DELINEATION OF EXPERIMENTAL LIVER-TUMORS IN RABBITS BY A NEW ULTRASOUND CONTRAST AGENT AND STIMULATED ACOUSTIC-EMISSION

RATIONALE AND OBJECTIVES. A new ultrasound contrast agent (SH U 543 A) , consisting of hollow biodegradable polymeric microparticles, and a n ew imaging technique (stimulated acoustic emission) were used for deli neation of experimental liver tumors, After intravenous injection, the se microparticles are phagocytosed by cells of the reticuloendothelial system (RES) and create a color-coded signal using color Doppler, Bec ause of the different distribution of phagocytic cells in healthy live r tissue and tumors, the delineation of focal lesions was to be tested . METHODS. Sixteen rabbits with VX2 liver turners received doses of 0. 15-mL SN U 563 A per kilogram of body weight intravenously. Liver inve stigations (UM9, HDI, L10-5, ATL, Bet-hell, USA) were performed in viv o before and after SW U 563 A application in B and color Doppler modes , Additionally, the liver and spleen of these rabbits were examined ex vivo in color Doppler, The sonographic diagnosis was confirmed by pat hology, RESULTS. After application of SH U 563 A, the healthy liver ti ssue of all rabbits was characterized by a typical mosaic color patter n in vivo and ex vivo, using color Doppler, Entire VX2 liver tumors we re detectable exclusively in color Doppler after SH U 563 A applicatio n, This was possible in 14 of 16 rabbits in vivo and in all 16 livers ex vivo, Furthermore, all ex vivo investigated spleens were color enha nced homogeneously. Sonographic diagnoses were in accordance with path ologic findings, CONCLUSIONS. SH U 563 A, combined with stimulated aco ustic emission, provides potential for delineation of small isoechogen ic liver lesions by sonography.