Multi -paramEtric Imaging to Assess Treatment REsponse After Stereotactic Radiosurgery of Brain Metastases

After stereotactic radiosurgery (SRS) of brain metastases, patients undergo a standard brain magnetic resonance imaging (MRI) to assess treatment response 12 weeks after completion of treatment. The interpretation of this standard MRI can sometimes be challenging as it can be difficult to differentiate tumour getting bigger/returning (progression/recurrence) from expected radiotherapy treatment-related changes known as radionecrosis. This study is a pilot brain imaging study that is investigating if readily available forms of imaging such as contrast-clearance analysis MRI (also known as TRAMs) and/or 18 Fluoromethyl-choline positron emission tomography/computerised tomography (18F-choline PET/CT) are equivalent to multi-parametric MRI in their ability to differentiate tumour from radionecrosis. Multi-parametric MRI has the most evidence for its ability to discriminate tumour from radionecrosis but is resource intensive and not routinely available in most centres.