Journal of magnetic resonance imaging : JMRI
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J Magn Reson Imaging · Jul 2009
Time-resolved three-dimensional magnetic resonance digital subtraction angiography without contrast material in the brain: Initial investigation.
To evaluate a novel magnetic resonance (MR) angiography (MRA) of three-dimensional (3D) MR digital subtraction angiography (MRDSA) without contrast material, which is essentially 3D true steady-state free precession (SSFP) with selected inversion recovery (IR) pulse using multiple cardiac phase acquisitions with a short increment delay in the assessment of normal cranial arteries, as a feasibility study before clinical use. ⋯ Time-SLIP 3D MRDSA is a simple method for obtaining hemodynamic information. Although more MR sequence improvement is needed, it can play an important role in assessing cranial arteries without contrast material.
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J Magn Reson Imaging · Jul 2009
Improved myelin water quantification using spatially regularized non-negative least squares algorithm.
To improve the myelin water quantification in the brain in the presence of measurement noise and to increase the visibility of small focal lesions in myelin-water-fraction (MWF) maps. ⋯ The MWF variability due to the measurement noise can be substantially reduced and the detection of small focal lesions can be improved by using the srNNLS algorithm.
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J Magn Reson Imaging · Jul 2009
Characterization of low-grade gliomas using RGB color maps derived from ADC histograms.
To use normalized apparent diffusion coefficient (nADC) histograms from patients with grade II oligodendroglioma (OD) and astrocytoma (AC) to generate RGB color maps that emphasize the differences between normal-appearing white matter (NAWM), oligo-like, and astro-like regions. ⋯ This technique allows for the visualization of biologically different regions within the whole tumor mass, which may aid in directing image-guided biopsies. This can be used to ensure that the biopsy is directed to regions that can more accurately define the dominant tumor characteristics.
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J Magn Reson Imaging · Jul 2009
Impact of cerebrospinal fluid contamination on brain metabolites evaluation with 1H-MR spectroscopy: a single voxel study of the cerebellar vermis in patients with degenerative ataxias.
To investigate the impact of cerebrospinal fluid (CSF) contamination on metabolite evaluation in the superior cerebellar vermis with single-voxel (1)H-MRS in normal subjects and patients with degenerative ataxias. ⋯ CSF contamination has a not negligible effect on the estimation of brain metabolites. The increase of Cr concentration in patients with cerebellar atrophy presumably reflects the substitutive gliosis which takes place along with loss of neurons.
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J Magn Reson Imaging · Jun 2009
Assessment of hepatic extraction fraction and input relative blood flow using dynamic hepatocyte-specific contrast-enhanced MRI.
To assess the feasibility to use dynamic hepatocyte-specific contrast-enhanced MRI (DHCE-MRI) as an imaging-based liver function test, and to compare two methods for deconvolutional analysis (DA) in healthy human subjects. ⋯ DHCE-MRI with Gd-EOB-DTPA enables the calculation of HEF and irBF. We regard these parameters as being markers of hepatic parenchymal function.