Table 1. Characteristics of the patients and datasets.
| Train set | Internal test set | External test set | ||
|---|---|---|---|---|
| Patients | 242 | 60 | 20 | |
| Age, yr | 63.5 ± 12.1 | 64.0 ± 9.7 | 65.9 ± 11.5 | |
| Sex | ||||
| Male | 126 | 25 | 11 | |
| Female | 116 | 35 | 9 | |
| Series* | 536 | 126 | 49 | |
| Images | 8615 | 2100 | 704 | |
| Labeled area, cm2 | 2478224 | 535952 | 223152 | |
| Metastasis lesions | 3743 | 600 | 175 | |
| Volume of each metastasis, cm3 | ||||
| ≤ 0.5 | 769 (20.5) | 81 (13.5) | 24 (13.7) | |
| > 0.5 to ≤ 1.0 | 1449 (38.7) | 220 (36.7) | 35 (20.0) | |
| > 1.0 to ≤ 2.0 | 1016 (27.1) | 200 (33.3) | 34 (19.4) | |
| > 2.0 | 509 (13.6) | 99 (16.5) | 82 (46.9) | |
| Metastases per patient | 13.1 ± 21.1 | 10.3± 13.6 | 8.75 ± 5.5 | |
Data are number of patients or lesions with percentages in parentheses, or mean ± standard deviation.
*Series indicates a stack of T1-weighted sequences from each patient. For whole spine MRI is acquired in two or three subsequent scans for large coverage, from the skull base to the coccyx, MRI of each patient consists of two to three series of T1-weighted image, depending on the protocol of the study center and MRI machine