Objective To investigate tumour-associated influencing factors for enhancement pattern of colorectal liver metastases (CLM) in contrast-enhanced ultrasonography (CEUS).

Methods Previously untreated patients with CLM were continuously recruited from applicants of our institute. Liver CEUS was performed in patients with surgically resectable primary and secondary cancer. 76 patients were finally incorporated into the analysis. After preoperative contrast-enhanced ultrasonography of liver, according to enhancement patterns, it was divided into three groups:ring enhancement group (16 cases), global inhomogeneous enhancement group (29 cases) and global homogeneous enhancement group (31 cases). Tumour-associated cliniocpathological characteristics was compared between three groups. Then influencing factors of enhancement pattern and the interrelationship were further analyzed.

Results Influencing factors of enhancement pattern were size of index lesion, sum of volume of liver metastases, tumour deposits status, preoperative CA19-9 level and carcino-embryonic antigen (CEA) level. The independent influencing factors of enhancement pattern were size of index lesion, sum of volume of liver metastases and preoperative CA19-9 level.

Conclusions Enhancement pattern of CLM in CEUS does have tumour-associated clinicopathological bases, It has certain value for judging tumor condition, whether contrast-enhanced ultrasound can reflect the tumor load of the liver, judge the level of tumor markers, the relationship between contrast-enhanced ultrasound and tumor nodule and whether it can be helpful for clinical prognosis judgment should be further explored.