Simple analytic variable density spiral design
نویسندگان
چکیده
منابع مشابه
Simple analytic variable density spiral design.
Variable density spirals have been proposed in a variety of applications, including MR fluoroscopy, cardiac imaging, and MR spectroscopic imaging. In this work, a simple analytic solution for designing a flexible set of variable density spiral trajectory waveforms is presented. The method enables real-time waveform prescription on scanners with limited computational power. Both slew rate-limite...
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Introduction: In the original variable-density (VD) spiral trajectory[1], the sampling density varies throughout the k-space trajectory; i.e., k(τ) = λτe , where the parameter α controls the rate of density variation. Here, we propose a k-space trajectory consisting of an Archimedean spiral[2] from the origin out to a given radius k1, and extending beyond k1 with a variable-density spiral of α>...
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The exact, hardware-constrained design of a spiral k-space trajectory requires the solution of a differential equation, thereby making real-time prescription difficult on scanners with limited computational power. This study describes a closed-form approximate solution for interleaved Archimedian spiral trajectories that closely matches the exact design. Both slew rate-limited and amplitude-lim...
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On the circular curve, lateral acceleration affects comfort. On the spiral, both lateral acceleration and jerk affect comfort. The determination of maximum curving speed on the basis of lateral acceleration only is not critical because the lateral acceleration is proportional to the square of speed whereas jerk is proportional to cubic power of speed. The maximum speed on a curve is thus signi...
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Introduction In functional MRI, spiral trajectory has been proposed to reduce the signal dropout in the frontal orbital and lateral parietal region affected by the susceptibility-induced field gradient (SFG) [1-2]. With a spiral-in trajectory, the entire k-space except the origin is sampled before the prescribed echo time TE. This reduces T2* weighting and enhances the BOLD contrast in regions ...
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ژورنال
عنوان ژورنال: Magnetic Resonance in Medicine
سال: 2003
ISSN: 0740-3194,1522-2594
DOI: 10.1002/mrm.10493