Validation of liver quantitative susceptibility mapping across imaging parameters at 1.5 T and 3.0 T using SQUID susceptometry as reference

PURPOSE: To validate QSM‐based biomagnetic liver susceptometry (BLS) to measure liver iron overload at 1.5 T and 3.0 T using superconducting quantum interference devices (SQUID)‐based BLS as reference. METHODS: Subjects with known or suspected iron overload were recruited for QSM‐BLS at 1.5 T and 3.0 T using eight different protocols. SQUID‐BLS was also obtained in each subject to provide susceptibility reference. A recent QSM method based on data‐adaptive regularization was used to obtain susceptibility and [Formula: see text] maps. Measurements of susceptibility and [Formula: see text] were obtained in the right liver lobe. Linear mixed‐effects analysis was used to estimate the contribution of specific acquisition parameters to QSM‐BLS. Linear regression and Bland–Altman analyses were used to assess the relationship between QSM‐BLS and SQUID‐BLS/ [Formula: see text]. RESULTS: Susceptibility maps showed high subjective quality for each acquisition protocol across different iron levels. High linear correlation was observed between QSM‐BLS and SQUID‐BLS at 1.5 T (r (2) range, [0.82, 0.84]) and 3.0 T (r (2) range, [0.77, 0.85]) across different acquisition protocols. QSM‐BLS and [Formula: see text] were highly correlated at both field strengths (r (2) range at 1.5 T, [0.94, 0.99]; 3.0 T, [0.93, 0.99]). High correlation (r (2) = 0.99) between 1.5 T and 3.0 T QSM‐BLS, with narrow reproducibility coefficients (range, [0.13, 0.21] ppm) were observed for each protocol. CONCLUSION: This work evaluated the feasibility and performance of liver QSM‐BLS across iron levels and acquisition protocols at 1.5 T and 3.0 T. High correlation and reproducibility were observed between QSM‐BLS and SQUID‐BLS across protocols and field strengths. In summary, QSM‐BLS may enable reliable and reproducible quantification of liver iron concentration.