Contrast-enhanced power doppler sonography in detection and differentiation of focal liver lesions.

The aim of the study is to evaluate the contrast enhanced power doppler technique as a method to detect and differentiate vascular patterns of focal liver lesions. Fourty-nine patients with focal liver lesions were included in the study, twenty-nine of them with malignant liver lesions (9 HCC, 20 metastatic), twenty patients with benign lesions (12 haemangiomas, 5 focal nodular hyperplasia, 3 focal steatosis). In all patients classic B-mode and power doppler sonography was performed prior to administration of the contrast medium Levovist (300 mg/ml) and a power doppler examination subsequent to medium administration. Contrast administration led to lowering the number of "no-flow" lesions from 19 to 11. Postcontrast scan analysis revealed markedly enhanced flow in 15 cases in comparison to only 4 in pre-contrast examinations. The pre-contrast power doppler showed central flow in 7, and peripheral in 26 focal liver lesions. On the other hand, the postcontrast study revealed a central flow in 14, and peripheral in 34 focal liver lesions. Statistical significance between pre- and post-contrast power doppler detection of vascularization existed in malignant focal liver lesions and haemangiomas. The same pre- and post-contrast evaluation proved to be statistically non-significant in the focal nodular hyperplasia and focal steatosis groups. Administration of contrast medium enables a better visualization of intratumor blood vessels in focal liver lesions. This, in combination with the power doppler technique, brings such scans close to angiographic findings.