Contrast-enhanced ultrasound features of histologically proven small (≤20 mm) liver metastases

We analyzed contrast-enhanced ultrasound (CEUS) features of histologically proved small (≤20 mm) liver metastases, in comparison to small (≤20 mm) hepatocellular carcinomas (HCC), to define the differentiate diagnoses value of CEUS in clinical practice.

Eighty-two cases of small (≤20 mm) liver metastases and 84 cases of small (≤20 mm) HCC were retrospectively reviewed. All patients had CEUS images. Two radiologists assessed CEUS enhancement pattern and time of enhancement in consensus. Statistical analyses were performed using SPSS v.19.0 (SPSS Inc., Chicago, IL). The χ² test and the independent sample t-test were used to compare the differences.

Comparing to small HCCs, rapid rim-like hyper-enhancement in arterial phase (56.1% in liver metastases vs. 2.3% in HCCs, p < .01), rapid wash-out and become hypo-enhancement in late arterial phase or early portal venous phase (96.4% in liver metastases vs. 22.6% in HCCs, p < .01) with central non-enhanced area in late phase were characteristic CEUS features of small metastases.

CEUS imaging enhancement findings reliably offer typical signs of small liver metastases, differentiate effectively with small HCCs. CEUS can help to improve the diagnostic confidence of small liver metastases.