- On chest CT in patients with COVID-19, four stages of evolution can be observed ; early stage (0-4 days), progressive stage (5-8 days), peak stage (10-13 days) and absorption stage (+14 days).
- The most common chest CT feature is bilateral ground-glass opacity (GGO) alone. Consolidations are the second most predominant feature.
- Early stage: Presence of unilateral or bilateral GGOs is the main radiological presentation.
- Progressive stage : Presence of bilateral multi-lobe distribution GGOs, crazy paving pattern and consolidation.
- Peak stage : Presence of dense consolidations, diffuse GGOs, crazy paving pattern and residual parenchymal bands.
- Absorption stage : Presence of GGOs as the demonstration of consolidation absorption. Crazy paving patterns are normally not present.
- 94% of patients discharged from hospital still present residual disease on final CT.
This data was provided by two studies :
- A longitudinal observational prospective study from China of 90 patients with suspected COVID-19 pneumonia. Inclusion criteria included at least one positive results of RT-PCR for COVID-19 and at least one CT scan presenting lung abnormalities before or after admission.
- A retrospective review from China of 21 patients with RT-PCR confirmed COVID-19 patients. Patients with severe respiratory distress and/or patients requiring oxygen at any given time of the disease were excluded.
- Wang, Y., Dong, C., Hu, Y., Li, C., Ren, Q., & Zhang, X. et al. (2020). Temporal Changes of CT Findings in 90 Patients with COVID-19 Pneumonia: A Longitudinal Study. Radiology, 200843. doi: 10.1148/radiol.2020200843. Retrieved from : https://pubs.rsna.org/doi/10.1148/radiol.2020200843
- Pan, F., Ye, T., Sun, P., Gui, S., Liang, B., & Li, L. et al. (2020). Time Course of Lung Changes On Chest CT During Recovery From 2019 Novel Coronavirus (COVID-19) Pneumonia. Radiology, 200370. doi: 10.1148/radiol.2020200370. Retrieved from : https://pubs.rsna.org/doi/10.1148/radiol.2020200370