Journal of magnetic resonance imaging : JMRI
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To develop a voxel-based analysis of an R2* map of healthy human brain that is automatic, reproducible, and realizable in a single examination on a 3T MR imager. Such a tool could be useful to measure iron accumulation in neurodegenerative diseases. ⋯ Our method, combining data acquisition and data processing, demonstrates the feasibility of voxel-based analysis on an R2* map and affords a high degree of sensitivity and good reproducibility while maintaining high spatial resolution.
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J Magn Reson Imaging · Dec 2007
Multiparametric differentiation of posterior fossa tumors in children using diffusion-weighted imaging and short echo-time 1H-MR spectroscopy.
To assess the combined value of diffusion-weighted imaging (DWI) and proton magnetic resonance spectroscopy (1H-MRS) in differentiating medulloblastoma, ependymoma, pilocytic astrocytoma, and infiltrating glioma in a pediatric population. ⋯ Linear discriminant analysis using DWI and MRS using water as internal reference, fully discriminates the four most frequent posterior fossa tumors in children.
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J Magn Reson Imaging · Dec 2007
Detecting groups of coherent voxels in functional MRI data using spectral analysis and replicator dynamics.
To investigate the relationship between functional MRI (fMRI) time series in the human brain, combining fMRI spectral analysis and replicator dynamics. ⋯ The application of replicator dynamics to spectral matrices is a reliable method for detecting groups of maximally coherent voxels. A replicator process is able to determine groups of voxels with the property that each voxel in the group exhibits a high coherence with every other group member. In contrast to the NCV approach, this method is parameter-free and does not require the a priori selection of a reference voxel.
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J Magn Reson Imaging · Dec 2007
Apparent diffusion coefficients in oligodendroglial tumors characterized by genotype.
To investigate whether oligodendroglial tumors with or without 1p/19q loss differ in their diffusion-weighted imaging characteristics. Oligodendroglial tumors with or without 1p/19q loss differ in their therapeutic responsiveness and prognosis, and recent reports also suggest that these tumors may differ in their magnetic resonance characteristics and blood volume. ⋯ This preliminary study identified differences in ADC and ATC between oligodendroglial tumor genotypes that may reflect underlying biology. Confirmation in a larger series is warranted.
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J Magn Reson Imaging · Dec 2007
MR imaging of the female pelvis at 3 Tesla: evaluation of image homogeneity using different dielectric pads.
To evaluate improvements in image homogeneity in pelvic MR imaging at 3 Tesla (T) using two different dielectric pads. ⋯ Dielectric pads consisting of either US gel or water are effective in improving image homogeneity of the pelvis on 3T MRI.