High resolution computed tomography and lung function in asbestos-exposed workers with normal chest radiographs

Area of Science:

• Pulmonary Medicine
• Radiology
• Occupational Health

Background:

• Asbestos exposure is a known cause of lung disease.
• Chest radiographs (X-rays) are standard for screening asbestos-exposed individuals.
• Subtle parenchymal abnormalities may be missed on standard chest radiographs.

Purpose of the Study:

• To evaluate the utility of high-resolution computed tomography (HRCT) in detecting lung abnormalities and functional impairment in asbestos-exposed workers with normal chest radiographs.
• To compare pulmonary function test (PFT) results between asbestos-exposed workers with normal versus abnormal HRCT findings.

Main Methods:

• Retrospective review of HRCT scans, clinical data, and PFT results.
• Inclusion of 169 asbestos-exposed workers with normal chest radiographs (ILO < 1/0).
• Categorization of HRCT findings into normal/near-normal, indeterminate, and abnormal/suggestive of asbestosis.

Main Results:

• HRCT identified abnormalities suggestive of asbestosis in 57 workers (Group 2) and normal/near-normal findings in 76 workers (Group 1).
• Groups 1 and 2 did not differ significantly in asbestos exposure duration, latency, smoking history, or airflow obstruction (FEV1/FVC%, %FEV1).
• Group 2 (abnormal HRCT) showed significantly lower vital capacity (79.0% vs 86.2%, p=0.005) and diffusing capacity (78.2% vs 87.1%, p=0.024) compared to Group 1 (normal HRCT).

Conclusions:

• HRCT is more sensitive than chest radiography for detecting parenchymal abnormalities in asbestos-exposed individuals.
• Asbestos-exposed workers with normal chest radiographs can exhibit HRCT-detectable lung abnormalities and significantly reduced lung function.
• HRCT can identify asbestos-exposed individuals with subclinical restrictive lung disease.