Table 2.

The proposed lexicon for description of chest CT imaging findings in coronavirus disease 2019 (COVID-19)

	Findings	Important definitions
Distribution pattern of lesion	Unilateral/bilateral Anterior/posterior Peripheral predominant/central predominant Focal/multifocal Round/linear/wedge-shaped/irregular opacity Right upper/right middle/right lower/left upper/left lower lobe One lobe/two lobes/three lobes/four lobes/five lobes involved	The outermost one-third of the lung field is considered peripheral and the rest is considered central Posterior/anterior is determined according to the mid-axillary line
Type of lesion	Pure GGO GGO with superimposed consolidation Reticulation Consolidation without GGO Predominant consolidation pattern Air bronchogram Crazy paving pattern White lung stage Melted sugar sign Parenchymal fibrotic bands Pleural effusion Cavity Pulmonary nodules Nodular pattern Lymphadenopathy Peribronchovascular distribution Bronchial wall thickening Halo sign Tree-in-bud pattern Bronchiectasis Airway secretions Interstitial emphysema Pulmonary fibrosis Pleural thickening Pneumothorax Pericardial effusion Vascular enlargement	Pure GGO: A hazy intensification in lung attenuation without obscuration of the underlying vessels GGO with consolidation: A central opacification with obscuring the underlying vessels surrounded by GGO Melted sugar sign: Gradual decrease in density of consolidation and turning into GGO Halo sign: Pulmonary nodule surrounded by GGO, representative of hemorrhage Tree-in-bud pattern: Multiple sites of centrilobular nodules along with branching linear opacities [29]