The role of contrast-enhanced ultrasound in detection of liver metastases from colorectal cancer: A prospective monocentric study

Abstract

e15105 Background: Up to 15–25% of patients with colorectal cancer (CRC) will develop metacronous liver metastases during the follow up. The management and prognosis of these patients depend heavily on the early detection of metastases. The most effective surveillance strategy has not yet being extablished. The introduction of second generation ultrasound contrast agents have improved the ability of contrast-enhanced ultrasound (CEUS) in detecting and characterizing liver lesions, showing that its accuracy is comparable to that of spiral CT and MRI with a liver contrast agent, with a cost and a time saving. We tested the sensitivity and specificity of CEUS in detecting liver metastases compared with the standard imaging modalities used in the follow up of CRC. Methods: We conducted a prospective study considering all patients with a diagnosis of CRC in high risk stage II, stage III or with a previous metastasectomy of the liver. In order to detect possible metastases, the patients were followed with a follow-up schedule including a six-monthly ultrasonography alternated to an annual CT, and a six-monthly CEUS with SonoVue contrast agent for the first 3 years. Results: From January 1st to December 2008 we executed 60 CEUS, identifying thirteen suspected liver lesions. 10/13 were confirmed metastases by CT, MRI or TC/PET. 2/13 resulted benign lesions. 1/13 resulted negative at the CT but positive with a MRI. Another additional case was missed by CEUS but detected by CT. CEUS improve specificity and sensitivity compared with baseline ultrasonography. We had an histological confirmation in all cases except one. The study is still recruiting patients. Conclusions: The clinical value of CEUS as a reliable alternative to CT or MRI in characterizing focal liver lesions has been expressed in various documents and guidelines. Our preliminary results confirm the similar diagnostic performance and confidence of CEUS compared to these imaging modalities in the follow up of CRC. Further clinical studies are still needed to strenghten the existing data. No significant financial relationships to disclose.