Quantifying Fetal Vertebral Body Calcium Changes Using Quantitative Susceptibility Mapping

In vivo fetal vertebral calcium content was quantified using local quantitative susceptibility mapping (QSM) collected as part of a STAGE double flip angle (FA) protocol. A strong decreasing average vertebral susceptibility as a function of gestational age was seen in 54 normal fetuses including 37 cases with QSM data available at both FA’s and 17 cases with QSM at one FA totaling 91 independent datasets. An almost one-to-one linear correlation was seen between the QSM values from both FA’s. These results provide strong evidence of an in vivo MR-based quantitative technique to measure calcium development pre-term.