Background Cardiovascular magnetic resonance (CMR) flow quantification for determining the ratio of flow between the pulmonary and systemic circulation (Qp/Qs) is used to quantify cardiac shunts. However, both the accuracy and precision of Qp/Qs can be influenced by measurement errors in flow quantification. Post-processing methods for stationary tissue background correction have been proposed to improve flow quantification accuracy. We sought to evaluate the changes in accuracy and precision of Qp/Qs following stationary tissue background correction. We hypothesized that stationary background correction would reduce the standard deviation (SD) of mean Qp/Qs compared to uncorrected measurements in clinical patients without cardiac shunts.