Post-COVID-19 sequelae in lungs: retrospective computed tomography analysis in selected tertiary care hospitals of Mangalore

Introduction
The radiological features of COVID-19 during the active disease process are well established, but the radio­logical features in the convalescent and post-recovery period of the disease are still unclear. The objectives of this study are to document and assess the proportion of the residual changes in lung post COVID-19 infection and to look for evidence and the proportion of fibrosis post COVID-19 infection on high-resolution computed tomography (HRCT).

Material and methods
HRCT thorax of COVID-positive cases done during the disease process and in the recovery/post recovery phase were included in the study. Sample Size: 75. Categorical data are represented in the form of frequencies and proportions. The 2 test was used as a test of significance for qualitative data. Continuous data are represented as mean and standard deviation. A p-value (probability that the result is true) of < 0.05 was considered as statistically significant after assuming all the rules of statistical tests.

Results
Initial computed tomography (CT) findings mainly included ground glass opacity (GGO) (93.3%), inter­lobular septal thickening (66.7%), consolidation (52.0%), and fibrotic bands (8.0%). Ninety-two per cent of the CT scans demonstrated some pulmonary change in the follow-up CT. This was mostly in the form of GGO (58%). Approximately 17% of cases showed fibrotic changes in the follow-up CT.

Conclusions
Post-COVID lung sequelae can be present in a significant number of patients. This are mostly seen in patients with severe initial disease and in older patients. Statistically significant post-COVID sequelae changes include GGO, fibrotic bands, and bronchiectasis.