SONOGRAPHIC EVALUATION OF FOCAL NODULAR HYPERPLASIAS (FNH) OF THE LIVER WITH A TRANSPULMONARY GALACTOSE-BASED CONTRAST AGENT (LEVOVIST)

Focal nodular hyperplasias (FNH) are hypervascular, benign focal liver lesions. Differentiation of FNH from other focal liver lesions is of clinical importance. The purpose of this study was to examine the impa ct of a new, transpulmonary echo-enhancing agent SHU 508A (Levovist) a nd recent Doppler techniques in the sonographic evaluation of FNH. 43 patients with 61 focal nodular hyperplasias of the liver were examined with grey scale ultrasound and power Doppler ultrasound. Levovist, a galactose-air-microbubble suspension was administered intravenously in all patients, either by bolus injection (400 mg ml(-1)) or continuous pump-infusion (300 mg ml(-1)). Visualization of the feeding vessels a nd vascularity of the lesions were evaluated. The resistance indexes ( RI) in the feeding vessel and the hepatic artery were assessed and com pared with the diameters of the FNH. The mean diameter of FNH was 4.3 cm (+/-1.0). Echo enhanced power Doppler ultrasound was superior to un enhanced power Doppler ultrasound in the detection of the feeding arte ry (85% vs 98%) in FNH and depicted the internal vascular architecture more clearly, especially in lesions located in the left lobe of the l iver. Lesions smaller than 3 cm did not show a characteristic vascular architecture with echo enhanced Doppler ultrasound. The resistance in dex of the feeding artery (mean: 0.51 +/- 0.08) is significantly (p<0. 0001) lower than that of the hepatic artery (mean 0.65 +/- 0.06) with a mean difference of -0.14 +/- 0.01 in the same patient. The RI of the feeding artery significantly decreased as the size of the FNH increas ed, whereas RI differences between the hepatic artery and the feeding artery increased with lesion size. Intravenous (iv) bolus injection of the contrast agent will depict the hypervascular nature of FNH more c learly than iv infusion, although the latter will significantly prolon g the diagnostic window. In conclusion, iv infusion of Levovist improv es the visualization of the feeding artery and the radiating vascular architecture in FNH located in the left lobe of the liver due to impro ved signal-to-noise ratio and results in more effective suppression of motion artefacts. Although echo enhanced Doppler ultrasound improves the detection of the low resistance arterial feeding vessel in small F NH, it will not, however, reveal a specific vascular pattern in these lesions.