Sökning: "Rörelsekorrigering"

Hittade 5 uppsatser innehållade ordet Rörelsekorrigering.

  1. 1. Respiratory Motion Correction in PET Imaging: Comparative Analysis of External Device and Data-driven Gating Approaches

    Master-uppsats, KTH/Fysik

    Författare :Nina Lindström Söraas; [2023]
    Nyckelord :PET CT; Tomographic reconstruction; Respiratory gating techniques; Image registration; Motion correction; PET CT; Tomografisk rekonstruktion; Gating tekniker; Bildregistrering; Rörelsekorrigering;

    Sammanfattning : Positron Emission Tomography (PET) is pivotal in medical imaging but is prone to artifactsfrom physiological movements, notably respiration. These motion artifacts both degradeimage quality and compromise precise attenuation correction. LÄS MER

  3. 2. Spatiotemporal PET reconstruction with Learned Registration

    Kandidat-uppsats, KTH/Skolan för elektroteknik och datavetenskap (EECS)

    Författare :Pierre Meyrat; [2022]
    Nyckelord :PET; Tomographic reconstruction; Deep Learning; MLEM; PET; Tomografisk rekonstruktion; Deep Learning; MLEM;

    Sammanfattning : Because of the long acquisition time of Positron Emission Tomography scanners, the reconstructed images are blurred by motion. We hereby propose a novel motion-correction maximum-likelihood expectation-maximization algorithm integrating 3D movements between the different gates estimated by a neural network trained on synthetic data with contrast invariance. LÄS MER

  4. 3. Assessment of Functional Connectivity Impairment in Rat Brains

    Master-uppsats, KTH/Skolan för kemi, bioteknologi och hälsa (CBH)

    Författare :Androula Savva; [2019]
    Nyckelord :;

    Sammanfattning : While the rodent model has long been used in brain research, there exists no standardisedprocessing routine that can be employed for analysis and investigation of disease models. Thepresent thesis attempts to investigate a diseased brain model by implementing a collection ofscripts, combined with algorithms from existing neuroimaging software, and adapting themto the rodent brain, in an attempt to examine when and how monaural canal atresia affectsthe functional connectivity of the brain. LÄS MER

  5. 4. Extracting Cardiac and Respiratory Self-Gating Signals from Magnetic Resonance Imaging Data

    Kandidat-uppsats, KTH/Skolan för teknik och hälsa (STH)

    Författare :Rebecca Hellström Karlsson; Tobias Peterson; [2015]
    Nyckelord :MRI; MR; magnetic resonance imaging; SG; self-gating; cardiac; cardiac MRI; sliding window reconstruction; motion artefacts; motion correction; 3D; signal filtering; MRI; MR; magnetisk resonanstomografi; SG; self-gating; hjärta; hjärt-MR; sliding window reconstruction; signalfiltrering; rörelseartefakter; rörelsekorrigering; 3D;

    Sammanfattning : Motion artefacts due to cardiac and respiratory motion present a daily challenge in cardiac Magnetic Resonance Imaging (MRI), and many different motion correction procedures are used in clinical routine imaging. To reduce motion artefacts further, patients are required to hold their breath during parts of the data acquisition, which is physically straining – especially when done repetitively. LÄS MER

  7. 5. In-Plane Motion Correction in Reconstruction of non-Cartesian 3D-functional MRI

    Master-uppsats, Datorseende; Tekniska högskolan

    Författare :Anette Karlsson; [2011]
    Nyckelord :MRI; fMRI; PRESTO-CAN; Motion Correction; Radial Sampling Pattern; Fourier domain; Circular Correlation; Gridding Reconstruction;

    Sammanfattning : When patients move during an MRI examination, severe artifacts arise in the reconstructed image and motion correction is therefore often desired. An in-plane motion correction algorithm suitable for PRESTO-CAN, a new 3D functional MRI method where sampling of k-space is radial in kx-direction and kz-direction and Cartesian in ky-direction, was implemented in this thesis work. LÄS MER