Enhanced relative BOLD signal changes inT2-weighted stimulated echoes
نویسندگان
چکیده
منابع مشابه
Effect of Phase-Encoding Reduction on Geometric Distortion and BOLD Signal Changes in fMRI
Introduction Echo-planar imaging (EPI) is a group of fast data acquisition methods commonly used in fMRI studies. It acquires multiple image lines in k-space after a single excitation, which leads to a very short scan time. A well-known problem with EPI is that it is more sensitive to distortions due to the used encoding scheme. Source of distortion is inhomogeneity in the static B0 field that ...
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Stimulated photon echoes (SPEs) with time duration comparable to the coherent lifetime and Rabi period have been investigated theoretically and experimentally with an angled beam configuration. The Rabi oscillation effects on both the transmitted field (optical nutation) and the SPE fields are explained by analytic solutions of Maxwell-Bloch equations. The theory also predicts that an echo can ...
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The nature of vascular contribution to blood oxygenation level dependent (BOLD) contrast used in functional MRI (fMRI) is poorly understood. To investigate vascular contributions at an ultrahigh magnetic field of 9.4 T, diffusion-weighted fMRI techniques were used in a rat forepaw stimulation model. Tissue and blood T(2) values were measured to optimize the echo time for fMRI. The T(2) of arter...
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Theory The proposed sequence is shown in Figure 1. The basic idea is to obtain a spin echo (SE) and a stimulated echo (STE) with different T1 weighting for T1 calculation. In contrast to the FastPACE technique, both echoes were acquired separately. Then, only magnitude images are required which allows for exploiting the Half Fourier technique and using phased array coils. Acquisition of the tru...
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Phase changes in blood oxygenation-level dependent (BOLD) fMRI have been observed in humans; however, their exact origin has not yet been fully elucidated. To investigate this issue, we acquired gradient-echo (GE) BOLD and cerebral blood volume (CBV)-weighted fMRI data in anesthetized cats during visual stimulation at 4.7T and 9.4T, before and after injection of a superparamagnetic contrast age...
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ژورنال
عنوان ژورنال: Magnetic Resonance in Medicine
سال: 2007
ISSN: 0740-3194,1522-2594
DOI: 10.1002/mrm.21369