What day to do a CT scan for coronavirus

2024 Author: James Gerald | [email protected]. Last modified: 2023-12-17 14:00

The use of computed tomography in diagnostics meets international standards. It is also an effective diagnostic tool for the COVID-19 pathogen. On what day should a CT scan be done for coronavirus and what exactly is it capable of showing?

Tomography is more effective than a genetic test

The lack of proven vaccines or specific treatment options for SARS-CoV-2 infection could overwhelm the healthcare sector with the sheer number of patients requiring ventilation.

All the more important is the rapid development of diagnostic methods that make it possible to quickly identify patients with potential complications. The need for this also arises due to the reduced sensitivity of PCR smear from the throat for the detection of SARS-CoV-2 infection at the stage of pneumonia and due to the lack of currently validated clinical guidelines for transferring a patient to intensive care.

Computed tomography (CT) scans involve the use of a computer to combine two-dimensional X-ray images and convert them to three dimensions. This method requires highly specialized equipment and is performed in a hospital by a specialist radiologist.

Scientists from Wuhan, where the coronavirus pandemic began, have conducted studies that show that computed tomography of the chest shows infection with the virus earlier than tests used today for a similar purpose. The effectiveness of the PCR test is estimated at 60-70%, which entails the need for additional verification of negative results.

The suspicion of a wrong outcome can arise especially in high-risk individuals, as well as in areas where the pathogen COVID-19 is widespread. Sensitivity to the presence of covid in 97% was achieved using computed tomography. A study on this topic was published by the British Thoracic Society.

On what day should a computed tomography be done

An important point is the timing of the investigation. People often turn to doctors with the question of what day to do a CT scan for coronavirus, and what it shows in the first few days after infection. Covid does not attack the lungs immediately. Even in the case of a serious illness, characteristic foci on the images are formed only 4-5 days after the first symptoms appear.

In most cases, computed tomography is prescribed 6-11 days after the identification of characteristic signs. A later test is possible, but an earlier test is not desirable. There is a possibility that the result will be false negative.

Doctors assure that the wrong timing of the test can give the wrong picture. Therefore, instead of making an appointment for a paid tomography on your own a few days after the change in health, you need to consult a specialist.

CT is especially indicated for symptomatic patients who have a negative PCR test but suspect a false negative result. For example, due to belonging to a higher risk group or the presence of widespread COVID-19 infection in the region where the person lives.

What tomography can show in the case of coronavirus

Lung damage with coronavirus looks almost the same as it happens in the case of a complicated flu course or an allergic reaction, if it is sufficiently pronounced. How destructively the virus is capable of acting on the tissues of the lower respiratory tract can be seen by the change in the pulmonary fields. On the finished CT scan, you can see 1 lesion or several such damaged areas.

What other characteristic changes can take place:

1. Areas of so-called frosted glass, which are areas of cloudiness. The occurrence of such a symptom is facilitated by a decrease in air filling of the lung in combination with the phenomena of inflammation and thickening of the walls of the alveoli. They are subsequently filled with a fluid called exudate. Usually this symptom is localized in the lower segment of the lung, near the pleura. Such foci can coalesce, affecting a significant area of the lower respiratory tract.
2. Another interesting feature is the cobblestone effect. It manifests itself as a thickening of the space that divides the lobes of the lower airways.
3. Other typical symptoms on CT images in people infected with coronavirus are vasodilation in the lesion and local expansion of the bronchioles - they are visible in various versions.

The foci of compaction can turn into fibrosis, but in some patients they disappear over time.

Thus, modern computed tomography devices, due to their high linear resolution and mechanisms that minimize the radiation dose received during the examination, are an excellent tool for detecting and monitoring pulmonary symptoms during COVID-19 infection. In addition, the test result can be obtained within a few minutes.

Opinion of doctors

Doctor I. Sokolov on his own page on the social network Facebook indicates to whom and in what cases a computed tomography should be done if a coronavirus is suspected. In his recommendations, he points out that COVID-19 may often show no symptoms at all until the 6th day of illness.

Therefore, in his opinion, one should observe the dynamics of pathology and prescribe a tomography from 6 to 11 days after the onset of symptoms, but not earlier. At the same time, he outlined the main categories of people who should definitely do such a survey.

Among them were people with a moderate and mild form of the disease, who have concomitant chronic diseases that can create an unfavorable prognosis for covid. He also included in this group people with moderate and severe pathology. At the same time, the expert drew attention to the fact that the results of the PCR test should not be taken into account here.

B. Brodetsky, head of the department of MRI and CT diagnostics at the Moscow city hospital named after Konchalovsky, believes that at the first signs of coronavirus, you should not run to the doctor to demand a computed tomography. First of all, the expert recommends focusing on the clinical picture and the presence of risk factors, to which he attributed diabetes, age over 65, bronchial asthma and other concomitant pathologies. At the same time, the physician is of the opinion that PCR is the main method for detecting coronavirus today.

Outcomes

1. Computed tomography is one of the most informative methods for detecting coronavirus pneumonia in the early stages.
2. Some doctors consider the PCR test as the main method for detecting coronavirus. But in the case when there is a possibility of a false negative result of such a study, you can resort to CT as an alternative.
3. Tomography should not be done in the first days of the onset of the disease. According to experts, this is more justified in the period from 6 to 11 days of illness, since the coronavirus does not attack the lungs immediately, but after a while.