Differential diagnosis of focal liver lesions in signal-enhanced ultrasound using BR 1, a second-generation ultrasound signal enhancer

AIM: The aim was to evaluate the diagnostic value of contrast-enhanced ultrasound in the differential diagnosis of focal liver lesions, in a blinded experiment. In clinical routine the examiner can generally be influenced by the patient's history. METHOD: 62 patients with focal liver lesions, which could not be clearly differentiated and diagnosed by conventional ultrasound, were examined with contrast-enhanced (BR1, SonoVue, Bracco) ultrasound and included in a blinded prospective and randomized study. The examinations performed on a Sequoia 512 (Acuson) in a coherent contrast imaging method were recorded by an S-VHS recorder and afterwards analyzed by an examiner who did not know the patient's history. The basis of the diagnosis was the dynamic appearance and enhancement of the ultrasound contrast enhancer in different phases of liver perfusion. The conformation of the diagnoses was made by corresponding reference methods, as computer tomography, magnetic resonance imaging, biopsy and clinical follow-up. RESULTS: The following diagnoses were confirmed by reference methods: 18 patients with metastases, 4 hepatocellular carcinomas, 19 haemangiomas, 6 focal nodular hyperplasias, 13 patients with focal fatty infiltration and 2 patients with focal fatty sparing. 59 out of 62 patients with one or more liver lesions were correctly diagnosed by contrast-enhanced ultrasound. CONCLUSION: Second-generation ultrasound contrast enhancers improve the differential diagnosis of benign and malignant liver lesions considerably, especially in a blinded study.