B 0 navigator enables respiratory motion navigation in radial stack‐of‐stars liver Look‐Locker T 1 mapping

作者：Jonathan Stelter, Kilian Weiss, Veronika Spieker, Julia A. Schnabel, Rickmer Braren, Dimitrios C. Karampinos · 发表于：Magnetic Resonance in Medicine · 年份：2025 · DOI：10.1002/mrm.30567 · 被引用次数：2 · 研究领域：Advanced MRI Techniques and Applications、Advanced Radiotherapy Techniques、Medical Imaging Techniques and Applications

Abstract Purpose To develop a self‐navigation approach to estimate respiratory motion for motion‐corrected liver mapping using a Look‐Locker acquisition with radial stack‐of‐stars trajectory. Methods The proposed method derives 1D field‐map profiles from the oversampled k‐space center to estimate a normalized breathing curve and the variation amplitude for each slice and coil. drift and contrast variations, inherent to the Look‐Locker acquisition, were modeled and corrected by fitting and demodulating drift and offset terms. The breathing curve was employed to bin data into motion states for motion‐resolved reconstruction, followed by water‐specific mapping. Simulations with an anatomical body model and in vivo experiments with a Look‐Locker multi‐echo gradient echo sequence were performed to validate the technique. The estimated normalized breathing curve was compared with magnitude‐ and phase‐based self‐navigation approaches using principal component analysis. Results The proposed self‐navigation reliably estimated the normalized breathing curve and the variation amplitude in simulations and in vivo. variation amplitudes increased with greater tissue displacement, with median values across slices and coils ranging from 4 to 15 Hz at 3 T in volunteers. Motion‐resolved reconstruction using the estimated breathing curve reduced motion artifacts and improved image and mapping quality compared to motion‐averaged reconstruction. Conclusion self‐navigation allows estimation of res...