Non-Contrast-Enhanced Hand MRA Using Multi-Directional Flow-Sensitive Dephasing

Zhaoyang Fan^1,2, Philip Hodnett¹, John Sheehan¹, Xiaoming Bi³, Sven Zuehlsdorff³, James Carr¹, Debiao Li^1,2

Noncontrast hand MRA using ECG-triggered 3D bSSFP with flow-sensitive dephasing (FSD) preparation has recently been demonstrated in patients with Raynauds disease. However, a conventional FSD module with flow-sensitizing gradient pulses applied in both readout and phase-encoding direction simultaneously is only sensitive to one-direction flow. We proposed a new FSD preparative module with two FSD sub-modules combined in series. In each submodule, gradient pulses are applied in one direction only. Its effectiveness was verified on a flow phantom and healthy volunteer hands. Additionally, a volunteer study was performed to investigate the MRA quality with FSD bSSFP using contrast-enhance MRA as reference.