نتایج جستجو برای: diffusion weighted imaging

تعداد نتایج: 673748  

2015
Markus Nilsson Filip Szczepankiewicz Danielle van Westen Oskar Hansson Mara Cercignani

PURPOSE Conventional motion and eddy-current correction, where each diffusion-weighted volume is registered to a non diffusion-weighted reference, suffers from poor accuracy for high b-value data. An alternative approach is to extrapolate reference volumes from low b-value data. We aim to compare the performance of conventional and extrapolation-based correction of diffusional kurtosis imaging ...

Journal: :Cases Journal 2008
Rahul Rathakrishnan Vijay K Sharma Bernard PL Chan

BACKGROUND Diffusion-weighted magnetic resonance imaging is a very sensitive tool for the early diagnosis of acute ischemic stroke. This is employed in some stroke centers as the primary screening tool to select patients eligible for thrombolysis. METHODS We present the case of a 49-years old Chinese man whose diffusion-weighted magnetic resonance imaging performed 12 hours of symptom onset w...

Journal: :AJNR. American journal of neuroradiology 1998
R B Schwartz R V Mulkern H Gudbjartsson F Jolesz

PURPOSE Hypertensive encephalopathy, a complex of cerebral disorders, including headache, seizures, visual disturbances, and other neurologic manifestations, is associated with a variety of conditions in which blood pressure rises acutely. It has been ascribed to either exuberant vasospasm with ischemia/infarction or breakthrough of autoregulation with interstitial edema. Diffusion-weighted MR ...

Journal: :Magnetic resonance in medicine 2007
Lin-Ching Chang Cheng Guan Koay Carlo Pierpaoli Peter J Basser

In typical applications of diffusion tensor imaging (DTI), DT-derived quantities are used to make a diagnostic, therapeutic, or scientific determination. In such cases it is essential to characterize the variability of these tensor-derived quantities. Parametric and empirical methods have been proposed to estimate the variance of the estimated DT, and quantities derived from it. However, the fo...

Journal: :Magnetic resonance imaging 2012
Pablo Casaseca-de-la-Higuera Antonio Tristán-Vega Santiago Aja-Fernández Carlos Alberola-López Carl-Fredrik Westin Raúl San José Estépar

Diffusion tensor imaging (DTI) constitutes the most used paradigm among the diffusion-weighted magnetic resonance imaging (DW-MRI) techniques due to its simplicity and application potential. Recently, real-time estimation in DW-MRI has deserved special attention, with several proposals aiming at the estimation of meaningful diffusion parameters during the repetition time of the acquisition sequ...

Journal: :Annals of the New York Academy of Sciences 2011
Brian A Wandell

This review summarizes recent ideas about the cortical circuits for seeing words, an important part of the brain system for reading. Historically, the link between the visual cortex and reading has been contentious. One influential position is that the visual cortex plays a minimal role, limited to identifying contours, and that information about these contours is delivered to cortical regions ...

2008
S. Tang Y. Fan H. Zhu W. Gao W. Lin D. Shen

Introduction Diffusion tensor imaging (DTI) has been widely used to construct the orientation and structure of fibers in biological tissues, particularly in the white matter of the brain [1]. The raw diffusion-weighted images (DWI) from which diffusion tensors are estimated, however, inherently contain large amounts of noise, leading to uncertainty in the estimation of the tensors and their der...

Journal: :Magnetic resonance imaging 2011
Seongjin Choi Dustin T Cunningham Francisco Aguila John D Corrigan Jennifer Bogner W Jerry Mysiw Michael V Knopp Petra Schmalbrock

Diffusion tensor imaging (DTI) and advanced related methods such as diffusion spectrum and kurtosis imaging are limited by low signal-to-noise ratio (SNR) at conventional field strengths. DTI at 7 T can provide increased SNR; however, B0 and B1 inhomogeneity and shorter T2⁎ still pose formidable challenges. The purpose of this study was to quantify and compare SNR at 7 and 3 T for different par...

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