Objective: To compare sensitivity and specificity of contrast enhanced ultrasonography (CEUS) with conventional ultrasonography (US) in detection of liver metastases in patients with colorectal adenocarcinoma (CRC) in a patient-by-patient analysis.
Materials and methods: A prospective study of 461 consecutive patients referred to the Department of Colorectal Surgery, Aarhus University Hospital with primary or local recurrence of CRC. In order to detect possible liver metastases all patients underwent liver US, followed by CEUS by another investigator. Multislice CT scanning (MDCT), and intraoperative ultrasonography (IOUS) were then performed. Fine-needle biopsy was performed on all suspicious lesions. Each examination was interpreted blindly and the combination of biphasic MDCT, IOUS, follow up and biopsy was the gold standard.
Results: Standard of reference found liver metastases in 54 patients (14.8%). Contrast enhanced ultrasonography improved the sensitivity significantly in detection of liver metastases from 0.69 by US to 0.80 (p=0.031). In 24 patients, CEUS found a higher number of metastases than US (p<0.001). The specificity (0.98) and the positive predictive value (0.86) was the same.
Conclusion: Contrast enhanced ultrasonography improves sensitivity in detection of liver metastases in patients with CRC and in nearly half of the cases CEUS found a higher number of metastases than US.