Passing electricity through gradient coils, which also cause the coils to vibrate, creates the magnetic field, causing a knocking sound inside the scanner.Īlthough the patient cannot feel these changes, the scanner can detect them and, in conjunction with a computer, can create a detailed cross-sectional image for the radiologist. The second magnetic field is then turned on and off in a series of quick pulses, causing each hydrogen atom to change its alignment when switched on and then quickly switch back to its original relaxed state when switched off.

Normally, the water molecules in the body are randomly arranged, but on entering an MRI scanner, the first magnet causes the water molecules to align in one direction, either north or south. At the center of each atom lies an even smaller particle called a proton, which serves as a magnet and is sensitive to any magnetic field. The human body is largely made of water molecules, which are comprised of hydrogen and oxygen atoms. These are the most important parts of the equipment. Share on Pinterest MRI scans work by rearranging water molecules in the body with magnets.Īn MRI scanner contains two powerful magnets. The latter is popular with children, as they can listen to music to calm any anxiety during the procedure. Staff will ensure that they are as comfortable as possible by providing blankets or cushions.Įarplugs or headphones will be provided to block out the loud noises of the scanner. Once the patient has entered the scanning room, the doctor will help them onto the scanner table to lie down. The radiologist, a doctor who specializes in medical images, will then talk the individual through the MRI scanning process and answer any questions they may have about the procedure. Patients will sometimes receive an injection of intravenous (IV) contrast liquid to improve the visibility of a particular tissue that is relevant to the scan. Often they can be given medication prior to the MRI to help make the procedure more comfortable. Individuals who are anxious or nervous about enclosed spaces should tell their doctor. This can also include medical devices, such as cochlear implants, aneurysm clips, and pacemakers. The doctor will ask the patient to remove any metal jewellery or accessories that might interfere with the machine.Ī person will probably be unable to have an MRI if they have any metal inside their body, such as bullets, shrapnel, or other metallic foreign bodies. As magnets are used, it is critical that no metal objects are present in the scanner. On arrival at the hospital, doctors may ask the patient to change into a gown. There is very little preparation required, if any, before an MRI scan. Share on Pinterest A person can listen to music in headphones to mask the loud and sometimes alarming sound of the MRI machine.

Medtronic clearview mri