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Objective To observe the curative effect of the microwave ablation (MWA) therapy for hepatocellular carcinoma (HCC) with arterio-venous fistula (AVF) in patients with intervention and operative contraindication,and to observe the clinical effect.Methods MWA therapy was offered to 24 patients with HCC combined with AVF accompanied with intervention and operative contraindication.The complete ablation rates,volume changes of tumors before and after treatment were observed.Color Doppler ultrasonography was performed to evaluate the peak flow rate and resistance index(RI)of AVF,width and flow rate change of portal vein.The lifetime of patients were also observed.Results All patients were treated with double needle therapy.The first time complete ablation was 75.0％ (18/24).Then they were followed up after 6 months.The volume of tumors was (72.9 ± 23.8)cm3 and (57.6 ± 19.8)cm3 (P ＜0.01) before and after treatment.The AVF disappeared in 20 cases,while flow rates of fistula orifice decreases obviously in the rest of them.The widths of portal veins decreased from (1.4 ± 0.9)cm to (1.3 ± 0.1)cm,while the flow rate of that increased from (7.5 ± 3.9)cm/s to (20.1 ± 2.9)cm/s.The survival rates of patients for one,two and three years were 66.6 ％ (16/24),37.5 ％ (9/24) and 20.8 ％ (5/24),respectively.Conclusions Most AVF disappeared after MWA therapy in HCC combined with AVF.The therapy can relieve portal hypertension symptom effectively and improve survival time and life quality of patients.So it is a good treatment for patients with HCC combined with AVF while with intervention and operative contraindication.
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Objective To explore the therapeutic results of percutaneous microwave ablation for patients with recurrence primary liver cancer after surgery and the factors influencing the survival after ablation therapy.Methods 102 patients who underwent hepatectomy for primary liver cancer in April 1998 to December 2010,and subsequent microwave ablation for recurrence hepatocellular carcinoma,were enrolled.Long term survival rates and prognostic factors after ablation were analyzed.Results The 1,3,5,and 7 year overall survival rates after ablation were 73.5％,53.5％,40.5％ and 17.7％.The 1,3,and 5 year overall survival rates for patients within one year recurrence after hepatectomy were 63.3％,38.9％,and 27.1％,respectively,which was significantly lower than that for patients after this time period in which the 1,3,and 5 year overall survival rates were 86.3％,72.3％ and 63.0％,respectively (P =0.003).Univariate analysis revealed that recurrence tumor size more than 3 cm,multiple tumors,poor Child-Pugh score,and AFP level ＞100 μg/L were risk prognostic factors of overall survival for patients who underwent ablation.Multivariate analysis identified multiple tumors,poor Child-Pugh score,and AFP level ＞ 100μg/L were the factors affecting overall survival.Conclusions Microwave ablation is of high clinical application value and is an effective minimally invasive treatment for recurrence hepatocellular carcinoma.Microwave ablation is equally effective when used in late recurrence,single tumor and tumor size≤3 cm.
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Objective To explore the characteristics of changes in temperature and stiffness within the microwave-induced ablation region.Methods A type of Thy-ablation microwave antenna was used upon a design of various combination of ablation duration and power to induce heated region in samples of fresh porcine liver.Three special sites were set to assess the corresponding temperature and stiffness in each heated region.The temperature was continuously measured by using electronic thermometer with microwave on going,while stiffness was determined 5min after the ending of ablation by using real-time ultrasonic elastography,strain ratio,a quantitative indicator.Results The SR values and temperature determinations decreased progressively from the central to the peripheral area of the heated region.There was a linear regression between the temperatures (X) and SRs (Y),with Y =0.666 X-37.17.A significant correlation exists between X and Y,with the correlation coefficient being 0.956(P ＜0.001).The stiffness and temperature at the central sites are variable with the changes of both ablation time and power,but little changed at the peripheral sites of heated-region,which we name a phenomenon due to the ending effect of microwave propagation.Conclusions Temperature and stiffness increase considerably following microwave radiation but they are heterogeneously distributed within the ablated region in porcine liver.The characteristic gradient changes are confirmed of both temperature and the elasticity.It is presumable that good recognition and understanding and full utilization of these characteristics are conducive to reasonable control of tumor microwave ablation therapy.
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Objective To investigate the elasticity reduction of liver tissue due to microwave ablation and the relevance to the histographic damages. Methods An experimental study using fresh porcine liver was designed. Elasto-ultrasonography scanning both in color display and strain ratio calculations was conducted before and 5 min after microwave ablation ( 2450 MHz) in manner of antenna insertion under ultrasound guidance to determine the alterations of the liver elasticity, in correspondence with the histopathologic assessment of each ROI. Results Elasto-ultrasonography showed a significant elasticity reduction and hardness augment of the targeted liver tissue and the corresponding histopathology revealed increases in the amount of massive coagulative necrosis and coking of liver cells after microwave irradiation,in proportional to the applied field power and working time. Conclusions Elasto-ultrasonography helps to demonstrate microwave-induced lesion in porcine liver got rapidly hardened. It is possible to estimate the tissue necrosis to the changing of tissue hardening.
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Objective To probe the correlation between the short-axis diameter(SD) of coagulation necosis and the microwave power(P) using a new type of internally cooled microwave antenna in ex vivo and in vivo liver model.Methods Fourteen microwave ablations were performed in swine livers ex vivo and canine livers in vivo under the microwave powers of 30-90W and the durations of 10 min and 20 min, respectively.The short-axis diameter(SD) and the long-axis diameter(LD) of the coagulation were measured.The difference of SD, LD and SD/LD in swine liver ex vivo and canine liver in vivo were compared.The relationship between the SD and microwave power was analysised using linear regression model.Results Under the same conditions,the SDs and LDs of the coagulations of canine livers in vivo were smaller than those of swine livers in ex vivo (P <0.01).There was such a higher linear relationship(r = 0.96-0.99, P <0.01) between the SD of coagulation and the power in vivo liver model as the results acquired in ex vivo.Conclusions Although the blood flow decreased the SDs of the coagulation of microwave ablation in liver in vivo, but there was still a higher linear relationship between SD and microwave power.
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Objective To evaluate the safety and efficacy of ultrasound-guided percutaneous microwave ablation of renal neoplasms.Methods Twenty-two patients with pathologically proven renal neoplasms(18 renal cell carcinoma,3 renal angiomyolipoma,1 oncocytoma)with diameters of 1.0 to 3.8 cm were treated by microwave ablation.Cooled-shaft needle antenna was percutaneously inserted into the tumors under ultrasound guidance.One antenna was used for tumors less than 2 cm,two antennas were used for tumors larger than 2 cm.One thermal couple was placed adjacent to the tumor monitoring temperature in real-time during ablation.Immediate treatment efficacy was assessed by contrast-enhanced ultrasound within 3 days after ablation.Short-term efficacy was assessed by contrast-enhanced CT and/or contrast-enhanced ultrasound at 1,3,6 months and every 6 months thereafter.Results Twenty tumors were completely ablated in a single session,2 tumors were completely ablated in 2 sessions.No complications occurred.No residual tumor or recurrence was observed during follow-up.Conclusions Ultrasound-guided pereutaneous microwave ablation appears to be a safe and effective technique for the management of renal neoplasms in selected patients.
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Objective To discuss the principle and the value of pereutanous microwave ablation for benign focal liver lesions. Methods Fourteen patients with 15 benign focal liver lesions received percutanous microwave ablation with 15G cool-tip microwave antenna. The maximum diameter of lesion was (26.2±13.6)mm (10 - 57 mm). Results Treatment sessions and total treatment time for single lesion were 1.4±0. 5 (1- 2) and (837±574)s (300- 2057 s). Follow-up range was 1- 35 months (median 6 months). The hepatic lesions were covered by coagulation necrosis region of ablation completely in all cases on contrast-enhanced at 1 month after ablation. The area of coagulation necrosis of ablation decreased on follow-up imaging in patients with more than 3 months follow-up. No complications happened in all cases. Side effects include pain (12/14) and fever (8/14) lasting I -9 days. The increase of serum transaminase decreased to normal at 1 week after ablation. Conclusions Percutanous microwave ablation has the merit of safety,minimal invasion, good ablation result and low incidence of side effect. Under the precondition of eareful choice of indication,pereutanous microwave ablation can be a selective treatment method for benign focal liver lesions.
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Objective To compare the effect of single implanted microwave ablation in continuous and interval irradiating in ex vivo pig muscular tissues, and to provide the experimental data for microwave ablation therapy of uterine fibroid clinically. Methods The pig muscular tissues ablations were performed with 2450 MHz microwave at same output power and action time. The irradiating modes were set as continuous wave and interval wave (emitting per 100 seconds intermitting 10 seconds and 20 seconds). The shape, size, thermal field temperature and the pathologic appearance of the ablation zone were evaluated. Results With the same output power and the same action time,the difference observed in the ablated shape, scope, ahead distance and thermal field temperature had no statistical significance, and the pathologic appearances of the ablated zone were same among the different action modes. Conclusions The difference between continuous and interval microwave ablation effects had no statistical significance in ex vivo pig muscular tissues with single implanted microwave. Both of these two modes may apply for uterine fibroid microwave ablation,and may result in same therapeutic efficacy.
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Objective To probe the correlation between the short-axis diameter(SD) of microwave coagulation and the time(T) and/or power(P) using a new type of internally cooled microwave antenna. Methods A MTC-3 microwave apparatus with a new type of internally-cooled microwave antenna was used to coagulate a fresh porcine liver in vitro. The correlation was analyzed between the SD of coagulation necrosis and the time and/or power. Results ①Under the same power, there was high linear relationship(r= 0.94- 0.98,P
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Objective To evaluate the value of power Doppler and contrast-enhanced ultrasonography in the detection of tumor after microwave tissue coagulation (MTC). Methods Ultrasound Microwave Theraphy-1 (UMT-1) equipment was used,and a 9 mm length antenna was inserted directly into the tumor at laparotomy in 10 VX 2-bearing rabbits. The energy output was 60 W?120 s per bout. Two-dimensional, power and contrast-enhanced (Levovist, 300 mg/ml, 0.3 ml/kg) imaging was performed pre- and post-treatment. Pathology examination was applied in contrast. Results Along the needle being narrow hyper echoic imaging, broad-equable hypo echoic imaging was observed around the center after MTC immediately and the edge of tumor was unclear. Intratumoral blood flow was observed in 4 VX 2 tumors with power ultrasonography while there was enhanced-signal in 10 VX 2 tumors using contrast-enhanced ultrasonography. These tumors were confirmed incomplete necrosis by pathology. Conclusions Contrast-enhanced power Doppler ultrasonography shows more sensitive in assessing the therapeutic effect of microwave on VX 2 tumor. Residual tumor can be seen as persistent color enhancement by using contrast-enhanced ultrasonography.
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Objective To explore ways for expanding the now-limited coagulation volume of percutaneous microwave coagulation therapy(PMCT) in liver in order to enhance the complete necrosis rate of large hepatic tumors with obviously fewer punctures. Methods Fresh pig livers in vitro and rabbit, pig livers in vivo with and without blood supply were coagulated using the self-designed HM-WIA microwave coagulator to make clear antenna length, microwave power, coagulation time and blood flow influence the microwave volume(MCV).Results The device enlarged the MCV by 3 times using single electrode with an antenna of 36 mm in length along with microwave power of 45-55 W and coagulation time of 15-19 min,the short axis of the coagulation area was 5.6 cm in vitro, 5.3 cm in vivo with no blood supply.The antenna 36 mm in length was proved the best in keeping the finest coagulation shape.The MCV was 2.8 times as large without blood supply as with it (P