Understand how the use of contrast in imaging tests works; risks are low

O use of contrast allows you to increase the sensitivity of medical and diagnostic tests by image 🇧🇷 Contrast media are substances introduced into the body that have different compositions and rarely cause adverse reactions.

Psychologist Bruna Nunes de Faria, 27, died on December 21 after feeling sick while receiving the contrast for an MRI at a clinic in Goiânia (GO). According to the victim’s relatives, the report from the Legal Medical Institute (IML), which will indicate the cause of death, should be released early next week.

Although the episode raised concerns about the risks of using contrast in exams experts claim that the procedure is safe and that the Adverse reactions are quite rare. 🇧🇷

“THE contrast reaction is very rare 🇧🇷 Cases of more severe reactions occur every 10,000 injections. Most serious cases can be reversed and resolved with proper care. Death is very rare, but unfortunately it can happen. Every time this happens, it generates all this concern”, says radiologist Cesar Higa Nomura, from Hospital Sírio-Libanês, in São Paulo.

Different types of contrast

The types of contrast can be barium, used in X-rays and computed tomography; iodine, adopted in X-rays, computed tomography and intervention; paramagnetics, for magnetic resonance imaging, and microbubbles, for ultrasound.

Contrast media are used to provide an anatomical and functional assessment of organs and body structures, as well as to enhance the vascularity and composition of potential lesions.

The application has specific and differentiated indications, according to clinical suspicion or known diagnosis. Contrast administration should be performed under medical supervision, following safety criteria. The indication, dosage and prescription of contrast agents must be made by a radiologist, in accordance with the Federal Council of Medicine (CFM).

According to the CFM, the radiologist must be in the physical space of the service during the entire time of the examination with contrast and accessible in case of intercurrences that require face-to-face assistance.

The physician responsible for requesting the exam must provide in the request the relevant clinical data and known diagnoses, in addition to the history of previous exams and possible intercurrences with contrasts.

“What is important to emphasize is that the use of contrast is important. It must be performed because it helps a lot in the diagnosis of some pathologies, especially in the case of cancer. Death is not frequent, on the contrary, it is very rare. The point that is important to emphasize is that there is no test to prevent it, unfortunately, and that in some cases it can happen”, says Nomura.

The doctor at Sírio-Libanês says that most of the adverse effects are mild. “The vast majority of reactions to contrast are mild, there are moderate and severe ones. One thing that is important to note is that there is a questionnaire that is done before all exams. Therefore, it is important to answer the questionnaire properly, which can sometimes help to know if that patient has a lot of allergies, if it is a patient who has already had several other serious reactions, ”he says.