Development of a quantitative BOLD phantom for validation of acquisition strategies.

A phantom to produce R2' (reversible transverse relaxation rate) contrast was developed by inducing subvoxel magnetic susceptibility variations that mimic the quantitative Blood Oxygenation Level Dependant (qBOLD) MRI signal. Microscopic glass bubbles were used for this purpose and offer a cheaper option for making large volume phantoms than existing phantoms that use precision polystyrene microspheres. A linear relationship between R2' and the glass bubble volume fraction was found. Comparisons of multiparametric qBOLD acquisitions between two MR vendors were also made. In the future, phantoms such as this could facilitate quality assurance for qBOLD acquisition strategies and assist with multicentre harmonization.