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Recommendations for using imaging methods for patients suspected of having a COVID-19 infection

Based on the available medical literature, CBR, through its Department of Thoracic Radiology recommends:

  1.  Computed tomography should NOT be used as a screening or for the initial diagnosis of COVID-19 imaging;
  2. Its use should be reserved for hospitalized, symptomatic patients in specific clinical situations. CT findings do not influence outcomes;
  3. When indicated, the protocol is a high resolution CT (HRCT), if possible with a low dose protocol. The use of intravenous contrast media, in general, is not indicated, being reserved for specific situations to be determined by the radiologist.
  4. After use by patients with a suspected or confirmed diagnosis of COVID-19 infection, the room and equipment used must undergo a disinfection process, as described in another CBR document: https://cbr.org.br/recomendacoes-gerais-de-prevencao-de-infeccao-pelo-covid19-para-clinicas-e-servicos-hospitalares-de-diagnostico-por-imagem/
  5.  When the chest X-ray is indicated, in suspected / confirmed cases, of inpatients, we must privilege the use of portable radiography, as the surfaces of these machines can be more easily cleaned and, still, the need to take patients to the hospital is avoided. image sector.

With the spread of COVID-19 infection worldwide and in our
country, imaging methods have received special attention and it is important to highlight
what would be the role of plain radiography and chest computed tomography in
context of a patient with suspicion or even with a confirmed diagnosis of COVID-19 infection. Several publications have described the most common findings in both radiographic and tomographic images.

The interest is even greater due to the scarcity of confirmatory serological tests in some specific countries and regions, as well as due to some reports originating from the infection in China in which CT has already shown findings even in patients with serological tests that are still negative. We emphasize that the recommendations and findings described here can be changed and / or supplemented due to the rapid evolution of the pandemic and to deal with acute cases of an infection in which all its nuances are not known.

Some key considerations must be made in relation to the use of imaging methods in the infection by COVID-19. The Centers for Disease Control (CDC), an American government agency, does not currently recommend Rx or CT for the diagnosis of COVID-19 infection. Serological tests remain the only specific method for this purpose. All international organizations, so far, reaffirm the need for laboratory confirmation, even in patients with clinical pictures and highly suggestive imaging findings. The imaging findings of COVID-19 infection are not specific and overlap with several other acute infections such as influenza, SARS, MERS and H1N1. Many of them are known to be much more prevalent than COVID-19.

It must also be considered that infection control in radiological services, which involves reducing the unsuitable use of imaging methods, is extremely important. We remind you that, for the proper disinfection of the CT / RX environment, a long time, sometimes over 30 minutes, may be required, restricting the ability to perform tests. For this reason, the need for well-defined indications for imaging exams.

Radiologists should be familiar with the imaging findings of the COVID-19 infection, which are briefly summarized here:

    1. Simple chest radiography:Chest radiographs typically show multifocal air space opacities similar to other coronavirus infections. Chest X-ray findings are delayed compared to HRCT.
    2. High-resolution chest CT: Pulmonary abnormalities in COVID-19 infection are usually opacities with peripheral, focal or multifocal ground-glass attenuation, and bilateral in 50-75% of cases. With the progression of the disease, between 9 and 13 days, there is the appearance of lesions with mosaic paving pattern and consolidations. Lesions disappear slowly for 1 month or more. In the pediatric group, the finding of consolidation surrounded by attenuation in ground glass (halo sign) seems to be more common than in adults.

To facilitate the understanding of these findings, we recommend the website
made available by the Italian Society of Medical Radiology, with images of the
COVID-19 infection: https://www.sirm.org/category/senza-categoria/covid-19/

It is noteworthy that the course of this pandemic is acute and the recommendations can be
changed / adjusted at any time.

click here and download this material in PDF.

 

Sources:
1. Societá Italiana di Radiologia Medica e Interventistica. https://www.sirm.org/

2. Coronavirus Disease 2019 (COVID-19): A Perspective from China. Radiology, Feb
2020. https://doi.org/10.1148/radiol.2020200490

3. CT Imaging Features of 2019 Novel Coronavirus (2019-nCoV). Radiology Feb,
2020. https://doi.org/10.1148/radiol.2020200230

4. Performance of radiologists in differentiating COVID-19 from viral pneumonia on
chest CT. Radiology, Feb 2020, https://doi.org/10.1148/radiol.2020200823

5. Chest CT Findings in Coronavirus Disease-19 (COVID-19): Relationship to
Duration of Infection. Radiology, Feb 2020, https://doi.org/10.1148/radiol.2020200463

6. Essentials for Radiologists on COVID-19: An Update — Radiology Scientific Expert
Panel. Radiology, Feb 2020, https://doi.org/10.1148/radiol.2020200527

7. Time Course of Lung Changes On Chest CT During Recovery From 2019 Novel Coronavirus (COVID-19) Pneumonia. Radiology, Feb 2020, https://doi.org/10.1148/radiol.2020200370

8. Radiology Perspective of Coronavirus Disease 2019 (COVID-19): Lessons From Severe Acute Respiratory Syndrome and Middle East Respiratory Syndrome. American Journal of Roentgenology 2020, 1-5. 10.2214 / AJR.20.22969

9. Xia W, et al. Clinical and CT features in pediatric patients with COVID-19 infection: Different points from adults. Pediatric pulmonology. 2020; 1-6. 10,102 / ppul.24718

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