Gray-scale Contrast Enhancement And Qualification In Rabbit Liver With SonoVue～(TM)

PART ONE:Experimental study of rabbit liver with contrast gray-scale imaging-doses and effectsObjective To study the relationship between doses of ultrasound contrast agent(UCA) and contrast-enhancement effects of gray-scale imaging in rabbit liver. Methods Ultrasound contrast agent SonoVue?in eight different doses (0.02 to 0.16ml/kg) was applied respectively in five normal rabbits in randomized order as a bolus in a marginal ear vein followed by a 1.5ml saline flush. Corresponding parameters of the time-intensity curve: time to enhancement(ET), time to peak intensity(PIT), peak signal intensity(PSI), mean transit time(MTT) and area under the curve(AUC) were measured using low mechanical index contrast gray-scale imaging and Wash-in/Wash-out time intensity curve software package. Results Along with an increase of the SonoVue?dose, the MTT and the AUC increased exponentially, and the ET decreased exponentially. The PSI of portal vein and liver parenchyma increased only in the dose range from 0.02ml/kg to0.10ml/kg (r=0.89 and 0.92, respectively), and decreased with a further increase of the UCA dose. A possible explanation for this effect is the bubble saturation and attenuation. No significant correlation was found between the UCA dose and the PIT(r=-0.35 and 0.22, respectively). Conclusion The parameters of time-intensity curve are influenced intensely by different UCA dose. It is important to grasp the relationship between the UCA doses and contrast-enhancement effects for microcirculatory quantification. The 0.1 ml/kg appears to be the optimal dose for tissue perfusion studying because it significantly improved videointensity and duration of enhancement and did not result in the bubble saturation and attenuation.