Kwan-Jin Jung1 and Brad Sutton1,2
1Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, IL, United States, 2Electrical & Computer Engineering, University of Illinois at Urbana-Champaign, Urbana, IL, United States
1Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, IL, United States, 2Electrical & Computer Engineering, University of Illinois at Urbana-Champaign, Urbana, IL, United States
Sodium MRI
is challenging due to its low sensitivity and short T2 and hence a
three-dimensional sequence with a spiral trajectory has been applied. The
spiral trajectory was shortened in the TPI method by accelerating the span at
the k-space origin using a radial start and then transiting into a spiral
trajectory. This popular TPI method, however, requires a very high gradient
slew rate when the 3D cone approaches the polar pole. This drawback has been
resolved by rotating a two-dimensional disc filled with interleaved TPI
trajectories. This method achieved the faster sweeping of TPI as well as a
uniform gradient slew rate over the sphere sampling. We are reporting some
artifacts in TPI-based scans not only in our study but also in other studies.
Figure 2.
Trajectories of the proposed RSD scheme. (A) The disc, filled with the
interleaved TPI trajectories shown in Fig. 1A, is rotated along the x-axis to
form a sphere. (B) A half-filled sphere with TPI discs.
Figure 3.
Sodium phantom images on 3 orthogonal slices. The red numbers on the larger
bottles count the bright rings of the annular pattern in each bottle. The dotted
yellow rectangle includes the smaller tubes with the center dark spot.