Value of contrast-enhanced ultrasound for diagnosis of focal liver lesions

Objective To assess the value of contrast-enhanced ultrasound to reveal differences between the benign and malignant focal liver lesions. Methods One hundred and three focal liver lesions were prospectively evaluated with real-time harmonic ultrasonographic imaging. A diagnostic score of 1 to 5 was given to each lesion before and after contrast injection and the diagnosis value was compared with ROC curve for differentiation between the benign and malignant focal liver lesions. Results Fifty-six of the 57 malignant liver lesions had diffuse or ring-like contrast enhancement in the arterial phase and it had sensitivity of 98.2%, specificity of 82.6%. Forty-seven of the 57 malignant lesions had demarcation enhancement appeared as hypoechoic lesion in the late phase and it had sensitivity of 82.5%, specificity of 84.8%. Centripetal fill-in enhancement from periphery enhancement as a sign of hemangioma had sensitivity of 81.8% and specificity of 100%. Early central star-like arterial enhancement as a sign of FNH had sensitivity of 66.7% and specificity of 99.0%. For differentiation of malignant and benign focal liver lesions, contrast-enhanced ultrasound had sensitivity of 98.2%, specificity of 91.3%, and had higher diagnostic value than conventional ultrasound. Receiver operating characteristic analysis revealed a significant improvement in this discrimination (area under the receiver operating characteristic curve, 0.811 at conventional ultrasound, 0.948 at contrast-enhanced ultrasound, P=0.000). Conclusion Contrast-enhancement ultrasound has characteristics for the benign and malignant focal liver lesions and greater value of clinical usefulness than conventional ultrasound.