What is the recommended CT chest protocol with or without contrast (computed tomography) for patients with recurrent pneumothorax?

CT Chest Protocol for Recurrent Pneumothorax

CT chest without contrast is the recommended protocol for evaluating patients with recurrent pneumothorax as it provides optimal visualization of lung parenchyma and pleural abnormalities without the need for contrast enhancement. 1

Rationale for Non-Contrast CT

• CT chest without IV contrast is the appropriate imaging modality for evaluating anatomical abnormalities that could predispose patients to recurrent pneumothorax, such as blebs, bullae, and other parenchymal abnormalities 1
• Non-contrast CT can effectively identify underlying pulmonary diseases that may contribute to pneumothorax recurrence, including emphysematous changes, bronchiectasis, and other structural abnormalities 1
• There is no relevant literature supporting the routine use of contrast-enhanced CT for evaluation of uncomplicated pneumothorax 1

When to Consider CT with Contrast

While non-contrast CT is generally preferred, contrast-enhanced CT may be indicated in specific circumstances:

• When there is suspicion of vascular abnormalities contributing to pneumothorax (e.g., pulmonary sequestration) 1
• If bronchial tumors are suspected as a cause of recurrent pneumothorax 1
• When evaluating for bronchopleural fistula, where CT with IV contrast is usually appropriate 1
• For presurgical planning, particularly when identifying feeding vessels is important 1

Clinical Approach to Imaging for Recurrent Pneumothorax

1. Initial Evaluation: Begin with chest radiography to confirm pneumothorax 1
2. Subsequent Imaging:
   • For uncomplicated recurrent pneumothorax: CT chest without IV contrast 1
   • For suspected vascular anomalies: CT chest with IV contrast or CTA chest 1
   • For suspected bronchopleural fistula: CT chest with IV contrast 1

Quantification and Management Implications

• CT allows precise quantification of pneumothorax volume, which has been shown to be the dominant parameter in decision-making regarding chest tube drainage 2
• Pneumothoraces greater than 35 mm on CT (measured radially from chest wall to lung parenchyma) typically require tube thoracostomy 3
• Smaller pneumothoraces (classified as "minuscule" or "anterior" on CT) may be safely observed without chest tube placement in patients not requiring positive pressure ventilation 4

Common Pitfalls to Avoid

• Relying solely on chest radiographs may miss occult pneumothoraces that are detectable on CT 5, 4
• Failing to evaluate for underlying lung pathology that may contribute to recurrence 1, 6
• Using contrast unnecessarily when non-contrast CT is sufficient for most cases of recurrent pneumothorax 1
• Not considering specialized CT protocols (such as CTA) when vascular anomalies are suspected 1