AIR CRESCENT SIGN

Causes of AIR CRESCENT SIGN

    1. Aspergilloma -(Most Common).
    2. Angioinvasive.A.
    3. Echinococcal cyst.
    4. TB.
    5. Rasmussen aneusrysm
    6. Lung abscess
    7. Bronchogenic Ca.
    8. Hematoma.
    9. PCP.

Saprophytic aspergillosis (Aspergilloma) is commonly associated with thickening of the wall of the cavity and adjacent pleura (due to hypersensitivity reaction). The pleural thickening may be the earliest 'radiographic' sign before any visible changes in the cavity.

The 5 forms of PULMONARY ASPERGILLOSIS include:

1. SAPROPHYTIC

2. Allergic Broncho Pulmonary Aspergillosis (ABPA) / Hypersensitivity reaction.
- Long standing bronchial   asthma;
- Finger-in-Glove appearance,
- Segmental and Subsegmental bronchi of upper lobes
- fungal hyphal impaction of affected bronchi with distal mucoid impaction with 30% showing hyperdensity /   frank calcification in CT.

3. SEMI-INVASIVE / Nectrotizing Aspergillosis.
4. AIRWAY INVASIVE.
5. ANGIOINVASIVE ASPERGILLOSIS.

Ref : RG article, 2001.