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

Aims: 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.

Methods: 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.

Results: 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).

Conclusion: 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.