Magnetic resonance imaging (MRI) of the brain uses a magnetic field, radio waves and a computer to create a detailed image of the complex structure of brain tissues. For a Brain MRI, the head is scanned with the help of an MRI machine. A Brain MRI gives a clear and detailed cross sectional image of the brain area giving a three-dimensional depiction of the brain. These cross sectional images can be projected and stored in a computer or printed on a film. Since Brain MRIs produce better soft tissue images than X-ray reports and can distinguish between the grey matter and the white matter of the brain, they help in locating defects in the brain tissues like, tumors, pituitary masses, radiation damage to the brain, brain swelling, abnormalities of blood flow, optic glioma and brain aneurysm more accurately and precisely. MRI has been able to identify lesions in brain in about 95% of patients as compared to the CT scan that identified lesions in about 25% of the patients. An MRI technique called diffusion/perfusion is used for scanning the brain and helps to detect a brain stroke within minutes of onset, allowing for earlier treatment.
Unlike x-rays, which are harmful to the brain, MRIs are a safer option for brain scanning because of no significant side effects. Gradient magnets are used to alter the magnetic field in the area that has to be scanned while the magnetic force is being applied. Brain MRI helps the technician to concentrate on the exact area of the patient’s brain they want to scan.
A new study has evolved where Brain MRIs are now being widely used for polygraph tests as well as to identify if a person is lying. It does so by tracking the flow of blood into certain areas of the brain, indicating increased activity of lying.