Motion-robust proton density fat fraction and T2∗ mapping in supraclavicular adipose tissue using radial stack-of-stars imaging

Purpose: Accurate quantification of proton density fat fraction (PDFF) and T2∗ in the supracalvicular (SCV) fossa is critical for studying brown adipose tissue (BAT), but is challenged by respiratory motion-induced B0 fluctuations. This study compares conventional Cartesian imaging to a radial stack-of-stars (SoS) trajectory, with and without retrospective temporal B0 correction, in terms of PDFF and T2∗ mapping precision. Methods: Motion-induced B0 fluctuations and tissue displacement were modeled using a digital anatomical phantom. Both Cartesian and radial SoS trajectories were simulated, with temporal B0 correction, relying on oversampling of the k-space center, applied to the radial SoS data. Additionally, repeated in vivo scans were performed in four volunteers using both trajectories. PDFF and T2∗ were quantified across repetitions. Results: Simulations demonstrated smaller PDFF and T2∗ errors in radial SoS compared to Cartesian imaging under the influence of simulated motion effects. In the simulations, the mean absolute PDFF error decreased from 1.07%PDFF with Cartesian to 0.47%PDFF with radial SoS, and the T2∗ error decreased from 7.50 ms to 3.37 ms. In vivo, radial SoS provided higher repeatability for both parameters compared to Cartesian acquisitions, as measured by the inter-scan coefficient of variation. Retrospective temporal B0 correction further improved the repeatability of T2∗ quantification. Conclusions: Radial SoS imaging improves motion robustness and repeatability of PDFF and T2∗ quantification in the SCV fossa compared to Cartesian acquisitions. Incorporating retrospective temporal B0 correction further enhances T2∗ reliability and may strengthen the precision of BAT activation studies.