Cross-sectional analysis of quantitative computed tomography parameters and pulmonary function in anti-synthetase...

To characterise longitudinal changes in chest computed tomography (CT) features and to investigate the relationship between quantitative CT and pulmonary functions in patients with anti-synthetase syndrome-associated interstitial lung disease (ASyS-ILD).

This retrospective study included 60 newly diagnosed patients with ASyS-ILD (April 2014-December 2022), who were positive for anti-synthetase antibodies and had undergone at least two chest CT examinations. Clinical, serological, pulmonary function test, and CT data were analysed. CT abnormalities and imaging patterns were assessed visually and quantitatively using semi-quantitative CT scoring and automated quantitative CT software. Patients were stratified according to clinical outcomes (regression, stability, or deterioration) and baseline disease severity.

Median follow-up duration was 25 months, during which 404 CT scans were reviewed. At baseline, ground-glass opacities, linear opacities, and consolidations were the predominant imaging findings. Over time, traction bronchiectasis showed significant progression (p<0.001), whereas consolidation, pleural thickening, and organising pneumonia (OP) patterns decreased significantly (p<0.05). Fibrotic patterns increased overall, particularly in the anti-PL-12 (100%), anti-Jo-1 (77.4%), and anti-EJ (77.8%) subgroups. Baseline traction bronchiectasis was more frequently observed in the stability and deterioration groups, whereas OP pattern and consolidation were more common in the regression group. Both CT scores and quantitative CT parameters, including mean lung density (MLD) and high-attenuation volume percentage (HAV%), showed strong correlations with FVC%, FEV1%, TLC, and VC, and moderate correlations with DLco%. Compared with the less advanced group, the more advanced group exhibited significantly higher CT scores (13.0±2.1 vs. 9.2±2.4, p<0.001), higher MLD values (-696±58 vs. -768±61, p=0.001) and HAV% (6.3±1.6 vs. 4.3±2.1, p=0.002), as well as lower low-attenuation volume percentage (LAV%) (5.6±8.0 vs. 11.3±10.1, p=0.049).

CT assessments in patients with ASyS-ILD demonstrate a progressive shift toward fibrotic patterns over time. Both CT scores and quantitative CT parameters are strongly associated with pulmonary function and reflect disease severity,supporting their potential value inindividualised clinical evaluation.