Purpose
Accurate quantification of proton density fat fraction (PDFF) and \({T_2}^*\) in the supracalvicular (SCV) fossa is critical for studying brown adipose tissue (BAT), but is challenged by respiratory motion-induced \(B_0\) fluctuations. This study compares conventional Cartesian imaging to a radial stack-of-stars (SoS) trajectory, with and without retrospective temporal \(B_0\) correction, in terms of PDFF and \({T_2}^*\) mapping precision.
Methods
Motion-induced \(B_0\) fluctuations and tissue displacement were modeled using a digital anatomical phantom. Both Cartesian and radial SoS trajectories were simulated, with temporal \(B_0\) 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 \({T_2}^*\) were quantified across repetitions.
Results
Simulations demonstrated smaller PDFF and \({T_2}^*\) 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 \({1.07\,\mathrm{\%}}_\textrm{PDFF}\) with Cartesian to \({0.47\,\mathrm{\%}}_\textrm{PDFF}\) with radial SoS, and the \({T_2}^*\) 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 \(B_0\) correction further improved the repeatability of \({T_2}^*\) quantification.
Conclusions
Radial SoS imaging improves motion robustness and repeatability of PDFF and \({T_2}^*\) quantification in the SCV fossa compared to Cartesian acquisitions. Incorporating retrospective temporal \(B_0\) correction further enhances \({T_2}^*\) reliability and may strengthen the precision of BAT activation studies.
