Using a multi-echo gradient echo sequence to calculate R2* and quantitative susceptibility maps and well as susceptibility-weighted imaging post processing the investigators hypothesize that the investigators would be able to distinguish between pseudoprogression and true progression with the use of an easily implementable sequence on clinical MRI scanners.

Post-treatment radiographic imaging change (PTRIC) is seen in approximately 50% of patients who are treated for brain neoplasms using chemotherapy and radiotherapy. PTRIC can be attributed to true disease progression or a form of benign radiographic enhancement, known in literature as pseudoprogression. Of these patients, 50% of them have benign radiographic enhancement that is usually spontaneously resolved and required no intervention. The other 50% require immediate medical intervention, or more aggressive treatment for true progression. Currently standard medical practise is to administer a prophylactic treatment of chemotherapy to all patients with PTRIC with a follow up scan 3-6 months after initial PTRIC diagnosis, leading to up to 50% of patients receiving an unneeded dose of chemotherapy. The investigators hope to take advantage of the differentiation in tissue types and vascularization between true progression tumour and pseudoprogression to be able to identify patients who would not need to be administered a prophylactic dose of chemotherapy.

Inclusion Criteria:

1. The subject must consent to participate.
2. The subject must be above the age of 18.
3. Patients must be classified as possible pseudoprogression or true progression
4. Patients scoring >= 70 on the karnofsky performance status.

Exclusion Criteria:

1. Any subject with contraindication to an MRI procedure as listed in the Magnetic Resonance Environment Screening Questionnaire.
2. Any subject who may be unable to tolerate the MRI environment due to physical size and/or known tendency to claustrophobia.
3. Any subject who does not expect to be available to attend the for the required study MRI scans
4. Patients scoring < 70 on the karnofsky performance status.
5. Attending radiation oncologist or neurologist determines patient is no longer able to consent for themselves.

Patients who have had treatment for brain neoplasms treated with radiation and/or chemotherapy who presents with post-treatment imaging changes on the MRI following treatment.