Improved test–retest reliability of R2* and susceptibility quantification using multishot multi-echo 3D EPI
Yujia Huang, Lin Chen, Xu Li, Jiaen Liu
Abstract
Purpose
This study aimed to evaluate the potential of 3D EPI for improving the reliability of T2*-weighted data and quantification of R2* 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 R2* and χ were quantified, and their interscan differences were used to evaluate the test–retest reliability. Interprotocol differences of R2* 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 R2* 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 T2*-weighted MRI and quantification of R2* and χ with reduced scan time, improved test–retest reliability, and similar accuracy compared with commonly used 3D GRE.