A reversed halo sign is a central ground-glass opacity surrounded by denser consolidation. Criteria include that the consolidation should form more than three-fourths of a circle and be at least 2 mm thick.[4] It is suggestive of cryptogenic organizing pneumonia,[5] but is only seen in about 20% of individuals with this condition.[4] It can also be present in lung infarction where the halo consists of hemorrhage,[6] as well as in infectious diseases such as paracoccidioidomycosis, tuberculosis, zygomycosis, and aspergillosis, as well as in granulomatosis with polyangiitis, lymphomatoid granulomatosis, and sarcoidosis.[7]