Radiological Society of North America Expert Consensus Document on Reporting Chest CT Findings Related to COVID-19: Endorsed by the Society of Thoracic Radiology, the American College of Radiology, and RSNA

Abstract

Routine screening CT for the identification of coronavirus disease 19 (COVID-19) pneumonia is currently not recommended by most radiology societies. However, the number of CT examinations performed in persons under investigation for COVID-19 has increased. We also anticipate that some patients will have incidentally detected findings that could be attributable to COVID-19 pneumonia, requiring radiologists to decide whether or not to mention COVID-19 specifically as a differential diagnostic possibility. We aim to provide guidance to radiologists in reporting CT findings potentially attributable to COVID-19 pneumonia, including standardized language to reduce reporting variability when addressing the possibility of COVID-19. When typical or indeterminate features of COVID-19 pneumonia are present in endemic areas as an incidental finding, we recommend contacting the referring providers to discuss the likelihood of viral infection. These incidental findings do not necessarily need to be reported as COVID-19 pneumonia. In this setting, using the term viral pneumonia can be a reasonable and inclusive alternative. However, if one opts to use the term COVID-19 in the incidental setting, consider the provided standardized reporting language. In addition, practice patterns may vary, and this document is meant to serve as a guide. Consultation with clinical colleagues at each institution is suggested to establish a consensus reporting approach. The goal of this expert consensus is to help radiologists recognize findings of COVID-19 pneumonia and aid their communication with other health care providers, assisting management of patients during this pandemic. Published under a CC BY 4.0 license.

Figure 1:

Typical CT imaging features for COVID-19. Unenhanced thin-section axial images of the lungs in a 52-year-old man with a positive RT-PCR (A–D) show bilateral, multifocal rounded (asterisks) and peripheral GGO (arrows) with superimposed interlobular septal thickening and visible intralobular lines (“crazy-paving”). Routine screening CT for diagnosis or exclusion of COVID-19 is currently not recommended by most professional organizations or the U.S. Centers for Disease Control and Prevention.

Figure 2:

Typical CT imaging features for COVID-19. Unenhanced thin-section axial (A–C) and coronal multiplanar reformatted images (D) of the lungs in a 77-year-old man with a positive RT-PCR show bilateral, multifocal rounded and peripheral GGO. Routine screening CT for diagnosis or exclusion of COVID-19 is currently not recommended by most professional organizations or the U.S. Centers for Disease Control and Prevention.

Figure 3:

Typical CT imaging features for COVID-19. Unenhanced axial (A–C) and sagittal multiplanar reformatted (D) images of the lungs in a 29-year-old man with a positive RT-PCR show multiple bilateral, rounded consolidations with surrounding GGO. Routine screening CT for diagnosis or exclusion of COVID-19 is currently not recommended by most professional organizations or the U.S. Centers for Disease Control and Prevention.

Figure 4:

Typical CT imaging features for COVID-19 and other diseases with similar findings. Posterior, peripheral, and rounded GGO and consolidation in axial images of four patients; COVID-19 (A, B), organizing pneumonia secondary to dermatomyositis (C), and influenza A pneumonia (D). Organizing pneumonia and influenza pneumonia can be indistinguishable from COVID-19 by CT. Routine screening CT for diagnosis or exclusion of COVID-19 is currently not recommended by most professional organizations or the U.S. Centers for Disease Control and Prevention.

Figure 5:

Indeterminate CT imaging features for COVID-19. Unenhanced axial images in two patients showing patchy GGO with nonrounded morphology and no specific distribution, in a case of COVID-19 pneumonia (A, B) and acute lung injury from presumed drug toxicity (C, D). Routine screening CT for diagnosis or exclusion of COVID-19 is currently not recommended by most professional organizations or the U.S. Centers for Disease Control and Prevention.

Figure 6:

Indeterminate CT imaging features for COVID-19. Widespread GGO with nonrounded morphology and no specific distribution in unenhanced axial images from two different patients secondary to acute lung injury from presumed drug toxicity (A) and Pneumocystis pneumonia (B). Routine screening CT for diagnosis or exclusion of COVID-19 is currently not recommended by most professional organizations or the U.S. Centers for Disease Control and Prevention.

Figure 7:

Atypical CT imaging features for COVID-19. Contrast-enhanced axial CT image (A) and frontal chest radiograph (B) showing segmental consolidation without significant GGO. Although this patient tested positive for COVID-19, the imaging features are not typical and could represent pneumonia related to COVID-19 or a secondary infectious process. Routine screening CT for diagnosis or exclusion of COVID-19 is currently not recommended by most professional organizations or the U.S. Centers for Disease Control and Prevention.

Figure 8:

Atypical CT imaging features for COVID-19. Axial images of the lungs of two patients showing cavitation (arrow) in Klebsiella pneumonia (A) and tree-and-bud opacities (circle) and a cavity (arrow) in nontuberculous mycobacterial infection (B). Routine screening CT for diagnosis or exclusion of COVID-19 is currently not recommended by most professional organizations or the U.S. Centers for Disease Control and Prevention.

Figure 9:

Atypical CT imaging features for COVID-19. Axial CT images from two different patients showing tree-in-bud opacities and centrilobular nodules, caused by respiratory syncytial virus (A) and active tuberculosis (B). A small cavity (arrow) is also present in (B) Routine screening CT for diagnosis or exclusion of COVID-19 is currently not recommended by most professional organizations or the U.S. Centers for Disease Control and Prevention.