Background Pulmonary fibrosis (PF) is a frequent manifestation in systemic sclerosis (SSc). Currently, high resolution computer tomography (HRCT) is the most common imaging technique used in the assessment of PF; however, its use involves high dose of ionising radiation. Recently the potential role of ultrasound (US) B-lines for the assessment of PF has been proposed (1-2). However studies aimed to test its validity are still lacking.
Objectives To investigate the validity, reliability and feasibility of the US in the assessment of PF by a correlation with HRCT, pulmonary function test (PFT) and histological findings in patients with SSc.
Methods Seventy-two patients with diagnosis of SSc were included. Each patient underwent clinical examination, PFT, chest HRCT and US. In 22 patients a histological assessment of the lung was assessed. HRCT and lung US were performed by experienced radiologist and rheumatologist respectively. A second rheumatologist carried out US examinations to assess the inter-observer agreement. In each patient a simplified US B-lines assessment as previously proposed (3) was performed. It included bilaterally 14 lung intercostal spaces (LIS): for the anterior chest: 2nd LIS along the para-sternal lines, 4th LIS along the mid-clavear, anterior axillary and mid-axillary lines. For the posterior chest: 8th LIS along the paravertebral, sub-scapular and posterior axillary lines. The following semiquantitative scoring was adopted was [0 = normal, (<5 B-lines); 1 = mild (from 6-15 B-lines); 2 = moderate (from 16 to 30 B-lines) and 3 = marked (>30 B-lines). For criterion validity, the histological assessment was considered the gold standard. Feasibility and intra-observer reliability was also investigated.
Results A total of 1008 LIS in 72 patients were assessed. A significant linear correlation between US B-lines, HRCT score (p<0.001) and histological assessment (p<0.0001) was found. Moreover, a positive correlation was obtained between US B-lines assessments and values of DLco (p=0.014). Both kappa values and overall agreement percentages of inter-observer showed an excellent agreement (0.943 and 93% respectively). The mean time spent for each US examination (including the 14 LIS), was 8.9 ±SD 1.4, range 6-12 minutes.
Conclusions Our preliminary results support the validity and reliability of US as additional imaging method in the assessment of PF in patients with SSc.
Gargani L, et al. Ultrasound lung comets in sistemic sclerosis: a chest sonography hallmark of pulmonary interstitial fibrosis. Rheumatology 2009;48:1382-7.
Barskova T, et al. Lung ultrasound for the screening of interstitial lung disease in very early systemic sclerosis Ann Rheum Dis 2013;72:390-5.
Gutierrez M, et al. Utility of a simplified ultrasound assessment to assess interstitial pulmonary fibrosis in connective tissue disorders-preliminary results. Arthritis Res Ther 2011:18;13:R134.
Disclosure of Interest None declared