Purpose: Contrast enhanced sonography using phase-inversion harmonic mode is a promising technique to detect and characterize hepatic lesions. Aim of the following study was to evaluate whether this technique can characterize liver tumors.
Material and methods: During January and December 2004, 46 patients with a solitary liver lesion were examined. The age of the 21 women and 25 men ranged between 37 and 82 years. The tumor size was between 8 mm and 14.5 cm. First conventional B-mode sonography and color-coded sonography were performed, followed by intravenous injection of the contrast agent SonoVue and continuous sonographic examination over 5 minutes using "low MI real-time" phase-inversion mode. The examination was video taped. The enhancement was evaluated qualitatively.
Results: Of the 21 malignant lesions, 20 could be correctly diagnosed as malignant. One of the malignant lesions was classified as benign. Of the 25 benign lesions, 21 could be classified correctly as benign, however, 4 lesions (2 hemangiomas, 1 adenoma, 1 teratoma) showed no enhancement in the portal and late phase and were incorrectly classified as malignant as well.
Conclusion: Using pulse-inversion harmonic US with SonoVue, liver lesions showing an isoechoic or hyperechoic enhancement can be classified as probably benign. Further work up is necessary in case of little or no enhancement on delayed phase imaging.