Brain MRI - Benefits and Risks
MRI may require you to receive an injection of contrast into the vein of your arm. The radiologist or technologist may ask if you have asthma or if you have allergies such as allergy to iodine or x-ray contrast material, to drugs, to food, or to the environment.
However, the contrast material used for an MRI exam, called gadolinium, does not contain iodine and is less likely to cause an allergic reaction than iodine containing contrast used for a CT exam.
Your radiologist should also know if you have any serious health problems and what surgeries you have undergone. Some conditions, such as severe kidney or liver disease may prevent you from receiving contrast material during an MRI exam.
Benefits
- MRI is a noninvasive imaging technique that does not involve exposure to ionizing radiation.
- MRI can help physicians evaluate both the structure of an organ and how it is working.
- MRI enables the discovery of abnormalities that might be obscured by bone with other imaging methods.
- Even without using contrast material, MRI can provide high-quality images of many blood vessels, making it very useful for patients prone to allergic reactions or with reduced kidney function.
- The contrast material used in MRI exams is less likely to produce an allergic reaction than the iodine-based contrast materials used for conventional x-rays and CT scanning.
Risks
- The MRI examination poses almost no risk to the average patient when appropriate safety guidelines are followed.
- If sedation is used, there are risks of excessive sedation. The technologist or nurse monitors your vital signs to minimize this risk.
- Although the strong magnetic field is not harmful in itself, implanted medical devices that contain metal may malfunction or cause problems during an MRI exam.
- There is a very slight risk of an allergic reaction if contrast material is injected. Such reactions usually are mild and easily controlled by medication. If you experience allergic symptoms, a radiologist or other physician will be available for immediate assistance.
- Nephrogenic systemic fibrosis is currently a recognized, but rare, complication of MRI believed to be caused by the injection of high doses of gadolinium contrast material in patients with very poor kidney function.
