The role of chest imaging in the diagnosis, management, and monitoring of coronavirus disease 2019 (COVID-19)

Abstract

Coronavirus disease 2019 (COVID-19) pandemic has posed a major public health crisis all over the world. The role of chest imaging, especially computed tomography (CT), has evolved during the pandemic paralleling the accumulation of scientific evidence. In the early stage of the pandemic, the performance of chest imaging for COVID-19 has widely been debated especially in the context of comparison to real-time reverse transcription polymerase chain reaction. Current evidence is against the use of chest imaging for routine screening of COVID-19 contrary to the initial expectations. It still has an integral role to play, however, in its work up and staging, especially when assessing complications or disease progression. Chest CT is gold standard imaging modality for COVID-19 pneumonia; in some situations, chest X-ray or ultrasound may be an effective alternative. The most important role of radiologists in this context is to be able to identify those patients at greatest risk of imminent clinical decompensation by learning to stratify cases of COVID-19 on the basis of radiologic imaging in the most efficient and timely fashion possible. The present availability of multiple and more refined CT grading systems and classification is now making this task easier and thereby contributing to the recent improvements achieved in COVID-19 treatment and outcomes. In this article, evidence of chest imaging regarding diagnosis, management and monitoring of COVID-19 will be chronologically reviewed.

Keywords: 2019 novel coronavirus; CO-RADS; COVID-19; SARS-CoV-2; The RSNA expert consensus statement.

Fig. 1

Example of chest CT patterns of RSNA classification. Axial CT images are categorized as (a) “Negative for pneumonia” meaning no features of pneumonia, (b) “Atypical appearance”, meaning typical for other infection but not COVID-19, e.g., bronchial pneumonia, lobar pneumonia, tuberculosis, or fungal infection, (c) “Indeterminate appearance”, meaning the presence of feature suspicious for COVID-19 but with overlaps with other diseases, drug-induced pneumonia, collagen disease-related lung diseases, or alveolar pulmonary edema, and (d) “Typical appearance”, meaning the typical pattern of COVID-19 pneumonia [49]

Fig. 2

Example of chest CT patterns of CO-RADS. Axial CT images are categorized as (a) CO-RADS 1, with no features of pneumonia, (b) CO-RADS 2, with features typical for infection other than COVID-19, e.g., bronchial pneumonia, lobar pneumonia, tuberculosis, or fungal infection, (c) CO-RADS 3, with features compatible with COVID-19 but also other diseases, e.g., alveolar pulmonary edema, (d) CO-RADS 4, with features suspicious for COVID-19 but with overlap with other diseases, drug-induced pneumonia or collagen disease-related lung diseases, and (e) CO-RADS 5, with typical pattern of COVID-19 pneumonia [49]

Fig. 3

Flow chart illustrating the categorization of ground-glass opacity in CO-RADS