Purpose: A systematic single-center analysis was performed to evaluate the efficacy of contrast-enhanced ultrasonography (CEUS) in the detection of colorectal liver metastases in patients with systemic chemotherapy in their medical history.
Materials and methods: Between May 2005 and December 2007, 48 patients were referred to our institution for further evaluation after chemotherapeutic pretreatment for colorectal liver metastases. In all cases, the liver was screened by both unenhanced and contrast-enhanced ultrasonography with SonoVue to detect focal liver lesions. The results of sonographic explorations were prospectively collected and compared with intraoperative findings including histopathological results as reference.
Results: A total of 40 patients underwent laparotomy and were included in the analysis. The rate of correct ultrasound findings (rate of detection) increased from 24 patients (60%) with 35 metastases (57.4%) to 31 patients (77.5%) with 50 metastases (82.0%) after administration of SonoVue. Thus CEUS showed a significantly improved sensitivity compared to unenhanced US in both patient-by-patient analysis (79.5 versus 63.2%, p = 0.041) and lesion-by-lesion analysis (82.0 vs. 60.3%, p = 0.0008). On the basis of the ultrasound results, the surgical strategy had to be changed in 16 (40.0%) cases examined by unenhanced US compared to only nine cases (22.5%) examined by CEUS (p = 0.002). In CEUS a higher number of lesions were identified with an increasing metastasis size.
Conclusion: After chemotherapeutic pretreatment, unenhanced US should be replaced by CEUS for the detection of liver metastases from colorectal carcinoma.