Dual Spin-Echo Proton Density-Weighted and T2-Weighted Knee Imaging with Asymmetric Spiral In-out Trajectories 

This work proposes a spiral dual echo spin-echo sequence with asymmetric in-out trajectories to increase the scan efficiency of the second echo. The sequence has been applied for simultaneous sagittal proton density-weighted and T2-weighted Dixon knee imaging. Volunteer scans have demonstrated the feasibility of using the proposed method to achieve up to 36% SNR improvement for T2-weighted images. High quality water and fat images can be obtained with comparable total scan time as the conventional non-Dixon Cartesian fast (turbo) spin-echo sequences with SENSE factors from 1.5 to 2. T2 maps can also be estimated from proton density-weighted and T2-weighted images.