Editing Brain tumor (section)

==== Other Types of Imaging Techniques ====
'''Computed Tomography (CT) Scan'''{{snd}} uses x-rays to take pictures from different angles and computer processing to combine the pictures into a 3D image. A CT scan usually serves as an alternative to MRI in cases where the patient cannot have an MRI due to claustrophobia or pacemaker. Compared to MRI, a CT scan shows a more detailed image of the bone structures near the tumor and can be used to measure the tumor's size.<ref name=":8">{{Cite web |title=Tests for Brain and Spinal Cord Tumors in Adults |url=https://www.cancer.org/cancer/brain-spinal-cord-tumors-adults/detection-diagnosis-staging/how-diagnosed.html |access-date=2022-11-28 |website=cancer.org |language=en}}</ref> Like an MRI, a contrast dye may also be injected into the veins or ingested by mouth before a CT scan to better outline any tumors that may be present. CT scans use contrast materials that are iodine-based and barium sulfate compounds. The downside of using CT scans as opposed to MRI is that some brain tumors do not show up well on CT scans because some intra-axial masses are faint and resemble normal brain tissue. In some scenarios, brain tumors in CT scans may be mistaken for infarction, infection, and demyelination. To suspect that an intra-axial mass is a brain tumor instead of other possibilities, there must be unexplained calcifications in the brain, preservation of the cortex, and disproportionate mass effect.<ref>{{Cite web |title=Recognizing intra-axial tumors on brain computed tomography (CT) {{!}} Medmastery |url=https://public-nuxt.frontend.prod.medmastery.io/guides/brain-ct-clinical-guide/recognizing-intra-axial-tumors-brain-computed-tomography-ct-and |access-date=2022-11-28 |website=public-nuxt.frontend.prod.medmastery.io |language=en}}</ref>

'''CT Angiography (CTA)'''{{snd}} provides information about the blood vessels in the brain using X-rays. A contrast agent is always required to be injected into the patient in the CT scanner. CTA serves as an alternative to MRA.

'''Positron Emission Tomography (PET) Scan'''{{snd}} uses radiolabelled substances, such as [[Fluorodeoxyglucose|FDG]] which taken up by cells that are actively dividing. Tumor cells are more actively dividing so they would absorb more of the radioactive substance. After injection, a scanner would be used to create an image of the radioactive areas in the brain. PET scans are used more often for high-grade tumors than for low-grade tumors. It is useful after treatment to help doctors determine if the abnormal area on an MRI image is a remaining tumor or a scar tissue. Scar tissues will not show up on PET scans while tumors would.<ref name=":8" />