Abstract Purpose To develop a rapid 2D free‐running myocardial mapping technique that is robust to through‐plane respiratory motion. Methods A free‐running golden angle radial sequence consisting of encoding and self‐navigated auto motion calibration (SNAC) was developed. The encoding adopted inversion recovery (IR) prepared interleaved multi‐slice acquisition with optimized inter‐slice gap to ensure a uniform excitation of the middle slice regardless of through‐plane respiratory motion. The flip angles were alternated between the odd and even IR readouts to correct flip‐angle errors. SNAC was designed to calibrate the through‐plane motion with the respiratory self‐navigation signal extracted from the free‐running sequence, and integrate the multi‐slice data into a through‐plane motion‐corrected 2D slice for mapping reconstruction. Numerical simulations were performed to optimize the key sequence parameters, followed by phantom and in‐vivo imaging to validate the accuracy and repeatability. Results Numerical simulations yielded the dual flip angles minimizing estimation errors and the adjacent slice offset achieving uniformity in the superimposed slice profile. Phantom experiments demonstrated a strong correlation between the proposed and reference method, and no dependence of the free‐running estimation on heart rates. Adding through‐plane respiratory motion correction significantly improved the in‐vivo mapping sharpness and visual quality. Validated against the conventional breath‐hold mapping technique, the motion corrected free‐running method achieved comparable mapping quality and repeatability. Conclusion Respiratory motion is effectively suppressed in the proposed 2D free‐running method, which achieves superior mapping with acceptable repeatability in a short scan time of 46 s.
Huang et al. (Thu,) studied this question.