Reasons for an MRI of the Brain

The medical test magnetic resonance imaging, or MRI, uses magnetic fields, radio waves and a computer to create pictures of the brain and the tissues around it. Using MRI, doctors can see detailed images of blood flow, brain and spinal fluid, and blood vessels in the brain. In many cases, an MRI provides clearer pictures than computed tomography, another type of imaging test.

Brain Tumors

• MRI of the head often helps doctors diagnose brain tumors. Tumors, which may be benign (non-cancerous) or malignant (cancerous), usually affect adults age 35 and over, the American Brain Tumor Association reports. When undergoing an MRI for a suspected brain tumor, a patient may receive injections of a special contrast dye, designed to show abnormal areas of growth.

Brain Bleeding and Stroke

• Because brain MRIs highlight problems with blood flow, these imaging tests are often used to diagnose bleeding in the brain (also called hemorrhage) or stroke, an interruption in oxygen flow to the brain. Stroke occurs when a blood vessel in the brain bursts, flooding the area surrounding brain cells, or when a blood vessel becomes blocked. According to the National Institute for Neurological Disorders and Stroke, an MRI of the head can show brain damage for stroke within one hour of the event. However, people who wear electrical devices, such as pacemakers or cochlear implants, cannot undergo MRI. MRI of the brain also helps diagnose bleeding in the brain caused by trauma.

Abnormal Brain Development

• MRIs of the brain may also help doctors diagnose and understand problems in brain development in children. MRIs can offer clues about psychosis, obsessive-compulsive disorder, epilepsy, autism and mental retardation. MRIs of the brain also aid in the diagnosis of cephalic disorders, problems with the structural development of the brain, and arteriovenous malformations, a circulatory problem that causes blood vessels to become tangled.

Multiple Sclerosis

• Doctors suggest brain MRIs for patients with symptoms of multiple sclerosis (MS), a chronic disease that disrupts the body's nerve signals to the brain. MRIs help find brain lesions, or changes, in the nerves of the brain. Using contrast dye in conjunction with MRI, doctors may also be able to tell which lesions have developed recently, which can offer clues as to how quickly the MS is progressing. Several newer types of MRI, including magnetic resonance spectroscopy, magnetization transfer imaging, diffusion-tensor MRI and functional MRI, offer more detailed information in the diagnosis of nervous system disorders, particularly MS.

Hormonal Disorders

• Brain MRIs aid in the diagnosis of certain types of hormonal imbalances, including acromegaly (a disease that causes enlarged bones and headaches), galactorrhea (a disorder that causes breast milk flow not caused by pregnancy or childbirth) and Cushing syndrome (a disorder that causes too much production of the hormone cortisol).