Early imaging methods – invasive and sometimes dangerous – such as pneumoencephalography and cerebral angiography have been abandoned in favor of non-invasive, high-resolution techniques, especially magnetic resonance imaging (MRI) and computed tomography (CT) scans, though MRI is typically the reference standard used. Neoplasms will often show as differently colored masses (also referred to as processes) in CT or MRI results. Benign brain tumors often show up as hypodense (darker than brain tissue) mass lesions on CT scans. On MRI, they appear either hypodense or isointense (same intensity as brain tissue) on T1-weighted scans, or hyperintense (brighter than brain tissue) on T2-weighted MRI, although the appearance is variable. Contrast agent uptake, sometimes in characteristic patterns, can be demonstrated on either CT or MRI scans in most malignant primary and metastatic brain tumors. Pressure areas where the brain tissue has been compressed by a tumor also appear hyperintense on T2-weighted scans and might indicate the presence a diffuse neoplasm due to an unclear outline. Swelling around the tumor known as peritumoral edema can also show a similar result.This is because these tumors disrupt the normal functioning of the BBB and lead to an increase in its permeability. More recently, advancements have been made to increase the utility of MRI in providing physiological data that can help to inform diagnosis and prognosis. Perfusion Weighted Imaging (PWI) and Diffusion Weighted Imaging (DWI) are two MRI techniques that reviews have been shown to be useful in classifying tumors by grade, which was not previously viable using only structural imaging.
Over 2018, it was projected that there would be 23,880 new cases of brain tumors and 16,830 deaths in 2018 as a result, accounting for 1.4 percent of all cancers and 2.8 percent of all cancer deaths. Median age of diagnosis was 58 years old, while median age of death was 65. Diagnosis was slightly more common in males, at approximately 7.5 cases per 100 000 people, while females saw 2 fewer at 5.4. Deaths as a result of brain cancer were 5.3 per 100 000 for males, and 3.6 per 100 000 for females, making brain cancer the 10th leading cause of cancer death in the United States. Overall lifetime risk of developing brain cancer is approximated at 0.6 percent for men and women. UK
Brain, other CNS or intracranial tumors are the ninth most common cancer in the UK (around 10,600 people were diagnosed in 2013), and it is the eighth most common cause of cancer death (around 5,200 people died in 2012). White British patients with brain tumour are 30% more likely to die within a year of diagnosis than patients from other ethnicities. The reason for this is unknown. Children
In the United States more than 28,000 people under 20 are estimated to have a brain tumor. About 3,720 new cases of brain tumors are expected to be diagnosed in those under 15 in 2019. Higher rates were reported in 1985–1994 than in 1975–1983.