Reducing Distortion in EPI Using Partial Fourier Encoding in the Kx-Direction

Samantha J. Holdsworth¹, Roland Bammer¹, Stefan Skare¹

Geometric distortion in EPI is related to the time between two consecutive echoes in the EPI train. To shorten the EPI readout and TE, the acquisition is often used with partial Fourier encoding in the ky-direction. We propose here to instead perform partial Fourier encoding in the kx-direction. In this way, the echo spacing between two consecutive echoes is reduced resulting in reduced geometrical distortion while keeping the SNR approximately equivalent. This approach can reduce geometric distortion by ~20% compared with EPI images acquired with partial Fourier encoding in ky.