Figure 1

Imaging sequence design of black-blood DP-TSE with rFOV. (A) The pulse-triggered data acquisition scheme consists of a black-blood (DIR) preparation module, a diffusion-preparation module, and a segmented 3D TSE kernel with reduced field-of-view. Two diffusion-weighted images were acquired in an interleaved fashion to minimize the mismatch between them. (B) Diffusion preparation module. A pair of bipolar gradients was used for diffusion encoding with complete compensation for first-order motion. Adiabatic refocussing pulse was used for its insensitivity to b1-inhomogeneity. In order to suppress residual arterial blood, additional flow-dephasing gradients were incorporated into the module with moderate first gradient moment of 1000 mTms²/m at both diffusion weightings. (C) Illustration of the reduced field-of-view scheme. Excitation slab is perpendicular to the slice direction whereas the refocussing slab was oriented to be perpendicular to the phase direction, limiting the imaging volume to the overlapping region between the two slabs (brown region). Because of the reduced imaging volume, phase encoding steps could be greatly reduced to shorten scan time.