Table 3.
Comparison of CT characteristics of COVID-19 patients at four time points, using the chi-square test or Fisher’s exact test
| Time | baseline | 1–6 days | 7–13 days | ≥ 14 days | p value |
|---|---|---|---|---|---|
| Number of patients | 29 | 29 | 27 | 28 | |
| Lesion-to-muscle density ratio (LMR) | − 6.9 (− 12.0, − 4.9) | − 2.2 (− 4.5, − 0.53) | − 4.9 (− 7.8, − 2.2) | − 10.7 (− 12.1, − 7.8) | < 0.001 |
| Number of involved lobes | 3 (1, 5) | 5 (2, 5) | 4 (2, 5) | 4 (2, 5) | 0.149 |
| Pulmonary inflammation index (PII) | 17.5 (5.0, 30.0) | 35.0 (11.3, 51.3) | 32.5 (20.0, 50.0) | 19.0 (10.6, 37.8) | 0.012 |
| Without lesions | 2 | 1 | 0 | 0 | < 0.001 |
| Increase in lesions | 0 | 24 | 8 | 4 | |
| Concurrent increase and decrease | 0 | 4 | 3 | 2 | |
| Decrease in lesions | 0 | 0 | 16 | 22 | |
| Interlobular septa thickening | 10 | 12 | 16 | 14 | 0.274 |
| Parenchymal bands | 4 | 13 | 21 | 21 | < 0.001 |
| Air bronchogram | 6 | 14 | 11 | 11 | 0.164 |
| Pleural thickening | 7 | 6 | 8 | 12 | 0.272 |
| Pleural effusion | 0 | 1 | 0 | 0 | 0.404 |
| Architectural distortion | 0 | 4 | 15 | 19 | < 0.001 |
Quantitative data were presented as median (Q25–Q75), using Kruskal-Wallis H test. Categorical data are presented as count, using chi-square test or Fisher’s exact test to calculate p values as appropriate. P < 0.05 was regarded as significantly different between four groups. Increase in lesions, concurrent increase and decrease, or decrease in lesions referred to the changes in the number and/or size of the lesions compared with the previous CT scan