Effect Of High Intensity Focused Ultrasound Irradiation In Vivo On Femoral Artery Of Rabbit

Background:High-intensity focused ultrasound (HIFU) is being a widely accepted as a purely non-invasive modality for induction of coagulative necrosis of biological tissue for tumor treatment. Preliminary clinical trials have produced promising results. The effect of artery is one of the most important aspects that determines the efficiency and safety of HIFU.Objective: To investigate the efficiency and safety of HIFU after rabbit's femoral artery ultrasonic irradiation. If the blood flow of target artery vessels can be reduced strikingly, the efficiency of HIFU may be improved.Methods: With operating frequency of 0.8MHz, focal intensity of about 8000W/cm2 and 10000W/cm2 was used. The average of the diameter of the rabbit's femoral artery is about 1.1mm calculated by the circumference of femoral artery. Forty-two rabbits were randomly divided into two groups and unilateral -femoral was chose at random. Then each was divided into three,Group A (n=8) 1st day, Group B (n=8)3rd day and Group C (n=8) 7th day after HIFU irradiation, all (n=5) of the amphi-blood flow of femoral artery for CDFI, two for DSA and 5 for pathological changes. And then target vessels were observed with Haematoxylin-Eosin (HE) staining, elasticity fibrin Victoria blue, ponceau's histochemical staining. Results: From the preliminary research, the reduction of peak, average blood flow of the rabbit's femoral artery with HIFU focal intensity 8000W/cm2 is 78.3â„…, 77.5â„… in group A;61.6â„…, 29â„…in group B and 45.3â„…,22.5â„… in group C(p<0.01)ï¼› with focal intensity 10000W/cm2 is 72.2â„…, 78.9â„…in group Aï¼› 58.6â„…, 57.9â„…in group B and 38.1â„…, 25.1â„…in group C(p<0.01).The above-mentioned results were confirmed with digital subtraction angiography (DSA).Conclusions: We have previously shown that artery vascular occlusion is possible and persists for several days. Based on the above results, in-depth research can be conducted to predict the efficiency from measuring the blood flow of the target's artery, which will contribute to the energy deposition of the targets in HIFU system. If the blood flow artery vessels of target can be reduced strikingly, the efficiency of HIFU may be improved.