In our study, the 3D UTE-Cones AFI and conventional UTE-Cones sequences (see Figure 1 ) were implemented on a 3T Signa TwinSpeed scanner (GE Healthcare Technologies, Milwaukee, WI). An 8-channel transmit/receive knee coil was used for both RF transmission and signal reception. The sequences used unique k-space trajectories that sampled data along evenly spaced twisted paths in the form of multiple cones (27 (link)–29 (link)). Data sampling began from the center of k-space and continued outwards. It began as soon as practical after the RF excitation with a minimal nominal delay time of 32 μs. Both RF and gradient spoiling were used to crush the remaining transverse magnetizations. In 3D UTE-Cones AFI, the areas of gradient crushers in TR1 and TR2 were 180 and 900 mT·ms/m respectively, and the RF phase increment was
(17 (link)). In 3D VTR or VFA UTE-Cones, the area of the gradient crushers was 180 mT·ms/m and the RF phase increment was
(17 (link)). The 3D UTE-Cones sequence allowed anisotropic resolution (e.g., high in-plane resolution and thicker slices) to provide an improved SNR and a reduced scan time relative to isotropic imaging (28 (link), 29 (link)).
(17 (link)). In 3D VTR or VFA UTE-Cones, the area of the gradient crushers was 180 mT·ms/m and the RF phase increment was
(17 (link)). The 3D UTE-Cones sequence allowed anisotropic resolution (e.g., high in-plane resolution and thicker slices) to provide an improved SNR and a reduced scan time relative to isotropic imaging (28 (link), 29 (link)).
