Chest CT practice and protocols for COVID-19 from radiation dose management perspective

Abstract

The global pandemic of coronavirus disease 2019 (COVID-19) has upended the world with over 6.6 million infections and over 391,000 deaths worldwide. Reverse-transcription polymerase chain reaction (RT-PCR) assay is the preferred method of diagnosis of COVID-19 infection. Yet, chest CT is often used in patients with known or suspected COVID-19 due to regional preferences, lack of availability of PCR assays, and false-negative PCR assays, as well as for monitoring of disease progression, complications, and treatment response. The International Atomic Energy Agency (IAEA) organized a webinar to discuss CT practice and protocol optimization from a radiation protection perspective on April 9, 2020, and surveyed participants from five continents. We review important aspects of CT in COVID-19 infection from the justification of its use to specific scan protocols for optimizing radiation dose and diagnostic information.Key Points• Chest CT provides useful information in patients with moderate to severe COVID-19 pneumonia.• When indicated, chest CT in most patients with COVID-19 pneumonia must be performed with non-contrast, low-dose protocol.• Although chest CT has high sensitivity for diagnosis of COVID-19 pneumonia, CT findings are non-specific and overlap with other viral infections including influenza and H1N1.

Keywords: COVID-19; Pandemics; Radiation protection; Tomography, X-ray computed.

Fig. 1

Transverse, low-dose, non-contrast chest CT image demonstrates typical peripheral, bilateral ground-glass opacities in a 65-year-old man with RT-PCR positive COVID-19 pneumonia (CTDIvol 2.2 mGy)

Fig. 2

Extensive motion artifacts in transverse, low-dose, non-contrast chest CT image of a 77-year-old man with RT-PCR positive COVID-19 pneumonia (CTDIvol 4.9 mGy). Despite motion artifacts, it is possible to detect multifocal bilateral pulmonary opacities. Although suboptimal, chest CT was not repeated