Routine screening CT for diagnosis or exclusion of COVID-19 is currently not recommended by most professional organizations or the US Centers for Disease Control and Prevention |
COVID-19 pneumonia imaging classification | Rationale | CT findings | Suggested reporting language |
Typical appearance | Commonly reported imaging features of greater specificity for COVID-19 pneumonia. | - Peripheral, bilateral, GGO with or without consolidation or visible intralobular lines ("crazy-paving")
- Multifocal GGO of rounded morphology with or without consolidation or visible intralobular lines ("crazy-paving")
- Reverse halo sign or other findings of organizing pneumonia (seen later in the disease)
| "Commonly reported imaging features of (COVID-19) pneumonia are present. Other processes such as influenza pneumonia and organizing pneumonia, as can be seen with drug toxicity and connective tissue disease, can cause a similar imaging pattern." |
Indeterminate appearance | Nonspecific imaging features of COVID-19 pneumonia. | - Absence of typical features AND
- Presence of:
- Multifocal, diffuse, perihilar, or unilateral GGO with or without consolidation lacking a specific distribution and are non-rounded or non-peripheral.
- Few very small GGO with a non-rounded and non-peripheral distribution.
| "Imaging features can be seen with (COVID-19) pneumonia, though are nonspecific and can occur with a variety of infectious and noninfectious processes." |
Atypical appearance | Uncommonly or not reported features of COVID-19 pneumonia. | - Absence of typical or indeterminate features AND
- Presence of:
- Isolated lobar or segmental consolidation without GGO
- Discrete small nodules (centrilobular, "tree-in-bud")
- Lung cavitation
- Smooth interlobular septal thickening with pleural effusion
| "Imaging features are atypical or uncommonly reported for (COVID-19) pneumonia. Alternative diagnoses should be considered." |
Negative for pneumonia | No features of pneumonia. | - No CT features to suggest pneumonia.
| "No CT findings present to indicate pneumonia. (NOTE: CT may be negative in the early stages of COVID-19.)" |
NOTES: - Inclusion in a report of items noted in parenthesis in the Suggested reporting language column may depend upon clinical suspicion, local prevalence, patient status as a PUI, and local procedures regarding reporting.
- CT is not a substitute for RT-PCR, consider testing according to local recommendations and procedures for and availability of RT-PCR.
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