Table 1.

Gross classification with post-vascular phase image of contrast-enhanced ultrasonography.

Study	N	Inclusion Criteria of Tumor	Treatment	Evaluation	Results
Hatanaka et al. [28]	29	Solitary and ≤5 cm ≤3 tumors and ≤3 cm	LR	Gross type (SN type or non-SN type)	Sensitivity, 96%; specificity, 80%; accuracy, 90%
Li et al. [29]	31	Early stage	LR	Microvascular invasion	Non-SN type in the post-vascular phase image was an independent predictor of microvascular invasion (OR, 30.51; 95% CI, 2.335–398.731, p = 0.009). Sensitivity, 93.3%; specificity, 81.3%; positive predictive value, 82.4%; negative predictive value, 92.9%
Nuta et al. [30]	73	Solitary and ≤5 cm	LR	Gross type (SN type or non-SN type) Outcome (recurrence)	In the post-vascular phase, predictability for high-grade malignant potential was as follows: sensitivity was 93%, specificity was 85%, positive predictive value was 97%, negative predictive value was 73%, and accuracy was 92%. Irregular defect pattern was one of the independent factors for metastatic recurrence (HR, 4.388; 95% CI, 1.008–19.089; p = 0.049).

CI: confidence interval; HR: hazard ratio; LR: liver resection; RFA: radiofrequency ablation; OR: odds ratio; SN: simple nodular.