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^* T 2 ∗ in the supracalvicular (SCV) fossa is critical for studying brown adipose tissue (BAT), but is challenged by respiratory motion-induced B₀ B 0 fluctuations. This study compares conventional Cartesian imaging to a radial stack-of-stars (SoS) trajectory, with and without retrospective temporal B₀ B 0 correction, in terms of PDFF and T₂^* T 2 ∗ mapping precision. Methods Motion-induced B₀ B 0 fluctuations and tissue displacement were modeled using a digital anatomical phantom. Both Cartesian and radial SoS trajectories were simulated, with temporal B₀ B 0 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^* T 2 ∗ were quantified across repetitions. Results Simulations demonstrated smaller PDFF and T₂^* T 2 ∗ 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 1.07 % PDFF with Cartesian to 0.47\,%PDFF 0.47 % PDFF with radial SoS, and the T₂^* T 2 ∗ 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