Target-shaped combined halo and reversed-halo sign, an atypical chest CT finding in COVID-19

Abstract

Typical chest CT findings in COVID-19 have been described as bilateral peripheral ground glass opacities, with or without consolidation. Halo sign and reversed halo sign have been reported as atypical imaging findings in this disease. However, to the best of our knowledge, combined presence of these signs has never been reported before. Herein, we present a COVID-19 patient with numerous atypical target-shaped, combined halo and reversed halo pulmonary lesions, in the absence of any other underlying disease.

Keywords: COVID-19; Lung diseases; Severe acute respiratory syndrome coronavirus 2; Tomography, X-ray computed.

Fig. 1

Baseline chest CT displaying multilobar peripheral consolidations with mixed configuration of ‘reversed halo’ and ‘halo’ signs. This appearance was embedded in areas of consolidation. The described patterns were seen in the anterior and apicoposterior segments of the left upper lobe with a maximum size of 33 × 24 mm (arrowhead) (A). Another well visualized peripheral halo consolidation and central round nodule was seen in the posterior segment of the right lower lobe (28 × 18 mm) (B). Two additional areas of peripheral complete halo and central nodular opacity were seen in the lateral segment of the right lower lobe and lateral segment of the left lower lobe, measuring 29 × 21 mm and 25 × 15 mm, respectively (C).

Fig. 2

Follow-up CT-scan, after 4 weeks of disease onset, showing diffuse multifocal patchy pure ground-glass opacities in both lungs, without consolidation. Significant clearance of lung fields in left upper lobe (A), right lower lobe (B), and bilateral lower lobes (C) is evident compared to the baseline. The patient denied any symptoms on the follow-up exam.