Sökning: "venous flow"

Visar resultat 6 - 10 av 99 avhandlingar innehållade orden venous flow.

1. 6. Distensibility in Arteries, Arterioles and Veins in Humans : Adaptation to Intermittent or Prolonged Change in Regional Intravascular Pressure

   Författare :Roger Kölegård; Ola Eiken; Toste Länne; KTH; []
   Nyckelord :MEDICIN OCH HÄLSOVETENSKAP; MEDICAL AND HEALTH SCIENCES; arterial stiffness; venous distensibility; venous flow characteristics; bedrest; pressure training; Physiology; Fysiologi;

   Sammanfattning : The present series of in vivo experiments in healthy subjects, were performed to investigate wall stiffness in peripheral vessels and how this modality adapts to iterative increments or sustained reductions in local intravascular pressures. Vascular stiffness was measured as changes in arterial and venous diameters, and in arterial flow, during graded increments in distending pressures in the vasculature of an arm or a lower leg. LÄS MER

3. 7. Non-invasive measurement of skeletal muscle blood flow using by photoplethysmography. Experimental studies on the human leg

   Författare :Qiuxia Zhang; Göteborgs universitet; []
   Nyckelord :MEDICIN OCH HÄLSOVETENSKAP; MEDICAL AND HEALTH SCIENCES; photoplethysmography; skeletal muscle blood flow; perfusion pressure; intramuscular pressure; venous obstruction; muscle exercise; non-invasive; limb elevation; vibration exposure; hyperaemia; foot pump.;

   Sammanfattning : The purpose of this thesis was to validate a new non-invasive photoplethysmography (PPG) method for measuring relative changes in local muscle blood flow (MBF) in the human leg. Experimental conditions expected to impede or increase local MBF were used to test responsiveness of the PPG. LÄS MER

4. 8. Regulation of Microvascular Blood Flow : a clinical and experimental study based on laser Doppler perfusion imaging

   Författare :Helena Golster; Linköpings universitet; []
   Nyckelord :MEDICINE; MEDICIN;

   Sammanfattning : Local blood flow reflexes in the foot skin of healthy controls and in young diabetic patients with or without nerve dysfunction have been studied using laser Doppler perfusion imaging (LDPI). A neurophysiological follow-up study on nerve dysfunction is presented as a complerhent to the work on blood flow regulation in the young diabetics. LÄS MER

5. 9. Fluid dynamic principles for analysis of intracranial pressure control : application towards space medicine and hydrocephalus

   Författare :Petter Holmlund; Anders Eklund; Sara Qvarlander; Jan Malm; Marek Czosnyka; Umeå universitet; []
   Nyckelord :MEDICIN OCH HÄLSOVETENSKAP; MEDICAL AND HEALTH SCIENCES; Intracranial pressure; posture; cerebrospinal fluid; microgravity; venous collapse; internal jugular vein; fluid dynamics; venous pressure; spaceflight-associated neuro-ocular syndrome; hydrocephalus; mathematical modeling; ultrasound; magnetic resonance imaging;

   Sammanfattning : Intracranial pressure (ICP) is an important component of the fluid dynamic environment of the brain and plays a central role with regards to the maintenance of normal cerebral blood flow and neuronal function. However, many regulatory mechanisms controlling the ICP are still poorly understood. LÄS MER

7. 10. 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