Journal of magnetic resonance imaging : JMRI
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J Magn Reson Imaging · Aug 2004
Comparative StudyFunctional MRI using multiple receiver coils: BOLD signal changes and signal-to-noise ratio for three-dimensional-PRESTO vs. single shot EPI in comparison to a standard quadrature head coil.
To compare the performance of single shot echo planar imaging (SSEPI) with three-dimensional-multishot echo-planar imaging (EPI) based on principles-of-echo-shifting-with-a-train-of-observations (PRESTO) in combination with a standard quadrature head coil and, as an alternative, a multiple receiver coil in intraoperative functional magnetic resonance imaging (fMRI). ⋯ SSEPI was superior due to its better SNR and a higher BOLD signal change in the defined settings, irrespective of the coil used. In a stereotactical setup the phased array coil can be used to generate fMRI data without loss of image quality.
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J Magn Reson Imaging · Aug 2004
Image construction methods for phased array magnetic resonance imaging.
To study image construction in phased array magnetic resonance imaging (MRI) systems from a statistical signal processing point of view. ⋯ It is demonstrated that phased array MRI reconstruction performance can be improved by the use of more elaborate statistical signal processing algorithms.
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J Magn Reson Imaging · Aug 2004
MRI of helium-3 gas in healthy lungs: posture related variations of alveolar size.
To probe the variation of alveolar size in healthy lung tissue as a function of posture using diffusion-weighted helium-3 hyperpolarized gas imaging. ⋯ The posture dependent variations in ADC were attributed to compression of the parenchyma under its own weight and the mass of the heart.
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J Magn Reson Imaging · Aug 2004
Diffusion anisotropy in subcortical white matter and cortical gray matter: changes with aging and the role of CSF-suppression.
To determine the relevance of cerebrospinal fluid (CSF)-suppression for the measurement of diffusion anisotropy in well-localized areas of the brain, particularly the subcortical white matter (WM) within the gyri and cortical gray matter (GM), in young and elderly subjects, and to assess the changes of water diffusivity in the brain with normal aging. ⋯ CSF-suppressed DTI yields more accurate measures of quantitative anisotropy in cortical and subcortical brain regions. Reductions of anisotropy with aging were predominantly observed in subcortical WM of the gyri.
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J Magn Reson Imaging · Jul 2004
Malignant hepatic tumor detection with ferumoxide-enhanced magnetic resonance imaging: is chemical-shift-selective fat suppression necessary for fast spin-echo sequence?
To determine whether chemical-shift-selective (CSS) fat suppression is necessary for ferumoxide-enhanced T2-weighted fast spin-echo (FSE) imaging in the detection of malignant hepatic tumors. ⋯ The CSS fat-suppressed FSE sequence was superior to the GRE sequence in the detection of HCCs, but the non-fat-suppressed FSE sequence was comparable to the GRE sequence. The non-fat-suppressed FSE sequence was superior to the CSS fat-suppressed FSE and GRE sequences in the detection of metastases. Optimal FSE imaging with CSS fat suppression or without aiming for the detection of HCCs or metastases, respectively, outperforms GRE imaging in ferumoxide-enhanced MRI.