Axial chest CT images in lung window settings obtained through the upper lobes in two COVID-19 patients showing multifocal GGOs with focal concentric narrowing of segmental pulmonary vessel (vascular knuckle sign) (red arrow in A) and deviation of vessel from the expected course (vessel angulation sign) (again denoted by red arrow in A) and obscuration of segmental pulmonary vessel near GGO producing invisible vessel sign (red arrows in B). GGO, ground glass opacity.