Pulmonary aspergillosis

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Pulmonary aspergillosis can present in 3 major forms:

• Aspergilloma
• fungal ball in an old tuberculous cavity
• shows Monad sign (usually also called air crescent sign)
• Allergic bronchopulmonary aspergillosis (ABPA)
• central bronchiectasis
• gloved finger appearance
• fleeting opacities
• Invasive aspergillosis
• in immunocompromised
• shows CT halo sign
• Note: Reverse CT halo/Atol sign is seen in Cryptogenic organizing pneumonia/bronchiolitis obliterans organising pneumonia (COP/BOOP)
• air crescent sign - it defines improvement/recovery in the underlying lesion with increased granulocyte activity (should not be confused with Monad sign which is also called air crescent sign as the air outlining the fungal ball is also in the shape of crescent) 

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Author: Dr Ayush Goel

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