Information gleaned from Hepatic Venous Oxygen Saturation (ShvO2) can be beneficial in the post-operative care of those who have undergone a partial hepatectomy. Previously this has been performed invasively. We hypothesise that Quantitative Susceptibility Mapping (QSM) can do so non-invasively. The ShvO2 of a healthy cohort of mice was manipulated with a hyperoxic gas challenge. Susceptibility was measured under normoxic and hyperoxic conditions, and ShvO2 was calculated from the measurements. Significant differences were measured in susceptibility and ShvO2 in response to the gas challenge. We conclude that QSM can non-invasively measure changes in ShvO2 in the pre-clinical liver in-vivo.