Dual-excitation flip-angle simultaneous cine and T1 mapping using spiral acquisition with respiratory and cardiac self-gating.
PURPOSE
To develop a free-breathing cardiac self-gated technique that provides cine images and  slice profile-corrected T1 maps from a single acquisition.


METHODS
Without breath-holding or electrocardiogram gating, data were acquired continuously on a 3T scanner using a golden-angle gradient-echo spiral pulse sequence, with an inversion RF pulse applied every 4 seconds. Flip angles of 3° and 15° were used for readouts after the first four and second four inversions. Self-gating cardiac triggers were extracted from heart image navigators, and respiratory motion was corrected by rigid registration on each heartbeat. Cine images were reconstructed from the steady-state portion of 15° readouts using a low-rank plus sparse reconstruction. The T1 maps were fit using a projection onto convex sets approach from images reconstructed using slice profile-corrected dictionary learning. This strategy was evaluated in a phantom and 14 human subjects.


RESULTS
The self-gated signal demonstrated close agreement with the acquired electrocardiogram signal. The image quality for the proposed cine images and standard clinical balanced SSFP images were 4.31 (±0.50) and 4.65 (±0.30), respectively. The slice profile-corrected T1 values were similar to those of the inversion-recovery spin-echo technique in phantom, and had a higher global T1 value than that of MOLLI in human subjects.


CONCLUSIONS
Cine and T1 mapping using spiral acquisition with respiratory and cardiac self-gating successfully acquired T1 maps and cine images in a single acquisition without the need for electrocardiogram gating or breath-holding. This dual-excitation flip-angle approach provides a novel approach for measuring T1 while accounting for  and slice profile effect on the apparent  .
['Zhou|Ruixi|R|0000-0001-9231-4987', 'Weller|Daniel S|DS|0000-0001-9818-7325', 'Yang|Yang|Y|', 'Wang|Junyu|J|0000-0001-8314-4525', 'Jeelani|Haris|H|', 'Mugler|John P|JP|', 'Salerno|Michael|M|0000-0001-7051-1031']
D062485:Breath Holding D006321:Heart D006801:Humans D007090:Image Interpretation, Computer-Assisted D019028:Magnetic Resonance Imaging, Cine D019047:Phantoms, Imaging D015203:Reproducibility of Results
cine T1 mapping self-gating dictionary learning cardiac MRI spiral trajectory