نتایج جستجو برای: diffusion volume
تعداد نتایج: 469130 فیلتر نتایج به سال:
BACKGROUND AND PURPOSE A subset of patients with malignant glioma develops conspicuous lesions characterized by persistent restricted diffusion during treatment with bevacizumab. The purpose of the current study was to characterize the evolution of these lesions and to determine their relationship to patient outcome. MATERIALS AND METHODS Twenty patients with malignant glioma with persistent ...
BACKGROUND AND PURPOSE The corticoreticular pathway (CRP) is known to be an important extrapyramidal tract for walking ability. However, little is known about the functional role of the CRP in recovery of walking ability. We investigated relation between the CRP and walking ability in chronic hemiparetic stroke patients. METHODS Among 209 consecutive patients, 54 patients, who showed complete...
The diffusive properties of adjacent muscles at rest were evaluated in male (n = 12) and female (n = 12) subjects using diffusion tensor imaging (DTI). The principle, second and third eigenvalues, trace of the diffusion tensor [Tr(D)], and two anisotropic parameters, ellipsoid eccentricity (e) and fractional anisotropy (FA), of various muscles in the human calf were calculated from the diffusio...
In this study, we evaluate the performance of a flow-based surface evolution fiber tracking algorithm by means of a physical anisotropic diffusion phantom with known connectivity. We introduce a novel speed function for surface evolution that is derived from either diffusion tensor (DT) data, high angular resolution diffusion (HARD) data, or a combined DT-HARD hybrid approach. We use the model-...
Diffusion-weighted imaging (DWI) and perfusion-weighted imaging (PWI) can rapidly detect lesions in acute ischemic stroke patients. The PWI volume is typically substantially larger than the DWI volume shortly after onset, that is, a diffusion/ perfusion mismatch. The aims of this study were to follow the evolution of the diffusion/ perfusion mismatch in permanent and 60- minute temporary focal ...
The development of cortical gray matter, white matter (WM) volume, and WM microstructure in adolescence is beginning to be fairly well characterized by structural magnetic resonance imaging (sMRI) and diffusion tensor imaging (DTI) studies. However, these aspects of brain development have rarely been investigated concurrently in the same sample and hence the relations between them are not under...
A spatially two-dimensional epidemic model is formulated by a reaction-diffusion system. The spatial pattern formation is driven by a cross-diffusion corresponding to a non-diagonal, uppertriangular diffusion matrix. Whereas the reaction terms describe the local dynamics of susceptible and infected species, the diffusion terms account for the spatial distribution dynamics. For both self-diffusi...
The diffusion signal in breast tissue has primarily been modelled using apparent diffusion coefficient (ADC), intravoxel incoherent motion (IVIM) and diffusion tensor (DT) models, which may be too simplistic to describe the underlying tissue microstructure. Formalin-fixed breast cancer samples were scanned using a wide range of gradient strengths, durations, separations and orientations. A vari...
Biomedical Imaging Research Institute, Cedars-Sinai Medical Center, Los Angeles, California, USA Full list of author information is available at the end of the article Figure 1 Typical T2 prepared (b = 0 s/mm) images, DWI (b = 450 s/mm) in three orthogonal directions, and ADC maps for M1M2 (top) and TRSE (bottom) diffusion preparation. M1M2 diffusion-prepared images clearly depict myocardium wi...
We consider the convergence of a volume corrected characteristics-mixed method (VCCMM) for advection-diffusion systems. It is known that, without volume correction, the method is first order convergent, provided there is a nondegenerate diffusion term. We consider the advective part of the system and give some properties of the weak solution. With these properties we prove that the volume corre...
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