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Updated: Aug 31, 2025
High-speed Particle Image Velocimetry Near Surfaces
Published on: June 24, 2013
Velocity-selective excitation: Principles and applications
Zungho Zun1, Taehoon Shin2,3,4
1Department of Radiology, Weill Cornell Medicine, New York, New York, USA.
Abstract:
Velocity-selective (VS) excitation is a relatively new type of excitation that can be useful for generating image contrast based on spin's motion. This review aims to explain the principles of VS excitation and their utilization for clinical applications. We first review the generalized excitation k-space formalism, which reveals a Fourier relationship between sequence parameters and excitation profiles for spins with arbitrary spatial location, off-resonance, and velocity. Based on the k-space framework, we analyze practical VS excitation pulse sequences that yield sinusoidal or sinc-shaped velocity profiles. Then we demonstrate how these two types of VS excitation can be used as magnetization preparation for clinical applications, including saturation- or inversion-based arterial spin labeling and black- or bright-blood angiography. We also discuss practical considerations and issues for each application, including the determination of design parameters and the effects of MR system errors, such as magnetic field offsets and eddy currents.
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