Arterial spin labelling (ASL) MRI is a non-invasive method for the quantitation of blood flow by imaging the effects of in-flowing magnetically tagged blood on tissue water in a region of interest. In 2015, guidelines for clinical use of ASL were proposed, however, these were still lacking in pre-clinical settings. Moreover, dysregulated cerebral blood flow is a component of many diseases including brain tumours. Therefore, our initial aims were to optimise pre-clinical ASL in rats to obtain quantitative measurements of cerebral blood flow and to apply this methodology to a model of brain metastasis to examine the perfusion changes that occur in this disease setting. Additionally, we wished to determine if ASL could be used as an alternative to dynamic contrast enhanced (DCE) MRI in assessing treatment outcome with vascular normalising agents such as bevacizumab (Avastin®), as it requires no exogenous contrast agents.