Associations of COVID-19 with post-acute dual-energy lung CT (DECT) measures

<bold>Background:</bold> COVID-19 causes acute damage to the lung parenchyma and vasculature, and persistent or post-acute damage has been reported. <bold>Aims:</bold> Test associations of COVID-19 history with post-acute lung parenchymal and vascular structure on DECT. <bold>Methods:</bold> Adults with history of hospitalized (severe) COVID-19, without mechanical ventilation, or non-hospitalized (non-severe) infection, were recruited from New York City starting in 2021. DECT was performed ≥6 months after COVID-19; the Omicron period was defined as November 2021 or later. Lung density was measured as the 15th percentile of the lung density histogram (%HU15). The adaptive multiple feature method defined % lung with ground glass/reticular pattern (AMFM_ggo-r). Pulmonary microvascular blood volume (PBV_m) was measured from the peripheral 2cm of the lung. Measures were regressed on COVID-19 history adjusted for age, sex, and smoking. <bold>Results:</bold> Of 103 COVID-affected participants (mean 51 years old, 47% male, 62% Hispanic, 11% current smoker), mean months-since-COVID was 16. 65/69(94%) of severe cases were pre-Omicron, vs 8/34(24%) of non-severe cases. %HU15 was higher with severe vs non-severe COVID-19 (+20HU, p=.009) and greater months-since-COVID in both pre-Omicron (+2HU, p=.03) and Omicron (+1HU, p=.04) periods. AMFM_ggo-r was higher with severe vs non-severe COVID-19 (+2.8%; p=.04) and with greater months-since-COVID in pre-Omicron (+0.4%; p=.01) and Omicron (+0.2%; p=.08) periods. PBV_m was not associated. <bold>Conclusion:</bold> Higher lung density and GGO/reticular abnormalities were observed after severe vs non-severe COVID-19 and with greater time-since-infection, consistent with persistent—and potentially progressive—inflammatory or fibrotic changes.