Effect of respiratory motion on free‐breathing 3D stack‐of‐radial liver relaxometry and improved quantification accuracy using self‐gating

Purpose To develop an accurate free‐breathing 3D liver mapping approach and to evaluate it in vivo. Methods A free‐breathing multi‐echo stack‐of‐radial sequence was applied in 5 normal subjects and 6 patients at 3 Tesla. Respiratory motion compensation was implemented using the inherent self‐gating signal. A breath‐hold Cartesian acquisition was the reference standard. Proton density fat fraction and were measured and compared between radial and Cartesian methods using Bland‐Altman plots. The normal subject results were fitted to a linear mixed model ( P .234). For patients, Bland‐Altman plots exhibited mean differences of 14.4 and 0.1 s −1 for free‐breathing stack‐of‐radial without self‐gating and with self‐gating, respectively, but no substantial proton density fat fraction differences. Conclusion The proposed self‐gating method corrects the respiratory motion bias and enables accurate free‐breathing stack‐of‐radial quantification of liver .