Reverse halo sign - COVID-19

Case contributed by Eid Kakish
Diagnosis certain


Low-grade fever, myalgia and dry cough. Positive COVID-19 RT-PCR. Labs revealed lymphocytopaenia and raised inflammatory biomarkers. Imaging performed 11 days after onset of symptoms, when patient developed worsening shortness of breath.

Patient Data

Age: 35 years
Gender: Female

There is a peripheral subpleural area of an incomplete rim of consolidation in the posterior segment of the right lower lobe, surrounding a central region of ground glass opacities, consistent with the "reverse halo sign" (best appreciated on the coronal MPR) associated with enlarged subsegmental vascular branches. 

A few other areas of ill-defined consolidation are also seen in the right lower lobe. 

Tiny ill-defined subpleural ground glass opacities in both upper lobes.

Selected axial and coronal reconstructed images show the reverse halo sign in this patient with COVID-19 pneumonia. 

Case Discussion

The reverse halo sign is not a commonly encountered CT finding in patients with COVID-19 pneumonia. Although, some studies have proposed that it can be a useful finding in distinguishing COVID-19 from other non-COVID related pneumonias, where it is even more rare. 

In COVID-19, the reverse halo sign has been found to prefer a peripheral lower lobe distribution. 


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