What is brain MRI?
Brain MRI is a medical test used to analyze brain activity by measuring the magnetic fields produced by electrical currents in the brain. It is arguably the most advanced method of recording and analyzing a functioning brain, with advantages over similar complementary techniques. It can measure brain activity by milliseconds, giving it an advantage over fMRI scanners, and can determine where in the brain the activity is occurring more accurately than an EEG (electroencephalogram).
What is brain MRI?
Brain MRI involves the use of special equipment to measure the small magnetic fields generated by neurons firing in the brain. The scan uses a superconducting quantum interference device (SQUID) and a computer to measure this neuromagnetic activity, which superimposes the results on an anatomical image of the brain. The SQUID is highly sensitive and is housed in a magnetically shielded room to negate interference from the Earth’s magnetic field, which is a billion times stronger than those generated by the brain.
Why is brain MRI performed?
Brain MRI is performed to map brain function for diagnostic reasons. One particular use is to identify the source of epileptic seizures within the brain. It is also used in pre-operative and pre-treatment planning for people with epilepsy, brain tumors or other injuries. Brain MRI scans are also useful in research, as they help scientists understand the brain.
Preparing for brain MRI
Jewelry and accessories are not allowed in the room, as they may interfere with the test, so it may be best to leave such items at home. Patients with implants (particularly metal implants) may not be able to have the scan for the same reason. As with all medical tests and procedures, follow your physician’s instructions before and during the test.
What to expect during the test?
Brain MRI is noninvasive and is usually performed as a day case. The patient sits in a magnetically shielded room and a large helmet filled with magnetic sensors is placed on the patient’s head. It fits loosely, so claustrophobia is rarely a problem. An EEG can be performed at the same time, which will involve attaching electrodes to the patient’s scalp. You may have to perform certain actions, answer questions, look at pictures, listen to sounds or read to assess how you respond to various stimuli and identify which parts of the brain are responsible for different things. You may also be asked to sleep during the test.