THE ROLE OF CHEST CT IN DECIPHERING INTERSTITIAL LUNG INVOLVEMENT: SYSTEMIC SCLEROSIS VERSUS COVID-19.

Orlandi, Martina; Landini, Nicholas; Sambataro, Gianluca; Nardi, Cosimo; Tofani, Lorenzo; Bruni, Cosimo; Bellando-Randone, Silvia; Blagojevic, Jelena; Melchiorre, Daniela; Hughes, Michael; Denton, Christopher P; Luppi, Fabrizio; Ruaro, Barbara; Della Casa, Francesca; Rossi, Francesca W; De Luca, Giacomo; Campochiaro, Corrado; Spinicci, Michele; Zammarchi, Lorenzo; Tomassetti, Sara; Caminati, Antonella; Cavigli, Edoardo; Albanesi, Marco; Melchiorre, Fabio; Palmucci, Stefano; Vegni, Virginia; Guiducci, Serena; Moggi-Pignone, Alberto; Allanore, Yannick; Bartoloni, Alessandro; Confalonieri, Marco; Dagna, Lorenzo; De Cobelli, Francesco; De Paulis, Amato; Harari, Sergio; Khanna, Dinesh; Kuwana, Masataka; Taliani, Gloria; Lavorini, Federico; Miele, Vittorio; Morana, Giovanni; Pesci, Alberto; Vancheri, Carlo; Colagrande, Stefano; Matucci-Cerinic, Marco

OBJECTIVE To identify the main computed tomography (CT) features that may help distinguishing a progression of interstitial lung disease (ILD) secondary to Systemic sclerosis (SSc) from COVID-19 pneumonia. METHODS This multicentric study included 22 international readers divided in the radiologist group (RAD) and non-radiologist group (nRAD). A total of 99 patients, 52 with COVID-19 and 47 with SSc-ILD, were included in the study. RESULTS Fibrosis inside focal ground glass opacities (GGO) in the upper lobes; fibrosis in the lower lobe GGO; reticulations in lower lobes (especially if bilateral and symmetrical or associated with signs of fibrosis) were the CT features most frequently associated with SSc-ILD. The CT features most frequently associated with COVID- 19 pneumonia were: consolidation (CONS) in the lower lobes, CONS with peripheral (both central/peripheral or patchy distributions), anterior and posterior CONS and rounded-shaped GGOs in the lower lobes. After multivariate analysis, the presence of CONS in the lower lobes (p < 0.0001) and signs of fibrosis in GGO in the lower lobes (p < 0.0001) remained independently associated with COVID-19 pneumonia or SSc-ILD, respectively. A predictive score was created which resulted positively associated with the COVID-19 diagnosis (96.1% sensitivity and 83.3% specificity). CONCLUSION The CT differential diagnosis between COVID-19 pneumonia and SSc-ILD is possible through the combination the proposed score and the radiologic expertise. The presence of consolidation in the lower lobes may suggest a COVID-19 pneumonia while the presence of fibrosis inside GGO may indicate a SSc-ILD.