Reverse Halo Sign-CT

Evidence of areas of irregular predominately peripheral consolidation in the right lower lobe with few areas of ground glass haze and nodular shadows. There is larger shadow in the left lower lobe with peripheral consolidation with airbronchogram surrounding relatively preserved lung parenchyma. There are areas of ground glass haze. The appearance in left lower lobe is suggestive of reverse halo sign or atoll sign which is classical of cryptogenic organising pneumonia versus differentials of this appearance. The cryptogenic organizing pneumonia in the majority of cases is an idiopathic disease, while less frequently it can be associated with infectious pneumonias, airway obstruction, aspiration, drug reaction, or collagen vascular disease associated with an intake of toxic substances. The prognosis is favourable because there is a good response to steroid therapyThis needs clinical correlation and follow up.