Table 1.

Various computed tomography (CT) patterns that could represent, raise suspicion of, or suggest alternative diagnosis for COVID-19 pneumonia as per British Society of Thoracic Imaging (BSTI) guidance.

CT patterns	CT findings
Classic COVID-19 pneumonia	Peripheral GGO Possible crazy-paving patterna Organising pneumoniab
Probable COVID-19 pneumonia	Mixture of bronchocentric and peripheral consolidation predominantly in the lower zones Organising pneumonia GGO scarce
Indeterminate	Does not fit in the three other categories with diffuse/patchy GGO that are not peripheral, fibrosis with ground glass, complex CT patterns Similar patterns to the above but clinical context is wrong or suggestive of alternative diagnosis
Non-COVID-19	Lobar pneumonia Cavitating consolidation Tree-in-bud/centrilobular opacities, lymph node enlargement, pleural effusions

GGO, ground-glass opacity.

^aCrazy paving pattern on CT includes GGO with inter/intralobular septal thickening.

^bOrganising pneumonia patterns on CT are bronchocentric/peripheral consolidation with reversed halo sign and peri-lobular pattern.²⁵