Table 1 Proposed reporting categories for CT findings related to COVID-19 [11]

CT mimickers of typical COVID-19

Commonly reported imaging features of greater specificity for COVID-19 pneumonia

Typical findings are:

1. Peripheral, bilateral, GGO with or without consolidation or crazy-paving

2. Multifocal GGO of rounded morphology with or without consolidation or crazy-paving

3. Reverse halo sign or other findings of organizing pneumonia

1. Influenza pneumonia

2. SARS and MERS pneumonia

3. Organizing pneumonia

4. Connective tissue disease (RA)

5. Drug toxicity

6. Acute interstitial pneumonia

CT mimickers of indeterminate COVID-19

Commonly reported imaging features of greater specificity for COVID-19 pneumonia

Absence of typical features AND presence of:

1. Multifocal, diffuse, perihilar or unilateral GGO with or without consolidation

2. Lacking of specific distribution

3. Non-rounded or non-peripheral GGO

1. Other causes of viral pneumonia

2. Atypical bacterial infections

3. Pneumocystis infection

4. Pulmonary edema

5. ARDS

6. Acute hypersensitivity pneumonitis,

7. Eosinophilic pneumonia

8. Diffuse alveolar hemorrhage

9. Pulmonary alveolar proteinosis

Conditions presented by clinical scenarios that mimic COVID-19 but with atypical CT features

Uncommonly or not reported CT features

Absence of typical or indeterminate features AND presence of:

1. Isolated lobar or segmental consolidation without GGO

2. Discrete small nodules (centrilobular or “tree in-bud”)

3. Lung cavitation

4. Smooth interlobular septal thickening with pleural effusion

Alternative diagnoses rather than COVID-19 should be considered such as typical bacterial pneumonia, TB or other non-infective processes