The objectives of the study are (1) to evaluate the feasibility of using a combined spin- and gradient- echo (SAGE) sequence in dynamic susceptibility contrast magnetic resonance imaging (DSC MRI) and (2) to determine quantitative estimates of vessel density and size to differentiate between areas of radiation necrosis and tumor recurrence.

Inclusion Criteria:

• Diagnosed with a brain metastasis or primary brain tumour and who will undergo MRI with contrast.

Exclusion Criteria:

• Subject or subject's legally authorized representative is unable or unwilling to consent to the study.
• Subject with documented contrast medium injection contraindication due to severe kidney disease or allergy.