Diagnosis of lung abscess is often based on radiologic results showing a cavitary lesion with air fluid level, though blood cultures are normally required to identify the specific pathogen.

• An irregularly shaped thick walled cavity with an air-fluid level is typically seen in lung abscess on chest x ray. ^[1]
• Abscess is often unilateral and single involving posterior segments of the upper lobes and the apical segments of the lower lobes as these areas are gravity dependent when lying down. ^[2]
• The presence of air-fluid levels implies rupture into the bronchial tree or rarely growth of gas forming organism.The extent of the air-fluid level within a lung abscess is often the same in posteroanterior or lateral views.
• Anaerobic infection may be suggested by cavitation within a dense segmental consolidation in the dependent lung zones.
• Lung infection with a virulent organism results in more widespread tissue necrosis.
• Up to one-third of lung abscesses may be accompanied by an empyema.^[3]
• Repeat chest radiographs must be obtained to determine the response of antimicrobial therapy.

Chest X-ray AP-veiw :demonstarting a large right side pulmonary cavity.

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