Background. The rare but disturbing consequence of the severe COVID-19 pneumonia is progressive degradation of lung tissue as bullous-emphysematous changes or vanishing lung syndrome (VLS).
Aim: to investigate the CT characteristics of vanishing lung syndrome in patients (pts) after severe COVID-19 pneumonia.
Methods. 67 pts who suffered severe pneumonia during the acute period of COVID-19 and need repeated hospital admission due to respiratory failure in the term 3?6 month after disease start were examined. All pts underwent CT scan. CT scans of pts with VLS were analyzed.
Results. VLS was revealed in 16 (12 (75%) men) from 67 pts aged 31 to 68 (52.6±3.3) years. The CT characteristics are shown in Table 1.
Table 1. VLS CT scan changes and their frequency (n, %)
| Parameter | abs | % |
| One side distribution | 6 | 37.5 |
| Two sides distribution | 6 | 37.5 |
| Diffuse lung involvement | 4 | 25 |
|
Solitary bulla: a large (~105x55mm) thin-walled cavity a cavity of destruction 76x92x76mm a cyst-like cavity 76x51x60 mm cyst-shaped cavity 60x45x43mm with a partition |
4 | 25 |
| Two bullas (the max size 89x61 and 37x49mm) | 3 | 18.8 |
| Multiple bullas | 5 | 31.3 |
| Bullous emphysema | 4 | 25 |
| Ground-glass opacities (GGO) | 12 | 75 |
| Interlobular septal thickening (ILST) | 12 | 75 |
| Fibrosis-like changes | 9 | 56.3 |
| Lung consolidation | 6 | 37.5 |
| Traction bronchiectasis | 5 | 31.3 |
| Air bronchogram | 1 | 6.3 |
| Pneumothorax | 3 | 18.8 |
| Pneumomediastinum | 1 | 6.3 |
Conclusion. After severe COVID-19 pneumonia not only GGO, ILST, fibrosis-like changes and lung consolidation, but the VLS occurs. Mainly VLS appears as the multiple bullas, solitary bullas and rare as bullous emphysema with diameter more 30 mm in a half of cases. The threatening complication of VLC is pneumothorax.