Common misconceptions about 3D FT MR imaging.
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Algorithms↗
Biomedical subjects
C Hawryszko
Publications and source records attributed to C Hawryszko.
Applications of voxel shifting in magnetic resonance imaging.
Due to the nature of three-dimensional Fourier transform (3-DFT) data acquisition in magnetic resonance imaging (MRI), the spatial relation between a resolved volume element (a voxel) and the object can be manipulated easily. Those manipulations have practical consequences in terms of registering slice positions with respect to features of interest in producing oblique reformatted images where volume resolution is preserved, and in generating reformatted images that project the viewing plane onto a surface through the object that has an arbitrary shape.
Fourier Analysis↗
Baseline deconvolution, phase correction, and signal quantification in Fourier localized spectroscopic imaging.
Lineshapes of spectra obtained through chemical-shift imaging are often distorted due to the delay in sampling necessary for application of phase-encoding gradients. We have developed an automated fitting procedure which simultaneously performs signal quantification, phase correction, and baseline deconvolution of such spectra. The fit is based on the maximum likelihood method and can be implemented in either the time or the frequency domain.
Fourier Analysis↗
Characterization of MR spectroscopic imaging of the human head and limb at 2.0 T.
Using section-select and phase-encoding gradients, the authors obtained phosphorus chemical shift images of the human head and limb. Phosphorus spectra were acquired from planar sections divided into voxels as small as 7 cm3 in calf muscle and 27 cm3 in brain, with total examination times, including setup and proton locator imaging, of roughly 1 hour. Both spin-echo and free induction decay (FID) methods were employed; the FID gave superior results. Signal-to-noise ratios for the beta-adenosine triphosphate and phosphocreatine resonances were as high as 10:1 and 13:1 from volumes of 27 cm3 in brain.
Brain↗
Metabolic response of glioblastoma to adoptive immunotherapy: detection by phosphorus MR spectroscopy.
In a patient with cerebral glioblastoma, metabolic disturbances were detected within the tumor and in the surrounding brain. Within the volume occupied by the tumor, phosphocreatine (PCr)/adenosine triphosphate was reduced and inorganic phosphate/PCr elevated, indicative of tissue necrosis. Loss of total 31P signal was consistent with reduced metabolite content within the area of tumor defined by CT and magnetic resonance (MR). These studies were accomplished with 31P MR spectroscopy at 2 T, using a volume head coil and the technique of two-dimensional phase-encoding to map regional metabolism across the entire cerebral cortex in voxels of 30 cm3. Using the same method, only minor variations in 31P metabolism were noted in six normal controls. Treatment with locally placed Interleukin-2 activated lymphocytes resulted in changes in both MR and 31P MR spectroscopy in the region of the tumor.
Brain Neoplasms↗