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Quantitative Magnetic Resonance Imaging To Investigate The Pathophysiology Of Alzheimers Disease
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Book Synopsis Quantitative Magnetic Resonance Imaging to Investigate the Pathophysiology of Alzheimer's Disease by : Marco Bozzali
Download or read book Quantitative Magnetic Resonance Imaging to Investigate the Pathophysiology of Alzheimer's Disease written by Marco Bozzali and published by . This book was released on 2021 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Global Clinical Trials for Alzheimer’s Disease by : Michel Grothe
Download or read book Global Clinical Trials for Alzheimer’s Disease written by Michel Grothe and published by Elsevier Inc. Chapters. This book was released on 2013-08-28 with total page 35 pages. Available in PDF, EPUB and Kindle. Book excerpt: In-vivo imaging markers of neuronal changes related to Alzheimer’s disease (AD) are ideally suited to be employed as diagnostic markers for early and differential diagnosis of AD as well as for the assessment of neurobiological effects of medical treatments in clinical trials. Novel molecular imaging techniques enable in-vivo detection of cerebral amyloid pathology, whereas magnetic resonance imaging (MRI)-based techniques, such as volumetric MRI and diffusion tensor imaging (DTI), provide structural lesion markers that allow tracking disease progression from preclinical through predementia to clinically manifest stages of AD. However, a widespread clinical use of these imaging biomarkers is hampered by considerable multi-centric variability related to differences in scanner hardware and acquisition protocols, but also by the lack of internationally agreed upon standards for analytic design and employed quantitative metrics. Several strategies for reducing multicenter variability in imaging measures have been proposed, including homogenization of the acquisition settings across scanner platforms, stringent quality assurance procedures, and artifact removal by means of post-acquisition image processing techniques. In addition, selection of appropriate statistical models to account for remaining multicenter variability in the data can further improve the accuracy and reproducibility of study results. The first projects for international standardization of image analysis methods and derived quantitative metrics have emerged recently for volumetric MRI measures. In contrast, the standardization and establishment of DTI-derived measures within a multicenter context are less well developed. Although molecular imaging techniques are already widely used in multicenter settings, sources of variability across sites and appropriate methods to reduce multicenter effects are still not explored in detail. Comparability of neuroimaging measures as AD biomarkers in worldwide clinical settings will finally depend on the establishment of internationally agreed upon standards for image acquisition, quality assurance, and employed quantitative metrics.
Book Synopsis Imaging Dementia by : Massimo Filippi
Download or read book Imaging Dementia written by Massimo Filippi and published by Springer Nature. This book was released on 2021-02-20 with total page 138 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book helps physicians select from among the currently available imaging tools, promoting the correct and cost-saving diagnosis and management of common dementias. Magnetic resonance (MR) and nuclear medicine techniques are routinely used to facilitate diagnosis, select therapies, provide information regarding the prognosis, and monitor therapy response in patients with cognitive impairment and dementia. Furthermore, the advent of quantitative MR techniques, such as diffusion-weighted imaging, perfusion imaging, etc. have opened up new opportunities to diagnose neurological diseases based on objective findings, and offer unique new insights into the main neurodegenerative diseases of the human brain. However, the practical value of various neuroimaging techniques in clinical practice has yet to be clearly defined, and their potential for future development is not yet fully appreciated. To help remedy the situation, this book offers practical and useful algorithms and rules that can be directly applied in the clinical setting. It provides concise content, together with a wealth of clinical case material.
Book Synopsis Neuroimaging in Dementia by : Frederik Barkhof
Download or read book Neuroimaging in Dementia written by Frederik Barkhof and published by Springer Science & Business Media. This book was released on 2011-02-11 with total page 295 pages. Available in PDF, EPUB and Kindle. Book excerpt: This up-to-date, superbly illustrated book is a practical guide to the effective use of neuroimaging in the patient with cognitive decline. It sets out the key clinical and imaging features of the various causes of dementia and directs the reader from clinical presentation to neuroimaging and on to an accurate diagnosis whenever possible. After an introductory chapter on the clinical background, the available "toolbox" of structural and functional neuroimaging techniques is reviewed in detail, including CT, MRI and advanced MR techniques, SPECT and PET, and image analysis methods. The imaging findings in normal ageing are then discussed, followed by a series of chapters that carefully present and analyze the key findings in patients with dementias. Throughout, a practical approach is adopted, geared specifically to the needs of clinicians (neurologists, radiologists, psychiatrists, geriatricians) working in the field of dementia, for whom this book will prove an invaluable resource.
Book Synopsis Components of Variance by : D.R. Cox
Download or read book Components of Variance written by D.R. Cox and published by CRC Press. This book was released on 2002-07-30 with total page 181 pages. Available in PDF, EPUB and Kindle. Book excerpt: The components of variance is a notion essential to statisticians and quantitative research scientists working in a variety of fields, including the biological, genetic, health, industrial, and psychological sciences. Co-authored by Sir David Cox, the pre-eminent statistician in the field, this book provides in-depth discussions that set forth the essential principles of the subject. It focuses on developing the models that form the basis for detailed analyses as well as on the statistical techniques themselves. The authors include a variety of examples from areas such as clinical trial design, plant and animal breeding, industrial design, and psychometrics.
Book Synopsis Study of Early Stages of Alzheimer's Disease Using Magnetic Resonance Imaging by : Adrià Casamitjana Díaz
Download or read book Study of Early Stages of Alzheimer's Disease Using Magnetic Resonance Imaging written by Adrià Casamitjana Díaz and published by . This book was released on 2020 with total page 173 pages. Available in PDF, EPUB and Kindle. Book excerpt: Alzheimer's disease (AD) is a neurodegenerative disorder that constitutes the most common dementia pathology. It represents a global epidemic that expands exponentially as the life expectancy increases with no yet useful treatment. Currently, it represents a huge social and economic burden for our societies and it is expected to tension public health infraestructures and finances in the near future.AD is characterized by amyloid plaque deposition and neurofibrillary tangles measured by ex-vivo examination of the brain. Recent developments in fluid biomarkers and brain imaging allow in-vivo quantification of pathophysiological processes of amyloid deposition or tau tangles formation in the brain, providing the community with highly sensitive and specific in-vivo biomarkers for Alzheimer's disease diagnosis. Abnormal levels of these biomarkers are thought as the initiating event to a cascade of subsequent events that continue with synapse loss, cell death, memory impairment, functional dysfunction and cognitive decline. All these events constitute the Alzheimer's continuum which can be broadly split into two main parts: an initial long and silent preclinical stage characterized by abnormal AD biomarkers and cognition within the normal range that could last from 15 to 30 years and a posterior clinical stage where subjects develop dementia symptoms.The etiology of AD is still poorly understood even though several risk factors are identified. Large observational studies can help the study of AD and its related biomarkers and risk factors. In this thesis we provide methodological tools for the analysis of Alzheimer's disease using magnetic resonance imaging (MRI). We focus on the study of subjects within the preclinial stage of AD by using statistical learning and pattern recognition frameworks to perform inferential statistics and develop predictive models.The main outcomes of this thesis are three-fold: firstly, we develop an open-source toolbox for nonlinear neuroimage analysis in population studies. While nonlinear association between medical images and several factors is already known, standard neuroimaging softwares only provide linear statistical frameworks that limit the analyses. Secondly, we study the relationship between brain structure using MRI and the underlying Alzheimer's pathology along the disease continuum and at different stages. The close relationship between MRI and clinical symptoms has been widely studied but describing AD using biomarkers instead of clinical phenotypes allows us to study preclinical stages of AD. Finally, we present a framework to predict cognitively unimpaired and amyloid positive subjects using MR imaging and machine learning. We report the results in a cross-sectional study and in a longitudinal study that compares the volumetric rate-of-change between subjects with different amyloid status. We further test the proposed methodology as a part of the triaging process in clinical trials showing great potential benefits.
Book Synopsis Magnetic Resonance in Dementia by : Frederik Barkhof
Download or read book Magnetic Resonance in Dementia written by Frederik Barkhof and published by Springer. This book was released on 2013-12-21 with total page 361 pages. Available in PDF, EPUB and Kindle. Book excerpt: This is the first work to take a comprehensive look at the application of Magnetic Resonance (MR) techniques in the diagnosis, follow-up and therapy monitoring of dementing illnesses. The authors present an overview of MR findings in neurodegenerative and vascular disorders leading to dementia. In doing so, they also discuss other diseases that lead to cognitive and/or behavioural deterioration, such as infectious inflammatory disorders, toxic encephalopathies, inborn errors of metabolism of adult onset and post-traumatic, post-radiotherapy and post-chemotherapy conditions. This authoritative, well-written and richly illustrated reference work is indispensable for anybody working in the field.
Book Synopsis Advanced Magnetic Resonance Imaging Techniques in the Diagnosis of Alzheimer's Disease (Ad), and Evaluation of Ad Pathogenesis in an Aging Brain by : Ka-Fung Henry Mak
Download or read book Advanced Magnetic Resonance Imaging Techniques in the Diagnosis of Alzheimer's Disease (Ad), and Evaluation of Ad Pathogenesis in an Aging Brain written by Ka-Fung Henry Mak and published by Open Dissertation Press. This book was released on 2017-01-27 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: This dissertation, "Advanced Magnetic Resonance Imaging Techniques in the Diagnosis of Alzheimer's Disease (AD), and Evaluation of AD Pathogenesis in an Aging Brain" by Ka-fung, Henry, Mak, 麥嘉豐, was obtained from The University of Hong Kong (Pokfulam, Hong Kong) and is being sold pursuant to Creative Commons: Attribution 3.0 Hong Kong License. The content of this dissertation has not been altered in any way. We have altered the formatting in order to facilitate the ease of printing and reading of the dissertation. All rights not granted by the above license are retained by the author. Abstract: Background: The impact of Alzheimer's disease (AD) on society's resources and manpower has been forecasted for more than a decade, and recent statistics across the globe reveal that it is forthcoming. Pioneering work since 1980s confirmed the pathological hallmarks of the disease, such as neuritic plaques, neurofibrillary tangles, amyloid-β peptides, and microtubule-associated tau proteins. There are many gaps in the full appraisal of this complex disease, which possibly begins early in life in susceptible individuals and present at different severity and speed. In current thesis, advanced magnetic resonance imaging (MRI) techniques were evaluated for their efficacy in diagnosis, and in exploring AD pathogenesis. Methods: In MRI volumetry/perfusion and diffusion studies, 20 and 18 AD subjects (different cohorts) were recruited respectively from the memory clinic of a University hospital, while 20 and 18 cognitively normal older adults (CN) were recruited respectively from elderly centers, community and university volunteers, as well as 17 young adults in the diffusion study. In MR Spectroscopy (MRS), 30 healthy volunteers of 3 different age ranges (20-39, 40-59, 60-89) were recruited. All studies were performed using a 3-tesla MRI scanner. For MRI volumetry, a standardized T1-weighted 3D volumetric Fast Field Echo sequence, and for pulsatile Arterial Spin Labeling (ASL), a Look-Locker-based echo-planar imaging sequence was employed. Single-shot echo-planar diffusion weighted imaging was used to examine white matter (WM) integrity; diffusion sensitizing gradients (b = 800 s/mm2) applied in 16 directions, and one additional image without diffusion gradient (b0 = 0 s/mm2). Single voxel MRS was performed in the limbic regions, with point resolved spectroscopy for volume selection and excitation for water suppression. Results: Voxel Based Morphometry with Diffeomorphic Anatomical Registration using Exponentiated Lie algebra and standard registration has similarly high efficacies as manual hippocampal volumetry in discriminating AD from CN. Using pulsatile ASL, we found impairment of hemodynamic parameters other than cerebral blood flow (CBF) in moderate AD, indicative of underlying vascular abnormality. Combined MR hippocampal volumetry and ASL CBF was superior to single measure in AD diagnosis. Using diffusion tensor imaging (DTI) techniques, parallel evidence of anterior WM disintegrity in normal elderly, and more extensively in the AD was found. AD showed further loss of WM integrity in the posterior brain regions, and such WM disintegrity may result from demyelination. In aging, we found increased choline and creatine, and N-acetyl-aspartate in cingulate gyri, which might suggest glial proliferation and neuronal hypertrophy respectively. Discussion: A 'one-stop-shop' study combining structural and perfusion MRI has improved efficacy in discriminating AD from CN. DTI showed possible WM retrogenesis in normal aging and AD, although ischemic effect on WM cannot be ruled out. Our MRS study highlighted metabolic changes with age, which could be compensatory to an increased energy demand coupled with a lower CBF. Neuroimaging is likely to have a great impact on early diagnosis of AD, which will benefit patient care, prognostication and future therapy. Hopefully, insights into the physiol
Book Synopsis Quantitative Magnetic Resonance Imaging by : Nicole Seiberlich
Download or read book Quantitative Magnetic Resonance Imaging written by Nicole Seiberlich and published by Academic Press. This book was released on 2020-11-18 with total page 1094 pages. Available in PDF, EPUB and Kindle. Book excerpt: Quantitative Magnetic Resonance Imaging is a ‘go-to’ reference for methods and applications of quantitative magnetic resonance imaging, with specific sections on Relaxometry, Perfusion, and Diffusion. Each section will start with an explanation of the basic techniques for mapping the tissue property in question, including a description of the challenges that arise when using these basic approaches. For properties which can be measured in multiple ways, each of these basic methods will be described in separate chapters. Following the basics, a chapter in each section presents more advanced and recently proposed techniques for quantitative tissue property mapping, with a concluding chapter on clinical applications. The reader will learn: The basic physics behind tissue property mapping How to implement basic pulse sequences for the quantitative measurement of tissue properties The strengths and limitations to the basic and more rapid methods for mapping the magnetic relaxation properties T1, T2, and T2* The pros and cons for different approaches to mapping perfusion The methods of Diffusion-weighted imaging and how this approach can be used to generate diffusion tensor maps and more complex representations of diffusion How flow, magneto-electric tissue property, fat fraction, exchange, elastography, and temperature mapping are performed How fast imaging approaches including parallel imaging, compressed sensing, and Magnetic Resonance Fingerprinting can be used to accelerate or improve tissue property mapping schemes How tissue property mapping is used clinically in different organs Structured to cater for MRI researchers and graduate students with a wide variety of backgrounds Explains basic methods for quantitatively measuring tissue properties with MRI - including T1, T2, perfusion, diffusion, fat and iron fraction, elastography, flow, susceptibility - enabling the implementation of pulse sequences to perform measurements Shows the limitations of the techniques and explains the challenges to the clinical adoption of these traditional methods, presenting the latest research in rapid quantitative imaging which has the possibility to tackle these challenges Each section contains a chapter explaining the basics of novel ideas for quantitative mapping, such as compressed sensing and Magnetic Resonance Fingerprinting-based approaches
Book Synopsis Investigation of Brain Pathology Using Magnetic Resonance Imaging by : Archana Chaudhari
Download or read book Investigation of Brain Pathology Using Magnetic Resonance Imaging written by Archana Chaudhari and published by Independent Author. This book was released on 2023-02-09 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Investigation of Brain Pathology using Magnetic Resonance Imaging (MRI) is an important area of research in neuroscience and clinical medicine. MRI is a non-invasive imaging technique that uses magnetic fields and radio waves to produce detailed images of the brain, allowing researchers and clinicians to study the structure and function of the brain in living subjects. MRI has revolutionized our understanding of brain pathology by allowing us to visualize the brain in exquisite detail. It can detect a wide range of neurological and psychiatric disorders, such as Alzheimer's disease, Parkinson's disease, multiple sclerosis, and brain tumors. MRI is also useful in identifying structural abnormalities in the brain, such as cysts, lesions, and malformations. In addition to structural imaging, MRI can be used for functional imaging, which provides information about brain activity. Functional MRI (fMRI) is a specialized type of MRI that detects changes in blood flow in the brain, which is an indirect measure of neural activity. fMRI has been used to study cognitive processes, such as attention, memory, and emotion, as well as to investigate the effects of drugs and other interventions on brain function. Overall, investigation of brain pathology using MRI is a critical tool in both basic research and clinical practice. By providing a non-invasive, detailed view of the brain, MRI has revolutionized our understanding of brain pathology and opened new avenues for diagnosis, treatment, and prevention of neurological and psychiatric disorders.
Book Synopsis Magnetic Resonance Spectroscopy Investigations of Alzheimer Disease by : Jacob Penner
Download or read book Magnetic Resonance Spectroscopy Investigations of Alzheimer Disease written by Jacob Penner and published by . This book was released on 2014 with total page 360 pages. Available in PDF, EPUB and Kindle. Book excerpt: Alzheimer disease is a progressively devastating neurodegenerative disease of the brain that impairs cognition and is ultimately fatal. Cholinesterase inhibitors are the current standard treatment for Alzheimer disease and they can alleviate some of the symptoms and thus improve quality of life. Cognitive measures aid in the diagnosis and monitoring of individuals with Alzheimer disease, but they do not directly measure disease pathophysiology. The purpose of this thesis is to investigate metabolic changes measured with proton magnetic resonance spectroscopy within the hippocampus and posterior cingulate, two brain regions known to be effected in Alzheimer disease, following cholinesterase inhibitor treatment. Such treatment is aimed at increasing the deficit of acetylcholine in Alzheimer disease. Secondly, to develop a 7 Tesla proton magnetic resonance spectroscopy data acquisition and metabolite quantification protocol to be used for future studies. In one study, proton magnetic resonance spectroscopy at 4 Tesla was used to measure the effects of four months of galantamine treatment (a cholinesterase inhibitor). An increase in the excitatory neurotransmitter glutamate was detected in the right hippocampus, and was associated with increased cognitive performance. In a second study, proton magnetic resonance spectroscopy at 3 Tesla was used to measure the effects of rivastigmine (a second cholinesterase inhibitor). The ratio of the neuronal marker N-acetylaspartate to creatine was decreased in the bilateral posterior cingulate cortex, which was associated with cognition. Finally, a quantitative proton magnetic resonance spectroscopy protocol at 7 Tesla was developed that incorporates subject-specific macromolecule removal. Absolute in vivo metabolite concentrations measured were in agreement with previous studies, and this protocol is ideal for applications in diseased conditions where macromolecule contributions may deviate from the norm.
Book Synopsis Development and Validation of Structural Magnetic Resonance Imaging (MRI)-based Biomarkers for Diagnosis and Prognosis of Prodromal Alzheimer's Disease by : Azar Zandifar
Download or read book Development and Validation of Structural Magnetic Resonance Imaging (MRI)-based Biomarkers for Diagnosis and Prognosis of Prodromal Alzheimer's Disease written by Azar Zandifar and published by . This book was released on 2019 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: "Alzheimer's disease (AD) is a neurodegenerative disease and the most common cause of dementia. Currently in Canada, there are about 750,000 people living with dementia with more than 60,000 new cases diagnosed each year. Considering the relative failures in recent clinical trials, combined with the promising prospect of life-style changes, early prediction of the future onset of dementia in the early stages of Alzheimer's disease continuum can be highly beneficial. Advances in better identifying future progressors may both enhance population design for clinical trials and better identify the at-risk populations for life-style interventions. This thesis focuses on enhancement of dementia onset in patients with Mild Cognitive Impairment (MCI) using structural Magnetic Resonance Images (MRI) driven markers. The volume of the hippocampus is one of the best-known MRI-based biomarkers for Alzheimer's disease. Here, it is investigated using four different automatic hippocampus segmentation methods, each enhanced with bias error correction. Results show that multi-atlas-based hippocampus segmentation methods are accurate and show high conformity with manual delineation, and they can be further enhanced using a bias correction technique. The methods compared are not significantly different in their ability to capture AD related pathology. The Cohen's d group difference in hippocampal volume between patients with Alzheimer's dementia and healthy controls is high for all the methods and is of medium size between patients with MCI who convert to dementia in the near future and to those who remain stable for all the methods.Due to the wide-spread use of hippocampal volume a recent effort has been made by researchers in the field to harmonize the hippocampus segmentation protocol. The resulting new protocol, known as the EADC-ADNI harmonized protocol or the HarP, needs more validation. I validate the protocol using a large multi-center database designed for AD biomarker research. The results show that the HarP-based automatic segmentation is an accurate hippocampal segmentation which can be used in AD-related research to capture the Alzheimer's pathology. The methods described above are used in a novel model to predict the onset of dementia in an MCI population during different follow-up periods. The model combines information from MRI-driven markers from the hippocampus and entorhinal cortex with cognitive scores at baseline and tries to predict the diagnostic stage of each subject in different time intervals following the baseline visit. The model produces promising results using information from both cognitive scores and MRI markers to reach higher performance. MRI markers are more sensitive, while cognitive scores bring specificity to the prediction. Furthermore, for a follow-up period of 5 years, the model reaches an area under the receiver operating curve of 0.92 and an accuracy of 87%. Therefore, the prognostic model demonstrates promise as a candidate to be used in the clinic to identify subjects with prodromal Alzheimer's dementia at the MCI stage. Finally, I show that the AD-related atrophy pattern is even present in cognitively normal subjects and can be captured through hippocampal-based markers. I show that there is a small effect size (as measured by Cohen's d) between hippocampal volume in subjects who progress to MCI and/or dementia or subjects who maintain their normal cognition, while the effect is of medium size for the hippocampal grade. This thesis evaluates different automatic and manual hippocampus segmentation techniques and validates hippocampus volume as the most widely used AD marker. Moreover, I present a model to predict the onset of dementia in subjects MCI. I further validate hippocampal driven markers as an Alzheimer's biomarker in very early stages of the disease. Therefore, the results of this work will improve early detection of Alzheimer's leading to decrease the prevalence of the disease." --
Book Synopsis Advanced Magnetic Resonance Imaging Techniques in the Diagnosis of Alzheimer's Disease (AD), and Evaluation of AD Pathogenesis in an Aging Brain by :
Download or read book Advanced Magnetic Resonance Imaging Techniques in the Diagnosis of Alzheimer's Disease (AD), and Evaluation of AD Pathogenesis in an Aging Brain written by and published by . This book was released on 2015 with total page 212 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Diffusion MRI by : Heidi Johansen-Berg
Download or read book Diffusion MRI written by Heidi Johansen-Berg and published by Academic Press. This book was released on 2013-11-04 with total page 627 pages. Available in PDF, EPUB and Kindle. Book excerpt: Diffusion MRI remains the most comprehensive reference for understanding this rapidly evolving and powerful technology and is an essential handbook for designing, analyzing, and interpreting diffusion MR experiments. Diffusion imaging provides a unique window on human brain anatomy. This non-invasive technique continues to grow in popularity as a way to study brain pathways that could never before be investigated in vivo. This book covers the fundamental theory of diffusion imaging, discusses its most promising applications to basic and clinical neuroscience, and introduces cutting-edge methodological developments that will shape the field in coming years. Written by leading experts in the field, it places the exciting new results emerging from diffusion imaging in the context of classical anatomical techniques to show where diffusion studies might offer unique insights and where potential limitations lie. Fully revised and updated edition of the first comprehensive reference on a powerful technique in brain imaging Covers all aspects of a diffusion MRI study from acquisition through analysis to interpretation, and from fundamental theory to cutting-edge developments New chapters covering connectomics, advanced diffusion acquisition, artifact removal, and applications to the neonatal brain Provides practical advice on running an experiment Includes discussion of applications in psychiatry, neurology, neurosurgery, and basic neuroscience Full color throughout
Book Synopsis Quantitative Analysis of Changes in Limbic Structures in Probable Alzheimer's Disease Using Coregistered SPECT and Magnetic Resonance Imaging by : David James Anthony Callen
Download or read book Quantitative Analysis of Changes in Limbic Structures in Probable Alzheimer's Disease Using Coregistered SPECT and Magnetic Resonance Imaging written by David James Anthony Callen and published by . This book was released on 2000 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: 'Background'. This study used MRI and coregistered SPECT to examine the changes that occur in the limbic system in Alzheimer's disease (AD). 'Methods'. A group of 40 AD patients was compared to a group of 40 age, sex, and education matched normal controls. Limbic structures (i.e., hippocampus, amygdala, anterior thalamus, hypothalamus, mamillary bodies, basal forebrain, septal area, fornix, and cingulate, orbitofrontal, and parahippocampal cortices) as well as non-limbic structures (i.e., posterior thalamus, caudate nucleus) were traced on a T1-weighted MR image using multiple slices and planes according to a set of predetermined guidelines. These traces were used to determine structural volume in order to assess the changes that occur in AD vs. normal aging. SPECT images from the same individuals were coregistered with the T1-weighed MR scans using a pixel by pixel algorithm from the AIR 3.0 software package (Woods et al., 1998). Once aligned, the tracings made on the MR image were transferred to the coregistered SPECT and used as regions of interest to obtain anatomically accurate, semi-quantitative limbic measures of perfusion relative to the cerebellum. 'Results'. Overall, the structures of the limbic system showed both volumetric and relative perfusion reductions in AD patients compared to normal controls. Some of these measures--namely, the volume of the septal area and medial amygdala-anterior parahippocampal cortex and the perfusion ratio of the posterior cingulate cortex--when used in combination, had high predictive accuracy (up to 100%). Sex differences were noted in the pattern of limbic atrophy and hypoperfusion associated with AD with men showing more widespread atrophy and hypoperfusion than women. Differences were also detected between AD patients with mild and more severe cognitive deficits. This suggests that volumetric and perfusion reductions become progressively larger over the course of the disease, although this could not be confirmed in a small longitudinal sample. 'Conclusions '. The limbic system is an integral part of AD pathology. Examining the volume and perfusion of limbic structures using MRI and SPECT may be useful in diagnosing and monitoring the progression of AD.
Book Synopsis The Quantitative Analysis of Vascular and Morphological Abnormalities in Mouse Models of Neurodegenerative Disease by : Kristof Govaerts (Doctor in Biomedical Sciences)
Download or read book The Quantitative Analysis of Vascular and Morphological Abnormalities in Mouse Models of Neurodegenerative Disease written by Kristof Govaerts (Doctor in Biomedical Sciences) and published by . This book was released on 2019 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Magnetic Resonance Imaging Techniques for Visualising the Development of Alzheimer's Disease-like Neurofibrillary Tau Pathology in Animal Models by : Ioannis Lavdas
Download or read book Magnetic Resonance Imaging Techniques for Visualising the Development of Alzheimer's Disease-like Neurofibrillary Tau Pathology in Animal Models written by Ioannis Lavdas and published by . This book was released on 2010 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: This thesis describes the development of magnetic resonance imaging (MRI) techniques to visualise neurofibrillary tau pathology in transgenic mice. Neurofibrillary pathology is a prominent pathological feature of Alzheimer's disease (AD) and is closely correlated to cognitive impairment and dementia. 19F and 1H MRI methods were developed with a 4.7 T preclinical system. To facilitate these experiments, RF saddle coils were designed and constructed that show good agreement with theoretical SNR calculations and produce uniform B1 fields. A copper wire surface coil, incorporating active decoupling electronics, was built to increase the sensitivity of 19F and 1H mouse brain experiments. A stripline transmission line resonator (TLR) was also developed as a surface coil receiver and because it does not need tuning and matching adjustments, it reduces experimental set up times significantly. An ultra-short echo time (UTE) pulse sequence was developed for imaging 19F compounds, designed to attach to sites of tau pathology in the brain and which were known to exhibit very short T2 relaxation times. Ex vivo, 19F MRI experiments using these compounds indicated low penetration of the blood brain barrier and a tendency for precipitation. An RF spoiled, short TE 3D gradient echo pulse sequence was optimised to produce artefact-free T1-weighted images of the mouse brain. Measurements from a preliminary study using high resolution, T1-weighted MRI showed that the ventricular areas of a control mouse were not appreciably different from those of a transgenic mouse. Software was developed to generate automated T2 brain maps from spin echo MRI data sets and was used to compare T2 relaxation times between a control and a transgenic mouse. This experiment showed that the T2 relaxation times of the tau transgenic mouse brain were prolonged when compared to those of a control mouse.
