Separation of Diamagnetic and Paramagnetic Susceptibility Sources in Liver Using DECOMPOSE-QSM

Quantitative susceptibility mapping (QSM) enables noninvasive assessment of liver iron based on its paramagnetic properties. However, the paramagnetic contribution of iron can be confounded by the competing diamagnetic sources within the same voxel, particularly collagen in fibrotic tissue. Magnetic source separation techniques can disentangle these opposing susceptibility effects within a voxel, potentially enabling independent detection of iron and collagen. In this study, we conducted an initial evaluation of DECOMPOSE-QSM using abdominal multi-echo MRI data from a small patient cohort with normal to moderate liver iron overload (N = 19) and varying degrees of fibrosis (N = 3). Source-separated paramagnetic susceptibility showed a stronger correlation with liver iron concentration (R² = 0.86, p < 0.05), whereas conventional QSM exhibited a weaker correlation (R² = 0.28, p = 0.08) in patients with normal to moderate iron overload. Furthermore, preliminary results in a small fibrotic cohort demonstrated that source-separated diamagnetic susceptibility exhibit trends comparable to conventional QSM, suggesting that the method preserves sensitivity to fibrosis-related tissue components.