SEMIQUANTITATIVE AND QUANTITATIVE ANALYSIS OF LUNG CT IN THE ASSESSMENT OF INTERSTITIAL LUNG DISEASE IN IDIOPATHIC INFLAMMATORY MYOPATHIES WITH A FOCUS ON ANTISYNTHETASE.

Background: Interstitial lung disease (ILD), is common in patients with idiopathic inflammatory myopathies (IIM) and strongly impact on patients’ morbidity and mortality. Patients with anti-aminoacyl-transfer RNA-synthetases (anti-ARS) antibodies are associated with an increased risk of ILD. Objectives: Defining the radiological characteristics of IIM patients, with special focus on serological groups, through qualitative, semiquantitative and quantitative analysis of lung CT. Methods: This was a prospective study conducted from 2016 to 2019. Ninety-eight IIM patients (35 men, 63 women) were included. Myositis specific autoantibodies (MSA) were assessed with Myositis Prophyle III (Euroimmune, Lubeck). Each patient had a baseline CT; the total score of Warrick (WS) was obtained at semiquantitative analysis. The radiological scores ILD% (interstitial lung disease %) and PVRS% (pulmonary vascular related structure) were the result of quantitative analysis in 61 patients (CALIPER). Pulmonary function tests (PFTs) included TLC%, FVC% and DLCO% (65 patients). The analysis was conducted in the whole group and divided in subgroups based on their MSA pattern: in particular anti-ARS (Group 1) and patients negative to MSA (Group 2) were analysed. Results: Positive correlations between ILD% and PVRS% (Rho=0.916; ρ=0.000), WS and ILD% (Rho=0.663; ρ=0.000) and WS and PVRS% (Rho=0.637; ρ The most relevant inverse correlations were found between ILD% and DLCO% (Rho=-0.590; ρ=0.001), PVRS% and DLCO% (Rho=-0.549; ρ Statistically significant higher values of WS, ILD% and PVRS% were found in Group 1 (WS=15, ILD%=11 and PVRS%=3.5), compared to Group 2 (WS=2.5, ILD%=0.84 and PVRS%=2.2). NSIP pattern resulted dominant represented in the two groups (80% Group 1, 75% Group 2). No statistically significant differences of DLCO%, FVC% and TLCO% were found. Conclusion: The inverse correlations between the radiological scores and the functional data TLC% and DLCO% (ρ Disclosure of Interests: None declared