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Table 1 Comparison of the chest CT categorization systems of COVID-19 [49]

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

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
  1. RSNA Radiological Society of North America, CO-RADS the COVID-19 reporting and data system, COVID-RADS the COVID-19 imaging reporting and data system, BSTI British Society of Thoracic Imaging, RT-PCR Real-time reverse transcription polymerase chain reaction