Chest CT Imaging Features of Progressive Phase COVID-19 Pneumonia and Evolution of Findings

Berrin Erok^{1, *}, Ali Önder Atça², Kenan Kıbıcı³

¹Department of  Radiology, Prof Dr Cemil Tascıoglu City Hospital, İstanbul, Turkey - ²Department of Radiology, Altinbas University School of Mediine Bahcelievler Medical Park Hospital,  İstanbul, Turkey - ³Department of Neurosurgery, Altınbas University School of Medicine Bahcelievler Medical Park Hospital, İstanbul, Turkey

Introduction: In the natural course of COVID-19 (coronavirus disease 2019) pneumonia, four stages have been described with aggrevation and extention of the lesions in the progressive stage and a more slower increase toward the maximum involvements in the peak stage before the absorption phase. A distinct pattern and time course of evolution is observed depending on the severity of the disease.

Materials and methods: We aimed to present chest CT findings of advanced stage Covid-19 pneumonia observed in our patients with rRT-PCR test-confirmed COVID-19, from the March 15 to August 15 2020.

Results: As the disease progress more central involvement of the lung with increased GGOs (with or withot reticulation) and consolidations occur and may be accompanied by development of organizing changes appearing usually as irregular, frequently linear consolidative opacities with possible bronchial changes. In addition, rarely encountered extraparenchymal findings and some atypical CT features unexpected to be identified in new coronavirus disease can be observed. In the survival patients this progressive period is followed by the absorption phase, which may or may not be accompanied by irreversible pulmonary changes like fibrosis or cystic formations. 

Conclusion: We believe that being familier with chest CT manifestations of advanced stage Covid-19 pneumonia and the changes throughout the disease process will be helpful in the management of Covid-19 pneumonia. Moreover, Covid-19 pneumonia can still be the concern in the presence of atypical findings either due to a coinfection/superinfection or as rarely occuring features with currently unknown mechanisms.