Table 2. Lesion types of referable thoracic abnormalities on chest radiographs (determined based on computed tomography [CT]).
| Lesion type | Institutions | P-value* | |||
|---|---|---|---|---|---|
| B | G | K | Total | ||
| (n = 1,694) | (n = 1,858) | (n = 2,335) | (n = 5,887) | ||
| Normal (no referable thoracic abnormality) | 1,571 | 1,594 | 2,105 | 5,270 | <0.001 |
| (92.7) | (85.8) | (90.1) | (89.5) | ||
| Target lesions† | 50 (3.0) | 68 (3.7) | 115 (4.9) | 233 (4.0) | 0.003 |
| Nodule/mass | 44(2.6) | 65 (3.5) | 94 (4.0) | 203 (3.4) | |
| Consolidation | 6 (0.4) | 3 (0.2) | 23 (1.0) | 32 (0.5) | |
| Pneumothorax | 0 (0.0) | 0 (0.0) | 1 (<0.1) | 1 (<0.1) | |
| Non-target lesions | 74 (4.4) | 205 (11.0) | 127 (5.4) | 406 (6.9) | <0.001 |
| Atelectasis or fibrosis | 18 (1.1) | 21 (1.1) | 22 (0.9) | 61 (1.0) | |
| Bronchiectasis | 35 (2.1) | 70 (3.8) | 21 (0.9) | 126 (2.1) | |
| Cardiomegaly | 5 (0.2) | 10 (0.5) | 28 (1.2) | 43 (0.7) | |
| Diffuse interstitial lung opacities | 4 (0.2) | 6 (0.3) | 10 (0.4) | 20 (0.3) | |
| Mediastinal lesion | 1 (0.1) | 0 (0.0) | 3 (0.1) | 4 (0.1) | |
| Pleural effusion | 1 (0.1) | 1 (0.1) | 1 (0.1) | 2 (0.1) | |
| Other | 13 (0.8) | 101 (5.4) | 46 (2.0) | 160 (2.7) | |
| Sum of target or non-target lesions | 127 | 277 | 250 | 654 | <0.001 |
| No. of lesion type per subject‡ | 0.07 (0–2) | 0.15 (0–2) | 0.11 (0–2) | 0.11 (0–2) | |
Note: Except where indicated, data are numbers of patients, with percentages in parentheses.
*Comparison of proportions between institutions for each lesion type by chi-squared tests.
†Target lesions were dedicated lesion types for the deep-learning algorithm used in this study.
‡No. of lesion types per subject was calculated in subjects with target or non-target lesions.
The numbers in parentheses are ranges.