Contrast-enhanced ultrasonography in diagnosing liver metastases

Dual-phase spiral computed tomography (CT) is still the primary imaging technique in the diagnosis of focal liver lesions. Contrast-enhanced ultrasonography (CEUS) is the most sensitive sonographic technique. The purpose of this study was to investigate the efficacy of CEUS in detecting liver metastases compared with CT as the standard of reference.

The examined group consisted of 51 patients (24 men and 27 women, age range: 27-84 years, mean: 57.4 years) suspected of liver metastases. The routine diagnostic approach consisted of B-mode US, CEUS, and CT. Final diagnosis was made at cytologic (n=18) or histologic examination (n=14) and in 9 patients by combining information from CT scans, medical history, and clinical and biochemical investigations.

Liver cysts and abscesses were detected in 10 patients. They were excluded from the further analyses. In the remaining 41 patients a total of 134 metastases were detected. In 15 patients with metastases, US images of the liver appeared normal. CEUS detected metastases in 36 patients. The sensitivities of the methods per patient were US 63.4% and CEUS 90.2%. Sensitivities of the methods per lesion were US 60.9%, CT 77.6%, and CEUS 90.2%. Application of contrast media (SonoVue) significantly increased diagnosing of liver metastases compared with standard sonography and CT.

CEUS increased diagnostic confidence in the detection and characterization of hepatic metastases compared with standard sonography. Real-time contrast-enhanced sonography is particularly advantageous in detecting small metastases.