Shorter hepatic transit time can suggest coming metastases: through-monitoring by contrast-enhanced ultrasonography?

Objective. The aim of this study was to assess the value of the hepatic transit time in suggesting coming liver metastases by contrast-enhanced ultrasonography (CEUS). Methods. Fifty patients with identified liver metastasis (metastasis group [Gmet]), 26 patients without liver metastasis (unclear group [Gunc]) who had proven extrahepatic malignant tumors, and 27 healthy control volunteers (control group [Gcon]) were included in this study. The Gmet group was divided into small and large subgroups. The Gmet group was also divided into pauci and multi subgroups. Every patient was examined by CEUS. The hepatic artery and hepatic vein arrival times were measured, and the difference between them was calculated as the hepatic artery-vein transit time (HAVTT). Patients in Gunc were given a CEUS examination and an enhanced computed tomography or magnetic resonance imaging examination 3 to 4 months later. Results. The HAVTTs in Gmet were significantly shorter than those in Gcon (P < .05), but there were no statistical differences among the subgroups. A normal cutoff point of 8 seconds in the HAVTTs could distinguish Gmet and Gcon with accuracy, sensitivity, and specificity of 97.40%, 92.59%, and 100%, respectively. As for Gunc, when an HAVTT shorter than 8 seconds was used to predict liver metastasis, the accuracy, sensitivity, and specificity were 92.30%, 100%, and 91.67%. Conclusions. The HAVTT may be a useful tool in monitoring liver micrometastases. If a patient with a primary malignant tumor has a shorter HAVTT, it suggests that an extra examination and additional therapy are needed.