CT imaging and lung segmentation analysis of SARS-CoV-2 variants and vaccination impacts on lung impairment quantification

This study analyzed Chest CT exams from 592 patients with SARS-CoV-2 between 2020 and 2022 using the open-source 3D Slicer software. We conducted lung segmentation and volume quantification to investigate inflated lung volume and different impairments volumes (inflammatory process and fibrosis, ground-glass opacities and the total affected lung) against SARS-CoV-2 variants (original strain, gamma, delta and omicron) during a mass vaccination campaign carried out in Botucatu/SP-Brazil (before, during, and after three doses). We aimed to verify whether these parameters (variants and vaccination) affected lung impairments. Our findings indicated that gamma variant was more detrimental than delta and omicron variants, with higher volumes in inflammatory process and fibrosis (13.78% against 9.00% and 8.90%), ground-glass opacity (31.73% against 25.81% and 29.04%) and total affected volume (45.99% against 35.26% and 38.43%), while a lower volume was observed for inflated lung volume (50.04% against 58.19% and 57.50%). The results also revealed substantial differences in pulmonary impairments between the first and the third vaccination stages. We noticed a reduction in volumes of inflammatory process and fibrosis (14.51% to 9.19%), ground-glass opacity (33.67% to 26.77%) and the total affected volume (48.60% to 36.42%), while inflated lung volume increased (48.80% to 58.12%). The study brings novelty approach and findings that enhances the understanding of variant-specific impacts on pulmonary impairments and highlights the vaccine efficacy in reducing lung damage from SARS-CoV-2.