Table 1 Comparison of the chest CT categorization systems of COVID-19 [49]
Level of suspicion | CO-RADS Category | COVID-RADS category | The RSNA expert consensus statement category | The BSTI guideline statement category |
|---|---|---|---|---|
Not interpretable | CO-RADS 0 (Scan technically insufficient for assigning a score) | Not defined | Not defined | Not defined |
Very low | CO-RADS 1 (Normal or noninfectious) | COVID-RADS 0 (Normal) | Negative for pneumonia (No features of pneumonia) | NON-COVID (70% confidence for alternative) |
COVID-RADS 1 (Atypical findings; noninfectious etiology or infectious etiology but inconsistent with COVID-19) | ||||
Low | CO-RADS 2 (Typical for other infection but not COVID-19) | Atypical appearance (Uncommonly or not reported features of COVID-19 pneumonia) | ||
Equivocal/unsure | CO-RADS 3 (Features compatible with COVID-19 but also other diseases) | COVID-RADS 2A (Fairly typical findings) COVID-RADS 2B (Combination of atypical findings with typical/fairly typical findings) | Indeterminate appearance (Nonspecific imaging features of COVID-19 pneumonia) | INDETERMINATE (< 70% confidence for COVID) |
High | CO-RADS 4 (Suspicious for COVID-19) | PROBABLE COVID-19 (71–99% confidence for COVID) | ||
Very high | CO-RADS 5 (Typical for COVID-19) | COVID-RADS 3 (Typical findings) | Typical appearance (commonly reported imaging features of greater specificity for COVID-19) | CLASSIC COVID-19 (100% confidence for COVID) |
Proven | CO-RADS 6 (RT-PCR positive for SARS-CoV-2) | Not defined | Not defined | Not defined |