Pulmonary involvement in polymyositis and dermatomyositis: sequential evaluation with CT

Area of Science:

• Radiology and Imaging
• Pulmonology
• Rheumatology

Background:

• Polymyositis (PM) and dermatomyositis (DM) are idiopathic inflammatory myopathies that can affect the lungs.
• Pulmonary involvement in PM/DM can manifest with diverse high-resolution CT (HRCT) findings.
• Understanding these CT patterns is crucial for diagnosis and monitoring treatment response.

Purpose of the Study:

• To characterize the typical HRCT findings of pulmonary involvement in PM/DM.
• To assess the changes in these CT findings before and after treatment.

Main Methods:

• Retrospective review of HRCT scans from 19 patients diagnosed with PM or DM.
• Sequential HRCT scans were obtained before and after treatment in 17 patients over 2-61 months.
• Treatment regimens included corticosteroids, immunosuppressants, or a combination.

Main Results:

• Initial CT findings included pleural irregularities, prominent interlobular septa, ground-glass attenuation, patchy consolidation, parenchymal bands, and subpleural lines.
• No honeycombing was observed.
• Sequential CT scans in 16 patients showed improvement in consolidation, parenchymal bands, and peribronchovascular thickening, evolving into less severe findings.

Conclusions:

• Patchy consolidation, parenchymal bands, and irregular peribronchovascular thickening are characteristic CT findings in PM/DM.
• These characteristic CT findings demonstrate reversibility following treatment for PM/DM.