Superresolution parallel magnetic resonance imaging: Application to functional and spectroscopic imaging

Ricardo Otazo, Fa Hsuan Lin, Graham Wiggins, Ramiro Jordan, Daniel Sodickson, Stefan Posse

    Research output: Contribution to journalArticle

    Abstract

    Standard parallel magnetic resonance imaging (MRI) techniques suffer from residual aliasing artifacts when the coil sensitivities vary within the image voxel. In this work, a parallel MRI approach known as Superresolution SENSE (SURE-SENSE) is presented in which acceleration is performed by acquiring only the central region of k-space instead of increasing the sampling distance over the complete k-space matrix and reconstruction is explicitly based on intra-voxel coil sensitivity variation. In SURE-SENSE, parallel MRI reconstruction is formulated as a superresolution imaging problem where a collection of low resolution images acquired with multiple receiver coils are combined into a single image with higher spatial resolution using coil sensitivities acquired with high spatial resolution. The effective acceleration of conventional gradient encoding is given by the gain in spatial resolution, which is dictated by the degree of variation of the different coil sensitivity profiles within the low resolution image voxel. Since SURE-SENSE is an ill-posed inverse problem, Tikhonov regularization is employed to control noise amplification. Unlike standard SENSE, for which acceleration is constrained to the phase-encoding dimension/s, SURE-SENSE allows acceleration along all encoding directions - for example, two-dimensional acceleration of a 2D echo-planar acquisition. SURE-SENSE is particularly suitable for low spatial resolution imaging modalities such as spectroscopic imaging and functional imaging with high temporal resolution. Application to echo-planar functional and spectroscopic imaging in human brain is presented using two-dimensional acceleration with a 32-channel receiver coil.

    Original languageEnglish (US)
    Pages (from-to)220-230
    Number of pages11
    JournalNeuroImage
    Volume47
    Issue number1
    DOIs
    StatePublished - Aug 1 2009

    Keywords

    • Parallel imaging
    • SENSE
    • Spectroscopic imaging
    • Superresolution
    • fMRI

    ASJC Scopus subject areas

    • Neurology
    • Cognitive Neuroscience

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