Semi-quantitative scoring system to quantify COVID-19 lung involvement [41]

Area involvedScores
No involvement0
< 5% involvement1
25% involvement2
26–49% involvement3
50–75% involvement4
> 75% involvement5

The total CT score is the sum of the scores of each of the five lung lobes and ranges from 0 (no involvement) to 25 (maximum involvement), which approximates the degree of lung involvement and has prognostic significance for subsequent disease progression [41]