Essays about: "k-space"

Showing result 11 - 15 of 15 essays containing the word k-space.

  1. 11. Improved Temporal Resolution Using Parallel Imaging in Radial-Cartesian 3D functional MRI

    University essay from Datorseende

    Author : Gustav Ahlman; [2011]
    Keywords : fMRI; PRESTO-CAN; SENSE; parallel imaging; temporal resolution; radial-Cartesian sampling; normalized convolution;

    Abstract : MRI (Magnetic Resonance Imaging) is a medical imaging method that uses magnetic fields in order to retrieve images of the human body. This thesis revolves around a novel acquisition method of 3D fMRI (functional Magnetic Resonance Imaging) called PRESTO-CAN that uses a radial pattern in order to sample the (kx,kz)-plane of k-space (the frequency domain), and a Cartesian sample pattern in the ky-direction. READ MORE

  3. 12. Using radial k-space sampling and temporal filters in MRI to improve temporal resolution

    University essay from Radiofysik

    Author : Patrik Brynolfsson; [2010]
    Keywords : fMRI; MRI; radial sampling; k-space; temporal filters;

    Abstract : In this master thesis methods for increasing temporal resolution when reconstructing radially sampled MRI data have been developed and evaluated. This has been done in two steps; first the order in which data is sampled in k-space has been optimized, and second; temporal filters have been developed in order to utilize the high sampling density in central regions of k-space as a result of the polar sampling geometry to increase temporal resolution while maintaining image quality. READ MORE

  4. 13. Using radial k-space sampling and temporal filters in MRI to improve temporal resolution

    University essay from Medicinsk radiofysik; Centrum för medicinsk bildvetenskap och visualisering, CMIV

    Author : Patrik Brynolfsson; [2010]
    Keywords : fMRI; MRI; radial sampling; k-space; temporal filters;

    Abstract : In this master thesis methods for increasing temporal resolution when reconstructing radially sampled MRI data have been developed and evaluated. This has been done in two steps; first the order in which data is sampled in k-space has been optimized, and second; temporal filters have been developed in order to utilize the high sampling density in central regions of k-space as a result of the polar sampling geometry to increase temporal resolution while maintaining image quality. READ MORE

  5. 14. Method for Acquisition and Reconstruction of non-Cartesian 3-D fMRI

    University essay from Bildbehandling; Tekniska högskolan

    Author : Per Thyr; [2008]
    Keywords : MRI; PRESTO; PRESTO CAN; rotation; sequence development; image reconstruction; gridding; phase correction;

    Abstract : The PRESTO sequence is a well-known 3-D fMRI imaging sequence. In this sequence the echo planar imaging technique is merged with the echo-shift technique. This combination results in a very fast image acquisition, which is required for fMRI examinations of neural activation in the human brain. READ MORE

  6. 15. Denoising of Complex MRI Data by Wiener-like Filtering in the Wavelet Domain - Application to High b-value Diffusion Weighted Imaging

    University essay from Lunds universitet/Sjukhusfysikerutbildningen

    Author : Adnan Bibic; [2006]
    Keywords : MRI; Medicine and Health Sciences;

    Abstract : Noise is a well-known problem in many imaging modalities. In magnitude magnetic resonance images, obtained by quadrature detection, the associated Rician distribution of noise constitutes a further complication. This type of noise is especially problematic at low signal-to-noise ratio (SNR) regions. READ MORE