Objective: To assess the value of contrast-enhanced ultrasound in the detection of arterial hypervascularity as a diagnostic criterion of hepatocellular carcinoma (HCC) in patients with focal lesions and liver disease.
Patients and methods: This prospective study included patients with chronic liver disease and focal liver lesions on ultrasound (US) examination. SonoVue was used as contrast agent. We employed a US imaging technique with contrast-specific software operating at a low mechanical index (< 0.14) (Hitachi EUB 6500). The contrast enhancement pattern was analyzed during the arterial phase and classified as diffuse (homogeneous or heterogeneous), peripheral, adjacent parenchyma-like enhancement, and absent. The diagnostic procedure was completed by combined study with computed tomography, magnetic resonance imaging, histologic data and clinical features.
Results: A total of 23 nodules in 22 patients were included in the study (one patient had two different US lesions). The final diagnosis was hepatocellular carcinoma (HCC) in 12 patients, benign lesions in nine, metastases in one and cholangiocarcinoma in one. In the 10 patients with diffuse contrast enhancement, the lesion was malignant and in the eight patients with diffuse homogeneous enhancement, the lesion was a HCC. Seventy-five percent of the patients with HCC had a diffuse enhancement pattern during the arterial phase. This pattern involved malignancy with 71.4% sensitivity, 100% specificity, 100% positive predictive value, 69.2% negative predictive value, and 82.6% accuracy. The diffuse homogeneous pattern involved HCC with 66.7% sensitivity, 100% specificity, 100% positive predictive value, 73.3% negative predictive value and 82.6% accuracy.
Conclusions: Contrast-enhanced US with SonoVue allows the vascularity of focal liver lesions to be assessed. In our study, 75% of patients with HCC showed arterial hypervascularity. A diffuse homogeneous enhancement pattern during the arterial phase was highly specific to HCC. In cirrhotic patients, this arterial pattern could avoid the need for further investigations, although clinical staging should be completed with another diagnostic test.