نتایج جستجو برای: diffusion weighted

تعداد نتایج: 251921  

2001
Hyo-Cheol Kim Kee-Hyun Chang In Chan Song Sang Hyun Lee Bae Ju Kwon Moon Hee Han Sang-Yun Kim

OBJECTIVE To compare conventional and diffusion-weighted MR imaging in terms of their depiction of the abnormalities occurring in Creutzfeldt-Jakob disease. MATERIALS AND METHODS We retrospectively analyzed the findings of conventional (T2-weighted and fluid-attenuated inversion recovery) and diffusion-weighted MR imaging in four patients with biopsy-proven Creutzfeldt-Jakob disease. The sign...

2008
E. L. Wu K-H. Cho T-D. Chiueh J-H. Chen

A Wideband diffusion tensor imaging is successfully performed to acquire two images in one single excitation. 2-slices are excited/acquired simultaneously using 2D Wideband modified pulse-gradient spin-echo sequence. The calculated diffusion tensors of the grapefruit are clearly displayed on the eigenvector map, and proven to be correct. The result of this study directly indicates a reduction o...

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: :AJNR. American journal of neuroradiology 2011
G Zaharchuk E U Saritas J B Andre C T Chin J Rosenberg T J Brosnan A Shankaranarayan D G Nishimura N J Fischbein

BACKGROUND AND PURPOSE DWI of the spinal cord is challenging because of its small size and artifacts associated with the most commonly used clinical imaging method, SS-EPI. We evaluated the performance of rFOV spinal cord DWI and compared it with the routine fFOV SS-EPI in a clinical population. MATERIALS AND METHODS Thirty-six clinical patients underwent 1.5T MR imaging examination that incl...

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...

Journal: :AJNR. American journal of neuroradiology 2000
J R Meyer A Gutierrez B Mock D Hebron J M Prager M T Gorey D Homer

BACKGROUND AND PURPOSE Recent technological advances in MR instrumentation allow acquisition of whole-brain diffusion-weighted MR scans to be obtained with b values greater than 1,000. Our purpose was to determine whether high-b-value diffusion-weighted MR imaging improved contrast and detection of signal changes in acute and chronic brain infarction. METHODS We prospectively evaluated the MR...

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