RESUMEN
Objective To compare bolus infusion and replenishment using real low mechanical index contrast enhanced ultrasound in assessing the change of renal cortical perfusion.Methods Using dopamine (i.v.) at the dose of 0.5,2.0,5.0μg · kg- 1 · min- 1 to change renal blood perfusion of 20 rabbits,then during bolus or contant injection of SonoVue,at coded pulse inversion mode,real-time contrast ultrasound was performed,the latter method needed destroying microbubble at a high MI when amplitude reach a steady state,then recording the replenishment,peak intensity(A) and time to peak (PPT) were obtained through raw time-intensity curve,and slope rate of TIC(k) was acquired by curve fitting,standard effective renal plasma flow(ERPF) was measured through 4-aminohippuric acid clearancerate method,meanwhile correlations between ERPF and parameters were analyzed,as well as the paired samples t test for each parameter before and after dopamine administration.Results The ascending branchs of raw TIC of bolus infusion increased sharply and were approximately straight,then descended gradually,while that of replenishment looked like two straightlines with different slopes,then stayed horizontal Both the value of A of two methods were positively correlated with ERPF ( r b =0.85,r re =0.66),and were different at the same ERPF,meanwhile the value of TTP were negatively correlated with ERPF( r b =-0.92,r re =- 0.76),and there were no statistically difference between the two methods.k from Gamma fitting was far from correct,while k from exponential fitting was apparently correlated with ERPF ( r re =0.77 ).Conclusions Both bolus injection and constant injection-replenishment method can assess renal cortical blood perfusion,TIC parameters A and TTP represent regional blood volume fraction and microbubble velocity respectively.Bolus-infusion with real low mechanical index is more precise and available.Comparing with k,TTP is more appropriate to reflect perfusion velocity.