Bipolar Diffusion Encoding with Implicit Spoiling of Undesired Coherence Pathways

Thorsten Feiweier¹

High-resolution DTI requires both high SNR and precise spatial alignment of images acquired with different diffusion encodings. While the bipolar (twice refocused) diffusion-encoding scheme effectively reduces eddy-current-induced distortions as compared to the monopolar Stejskal-Tanner approach, it involves increased TE due to the need for additional spoiler gradients. A new bipolar diffusion-encoding variant is discussed here, omitting the need for explicit spoiling. This approach allows for a markedly reduced TE and correspondingly increased SNR with negligible impact on eddy current suppression efficiency.