Usefulness of contrast-enhanced intraoperative ultrasonography (CE-IOUS) in patients with colorectal liver metastases after preoperative chemotherapy.

The aim of this study was to evaluate the ability of contrast-enhanced intraoperative ultrasonography to detect colorectal liver metastases after preoperative chemotherapy compared with intraoperative ultrasound and preoperative imaging techniques.From January 2010 to December 2011, 28 patients with colorectal liver metastases underwent intraoperative ultrasonography and contrast-enhanced intraoperative ultrasonography during hepatectomy following preoperative chemotherapy. The findings were compared to preoperative imaging using contrast-enhanced ultrasonography, computed tomography, magnetic resonance imaging, and/or fluorodeoxyglucose positron emission tomography.Preoperative imaging techniques detected 58 metastatic lesions in 28 patients. In 32 % of patients (n = 9), intraoperative ultrasound detected 24 missed hepatic nodules. In 14 % of patients (n = 4), contrast-enhanced intraoperative ultrasonography detected an additional six nodules and change in operative management occurred in 18 % of patients. Using univariate analysis, we found three factors significantly related to detection of additional metastases with contrast-enhanced intraoperative ultrasonography: three or more metastases before chemotherapy (p = 0.047), resolution of at least one metastasis (p = 0.011), and small liver metastases (largest lesion size ≤20 mm) after chemotherapy (p = 0.007).In patients undergoing surgery for colorectal liver metastases after chemotherapy, contrast-enhanced intraoperative ultrasonography improved both the sensitivity of intraoperative ultrasonography to detect liver metastases and the R0 hepatic resection rate.