Table 1. The basic information of the included literatures.
| First author | Publication year | Number of nodules | Number of malignant nodules | Number of benign nodules | Diagnostic method |
|---|---|---|---|---|---|
| Deng (28) | 2014 | 175 | 56 | 119 | CEUS |
| Jin (29) | 2017 | 74 | 34 | 41 | CEUS |
| Li (30) | 2015 | 80 | 50 | 30 | CEUS |
| Liu (31) | 2019 | 131 | 72 | 59 | Conventional ultrasound |
| Li (32) | 2015 | 103 | 53 | 50 | Conventional ultrasound |
| Shuzhen (33) | 2012 | 291 | 66 | 225 | Conventional ultrasound |
| Wang (34) | 2019 | 102 | 27 | 75 | Conventional ultrasound |
| Wu (35) | 2016 | 96 | 4 | 92 | CEUS |
| Zhang (36) | 2010 | 104 | 51 | 53 | CEUS |
| Zhao (37) | 2019 | 117 | 57 | 60 | CEUS |
| Zhao (38) | 2015 | 102 | 63 | 39 | Conventional ultrasound |
CEUS, contrast-enhanced ultrasound.