Point spread function mapping with parallel imaging techniques and high acceleration factors: Fast, robust, and flexible method for echo‐planar imaging distortion correction

TLDR

Echo‑planar imaging is an ultrafast MR technique that suffers from geometric distortions, prompting the development of various correction methods. The study presents enhancements to the point spread function mapping approach to provide reliable, fully automated distortion correction for echo‑planar images at high field strengths. The new method, fully compatible with parallel imaging, accelerates PSF acquisition beyond the number of coil elements and introduces a visualization framework for distortions across different imaging and reconstruction techniques. The technique reliably produces PSF datasets with acceleration factors exceeding coil count and performs accurately on phantom and volunteer scans up to 4 T. © 2004 Wiley‑Liss, Inc.

Abstract

Abstract Echo‐planar imaging (EPI) is an ultrafast magnetic resonance (MR) imaging technique prone to geometric distortions. Various correction techniques have been developed to remedy these distortions. Here improvements of the point spread function (PSF) mapping approach are presented, which enable reliable and fully automated distortion correction of echo‐planar images at high field strengths. The novel method is fully compatible with EPI acquisitions using parallel imaging. The applicability of parallel imaging to further accelerate PSF acquisition is shown. The possibility of collecting PSF data sets with total acceleration factors higher than the number of coil elements is demonstrated. Additionally, a new approach to visualize and interpret distortions in the context of various imaging and reconstruction methods based on the PSF is proposed. The reliable performance of the PSF mapping technique is demonstrated on phantom and volunteer scans at field strengths of up to 4 T. Magn Reson Med 52:1156–1166, 2004. © 2004 Wiley‐Liss, Inc.