What Are MRI Scans And What Are They For?
MRI (Magnetic Resource Imaging) scans are one of the most widely used diagnostic radiology techniques in existence today. They use magnetism, radio waves and computers to produce images of a body’s internal structures. The technique goes back to 1952 when Herman Carr produced a one-dimensional MRI image for inclusion in his Harvard PhD thesis. Since then it has been refined and become more sophisticated so that today MRI machines are used to detect disease throughout the body.
In the head, for example, they can be used to detect trauma to the brain seen through bleeding and swelling. They can also evaluate damage to the spinal cord after injury, detect problems with the heart or aorta and provide valuable information on the structure of the joints, soft tissues and bones. The results of an MRI scan can help doctors and surgeons make vital decisions on the need for surgery, or other appropriate forms of treatment. It is particularly useful for imaging the brain, muscles, heart and cancers because it provides a strong contrast between the different soft tissues within the body.
If it is decided that a patient needs an MRI scan then they have to be properly prepared beforehand. To begin with, all metallic objects on the body (piercings, jewellery etc) have to be removed so they don’t interfere with the magnetic field. If the patient is particularly anxious about the procedure or the possible diagnosis then they may also be given a sedative injection to help calm them down. This is important because, for the MRI scan to be successful, the subject has to lie as still as possible and breathe normally – things that might be difficult if they are not relaxed enough.
MRI machines are large enough to enclose an entire human body. To have their scan, the patient will be inserted into an enclosed environment containing a large, powerful magnet. The magnetic field is used to align the magnetisation of atomic nuclei in the body. The operator of the scanner will maintain communication with the patient throughout the procedure to keep them relaxed. As the scan is carried out there will be repetitive clicking noises. Intravenous contrast injections may also be injected, if necessary, to enhance the quality of the images. The time taken to complete the scan can range from 30 minutes to an hour and a half, depending on the area of the body it is focused on.
An MRI scan is totally painless for the patient and also has the advantage of avoiding radiation exposure through x-rays. However, whilst there are no known side effects to this procedure, there are certain minor risks associated with it. For example, if patients have metallic elements inside their body such as pacemakers, steel plates or metal clips in or around the eyeballs then they cannot be scanned using an MRI because of the possibility that the magnet might move or interfere with these. Another minor risk is the possibility that a patient with claustrophobic tendencies might panic within the machine and disrupt the process. They should inform the practitioner of this beforehand so they can administer a sedative, as mentioned above, if necessary.
Once the scan is completed, the patient will need to wait to obtain the results, which shouldn’t usually take long. A radiologist will need to look through the visual images of the scan to interpret the result. They will then compile a report to pass on to the practitioner, detailing findings and possible diagnoses. Once this has been completed, the practitioner can discuss the findings with their patient and think about their treatment options.
In future, MRI scanners may come to be smaller and therefore more portable and also possibly less intimidating for those of a nervous disposition. Newer scanners may also have greater scope for identifying other kinds of infections or tumours of the soft tissues in the hands, feet etc. – something the current technologies are not particularly suited to.
Summary: MRI scans are arguably one of the most important medical developments of the last century, allowing doctors to examine the international workings of the body and make more accurate diagnoses. This article looks briefly at how they work and in which situations they are used.