Rasim Boyacioglu1 and Mark Griswold1
1Radiology, Case Western Reserve University, Cleveland, OH, United States
1Radiology, Case Western Reserve University, Cleveland, OH, United States
We report the presence of frequency
drifts in MRF data that might affect the tissue property maps. We show that
these can be compensated with a dictionary update for 2D and with a novel
reconstruction framework for 3D. Results show significant improvements in the
quality of the quantitative maps.
Figure 3. T2 values are hardly changed between different
reconstructions. Off-resonance maps are shifted overall but the contrast
between the tissues is preserved. T1 underestimation is resolved with frequency
drift correction (blue arrows). The major improvement on Γ
maps with narrower frequency distributions expresses itself in T2* maps as
elevated values and sharper contrast (red arrow). Please note the corrected Γ in white
matter which is supposed to be on the lower end of Γ range.
Figure 4. 3D T1 and T2 maps of the same slice plotted for FISP MRF,
generic MRFqRF and MRFqRF with frequency drift correction. It can be observed
that T1 improvement in 3D is significantly more than 2D, this is probably due
to accrued frequency over much longer 3D acquisition. The T1 FISP contrast
between gray matter and white matter is replicated with drift correction
whereas the generic reconstruction has elevated blurring throughout the slice (blue
arrows).