Data From: B1 Field inhomogeneity correction for qDESS T2 mapping: application to rapid bilateral knee imaging

<p><strong>Purpose</strong>: T2&nbsp;mapping is a powerful tool for studying osteoarthritis (OA) changes and bilateral imaging may be useful in investigating the role of between-knee asymmetry in OA onset and progression. The quantitative double-echo in steady-state (qDESS) can provide fast simultaneous bilateral knee T2&nbsp;and high-resolution morphometry for cartilage and meniscus.<br> The qDESS uses an analytical signal model to compute T2&nbsp;relaxometry maps, which require knowledge of the flip angle (FA).&nbsp;<br> In the presence of B1&nbsp;inhomogeneities, inconsistencies between the nominal and actual FA can affect the accuracy of T2&nbsp;measurements.<br> We propose a pixel-wise B1&nbsp;correction method for qDESS T2&nbsp;mapping exploiting an auxiliary B1&nbsp;map to compute the actual FA used in the model.<br> &nbsp;<br> <strong>Methods</strong>:&nbsp;The technique was validated in a phantom and in vivo with simultaneous bilateral knee imaging.&nbsp;<br> T2&nbsp;measurements of femoral cartilage (FC) of both knees of six healthy participants were repeated longitudinally to investigate the association between T2&nbsp;variation and B1.</p> <p><strong>Results</strong>:&nbsp;The results showed that applying the B1&nbsp;correction mitigated T2&nbsp;variations that were driven by B1&nbsp;inhomogeneities.&nbsp;<br> Specifically, T2&nbsp;left-right symmetry increased following the B1&nbsp;correction (rc&nbsp;= 0.74 &gt;&nbsp;rc&nbsp;= 0.69). Without the B1&nbsp;correction, T2&nbsp;values showed a linear dependence with B1. The linear coefficient decreased using the B1&nbsp;correction (from 24.3 <span class="math-tex">\(\pm\)</span>&nbsp;1.6 ms to 4.1 <span class="math-tex">\(\pm\)</span>&nbsp;1.8) and the correlation was not statistically significant after the application of the Bonferroni correction (p-value &gt;&nbsp;0.01).<br> &nbsp;<br> <strong>Conclusion</strong>:&nbsp;the study showed that B1 correction could mitigate variations driven by the sensitivity of the qDESS T2&nbsp;mapping method to B1, therefore increasing the sensitivity to detect real biological changes. The proposed method may improve the robustness of bilateral qDESS T2&nbsp;mapping, allowing for an accurate and more efficient evaluation of OA pathways and pathophysiology through longitudinal and cross-sectional studies.</p> <p><strong>This repository contains the raw data for reproducing the&nbsp;results reported in the paper. The data are provided in NIFTI format. The repository also contains the MALTAB&nbsp;scripts used to compute B₁ maps from the NIFTI data.</strong></p>