Comparison of diagnostic performance of unenhanced vs Sono Vue - Enhanced ultrasonography in focal liver lesions characterization. The experience of three Italian centers

Purpose. To evaluate the diagnostic performance of contrast-enhanced US with SonoVue® (Bracco, Milan, Italy) compared to baseline US in focal hepatic lesions characterization. Materials and methods. A comprehensive number of four operators from 3 hospitals evaluated 57 consecutive patients with 60 focal hepatic lesions (28 hepatocellular carcinomas, 11 metastases, 13 hemangiomas, 1 hepatocellular adenoma and 7 focal nodular hyperplasias) by baseline gray-scale ultrasound (US) and color Doppler US. The same lesions were subsequently scanned by contrast-enhanced US after intravenous bolus administration of 2,4-4,8 ml of SonoVue by employing intermittent high or continous low transmit power imaging. The diagnosis of lesions nature (benign or malignant) and histotype proposed by the on-site operator was finally compared to the definite diagnosis reached by reference procedures (multiphasic contrast-material enhanced helical-computed tomography or magnetic resonance in 24 lesions and fine needle US guided biopsy in 36 lesions). Diagnostic performance (sensitivity, specificity and overall accuracy expressed by the agreement with the reference procedures) of baseline and contrast enhanced US were compared. Results. Differences in sensitivity (baseline vs contrast-enhaced US: 13/39 [33%] vs 32/39 [82%]), specificity (baseline vs contrast-enhaced US: 12/21 [57%] vs 16/21 [76%]) and overall accuracy (baseline vs contrast-enhaced US: 25/60 [41%] vs 47/60 [78%]) were significant (p<0.05; McNemar test). Conclusions. SonoVue-enhanced US determined a significant improvement in diagnostic performance in the characterization of focal liver lesions if compared to baseline US.