Improved test–retest reliability of R2* R₂^ and susceptibility quantification using multishot multi‐echo 3D EPI

Abstract Purpose This study aimed to evaluate the potential of 3D EPI for improving the reliability of ‐weighted data and quantification of decay rate and susceptibility ( χ ) compared with conventional gradient‐echo (GRE)‐based acquisition. Methods Eight healthy subjects in a wide age range were recruited. Each subject received repeated scans for both GRE and EPI acquisitions with an isotropic 1 mm resolution at 3 T. Maps of and χ were quantified, and their interscan differences were used to evaluate the test–retest reliability. Interprotocol differences of and χ between GRE and EPI were also measured voxel by voxel and in selected regions of interest to test the consistency between the two acquisition methods. Results The quantifications of and χ using EPI protocols showed increased test–retest reliability with higher EPI factors up to 5 as performed in the experiment and were consistent with those based on GRE. Conclusion The result suggests that multishot multi‐echo 3D EPI can be a useful alternative acquisition method for ‐weighted MRI and quantification of and χ with reduced scan time, improved test–retest reliability, and similar accuracy compared with commonly used 3D GRE.