Physical phantoms have been widely used for performance evaluation of magnetic resonance imaging (MRI). Although there are many kinds of physical phantoms, most MRI phantoms use fixed configurations with specific sizes that may fit one or a few different types of radio frequency (RF) coils. Therefore, it has limitations for various image quality assessments of scanning areas.
View Article and Find Full Text PDFObjective: The identification of the corticospinal tract (CST) pathway with a deterministic fiber tracking approach is limited because of crossing fibers, especially for the hand fibers of the CST due to the crossing superior longitudinal fasciculus (SLF). We examined a patient with congenital bilateral perisylvian syndrome (CBPS) who did not have the SLF, in order to visualize CST hand fibers that were not affected by crossing fibers.
Methods: A 10-year-old girl without the SLF due to CBPS and three normal healthy subjects participated in this study.
The corticospinal tract is the motor pathway in the human brain, and corona radiata (CR) is an important location to diagnose stroke. We detected hand and foot motor fiber tracts in the CR to investigate accurate locations using diffusion-tensor imaging (DTI) and functional imaging. Ten right-handed normal volunteers participated in this study.
View Article and Find Full Text PDFTo attain the volumetric information of the optic radiation in normal human brains, we performed diffusion tensor imaging examination in 13 healthy volunteers. Simultaneously, we used a brain normalization method to reduce individual brain variation and increase the accuracy of volumetric information analysis. In addition, tractography-based group mapping method was also used to investigate the probability and distribution of the optic radiation pathways.
View Article and Find Full Text PDFOpen-configuration magnetic resonance imaging (MRI) systems are becoming increasingly desirable for musculoskeletal imaging and image-guided radiotherapy because of their non-claustrophobic configuration. However, geometric image distortion in large fields-of-view (FOV) due to field inhomogeneity and gradient nonlinearity hinders the practical applications of open-type MRI. We demonstrated the use of geometric distortion correction for increasing FOV in open MRI.
View Article and Find Full Text PDFLittle is known about the location of the corticospinal tract (CST) at the corona radiata (CR). In the current study we attempted to elucidate the location of the CST for the hand at the CR using diffusion tensor tractography analysis based on functional MRI activation results. Functional MRI was performed at 1.
View Article and Find Full Text PDFTractography using diffusion tensor magnetic resonance imaging (DT-MRI) is a method to determine the architecture of axonal fibers in the central nervous system by computing the direction of greatest diffusion in the white matter of the brain. To reduce the noise in DT-MRI measurements, a tensor-valued median filter, which is reported to be denoising and structure preserving in the tractography, is applied. In this paper, we proposed the successive Fermat (SF) method, successively using Fermat point theory for a triangle contained in the two-dimensional plane, as a median filtering method.
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