Q. What types of brain scans or neuroimaging tests are there?

A. There are two main types of neuroimaging tests: structural and functional. Structural imaging creates a “snapshot” of the brain’s structure, including bone, tissue, blood vessels, tumors, infection, damage, or bleeding, such as from a stroke. Functional imaging reveals the brain’s ever-changing activity and chemistry by measuring the rate of blood flow, chemical activity, and electrical impulses in the brain during specific tasks.

Q. Are there risks associated with brain scans?

A. Brain scans are relatively safe and do not cause any pain. However, risks include exposure to magnetic fields and radiation. Safety measures are used to limit these risks, such as using the lowest possible radiation or magnetic level to do the scan. Children and teens may be more sensitive to these risks. If your child needs a brain scan, ask if there are special precautions you can take or whether a different type of brain scan can be used. Ask the doctor doing the scan if the machine’s settings have been adjusted for a child. Women who are pregnant or breastfeeding should also talk with their doctor about how to prepare for any type of brain scan. While most types of scans pose little risk to the developing fetus, the doctor may make different recommendations to accommodate pregnancy. Another possible risk is claustrophobia or a fear of small spaces. Many brain-scanning machines look like large tubes or giant “donuts” that are open on both ends. The machines can be very loud while scanning takes place. Some people feel scared or nervous when inside the machines. Sometimes.