Finding an inexpensive fiducial surface marker for use in magnetic resonance imaging in both the clinical and research settings

A fiducial marker displays on an image as a distinct high intensity region to pinpoint specific landmarks and pathologies as well as allowing images from different sources to be registered against each other. While commercial markers are clearly visualised in magnetic resonance images (MRI), they are expensive and typically single use, making the cost of research requiring multiple markers prohibitive. We assessed various ‘everyday’ items, to find a reliable alternative to commercial surface fiducial markers. Depending on the MRI sequence required, four alternative cheap and easily sourced markers were determined. The fish oil capsule is already commonly used in clinical MRI departments but the capsule is too large for some applications and is a rupture risk under body weight. Ultimately, the Vitamin D capsule provided an excellent balance between availability, size, cost, usability and quality of visualisation for all the common MRI sequences analysed.