MRI: contrast agent
All content is checked by medical journalists.MRI contrast media can sometimes show the relevant structures better on cross-sectional images of the body and delimit them more clearly from other tissues. The doctor usually administers such a contrast medium through an access on the arm or in the groin. Read here which contrast media are used and the risks involved in contrast media MRI.
When is an MRI contrast agent necessary?
An MRI without a contrast agent is largely risk-free, but not sufficient for all issues. The use of contrast media makes sense whenever the tissue in question appears in similar gray levels. This is the case, for example, when examining suspicious foci in the spleen, pancreas or liver or when investigating tumors and metastases. Areas with poor blood circulation can also be found by administering contrast medium, for example scarring or blocked blood vessels after a stroke.
Contrast media used in MRI
Substances containing gadolinium, iron oxides and manganese compounds are often used for an MRI with contrast agent. While gadolinium can only be administered through a vein, the patient can also drink the other two substances. This is particularly useful when examining the gastrointestinal tract.
MRI contrast media: side effects
In healthy patients, MRI contrast agents usually cause only mild side effects such as:
- Warmth, cold or tingling sensation
- Headache
- general malaise
- Skin irritation
In some cases, MRI contrast agents also cause allergic reactions.
However, some people do not tolerate the contrast agent administered so well. These are mainly patients with impaired kidney function. They excrete the contrast medium poorly. For this reason, the doctor always checks the patient's kidney function before administering contrast medium.
In the case of existing kidney weakness, so-called nephrogenic systemic fibrosis (NSF) can occur in rare cases when gadolinium-containing contrast media are administered. This connective tissue disease is characterized by an increase in connective tissue in the skin, joints or internal organs. Gadolinium can also be deposited in certain areas of the brain. This can lead to secondary symptoms such as pain or abnormal sensations.
A reassessment of the safety profile is a controversial issue among experts. The contrast media gadobutrol, gadoteric acid and gadoteridol are currently still in use, but with the recommendation to use them in the lowest dose. In the interests of patient safety, doctors decide on the use of gadolinium-containing contrast media after weighing the risks and benefits on a case-by-case basis.
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