What is a common imaging feature of aspergillosis on CT during recovery?

What is a common imaging feature of aspergillosis on CT during recovery?

• A. Halo sign
• B. Air crescent sign
• C. Tree-in-bud sign
• D. Reverse halo sign

Answer: (B)

Imaging features of aspergillosis evolve with disease stage, and during recovery the CT most commonly shows the air crescent sign. This appears as a crescent-shaped lucency within a cavity surrounding a residual nodule or area of prior consolidation. It reflects healing after treatment and neutrophil recovery, as necrotic tissue is cleared and air fills the surrounding cavity. The halo sign is typical of the early invasive phase, not recovery. Tree-in-bud points to small-airway disease, while the reverse halo sign is seen in other contexts like organizing pneumonia and is not the classic recovery indicator for aspergillosis. Seeing an air crescent often aligns with clinical improvement, though radiographic changes can lag behind.

Imaging features of aspergillosis evolve with disease stage, and during recovery the CT most commonly shows the air crescent sign. This appears as a crescent-shaped lucency within a cavity surrounding a residual nodule or area of prior consolidation. It reflects healing after treatment and neutrophil recovery, as necrotic tissue is cleared and air fills the surrounding cavity. The halo sign is typical of the early invasive phase, not recovery. Tree-in-bud points to small-airway disease, while the reverse halo sign is seen in other contexts like organizing pneumonia and is not the classic recovery indicator for aspergillosis. Seeing an air crescent often aligns with clinical improvement, though radiographic changes can lag behind.