| Objective: To investigate the value of contrast-enhanced ultrasonography(CEUS) with SonoVue in hepatocellular carcinoma with radiofrequencyablation treatment (RFA),evaluate the treatment of RFA quantitatively bytime-intensity curve (TIC),and to compare the efficacy of RFA usingCEUS and without contrast medium administration.Materials and methods:1. PatientsSixty one patients who had hepatocellular carcinoma were underwentpercutaneous RFA guiding with US from October2010to November2011.The criterion in the research were:(1) no more than4HCC lesions in onepatient;(2) maximum diameter of main tumor less than8cm;(3) prothrombintime ratio greater than50%and platelet count greater than50000/μl;(4)absence of thrombosis in the main branch of the portal vein and extrahepaticmetastases. All cases were divided into2groups including CEUS group andcontrol group:(1)CEUS group:30patients with38HCC lesions underwentCEUS before RFA treatment;(2)control group:31patients with40HCC lesionswho only underwent conventional US without contrast-enhancedultrasonography before RFA served as the control group.There were nosignificant differences in baseline characteristics between the two groups.2. Contrast agent and instrumentsThe US contrast agent SonoVue was used in all studies.Contrast-enhanced US was performed by using PHILIPS-IU22ultrasonicdevice,RFA was performed by using cooled-tip radiofrequency lesiongenerator of the United States Valleylab company．3. Methods First of all, a conventional US of the liver, using the gray scale and colordoppler flow imaging(CDFI) was performed to identify the location,number,size,border and the blood supply of the tumor in the two groups.When the location of the lesion was identified by conventionalultrasound,the real-time gray-scale harmonic imagine mode was initiated.After a total of2.4ml SonoVue was injected quickly in bolus,the perfusionand enhancement pattern of the target lesions were continuously observedthroughout arterial,portal and delay phases of contrast-enhancedultrasonography.A second injection of contrast medium was given when thefirst injection was not satisfactory or if another lesion needed to beobserved.The RFA protocol was designed on the basis of CEUS informationin the CEUS group and performed ultrasound-guided radiofrequency ablation.Contrast-enhanced ultrasonography scan of the CEUS group was performed toassess treatment efficacy20-40minutes after RFA,and retreatment can beperformed in the same session in case there was any residual unablated tumoror recurrence.Whereas it was designed based on the US,CT or MRIinformation in control group.Conventional ultrasound, CECT and (or) CEUS were performed forregular follow-up in all patients after RFA, the follow-up period was at least3months for each case.The final diagnosis of tumor necrosis or residual wasbased on CECT examination.4. Quantitative analysis methods of contrast ultrasoundThe pre-and post-procedural,patients in CEUS group underwentexamination using CEUS and analyzed the contrast-enhanced ultrasoundfindings by the Philips QLAB-ROI quantitative analysis software. Selectednon-necrotic part of tumor tissue and the same depth of tumor beyond the areaof the hepatic tissue as a region of interest,and compared quantitatively byanalysis of the TIC.Quantitative analysis parameters included:Initial time(IT),Initial intensity(II), Time to Peak(TTP), Peak Intensity(PI), the meanenhancement rate (V1) and the mean declined rate (V2). Results：1. The lesions with indistinct boundary before the contrast-enhancedultrasound will became more larger in size,more irregular in shape andmore distinctly in margin,the difference was statistically significant(P<0.05).2. ROI of HCC areas were compared with the liver parenchyma beforeRFA therapy,the results revealed that the parameters of IT and TTP of thetumors were obviously less than the liver parenchyma (P <0.05),but theparameters of V1and V2were obviously more than the liver parenchyma(P<0.05),the pre-procedural analysis of TIC demonstrated the parameters ofenhancement rate and decline rate of the hepatic carcinoma were faster thanthe surrounding liver parenchyma, the difference was statistically significant.3. After RFA therapy, ROI of the residual tumors were compared withthe post-procedural liver parenchyma.The results revealed that theparameters of IT and TTP of the residual disease were obviously less thanthe post-procedural liver parenchyma,but the parameters of V1and V2wereobviously more than the post-procedural liver parenchyma,the differencewas statistically significant(P＜0.05).4. Conventional ultrasound, CECT and (or) CEUS were performedfor regular follow-up in all patients after RFA,the follow-up period was atleast3months for each case.The final diagnosis of tumor necrosis or residualwas based on CECT examination.The complete necrosis rate after initialRFA in CEUS group was89.5%(34/38tumors),which was significantlyhigher than70.0%(28/40tumors) of the control group,the difference wasstatistically significant(P＜0.05).5. Contrast-enhanced ultrasonography,obtained after RFA,showed nomicrovascular perfusion in necrosis whereas microvascular perfusion in theresidual tumor.There was no perfusion enhancement in necrosis infollow-up．Conclusion：1.CEUS can be used to more accurately to define the exact size andinvasive range of lesions before RFA,therefore provides valuable information for the ablation range and selection of treatment of HCC.2.The time-intensity curve (TIC) and acoustic quantified parametersof CEUS were beneficial to reflect the minute difference of microva-scular perfusion among the liver tumors,the hepatic parenchyma,and theresidual tumor. Harmonic imaging of contrast-enhanced US combiningwith quantitative analysis played an important role in determining thenature of the tumor before RFA therapy and depicting residual tumorimmediately after RFA and follow-up,consequently reduced localrecurrence．3. CEUS can accurately discriminate the coagulation necrosis fromresidual tumors after RFA in a few days, and detect benign peri-tumoralenhancement.It is an effective method to adequately assess the therapeuticresponse in radiofrequency ablation of hepatocellular carcinoma. |
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