Chronic pulmonary thromboembolism. Air trapping on computed tomography and correlation with pulmonary function tests

Area of Science:

• Pulmonary Medicine
• Radiology
• Cardiovascular Imaging

Background:

• Chronic pulmonary embolism (CPE) can lead to persistent lung abnormalities.
• Computed tomography (CT) is crucial for diagnosing and evaluating CPE.
• Correlation between imaging findings and pulmonary function is essential for understanding disease impact.

Purpose of the Study:

• To evaluate lung attenuation on inspiratory/expiratory CT and CT angiography (CTA) in patients with CPE.
• To correlate CT findings with pulmonary function test (PFT) results.
• To assess the relationship between clot presence and lung attenuation patterns.

Main Methods:

• Retrospective review of 9 CPE patients and 9 age-matched controls.
• Analysis of paired inspiratory/expiratory CT and CTA images.
• Subjective assessment of lung attenuation and air trapping, correlated with PFTs.

Main Results:

• Lower attenuation (mosaic perfusion) and air trapping were prevalent in CPE patients.
• Air trapping was associated with proximal arterial stenosis and reduced contrast enhancement.
• Extent of air trapping inversely correlated with PFT parameters of peripheral airway obstruction (e.g., maximum mid-expiratory flow rate).

Conclusions:

• Air trapping is a frequent finding in chronic pulmonary embolism, occurring in areas of hypoperfusion.
• The degree of air trapping correlates with the severity of peripheral airway obstruction.
• CT findings, particularly air trapping, provide valuable insights into the functional consequences of CPE.