Flow distortion and signal loss in spiral imaging
نویسندگان
چکیده
منابع مشابه
In-vivo distortion of through-plane flow by spiral phase-contrast imaging
Background The effects of off-resonance frequency errors during spiral readouts [Yudilevich and Stark, 1987] are known. Here we explain previously unrecognised intra-voxel dephasing consequences of two sources of phase curvature over the vessel cross-section in through-plane flow imaging using spirals i.e. off-resonance and the velocityencoded phase-shift, including the consequences for invivo ...
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BACKGROUND The medial temporal lobe (MTL) contains subregions that are subject to severe distortion and signal loss in functional MRI. Air/tissue and bone/tissue interfaces in the vicinity of the MTL distort the local magnetic field due to differences in magnetic susceptibility. Fast image acquisition and thin slices can reduce the amount of distortion and signal loss, but at the cost of image ...
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Introduction Echo-planar imaging (EPI) is a group of fast data acquisition methods commonly used in fMRI studies. It acquires multiple image lines in k-space after a single excitation, which leads to a very short scan time. A well-known problem with EPI is that it is more sensitive to distortions due to the used encoding scheme. Source of distortion is inhomogeneity in the static B0 field that ...
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Introduction Single-shot spiral imaging is a very efficient technique to acquire dynamic data for fMRI experiments rapidly and has profound advantages over single-shot EPI as it distributes the burden over two gradient axes. Similar to EPI, spirals suffer from geometric image distortions, T2*-related blurring, and signal dropout/pile-up artifacts. Parallel imaging (PI) has shown great utility t...
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ژورنال
عنوان ژورنال: Magnetic Resonance in Medicine
سال: 1999
ISSN: 0740-3194,1522-2594
DOI: 10.1002/(sici)1522-2594(199905)41:5<1023::aid-mrm22>3.3.co;2-t