readout gradient
The magnetic field gradient applied during signal acquisition to spatially encode MRI data along the frequency-encoding direction.
Full Definition
The readout gradient is a linear magnetic field gradient applied during the analog-to-digital conversion of the MRI signal, providing spatial encoding along the frequency-encoding axis. This gradient causes protons at different spatial locations to precess at slightly different frequencies, allowing their signals to be separated during Fourier transformation. The readout gradient determines the field of view and resolution along the frequency-encoding direction and must be optimized to balance spatial resolution, signal-to-noise ratio, and acquisition time while avoiding aliasing artifacts.
Usage
Usage note: Distinguish from other gradient types; specify bandwidth when relevant.
In Context
- "The readout gradient bandwidth was increased to 500 Hz/pixel to minimize chemical shift displacement." — Sequence optimization report
- "Asymmetric readout gradients were employed to reduce echo time and improve T2* sensitivity." — Technical protocol description