Top-up algorithm for single k-space from single-shot EPI

Abstract

Top-up algorithm requires two EPI images with opposite gradient polarities to make one corrected image. Here, top-up algorithm with a single k-space is proposed for single-shot pseudo-centric EPI, where a k-space can be separated into two halves with opposite distortions. A field map could be estimated by applying top-up algorithm to the two halves. The estimated map compensated the distortions well while preserving inner brain structures. The proposed approach provided 1.8 times higher perfusion SNR than conventional linear EPI. The approach is promising for magnetization-prepared imaging that requires high SNR, high temporal resolution, and minimal distortion with no additional scan.