DEVELOPMENT OF RADIOLOGICAL ABNORMALITIES ON CHEST CT SCAN IN COVID-19 PATIENTS

SESSION TITLE: Chest Infections Posters 10 SESSION TYPE: Original Investigation Posters PRESENTED ON: 10/11/2023 12:00 pm - 12:45 pm PURPOSE: To assess chest CT abnormalities 3 and 12 months after discharge for COVID-19 during the first wave of the pandemic, from February to June 2020. Participants in this study were treated on a compassionate care basis, since no specific treatment regimens were established at that time. METHODS: Low-dose, thin-section CT images were obtained in supine and prone position, during breath-holding and deep inspiration. The tube current was adjusted to each patient’s weight with shortest possible rotation time. The presence and extent of ground-glass opacities (GGO), parenchymal bands (PB), reticulation (RET) (grade 1-2), and mosaic pattern (MP) was evaluated. The lung parenchyma was assessed at four different levels in the transverse plane, and findings were quantified by two independent, experienced thoracic radiologists, unaware of the patients’ clinical history. For each predefined chest CT feature, they assessed the extent of affected lung parenchyma in each level (None= score 0; 1-2 % of the lung parenchyma = 1; 3-10 % = 2; 11-60 % = 3). The scores at the four levels were summed to an ordinal chest CT severity score (CSS) on a 0 = no abnormalities to 12 = severe scale. Scores were compared using Wilcoxon sign rank test. RESULTS: Of 242 participants, 124 had at least one CT abnormality at 3 months and completed a follow-up chest CT at 12 months. Among those 124, GGO was the most common finding at both time points. The GGO CSS decreased from 3 to 12 months, from median GGO CSS 3 (interquartile range (IQR) 0-8) to 0.5 (IQR 0-4), p<0.001. At 12 months, a GGO CSS of 0 was found in 62 patients (50%), a GGO CSS of 1 in 11 (9%) a GGO CSS of 2 in 7 (6%), a GGO CSS of 3 in 12 (10%), a GGO CSS of 4 in 10 (8%), and a GGO CSS ≥ 5 in 22 (18%). The second most common finding was PB, which increased from 3 to 12 months, from median CSS 0 (IQR 0-7) to median CSS 0.5 (IQR 0-8), p=0.003. MP decreased over time from MP CSS median of 0 (IQR 0-8) to 0 (0-7), p<0.001. There was no difference in RET between the two time points (RET grade 1, p=0.13 and RET grade 2, p=0.09). CONCLUSIONS: The extent of parenchymal bands on chest CT, an indication of pulmonary fibrosis, increased from 3 to 12 months after hospitalization for COVID-19, while ground glass opacities and mosaic pattern, indications of pulmonary inflammation, decreased. CLINICAL IMPLICATIONS: The spontaneous decrease in inflammatory changes found on chest CT during the first year after hospitalization for COVID-19 is encouraging, while the increase of potential fibrotic-like findings such as parenchymal bands highlights the need for clinical follow-up of selected COVID-19 patients. DISCLOSURES: No relevant relationships by Trond Mogens Aaløkken No relevant relationships by Einar Hopp No relevant relationships by Carin Meltzer No relevant relationships by Jezabel Rivero Rodriguez No relevant relationships by Ole Henning Skjønsberg No relevant relationships by Knut Stavem No relevant relationships by Tøri Vigeland Lerum