MRI‐based quantitative susceptibility mapping (QSM) and R2* mapping of liver iron overload: Comparison with SQUID‐based biomagnetic liver susceptometry

Purpose We aimed to determine the agreement between quantitative susceptibility mapping (QSM)‐based biomagnetic liver susceptometry (BLS) and confounder‐corrected R2* mapping with superconducting quantum interference device (SQUID)‐based biomagnetic liver susceptometry in patients with liver iron overload. Methods Data were acquired from two healthy controls and 22 patients undergoing MRI and SQUID‐BLS as part of routine monitoring for iron overload. Magnetic resonance imaging was performed on a 3T system using a three‐dimensional multi‐echo gradient‐echo acquisition. Both magnetic susceptibility and R2* of the liver were estimated from this acquisition. Linear regression was used to compare estimates of QSM‐BLS and R2* to SQUID‐BLS. Results Both QSM‐BLS and confounder‐corrected R2* were sensitive to the presence of iron in the liver. Linear regression between QSM‐BLS and SQUID‐BLS demonstrated the following relationship: QSM‐BLS = (−0.22 ± 0.11) + (0.49 ± 0.05) · SQUID‐BLS with r 2 = 0.88. The coefficient of determination between liver R2* and SQUID‐BLS was also r 2 = 0.88. Conclusion We determined a strong correlation between both QSM‐BLS and confounder‐corrected R2* to SQUID‐BLS. This study demonstrates the feasibility of QSM‐BLS and confounder‐corrected R2* for assessing liver iron overload, particularly when SQUID systems are not accessible. Magn Reson Med 78:264–270, 2017. © 2016 International Society for Magnetic Resonance in Medicine