no information is available in the literature on carotid artery disease in MS. The USA National MS Society has therefore called for more research to be done in this area. This cross-sectional observational sub-study will determine, by ultrasound (B-Mode, Colour and Pulsed-wave Doppler), the prevalence of chronic venous insufficiency (CCSVI) and carotid artery disease in the selected sample of MS patients within the region of the Western Cape, South Africa. Biochemical data; lifestyle factors such as physical activity and smoking; and nutritional status of MS patients were determined from the main study entitled: “The development of a comprehensive gene-based, pathology supported intervention program for improved quality of life in patients diagnosed with multiple sclerosis” (Division of Chemical Pathology, NHLS, Tygerberg Hospital, and University of Stellenbosch). Twenty-nine (29) patients were aged between 28-64years and they suffered from MS for 0.83-27years. A larger proximal and mid cross-sectional diameter (CSD) of the right IJV compared to the left (differences significant, P= 0.026 and P=0.023) was demonstrated. Increased intima media thickness (IMT) was present in 13.33% of the non-smoking MS group and 20% in the smoking MS group. IJV reflux was evident in 13.33% of the MS group. A significant reduction of cross-sectional diameters of the IJV’s was evident in smoking MS patients; suggesting that smoking is not only a risk factor for atherosclerotic disease but could also be related to narrowing of the major neck veins. This study also supports findings of other studies viz that there’s no significant correlation between extracranial venous abnormalities and MS. Early carotid artery disease was noted in smoking and non-smoking MS patients, however the findings were non-significant.
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"Depression and quality of life in stroke: a magnetic resonance imaging study." Thesis, 2011. http://library.cuhk.edu.hk/record=b6075402.
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Lu, Jinyan.Thesis (Ph.D.)--Chinese University of Hong Kong, 2011.
Includes bibliographical references (leaves 75-86).
Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web.
Abstract also in Chinese; some appendixes in Chinese.
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"The value of extracranial arterial blood flow volume in ischaemic cerebrovascular disease." 2002. http://library.cuhk.edu.hk/record=b6073449.
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Ho Sin Yee, Stella."August 2002."
Thesis (Ph.D.)--Chinese University of Hong Kong, 2002.
Includes bibliographical references (p. 167-193).
Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web.
Mode of access: World Wide Web.
Abstracts in English and Chinese.
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Lobo, Diana Filipa Duarte. "Cerebrovascular and Blood-Brain Barrier Impairments in Machado-Joseph Disease." Master's thesis, 2017. http://hdl.handle.net/10362/25829.
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Central Nervous System (CNS)-barriers are essential to maintain brain homeostasis,
protection and nutrition. Blood-brain barrier (BBB) is mainly constituted by brain endothelial cells, pericytes and astrocytes that restrict the communication between blood and the brain parenchyma. Blood-cerebrospinal fluid barrier (BCSFB) controls molecular exchange between and the cerebrospinal fluid in the epithelial cells of choroid plexus. Both barriers express tight junction (TJ) proteins that limit the paracellular permeability between adjacent cells.
In several neurodegenerative diseases, BBB dysfunction has been associated with
neuroinflammation and TJs disruption with consequent enhancement of pathogenesis. Machado-Joseph Disease (MJD), also a neurodegenerative disorder, is caused by an expansion in CAG repeats in MJD1 gene that codifies for mutant ataxin-3 protein and causes neurodegeneration and neuroinflammation.
The aim of this work was to evaluate the cerebrovascular and CNS-barriers integrity in
MJD. To accomplish that, we first assessed BBB permeability by quantifying the Evans blue (EB) extravasation in the brain of a transgenic mouse model of MJD. In a second experiment, we aimed at investigating which mechanisms were involved in BBB disruption, by analyzing: the presence of mutant ataxin-3 in cerebellar blood vessels, fibrin extravasation across BBB, and the expression of TJ-associated proteins. Finally, perfusion and vascular permeability were evaluated by Dynamic Contrast Enhanced-Magnetic Resonance Imaging (DCE-MRI).
The results of this work showed that BBB is disrupted in this MJD mouse model, which
was demonstrated by Evans blue and fibrin extravasation. Both barriers showed alterations in TJs expression. Occludin was cleaved in both barriers, claudin-5 was upregulated in BBB, whereas ZO-1 showed a tendency to be decreased in BCSFB. Furthermore, it was demonstrated the presence of ataxin-3 aggregates in cerebellar blood vessels. Finally, DCE-MRI confirmed an increased blood volume and higher vascular permeability in MJD mice.
In conclusion, this work demonstrated that cerebrovasculature and CNS-barriers are
impaired in MJD.
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"Cognitive impairment and psychiatric morbidity in Chinese stroke patients: clinical and imaging characterization." Thesis, 2010. http://library.cuhk.edu.hk/record=b6074863.
Full textAbstract:
Frontal lobe atrophy (FLA) is associated with late-life depression and cognitive impairment, although the pathogenesis of FLA in stroke is unclear. In an aim to ascertain whether FLA is affected by WMLs, we analyzed the MRIs of 471 Chinese ischemic stroke patients. Lobar atrophy was defined by a widely-used visual rating scale. WML severity was rated using the Fazekas scale. There was no correlation between PVH and DWMH and temporal and parietal atrophy. The results of this study suggest that FLA in ischemic stroke may be associated with SVD.Poststroke depression (PSD) is the most common form of poststroke psychiatric morbidity. Small subcortical infarcts (SSIs) can result from small vessel disease (SVD) and large artery disease (LAD). No study has yet explored PSD in different etiological types of SSIs. To address this gap, 127 patients with SSIs resulting from LAD or SVD were examined. PSD was evaluated with the Geriatric Depression Scale (GDS) three months after stroke. The LAD group had a significantly higher frequency of PSD, and LAD was found to be a significant independent risk factor for PSD. This study suggests that cerebral blood perfusion may play an important role in PSD.
Post-stroke emotional lability (PSEL) is a distressing and embarrassing complaint among stroke survivors. Lesions located in various cortical and subcortical areas are thought to be involved in the pathophysiology of PSEL.The clinical significance of microbleeds (MBs) in the development of psychiatric conditions following stroke is unknown. We carried out a study to examine the association between PSEL and MBs in 519 Chinese patients with acute ischemic stroke admitted consecutively. PSEL was evaluated three months after the index stroke, and the number and location of MBs were evaluated with MRI. According to Kim's criteria, 74 (14.3%) of the patients had PSEL. Our results suggest that MBs in the thalamus may play a role in the development of PSEL. The importance of MBs in PSEL and other psychiatric conditions in stroke survivors warrants further investigation.
The first study reported in this thesis involved 328 Chinese ischemic stroke patients who were administered a series of neuropsychological tests covering seven domains three months after stroke. Two hundred and fifty-six of these patients were followed-up for one year. Volumetry of the infarcts, WMLs, and hippocampus atrophy on magnetic resonance imaging (MRI) was conducted. The prevalence of cognitive impairment was 54.9% at baseline and 52.4% at the one-year follow-up, although most of the patients (85.5%) remained cognitively stable. The evolution of cognitive impairment no dementia (CIND) at the one-year follow-up was bidirectional, with 11.2% progressing to dementia and 21.0% reverting to cognitive intact. WMLs volume rather than hippocampal volume was a significant predictor of cognitive impairment, cognitive decline, and delayed dementia. WMLs also had an independent effect on executive function, attention, visual memory, visuoconstruction, and visuomotor speed.
This thesis investigates the clinical and imaging characterization of cognitive impairment and psychiatric morbidity in Chinese stroke patients. The conclusions of the studies reported herein can be summarized as follows. (1) The prevalence of cognitive impairment is high among Chinese poststroke patients, but most remain cognitively stable at one year after stroke; WMLs rather than hippocampal atrophy predict cognitive impairment, longitudinal cognitive decline, and delayed dementia; (2) DLPFC atrophy is correlated with poor verbal fluency in elderly women with stroke, but not in their male counterparts; (3) LAD may be associated with PSD in patients with small subcortical infarcts; (4) MBs in the thalamus are associated with PSEL; (5) frontal lobe infarction and diabetes may be risk factors of insomnia symptoms in stroke patients; and (6) FLA in ischemic stroke may be associated with SVD. (Abstract shortened by UMI.)
Chen, Yangkun.
Adviser: Wai Kwong Tang.
Source: Dissertation Abstracts International, Volume: 72-04, Section: B, page: .
Thesis (Ph.D.)--Chinese University of Hong Kong, 2010.
Includes bibliographical references (leaves 217-238).
Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web.
Electronic reproduction. Ann Arbor, MI : ProQuest Information and Learning Company, [200-] System requirements: Adobe Acrobat Reader. Available via World Wide Web.
Abstract also in Chinese.
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Zivadinov, R., G. U. Poloni, K. Marr, C. V. Schirda, C. R. Magnano, E. Carl, N. Bergsland, et al. "Decreased brain venous vasculature visibility on susceptibility-weighted imaging venography in patients with multiple sclerosis is related to chronic cerebrospinal venous insufficiency." 2011. http://hdl.handle.net/10454/6252.
Full textAbstract:
BACKGROUND: The potential pathogenesis between the presence and severity of chronic cerebrospinal venous insufficiency (CCSVI) and its relation to clinical and imaging outcomes in brain parenchyma of multiple sclerosis (MS) patients has not yet been elucidated. The aim of the study was to investigate the relationship between CCSVI, and altered brain parenchyma venous vasculature visibility (VVV) on susceptibility-weighted imaging (SWI) in patients with MS and in sex- and age-matched healthy controls (HC). METHODS: 59 MS patients, 41 relapsing-remitting and 18 secondary-progressive, and 33 HC were imaged on a 3T GE scanner using pre- and post-contrast SWI venography. The presence and severity of CCSVI was determined using extra-cranial and trans-cranial Doppler criteria. Apparent total venous volume (ATVV), venous intracranial fraction (VIF) and average distance-from-vein (DFV) were calculated for various vein mean diameter categories: < .3 mm, .3-.6 mm, .6-.9 mm and > .9 mm. RESULTS: CCSVI criteria were fulfilled in 79.7% of MS patients and 18.2% of HC (p < .0001). Patients with MS showed decreased overall ATVV, ATVV of veins with a diameter < .3 mm, and increased DFV compared to HC (all p < .0001). Subjects diagnosed with CCSVI had significantly increased DFV (p < .0001), decreased overall ATVV and ATVV of veins with a diameter < .3 mm (p < .003) compared to subjects without CCSVI. The severity of CCSVI was significantly related to decreased VVV in MS (p < .0001) on pre- and post-contrast SWI, but not in HC. CONCLUSIONS: MS patients with higher number of venous stenoses, indicative of CCSVI severity, showed significantly decreased venous vasculature in the brain parenchyma. The pathogenesis of these findings has to be further investigated, but they suggest that reduced metabolism and morphological changes of venous vasculature may be taking place in patients with MS.
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Sabra, Dalia. "Arterial stiffness and brain health : investigating the impact of sex-related differences." Thèse, 2019. http://hdl.handle.net/1866/23672.
Full textAbstract:
Introduction: Il est bien établi que les maladies vasculaires, cérébrovasculaires et cardiovasculaires se manifestent différemment chez les hommes que chez les femmes. La rigidité artérielle (RA), un prédicteur indépendant de la maladie cardiovasculaire (MCV), a été associée à des changements de la réactivité cérébrovasculaire (RCV) et à un déclin cognitif lors du vieillissement. Plus précisément, les personnes âgées ayant une RA plus élevée présentent un déclin plus marqué au niveau des tâches exécutives. Une diminution des fonctions exécutives (FE) est également liée à une réduction de la RCV chez les personnes âgées. Cependant, il est important de noter que la relation entre la RA et la RCV est plus complexe. Certaines études montrent une diminution de la RCV associée avec une RA plus élevée, tandis que d’autres rapportent une RCV préservée avec une RA élevée. De plus, des travaux récents suggèrent que les différences de concentration en hématocrit (HCT) pourraient avoir une incidence sur les mesures de RA. Ici, nous avons étudié le rôle possible du sexe et de l'HCT sur ces relations hémodynamiques.
Méthodes: Des acquisitions ont été effectuées chez 48 adultes âgés en bonne santé (31 femmes, 63 ± 5 ans) dans un scanneur d’imagerie par résonance magnétique (IRM) 3T. Des données de marquage de spin artériel pseudo-continu utilisant des lectures à double écho ont été collectées pendant un défi d'hypercapnie (changement de CO2 de 5mmHg, pendant deux blocs de 2 minutes). La RCV a été calculée comme étant le % de changement du signal de débit sanguin cérébral (% ∆CBF) par changement de mmHg dans le CO2 à la fin de l’expiration. Les données de vitesse d’onde de pouls (VOP) aortique ont été acquises à l’aide d’une série de contraste de phase cine encodée par la vitesse durant 60 phases cardiaques avec un encodage en vélocité de 180cm/s dans le plan. La VOP dans l'arcade aortique a été calculée entre l'aorte ascendante et descendante. Les analyses statistiques ont été effectuées à l'aide de SPSS.
Résultats: Un test de modération contrôlant pour l’âge et le volume des hyperintensités de la matière blanche a révélé un effet direct significatif de la VOP sur la RCV (β = 1,630, IC à 95% [.654, 2,607), ainsi que de la VOP sur la FE (β = -. 998, IC 95% [-1,697, -,299]). Le sexe a modéré la relation entre VOP et RCV (β = -1,013, IC 95% [-1,610, -,4169]), et VOP et FE (β =
.447, IC 95% [.020, .875]). En outre, il existait un effet significatif de l’HCT sur les différences de sexe observées dans l’effet de modération (VOP * SEXE) sur la FE (β = -0,7680, SE = 0,3639, IC 95% [-1,5047, -0,0314], p = 0,0414).
Conclusion: Nos résultats indiquent que les relations entre la VOP, la RCV et la FE sont complexes et que le sexe et l’HCT modulentces relations. L’influence des variations hormonales (p. ex. la ménopause) sur ces relations devrait être étudiée dans le futur et pourrait permettre de personnaliser les stratégies de prévention des MCV.Introduction: It is well established that sex differences exist in the manifestation of vascular, cerebrovascular and cardiovascular disease. Arterial stiffness (AS), an independent predictor of cardiovascular disease (CVD), has been associated with changes in cerebrovascular reactivity (CVR) and cognitive decline in aging. Specifically, older adults with increased AS show a steeper decline on executive function (EF) tasks. Decreased EF is also linked with reduction in CVR among older adults. Interestingly, the relationship between AS and CVR is more complex, where some works show decreased CVR with increased AS, and others demonstrate preserved CVR with higher AS. In addition, recent work suggests that measurements of AS may be affected by differences in the concentration of hematocrit (HCT). Here, we investigated the possible role of sex and HCT on these hemodynamic relationships. Methods: Acquisitions were completed in 48 healthy older adults (31 females, 63 ± 5 years) on a 3T MRI. Pseudo-continuous arterial spin labeling using dual-echo readouts were collected during a hypercapnia challenge (5mmHg CO2 change, during two, 2 min blocks). CVR was calculated as the %∆CBF signal per mmHg change in end-tidal CO2. Aortic PWV data was acquired using a cine phase contrast velocity encoded series during 60 cardiac phases with a velocity encoding of 180cm/s through plane. PWV in the aortic arch was computed between ascending and descending aorta. Statistical analyses were done using SPSS. Results: A moderation model test controlling for age and white matter hyperintensity volume revealed a significant direct effect of PWV on CVR (β=1.630, 95% CI [.654, 2.607), as well as PWV on EF (β=-.998, 95% CI [-1.697, -.299]). Sex moderated the relationship between PWV and CVR (β=-1.013, 95% CI [-1.610, -.4169]), and PWV and EF (β=.447, 95% CI [.020, .875]). In addition, there was a significant effect of HCT on the sex differences observed in the moderation effect (PWV*SEX) on EF (β=-0.7680, SE = 0.3639 ,95% CI [-1.5047, -0.0314], p=0.0414). Conclusion: Together, our results indicate that the relationships between PWV, CVR and EF is complex and in part mediated by sex and HCT. Future work should investigate the role of hormone variations (e.g., menopause) on these relationships to better personalize CVD prevention strategies.