POS0842 LUNG ULTRASOUND TO ASSESS THE SEVERITY OF INTERSTITIAL LUNG DISEASE IN SYSTEMIC SCLEROSIS
Authors: C. Bruni, L. Mattolini, L. Tofani, L. Gargani, N. Landini, G. Lepri, M. Orlandi, S. Guiducci, S. Bellando Randone, M. Matucci-Cerinic
Journal: Annals of the Rheumatic Diseases (2021)

Background: Interstitial lung disease (ILD) is one of the most common complications and one of the main causes of morbidity and mortality in Systemic Sclerosis (SSc). High-resolution computed tomography (HRCT) is the gold standard for the diagnosis of ILD and it allows its quantification. Among semi-quantitative methods, Goh et al proposed a semi-quantitative scoring system to visually quantify ILD extent, with categorical cut-off of 20% to distinguish limited and extensive parenchymal involvement with prognostic implications. More recently, the use of radiomics has allowed the objective quantification of ILD through the use of dedicated software, which calculate different parameters of lung density. Given the exposure to ionizing radiation that the procedure entails, other methods of ILD evaluation are being studied, among which lung ultrasound (LUS) identifies the B-lines as a main feature of ILD. So far, different evidences have proposed the use of LUS for the screening of ILD, even in the early phases of the disease and in subclinical lung involvement. Objectives: the aim of this study is to test the role of LUS in quantifying the severity of SSc-ILD, evaluated with both semi-quantitative visual radiological and quantitative radiomic scores. Methods: Adult SSc patients classified according to the ACR/EULAR 2013 criteria patients were assessed with pulmonary function test (PFTs), lung ultrasound and HRCT over 60 days. CT images were analysed qualitatively (by presence/absence of ILD), semi-quantitatively (categorical Goh score &lt;20% vs&gt; 20% of extent and the continuous extent Goh score made from 5 levels’ assessment– 0 to 100%) and quantitatively [with the densitometric radiomic data obtained through the Horos software - Mean lung attenuation (MLA), Standard Deviation (SD), Kurtosis, Skewness and Lung volume (LV)]. LUS was used to quantify the B-lines detected in each patient by scanning a total of 13 intercostal spaces, on both anterior and posterior chest wall. Results: Among 59 SSc patients (81% women, mean age 48±14 years, 45% anti-Scl70 positive), 23 (39%) presented ILD on HRCT, of which 14 limited and 9 extensive. The mean visual semi-quantitative score was 6%, ranging from 0 to 66%. Our data showed a significantly different number of B-Lines in ILD vs non-ILD patients (median 38 vs 9, p &lt;.005), a result which was further confirmed among non-ILD vs ILD&gt; 20% (median 47 vs 9, p=.001) and ILD &lt;20% (median 36 vs 9, p=.001) patients. Conversely, the number of B-lines was not statistically different between patients with ILD &lt;20% and &gt;20% (median 47 vs 36, p=.78). We observed a significant negative correlation between the number of B-lines and FVC (r=-.472, p&lt;.05) TLC (r=-.436, p=.003), DLco (r=-.515, p&lt;.001), DLCO/VA (r=.-306, p=.03). Finally, the number of B-lines showed a statistically significant correlation with the Goh score on 5 levels (r=.437, p=.001), MLA (r=.571, p&lt;.001), kurtosis (r=-.285, p=.028), skewness (r=-.370, p = .004) and LV (r=-.277, p=.033). All data were confirmed analysing anterior and posterior B-Lines separately. Conclusion: Our study confirms that LUS represents a useful tool for the identification of SSc-ILD. In addition, we showed that LUS may be useful also for the quantification of the severity of SSc-ILD, by correlating with PFT parameters, radiomics parameters and visual radiological evaluation. Together with the PFTs, LUS could be used to increase the accuracy of the screening and, potentially, of the follow-up of SSc-ILD patients. Disclosure of Interests: Cosimo Bruni: None declared, Lavinia Mattolini: None declared, Lorenzo Tofani: None declared, Luna Gargani Consultant of: GE Healthcare, Philips Healthcare and Caption Health, Nicholas Landini: None declared, Gemma Lepri: None declared, Martina Orlandi: None declared, Serena Guiducci: None declared, Silvia Bellando Randone: None declared, Marco Matucci-Cerinic: None declared