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Visar resultat 1 - 5 av 10 avhandlingar som matchar ovanstående sökkriterier.

1. 1. Cerebral blood flow and intracranial pulsatility studied with MRI : measurement, physiological and pathophysiological aspects

   Författare :Anders Wåhlin; Anders Eklund; Jan Malm; Richard Birgander; William G Bradley; Umeå universitet; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Arterial Pulsatility; cerebrospinal fluid; cerebral blood flow; venous flow; intracranial pressure; pulse pressure; dementia; hippocampus; multiple sclerosis; magnetic resonance imaging; radiofysik; radiation physics;

   Sammanfattning : During each cardiac cycle pulsatile arterial blood inflates the vascular bed of the brain, forcing cerebrospinal fluid (CSF) and venous blood out of the cranium. Excessive arterial pulsatility may be part of a harmful mechanism causing cognitive decline among elderly. LÄS MER

3. 2. Blood flow assessment in cerebral arteries with 4D flow magnetic resonance imaging : an automatic atlas-based approach

   Författare :Tora Dunås; Anders Eklund; Anders Wåhlin; Jan Malm; Einar Heiberg; Umeå universitet; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Circle of Willis; 4D flow MRI; Cerebral arteries; Vascular disease; Stroke; Automatic labeling; Probabilistic atlas; Cerebral blood flow; Neuroimaging; Magnetic Resonance Imaging;

   Sammanfattning : Background: Disturbed blood flow to the brain has been associated with several neurological diseases, from stroke and vascular diseases to Alzheimer’s and cognitive decline. To determine the cerebral arterial blood flow distribution, measurements are needed in both distal and proximal arteries. LÄS MER

4. 3. 4D flow MRI and modelling to assess cerebral arterial hemodynamics : method development and evaluation, with implementation in patients with symptomatic carotid stenosis

   Författare :Madelene Holmgren; Anders Eklund; Jan Malm; Anders Wåhlin; Sara Qvarlander; Ronnie Wirestam; Umeå universitet; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; MEDICIN OCH HÄLSOVETENSKAP; MEDICAL AND HEALTH SCIENCES; 4D flow MRI; carotid stenosis; cerebral blood flow; cerebral arterial compliance; cerebrovascular resistance; circleof Willis; computational fluid dynamics; magnetic resonance imaging; stroke; vascular disease; Neurology; neurologi;

   Sammanfattning : Blood flow measurements are important for understanding the development of cerebrovascular diseases. With 4D flow magnetic resonance imaging (4D flow MRI), simultaneous velocity measurements are obtained in all cerebral arteries in a scan of about ten minutes. However, 4D flow MRI is a relatively new technique. LÄS MER

5. 4. Cerebral arterial pulsatility imaging using 4D flow MRI : methodological development and applications in brain aging

   Författare :Tomas Vikner; Anders Wåhlin; Anders Eklund; Jan Malm; Lars Nyberg; Susanne Schnell; Umeå universitet; []
   Nyckelord :MEDICIN OCH HÄLSOVETENSKAP; MEDICAL AND HEALTH SCIENCES; MEDICIN OCH HÄLSOVETENSKAP; MEDICAL AND HEALTH SCIENCES; Magnetic resonance imaging; 4D flow MRI; medical image analysis; cerebral hemodynamics; arterial pulsatility; DCE MRI; blood-brain barrier; white matter lesions; perivascular spaces; cerebral small vessel disease; hippocampus; cognition; aging; biomedicinsk strålningsvetenskap; Biomedical Radiation Science;

   Sammanfattning : 4D flow magnetic resonance imaging (MRI) is increasingly recognizedas a versatile tool to assess arterial and venous hemodynamics. Cerebral arterial pulsatility is typically assessed by analyzing flow waveforms over the cardiac cycle, where flow amplitude is a function of cardiac output, central arterial stiffness, and cerebrovascular resistance and compliance. LÄS MER

7. 5. Static electrification of teflon by metals

   Författare :Anders Wåhlin; Umeå universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES;

   Sammanfattning : The electrification of a system consisting of a metal and polytetrafluoro-ethylene (Teflon) has been investigated under relative motion. First, the electrification charge received by the insulator was measured when velocity, radius of curvature of the metal electrode and normal force were varied. LÄS MER