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Often, we go to the doctor and he orders several tests that we haven’t even heard of, do we? One of the most requested is MRI, as it is able to detect or confirm many health problems .

But do you know what resonance is for? How it works? Why did the doctor recommend this test? Whether it is necessary to use contrast or to be accompanied? Yes, these are just a few questions that go through the mind of those who need to do it.

Calm down, we will help you! In this post we clarify the main doubts about magnetic resonance imaging. Read on to find out more!

What is MRI?

It is a high definition image exam, capable of showing even the internal structures of the organs very clearly. For this reason, it is the most suitable to detect diseases and serious problems internally.

Also known as Nuclear Magnetic Resonance (NMR), the test differs from others in that it provides the doctor with a more complete view of the size, location and composition of tissues. In addition, it is necessary to differentiate it in some types, according to the part analyzed:

  • intracranial resonance: analyzes the central nervous system, as well as its nerve formations, veins and arteries;
  • resonance of the abdomen, chest or pelvis: it serves to diagnose diseases in organs such as uterus, ovaries, prostate, intestine, kidneys, bladder, liver,  heart , among others;
  • spine resonance: checks spinal and spinal cord problems;
  • joint resonance : helps to analyze soft tissues, such as tendons and ligaments, in joints such as elbows, knees and shoulders.

How does this exam work?

The machine works with a large magnet, which interacts with the cells of our body, forming a large magnetic field, as well as radio frequency pulses. The device captures the agitation of the body’s molecules and transmits the information to a computer.

The images are created in three different planes: vertical, horizontal and another that divides the body into layers. No type of radiation is emitted on MRI, unlike other tests, such as x-rays. This whole process is done in about 15 to 30 minutes, being a very thorough exam.

When is resonance indicated?

Due to the possibility of detailing the body structures, resonance is indicated whenever it is necessary to look more closely at any problem. Thus, the doctor can order it right from the start or after other tests have not been sufficient to visualize the tissue.

Anyway, it is more recommended for detailing the soft parts of the body, such as muscles and organs. In the case of fractures or bone problems, it is better to use x-rays or computed tomography.

What problems does it help to detect?

Resonance can be applied to specific parts, as mentioned above, or to the entire length of the body. It helps to identify different types of problems, such as tumors, infections, injuries and other diseases. Thus, it can be recommended to detect:

  • changes in blood vessels, as in the case of clots and aneurysms;
  • neurological diseases, such as brain tumors, Alzheimer’s disease, multiple sclerosis or stroke;
  • musculoskeletal injuries, such as ligament injuries, tendonitis, cysts (like Tarlov’s) or herniated discs;
  • inflammations or infections in the brain, joints or nerves;
  • masses or tumors in any organ of the body.

How is the preparation for the exam?

Magnetic resonance imaging is a  very simple exam , not requiring much preparation, in most cases. However, some type of sedation may be necessary if the patient is claustrophobic, with dementia, schizophrenia or is unable to stand still.

It is necessary to emphasize that it is essential to remain completely immobile during the entire exam time. Not to mention that it is made in a magnetic tube, in which some people may feel uncomfortable, hence the need for a sedative.

In addition, it may be necessary to apply some intravenous contrast, when the structure to be checked is difficult to see, such as blood vessels or tumors. Thus, the procedure is more reliable, and it is not necessary to perform other, more invasive exams.

Contrast or sedation is given in the room where the machine is located, without the need for prior preparation. They are taken orally or an intravenous catheter is inserted before entering the machine. Then, these substances are naturally eliminated by the body.

In the case of contrast, there is a possibility of allergy, and should not be used, yet, in people with kidney failure or liver problems, which need to be reported to the doctor promptly. Other side effects, such as metallic taste, headaches and a feeling of heat, can also be noticed, but they are transient.

Are there any side effects or contraindications?

Because it does not emit radiation, MRI is considered to be of low risk and has no serious side effects or contraindications. However, as the machine works with the emission of magnetic waves, it should not be used in patients with metals throughout the body.

Thus, it cannot be used on people with pins (as in the case of fractures), pacemakers, prostheses or any other type of metallic part. Even tattooed people must go through a check first, since many inks used in tattoos contain iron or other metals in the composition.

There is also no limit to the performance of resonances during the year. However, it is indicated only for diagnosis when there is a suspicion and not for checkups, even because it is a test with a slightly higher value compared to others.

Another common question is whether the patient should bring a companion. It is not always necessary, but it is recommended when sedation is used. Anyway, another person is welcome to calm down and keep company during the exam, which can bring tension and discomfort, depending on the situation and the suspicion of a serious illness, for example.

Anyway, MRI is a  complete and very safe exam . Therefore, it is essential to perform it whenever the doctor requests it. Therefore, reliable clinics should be sought , offering a good structure and the best professionals.


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