No abstract available.
Diffusion Tensor Imaging* ; Diffusion*

A model theory of passive-targeted drug delivery in sphere-shaped solid tumors is introduced on the basis of Fick's law of diffusion, with appropriate boundary and initial conditions. For a uniform initial concentration inside the tumor, the concentration is obtained as a function of time and radial position. The concentration is shown to approach the equilibrium distribution as the time elapses, as is expected by the Gedanken Experiment. The time-evolution rate is found to be determined by the diffusion coefficient of the drug in the tissue, the size of the tumor, the volume of the drug-injected region, and the concentration gradient at the boundary.
Diffusion ; Jurisprudence

No abstract available.
Diffusion* ; Teicoplanin*

Internal capsular genu infarcts infrequently cause cognitive impairment and behavioral changes, and little is known about the underlying mechanism. Using diffusion-tensor imaging (DTI) and the fractional anisotropy (FA) index in the region of interest (ROI) and ipsilesional frontal cortex, we evaluated two patients with internal capsular genu infarction who presented with frontal dysfunction and cognitive impairment. The reported findings help to elucidate the mechanism underlying cognitive deterioration in internal capsular genu infarction.
Anisotropy ; Diffusion ; Diffusion Tensor Imaging ; Humans ; Infarction

PURPOSE: Diffusion tensor imaging (DTI) data must be analyzed by an analyzer after data processing. Hence, the analyzed data of DTI might depend on the analyzer, making it a major limitation. This paper reviewed previous DTI studies reporting the repeatability and reproducibility of data from the corticospinal tract (CST), one of the most actively researched neural tracts on this topic. MATERIALS AND METHODS: Relevant studies published between January 1990 and December 2018 were identified by searching PubMed, Google Scholar, and MEDLINE electronic databases using the following keywords: DTI, diffusion tensor tractography, reliability, repeatability, reproducibility, and CST. As a result, 15 studies were selected. RESULTS: Measurements of the CSTs using region of interest methods on 2-dimensional DTI images generally showed excellent repeatability and reproducibility of more than 0.8 but high variability (0.29 to 1.00) between studies. In contrast, measurements of the CST using the 3-dimensional DTT method not only revealed excellent repeatability and reproducibility of more than 0.9 but also low variability (repeatability, 0.88 to 1.00; reproducibility, 0.82 to 0.99) between studies. CONCLUSION: Both 2-dimensional DTI and 3-dimensional DTT methods appeared to be reliable for measuring the CST but the 3-dimensional DTT method appeared to be more reliable.
Diffusion Tensor Imaging ; Diffusion ; Methods ; Pyramidal Tracts

No abstract available.
Diffusion Tensor Imaging ; Diffusion ; Hemiplegia ; Humans

Anoperineal tuberculosis is a rare extrapulmonary form of the disease and may present as abscess. We report a case of anoperineal tuberculous abscess, which showed low signal intensity on T1-weighted images, high signal intensity on T2-weighted images and diffusion restriction on diffusion weighted images.
Abscess ; Diffusion ; Tuberculosis

Diffusion tensor tractorgraphy which is based on line propagation method with brute force approach is implemented and the vector correlation function is proposed in addition to the conventional fractional anisotrophy value as a criterion to select seed points. For the whole tractography, the proposed method used 41% less seed points than the conventional brute force approach for FA > or =0.3 and most of the fiber tracks in the outer region of white matter were removed. For the corticospinal tract passing through region of interest, the proposed method has produced similar results with 50% less seed points than conventional one.
Diffusion ; Pyramidal Tracts

High signal intensity on diffusion-weighted image (DWI) at the site of venous occlusion has previously been reported in cerebral venous thrombosis (CVT). The frequency and diagnostic value of these signal changes in CVT were unknown. Some authors suggest that the presence of high signal intensity on DWI in occluded veins might help diagnose CVT and suggest low rate of recanalization. We experienced two cases of CVT with high signal intensity at the site of intravascular clot on DWI.
Diffusion* ; Veins ; Venous Thrombosis*

No abstract available.
Alexander Disease* ; Diffusion*