David Leitão1, Raphael Tomi-Tricot2, Pip Bridgen1, Tom Wilkinson1, Patrick Liebig3, Rene Gumbrecht3, Dieter Ritter3, Sharon Giles1, Ana Baburamani1, Jan Sedlacik1, Joseph V. Hajnal1,4, and Shaihan J. Malik1,4
1Biomedical Engineering and Imaging Sciences, King's College London, London, United Kingdom, 2MR Research Collaborations, Siemens Healthcare Limited, Frimley, United Kingdom, 3Siemens Healthcare GmbH, Erlangen, Germany, 4Centre for the Developing Brain, King's College London, London, United Kingdom
1Biomedical Engineering and Imaging Sciences, King's College London, London, United Kingdom, 2MR Research Collaborations, Siemens Healthcare Limited, Frimley, United Kingdom, 3Siemens Healthcare GmbH, Erlangen, Germany, 4Centre for the Developing Brain, King's College London, London, United Kingdom
Direct Saturation Control is a
novel RF pulse design method that considers the saturation of semisolids
directly, rather than the flip angle. We designed pTx composite pulses to achieve
spatially uniform Magnetization Transfer Ratio (MTR) maps at 7T in presence of
strong B1+ inhomogeneity.
Figure 2
- Magnetization Transfer Ratio (MTR) maps from one volunteer obtained with
saturation prep-pulse applied using CP (top row) and DSatC (bottom row) modes using Target=0.6μT2 and TR=23ms. For both modes the saturation prep-pulse was applied with different
number of sub-pulses: 1 (left column), 2 (middle column) and 3 (right column).
The observed MTR correlates well with the predicted <B12> (Figure 3). The solution for 1 sub-pulse is
not uniform, and this is also predicted from <B12>.
Figure 5
– Results from the gradient demonstration using the non-blipped (top row) and
blipped (bottom row) saturation pulses in Figure 4. (a,d) MTR maps, (b,e) <B12> of the saturation pulse and (c,f) flip angle
from the RF and gradients applied.
