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Multimodal Imaging Radiomics and Machine Learning
Published in Ayman El-Baz, Jasjit S. Suri, Big Data in Multimodal Medical Imaging, 2019
Gengbo Liu, Youngho Seo, Debasis Mitra, Benjamin L. Franc
Image segmentation directly determines the accuracy of the extracted feature data. Image segmentation methods can be classified as manual, semi-automatic and fully automatic methods. The first two segmentation methods are applied widely, and the last method is still in the development stage. Manual segmentation has the advantage of high accuracy for objects with clear boundaries and is also suitable for irregular objects with blurred boundaries but has the disadvantage of being time-consuming and inefficient. This disadvantage does not meet the requirement of high-throughput data extraction from mass datasets, needed for a Big-Data radiomics approach. Semi-automatic and automatic segmentation are able to provide high-throughput data processing and have a higher reproducibility and consistency. Semi-automatic segmentation refers to the process whereby automatic segmentation is aided by manual interventions at different stages of segmentation. The semiautomatic segmentation algorithms include region-growing methods, volumetric CT-based segmentation (e.g., 3D-Slicer) [10], graph cuts-based method [11] and active contours (snake) algorithms [12]. And fully automatic segmentation refers to the process whereby segment boundaries of objects are assigned fully automatically by software. The automatic segmentation applications include white matter hyperintensities automated segmentation algorithm [13], brain tumor image analysis [14] and automatic MRI bone segmentation [15], etc.
Outdoor Air Pollution
Published in William J. Rea, Kalpana D. Patel, Reversibility of Chronic Disease and Hypersensitivity, Volume 4, 2017
William J. Rea, Kalpana D. Patel
Cognitive dysfunction, gait abnormalities, falls, and depression occurred.359–361 White matter lesions impair frontal lobe function362 and indicate abnormalities of the subcortical fiber system.363 Histopathology correlates in the elderly include enlarged Virchow–Robin spaces, degeneration of axons and myelin, and gliosis.364,365 Progressive white matter hyperintensities in older adults are related to changes in regional cerebral blood flow.366 Vascular changes predominantly involving subcortical areas (e.g., white matter, in basal ganglia, thalamus, and hippocampus) are seen in both AD and vascular dementia in patients, and in mixed dementia cases.367 The common denominator for the hyperintense white matter lesions detected by brain MRI appears to be a vascular lesion with perivascular gliosis and enlarged Virchow–Robin spaces. Based on Calderon-Garciduenas's pilot results, it is suggested that the white matter lesions detected in 56.5% of Mexico City children tested represent the extreme of the vascular lesions with a breakdown of the BBB, and that the vascular pathology is likely of a diffuse nature as seen in young dogs.
Headache
Published in Anthony N. Nicholson, The Neurosciences and the Practice of Aviation Medicine, 2017
The diagnosis of migraine is clinical and no specific laboratory or imaging investigations are required. However, tests are often sought, including brain imaging and a routine blood screen, probably to reassure the practitioner as much as the patient. Although computed tomography of the brain will usually identify major structural intracranial lesions, magnetic resonance imaging is much more sensitive and avoids the use of ionizing radiation. Imaging is generally normal in patients with migraine, although there is a higher incidence of non-specific white matter hyperintensities (Kruit et al, 2004). The significance of these abnormalities of the white matter is uncertain. There is no evidence that they are linked to neurological deficits, although long-term follow-up studies have not yet been completed. More recently, a possible link between migraine, non-specific white matter lesions on imaging and patency of the foramen ovale has been suggested, although the evidence is still weak (Schwedt et al., 2008).
The New Zealand Genetic Frontotemporal Dementia Study (FTDGeNZ): a longitudinal study of pre-symptomatic biomarkers
Published in Journal of the Royal Society of New Zealand, 2023
Brigid Ryan, Ashleigh O’Mara Baker, Christina Ilse, Kiri L. Brickell, Hannah M. Kersten, Joanna M. Williams, Donna Rose Addis, Lynette J. Tippett, Maurice A. Curtis
Cortical reconstruction and volumetric segmentation of T1 data will be performed with the Computational Anatomy Toolbox (cat12; Gaser et al. 2022; implemented in SPM12), and measures of volumetrics, cortical thinning and grey matter intensity will be compared between carriers and non-carriers in a priori ROIs. Lesion probability maps of white matter hyperintensities generated from the T2 Flair image using the lesion prediction algorithm (Schmidt et al. 2012; implemented in the LST toolbox, www.statistical-modelling.de/lst.html), and regional cerebral blood flow maps generated from pcASL images using BASIL – Bayesian Inference for Arterial Spin Labelling MRI (Chappell et al. 2009; implemented in FSL, https://fsl.fmrib.ox.ac.uk/) will be compared between carriers and non-carriers.
Lessons learned from 25 Years of Research into Long term Consequences of Prenatal Exposure to the Dutch famine 1944–45: The Dutch famine Birth Cohort
Published in International Journal of Environmental Health Research, 2021
Susanne R. De Rooij, Laura S. Bleker, Rebecca C. Painter, Anita C. Ravelli, Tessa J. Roseboom
In a subsample study of 120 participants, we performed MRI scans of the brain. These scans showed that intracranial volumes and overall brain size were smaller in men who had been exposed to famine in early gestation (De Rooij et al. 2016b). The overall reduction in brain size after prenatal famine exposure in men was ~5%. While another Dutch famine-based study had demonstrated more white matter hyperintensities in individuals prenatally exposed to famine, we did not find any evidence for that in our cohort (Hulshoff Pol et al. 2000; De Rooij et al. 2016b). We did find that overall perfusion of the brain seemed worse in men and women exposed to undernutrition in early gestation, and that particularly in exposed men perfusion of the anterior and posterior cingulate cortices was lower compared to unexposed men (De Rooij et al. 2019). Lower perfusion in these areas has been shown to be associated with neurodegenerative diseases (Mutsaerts et al. 2015). This may suggest that men exposed to famine in early gestation are at higher risk for neurodegenerative diseases. The latter is substantiated by our finding that exposed men also demonstrated a higher BrainAGE, which is an MRI-based measure providing an estimate for the clinical aging of the brain (Franke et al. 2018).
Blink reflex parameters in baseline, active, and head-impact Division I athletes
Published in Cogent Engineering, 2018
D.P. Garner, J.S. Goodwin, N.T. Tsai, R.T. Kothera, M.E. Semler, B.J. Wolf
Concussive events result in symptomatic deficits in attention, executive function, learning and memory. As such, tools have been developed to assess cognitive changes indicative of brain injury. However, concussive trauma is not restricted to the regions of the brain responsible for cognitive function and does not address physiological changes that may occur with a concussive event. Such trauma has been cited to result in deep white matter hyperintensities (areas in the white matter that indicate due to axonal loss) that have been detected via MRI 24–72 h post concussive event (Hughes et al., 2004). Boele and colleagues (2010) cited that lesions in the rabbit cerebellar cortex were related to abnormal blink responses, with shortened latency and amplitude of the conditioned eye blink response. For humans, Fitzek and colleagues also cited specific pathways which were affected by lesions, noting abnormalities in the R2 loop of the blink reflex with that loop passing through the descending trigeminal spinal track and onward to the spinal trigeminal nucleus (Fitzek et al., 1999). Thus, understanding the effect of such lesions and areas where these lesions occur will be important in understanding effect on blink reflex.