MRI is a type of scan which does detailed imaging of a person’s deeper tissues. Although ultrasound and CT scan are more common, MRI can help doctors generate higher definition images of the human body. It is used to detect, diagnose or determine the treatment progress of a number of conditions like stroke, spinal cord or brain injury and tumor. It works by aligning the hydrogen nuclei or protons that make up the water in the living tissues of the body to the magnetic field created by the MRI scanner. When the protons return to their normal spin, they create a radio signal that can be turned into an image of the part of the body that needs to be investigated. The biggest advantage that an MRI has over a CT scan or an X-Ray is that it does not use harmful radiation to obtain results. It is, however, more expensive than other kinds of scans.
During an MRI scan, a person is made to lie on a movable table and slid into a dome-like structure. The MRI technician will speak via the intercom to ensure the person is comfortable. When the radio waves are directed to one’s body, one will hear a loud rhythmic thumping. One will be given cotton strips or earplugs to block the sound. One must stay as still as possible as movement will blur the image. Contrast agents are sometimes given intravenously before the person goes in for an MRI scan in order to obtain brighter images. The experience can be slightly claustrophobic if one is afraid of confined spaces. Some people experience a twitching sensation when the nerves are stimulated by the magnetic field. The scan might take from 20 minutes to an hour.
The strong magnetic field created by the MRI can be dangerous if a person with any kind of metal implants undergoes the scan. Hence, it is important to inform the radiologist if one has anything from pacemakers to cochlear implants. Other kinds of objects that should be kept away from an MRI scanner include vagus nerve stimulators, implantable defibrillators, insulin pumps and deep brain stimulators. One also needs to remove any kind of metal jewellery or accessories before undergoing an MRI scan. Although bracings and fillings are not dangerous, they might affect the quality of the image. Sometimes additional images may be required.
