Sökning: "Jan Malm"

Visar resultat 11 - 15 av 21 avhandlingar innehållade orden Jan Malm.

  1. 11. The search for reversibility of Idiopathic normal pressure hydrocephalus : Aspects on intracranial pressure measurments and CSF volume alteration

    Författare :Niklas Lenfeldt; Jan Malm; Anders Eklund; Katrine Riklund-Åhlström; John D. Pickard; Umeå universitet; []
    Nyckelord :MEDICIN OCH HÄLSOVETENSKAP; MEDICAL AND HEALTH SCIENCES; Idiopathic normal pressure hydrocephalus; intracranial pressure; subcortical ischemia; neuronal integrity; cortical activation.; infusion test; cerebrospinal fluid dynamics; outflow resistance; compliance; elastance; proton spectroscopy; functional MRI; external lumbar drainage; Neurology; Neurologi;

    Sammanfattning : BACKGROUND: Idiopathic normal pressure hydrocephalus (INPH) is still a syndrome generating more questions than answers. Today, research focuses mainly on two areas: understanding the pathophysiology – especially how the malfunctioning CSF system affects the brain parenchyma – and finding better methods to select patients benefiting from a shunt operation. LÄS MER

  3. 12. Analysis of ICP pulsatility and CSF dynamics : the pulsatility curve and effects of postural changes, with implications for idiopathic normal pressure hydrocephalus

    Författare :Sara Qvarlander; Anders Eklund; Jan Malm; Richard Birgander; Martin U Schuhmann; Umeå universitet; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Cerebrospinal fluid; CSF dynamics; Intracranial pressure; Pulse pressure; Normal pressure hydrocephalus; Posture; Predictive tests; Mathematical modelling; Magnetic resonance imaging; Infusion tests;

    Sammanfattning : The volume defined by the rigid cranium is shared by the brain, blood and cerebrospinal fluid (CSF). With every heartbeat the arterial blood volume briefly increases and venous blood and CSF are forced out of the cranium, leading to pulsatility in CSF flow and intracranial pressure (ICP). LÄS MER

  4. 13. Analyses of shotcrete stress states due to varying lining thickness and irregular rock surfaces

    Författare :Andreas Sjölander; Anders Ansell; Richard Malm; Fredrik Johansson; Jan Alemo; KTH; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Shotcrete; cracking; shrinkage; block load; varying thickness; numerical simulations; fibre reinforcement; Byggvetenskap; Civil and Architectural Engineering;

    Sammanfattning : Shotcrete is sprayed concrete applied pneumatically under high pressure and was invented in the beginning of the 1900's. This new technique decreased the construction time and since steel fibres were introduced in the shotcrete during the 1970's, shotcrete has been the primary support method for tunnels. LÄS MER

  5. 14. 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. 15. 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