| Objective: To investigate the effectiveness, security, and feasibility ofHIFU ablation of spleen for the treatment of hypersplenism. Methods: (1)15 healthy mongrel dogs were randomly divided into 3groups : normal (n=3), control (n=5, ligation of splenic vein), and treatmentgroup(n=7, ligation of splenic vein and HIFU treatment). Dog models ofcongestive splenomagely and hypersplenism were established by theligation of splenic vein and its collateral branches. Dogs in the treatmentgroup were undergone spleen ablation with portable instrument of HIFUunder direct vision via laparotomy 3 weeks after ligation. The observationalindexes such as peripheral blood cell counts, volume of spleen, function ofliver and kidney, serum amylase, and histopathological changes weremeasured regularly. (2)Congestive splenomagely and hypersplenismmodels in 5 healthy mongrel dogs were established by ligation of splenicvein and its collateral branches. 3 weeks after operation, the experimentalanimals received extracorporeal HIFU irradiation at different acousticpower and exposured time. By observing the variation of B-modesonogram and the pathological changes of spleen after fixed-spotirradiation, and surveying the damage of the perisplenic organs, weevaluate the value of real-time monitoring with B model ultrasound and thesecurity of HIFU in the progress of ablation. Results: (1)The results showed that stable thrombocytopenia,erythropenia and splenomegaly were presented in the dogs with splenicvein ligation. WBC counts remained the same before and after ligation indogs. (2)Coagulative necrosis of spleen induced by HIFU irradiation weredemonstrated on pathological findings. The normal structure of spleeictissue had been damaged with clear karyorrhexis and karyolysis 3 days later,the repair of lesions had been identified, the granulation tissue regeneratedsignificantly 7 days later, the lesions were replaced by granulation tissueand fibrous tissue gradually 14 days after HIFU. No major complicationsincluding abscess or rupture of spleen, seroperitoneum and dog deathoccurred. The volume of spleen at the terminal of the experiment in thetreatment group(150.8±25.4cm3) was obviously smaller thanthat(302.9±46.2cm3) before therapy and that(270.7±31.8cm3) in controlgroup at the same time points, it's near to normal. The counts of PLT andRBC in peripheral blood of the model dogs in the treatment groupincreased gradually after therapy, compared with that of normal group atthe same time-point, there were no difference at the 2nd week and the 4thweek after therapy respectively(P>0.05). The counts of WBC increasedtransiently after therapy, it was a little higher than normal, then declined tothe normal level quickly. Moreover, there was no significant difference inhepatic function, renal function and the serum amylase levels before andafter therapy. (3)Immediately after extracorporeal HIFU fixed-spotirradiation, the targeted zone appeared hyperecho. The grayscale values andthe areas of hyperechoic region increased along with the increase ofacoustic power or exposure time. Though the grayscale values and the areasof hyperechoic region were decreased as time went by, they became stableat 2 minutes later after irradiation. Coagulative necrosis of spleen can alsobe expected by extracorporeal HIFU irradiation on pathological findings.There was no difference between the maximum areas of the lesion and themaximum areas of hyperechoic region 5 minutes after irradiation(P>0.05).(4)The treatment-related adverse events were red swelling in the skin ofabdominal wall after extracorporeal HIFU irradiation, and hematom onintestinal wall was found in one dog at 3 days after irradiation, the otherdogs were no perisplenic apparatus injuries. Conclusion: The study demonstrated that HIFU irradiation vialaparotomy can induce coagulative necrosis in the parenchyma of spleen,diminute the volume of spleen, increase the peripheral blood cell count,then alleviate the hypersplenism to some extent. B model ultrasound can bean effective way to realize real time monitoring of...
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