Pulse inversion sonography in the early phase of the sonographic contrast agent Levovist: differentiation between benign and malignant focal liver lesions.

OBJECTIVE: To determine whether examination of focal liver lesions by pulse inversion sonography in the early perfusion phase of the contrast agent Levovist (SH U 508A; Schering AG, Berlin, Germany) enables distinction between benign and malignant lesions. METHODS: Seventy-two patients were examined. The cause of the lesion was confirmed by liver biopsy, computed tomography, or both or by hepatic iminodiacetic acid-enhanced scintigraphy. Forty-two patients had malignant liver lesions, and 30 had benign liver lesions. After injection of 2 g of Levovist intravenously, analysis of Levovist arrival was performed by the interval delay imaging technique for 60 seconds. RESULTS: The early arrival of Levovist less than 30 seconds after injection was used as an indicator for malignancy and had specificity of 67% and sensitivity of 60% (P < .05). The central starlike fill-in as a sign for focal nodular hyperplasia had specificity of 100% and sensitivity of 67% (P < .001). The rimlike pattern followed by centripetal fill-in as a sign for hemangioma had specificity of 100% and sensitivity of 18% (P < .01). In contrast, the early diffuse stippled arrival pattern was found in 60% of malignant lesions and also in 33% of cases of focal nodular hyperplasia and in 1 patient with an adenoma. CONCLUSIONS: Analysis of Levovist arrival time cannot distinguish between a malignant or benign lesion in individual cases. However, the central starlike arrival pattern is characteristic of focal nodular hyperplasia.