Material and Method: The medical records of all SSc-ILD patients who presented at the Rheumatology Clinic, Chiang Mai University Hospital were retrospectively reviewed. Patients with the availability of echocardiography performed within six months of the corresponding HRCT were included. The extent of ground glass, lung fibrosis, and honeycombing were scored. The maximum diameter of the main pulmonary artery (MPAD) and ascending aortic diameter (AD) were measured. The PAH was defined by sPAP ≥45 mmHg.

Results: Fifty patients with SSc-ILD diagnosed with HRCT were included. Echocardiography identified 19 (38.0%) patients with PAH. The SSc-ILD with PAH had significantly higher mean (SD) lung fibrosis (9.9 [3.6] vs. 7.8 [3.5], p = 0.03), and CT-total scores (20.5 [6.9] vs. 14.9 [6.2], p<0.01) than those without PAH. In the total group, the CT-total score correlated positively with sPAP (r = 0.384, p<0.01). No significant correlation of MPAD or MPAD/AD with sPAP was found.

Conclusion: SSc-ILD with PAH had more severe lung fibrosis than those without PAH. The calculated total HRCT score may be useful to identify PAH in SSc-ILD.

Keywords: High resolution computed tomography (HRCT), Systemic sclerosis (SSc), Echocardiography, Interstitial lung disease (ILD), Pulmonary arterial hypertension (PAH)