Dual‐excitation flip‐angle simultaneous cine and T1 mapping using spiral acquisition with respiratory and cardiac self‐gating

• Published in: Magnetic resonance in medicine Vol. 86; no. 1; pp. 82 - 96
• Main Authors: Zhou, Ruixi, Weller, Daniel S., Yang, Yang, Wang, Junyu, Jeelani, Haris, Mugler, John P., Salerno, Michael
• Format: Journal Article
• Language: English
• Published: Hoboken Wiley Subscription Services, Inc 01.07.2021
• Subjects: cardiac MRI; cine; Convexity; Data acquisition; dictionary learning; EKG; Electrocardiography; Excitation; Gating; Heart; Human subjects; Image acquisition; Image quality; Image reconstruction; Inversions; Mapping; Navigators; self‐gating; Signal quality; spiral trajectory; T1 mapping
• ISSN: 0740-3194; 1522-2594; 1522-2594
• DOI: 10.1002/mrm.28675

Purpose To develop a free‐breathing cardiac self‐gated technique that provides cine images and B1+ 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 B1+ and slice profile effect on the apparent T1∗.