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The use of the so-called Magnetic resonance imaging is a concern for some patients. They wonder about the harmfulness or possible side effects of administering such substances. Today, we dispel all doubts and explain what the contrast in magnetic resonance imaging is, when it is used and what are the possible complications after its administration.
What is Magnetic Resonance Imaging?
Magnetic resonance imaging is one of the imaging methods in which an image of the inside of the patient’s body is obtained without disturbing its tissues. Therefore, it is an important element in the diagnosis of many diseases. The principle of this method is as follows: the MRI device has a strong magnet. Its use causes the hydrogen and oxygen atoms of the patient’s water to become magnetized. Then they are exposed to radio waves. They then enter a temporary excited state.
During the return to the initial state, the emission of electromagnetic waves by previously excited particles occurs. These waves have the same frequency as the previously used radio waves, and this phenomenon is called magnetic resonance. The waves emitted by molecules in the tissues are read by special sensors, from which the data is interpreted by a computer program. Then the test results are presented in the form of a series of images on the computer screen.
What is MRI contrast and when is it used?
A contrast agent is a substance that has the ability to temporarily accumulate in human tissues, affecting their ability to emit radio waves. Depending on the needs, the doctor can administer both agents that will increase the clarity of the image of a given tissue or organ in the magnetic resonance image, and suppress their visibility to make it easier to see others. MRI contrast is used in the diagnosis of diseases such as:
- nervous system diseases, e.g. multiple sclerosis, Alzheimer’s disease, Parkinson’s disease, stroke,
- numerous neoplastic diseases, especially of the brain and spinal cord, lungs, genital organs of men and women and others,
- cardiovascular disease, for example some forms of coronary artery disease, where cheaper imaging methods have not produced conclusive results
- injuries of muscles, bones and joints.
Is MRI with contrast harmful?
There are many myths and misunderstandings about MRI contrast. Some people believe that contrast agents are dangerous to health and look for ways to flush the contrast out of the body after the examination. However, this is a greatly exaggerated approach. For most people, the contrast does not pose any health risk. People with thyroid problems, such as an overactive thyroid gland, sometimes fear whether the iodine contained in the contrast will disturb its functioning. They do not know, however, that it is present in such trace amounts that the contrast cannot have any effect on the functioning of the thyroid gland. The main reservations regarding the use of contrast are allergic reactions and kidney disease.
To check if the patient is allergic to contrast, a biological test is first performed, involving the administration of a small amount of the agent. If an allergic reaction does occur, antiallergic drugs are given. Then the biological test is repeated. If an allergic reaction does not occur, there are no contraindications for the procedure.
The question of applying contrast to people with kidney disease is a bit more complicated. Unfortunately, it is known that contrast agents put some strain on this pair of organs. Therefore, it is mandatory to test the creatinine level in the blood before performing the magnetic resonance imaging. It informs your doctor about your kidney function. If the results are normal, the standard amount of contrast agent may be given. However, when irregularities are found, the matter requires a bit more attention. The amount of the agent should be appropriately reduced so as not to strain the patient’s kidneys and worsen their condition. Unfortunately, too little contrast can make the test very low diagnostic value. On the other hand, inadvertent administration of too much contrast agent can cause a number of complications in a person with renal insufficiency, including exacerbation of the disease and the need for dialysis.
How to prepare for MRI with contrast?
If the doctor has decided to administer the contrast for the MRI scan, it means that you must be on an empty stomach for at least 6 hours before the examination. The exception is still mineral water, which can and should be taken up to 3 hours before the procedure.
In addition, the standard restrictions against MRI apply, especially the need to get rid of any metal objects, electronic devices, as well as makeup and hairspray in the event of a head resonance imaging. All of the above can interfere with the measurement of the MRI device. See which facilities in your area offer magnetic resonance imaging.