Search results for "fusion"
showing 10 items of 4513 documents
Identification of proprioceptive thalamocortical tracts in children: comparison of fMRI, MEG, and manual seeding of probabilistic tractography
2022
Publisher Copyright: © The Author(s) 2022. Published by Oxford University Press. Studying white matter connections with tractography is a promising approach to understand the development of different brain processes, such as proprioception. An emerging method is to use functional brain imaging to select the cortical seed points for tractography, which is considered to improve the functional relevance and validity of the studied connections. However, it is unknown whether different functional seeding methods affect the spatial and microstructural properties of the given white matter connection. Here, we compared functional magnetic resonance imaging, magnetoencephalography, and manual seedin…
Korelācija starp fuzionālām rezervēm un maksimālo stereoredzes leņķi
2021
Maģistra darbs ir uzrakstīts angļu valodā uz 43 lappusēm. Tas satur 20 attēlus, 3 tabulas un 63 atsauces uz literatūras avotiem. Pētījuma mērķis bija novērtēt, kāda korelācija pastāv starp fuzionālo verģenču rezervēm un maksimālo stereoredzes leņķi. Pētījumā piedalījās 22 dalībnieki, kuriem tika veikta redzes pārbaude Nove Mesto nad Vahom, Slovākijas klīnikā. Pētījumā tika paveikts, pirmkārt, tika analizētas pozitīvās un negatīvās fuzionālās verģences rezerves un salīdzinātās ar normām. Otrkārt, tika analizēti maksimālie stereoredzes krustotās un nekrustotās disparitātes leņķi. Treškārt, tika analizēta korelācija starp visām iespējamām kombinācijām (starp fuzionālām verģences rezervēm un st…
Comparative vs. Transcendental Approaches to Justice: A Misleading Dichotomy in Sen'sThe Idea of Justice
2012
This paper examines the distinction drawn by Amartya Sen between transcendental and comparative theories of justice, and its application to Rawls' doctrine. It then puts forward three arguments. First, it is argued that Sen offers a limited portrayal of Rawls' doctrine. This is the result of a rhetorical strategy that depicts Rawlsian doctrine as more “transcendental” than it really is. Although Sen deploys numerous quotations in support of his interpretation, it is possible to offer a less transcendental interpretation of Rawls. Second, the dichotomy between transcendental and comparative approaches to questions of justice is partly misleading, insofar as any plausible moral doctrine has b…
Drifting through Basic Subprocesses of Reading: A Hierarchical Diffusion Model Analysis of Age Effects on Visual Word Recognition
2016
International audience; Reading is one of the most popular leisure activities and it is routinely performed by most individuals even in old age. Successful reading enables older people to master and actively participate in everyday life and maintain functional independence. Yet, reading comprises a multitude of subprocesses and it is undoubtedly one of the most complex accomplishments of the human brain. Not surprisingly, findings of age-related effects on word recognition and reading have been partly contradictory and are often confined to only one of four central reading subprocesses, i.e., sublexical, orthographic, phonological and lexico-semantic processing. The aim of the present study…
Mechanisms of Cell-Volume Regulation in the Central Nervous System
2017
Function and viability of every cell is dependent on the proper control of its shape and volume. In the brain, which is protected by a rigid outer shell, cell-volume regulation is of particular importance, since large volume changes affect cerebral perfusion and, hence, function. Neuronal activation leads to constant changes of the ionic and metabolic composition of the brain’s extracellular space. These changes are buffered by astrocytes on the expense of constant changes in cell volume. Under pathological conditions, the ability of astrocytes to maintain the homeostasis of the brain is overwhelmed and permanent cell swelling, cytotoxic edema, occurs. The current chapter describes the prin…
Optical Studies of the Capillary Refill Kinetics in Fingertips
2009
A new methodology for temporal analysis of the capillary refill processes by means of photoplethysmography (PPG) contact probe operating in the blue region of spectrum has been developed. A corresponding prototype device for finger measurements has been created and clinically tested. Results demonstrated that both AC and DC components of the blue PPG bio-signals are sensitive to the capillary occlusion and refill. Real-time measurements of the skin capillary refill kinetics by this technology can be used for noninvasive diagnostics of the peripheral perfusion disorders.
Bestimmung der myokardialen Perfusionsreserve bei KHK-Patienten mit der kontrastmittelverstärkten MRT: Ein Vergleich zwischen semiquantitativer und q…
2002
OBJECTIVE Comparison between two semiquantitative methods and a quantitative evaluation of myocardial blood flow (MBF) for assessment of myocardial perfusion reserve (MPR) in patients with CAD. MATERIAL AND METHODS 9 patients with coronary stenoses > 50 % were examined with an ECG-gated Saturation Recovery Turbo FLASH sequence by using Gd-DTPA as contrast agent (CA). The entive measurements were performed both during rest and hyperemia induced by adenosine. The up-slopes of the signal-time S(t) curves in the myocardium and left ventricular (LV) cavity were evaluated by a linear fit. MPR was calculated from the original up-slopes of the myocardial S(t) curves and from the up-slopes, which we…
Avoiding lumbar segmental arteries injury in oblique lateral interbody fusion procedure
2020
Lumbar interbody fusion is performed to treat several spinal disorders and involves the insertion of a structural graft into an intervertebral disk space to promote bony arthrodesis. Although the posterior approach to the lumbar spine was long the most frequently adopted surgical strategy to perform fusion, anterior approaches, first introduced in 1906, have recently blossomed. Patient expectations and increasing demands for shorter hospital stay and early recovery have led to more innovative surgical techniques to reduce iatrogenic injury and postoperative morbidity. Depending on the level to be treated, several approaches have been developed, each dealing with peculiar anatomic obstacles:…
Comparison of the quantitative first pass myocardial perfusion MRI with and without prospective slice tracking: Comparison between breath-hold and fr…
2010
Physiologic motion of the heart is one of the major problems of myocardial blood flow quantification using first pass perfusion-MRI method. To overcome these problems, a perfusion pulse sequence with prospective slice tracking was developed. Cardiac motion was monitored by a navigator directly positioned at heart's basis to overcome no additional underlying model calculations connecting diaphragm and cardiac motion. Additional prescans were used before the perfusion measurement to detect slice displacements caused by remaining cardiac motion between navigator and the perfusion slice readout. The pulse sequence and subsequent quantification of myocardial blood flow was tested in healthy pigs…
Temperature Measurement by Diffusion-Weighted Imaging
2021
Diffusion-weighted imaging (DWI) thermometry is a magnetic resonance-based imaging tool that allows the noninvasive measurement of brain core temperature. Although only applicable to cerebrospinal fluid, it is thought to be potentially useful in assessing the thermal pathophysiology of the brain in both patients and healthy subjects. The objective of this article is to provide a concise but thorough review of the basic physical principles and the principal applications of DWI thermometry as a potential method to elucidate the pathophysiology of several brain diseases and neurologic syndromes.