3D-TSE Dixon sequence with preserved short echo spacing for second and subsequent echoes

Motivation: Common to existing TSE Dixon sequences is that the chemical shift between water and fat is encoded by shifting the readout window away from the spin-echo time point. The shifting prolongs the echo spacing by twice the shift. A short echo spacing is an important component of modern 3D-TSE sequences to enable high resolution 3D imaging in clinically acceptable times. Goal(s): Develop a 3D-TSE Dixon sequence with unchanged echo spacing. Approach: Encode the chemical shift via the excitation. Acquire in-phase and opposed-phase data for 2pt-Dixon symmetric around the spin-echo time point. Results: Homogeneous fat-water separation in knee, hand and ankle. Impact: 3D-TSE 2pt-Dixon sequence with unchanged echo spacing between second and subsequent echoes compared to a conventional 3D-TSE sequence with same acquisition parameters.