Evaluation Of Radiofrequency Ablative Lesions Of Hepatocellular Carcinoma By Real Time Ultrasound Elastography

Objective Radiofrequency ablation(RFA) has been proved to be aneffective, non-surgical, regional treatment to cure hepatic malignant tumors. It iscrucial to assess the effectiveness of ablative treatment in this process andcontrast enhance ultrasound(CEUS) has been proved having the similarusefulness with contrast enhance Computerized Tomography(CT) and/orMagnetic Resonance Imaging(MRI). However, technical difficulties existed forimmediate curative effect evaluation, result from the influence of heperechoic“cloud” of gas and inflammation of the congestion causing by ablation. Firstly,we performed animal experiments (both in vitro and in vivo) which showedreal-time ultrasound elastography(RTE) can be used to assess the ablative zone,whether it is able to evaluate ablation lesions in patients is worth studying. Thus,we conduct this survey to evaluate that whether RTE, which is also comparingwith base-line ultrasound(BUS) and CEUS, can be used to estimate theradiofrequency ablative lesions in patients with hepatic malignant tumors.Methods A total of34lesions in29patients with hepatocellularcarcinomas(HCCs) which were confirmed by biopsy were included in this survey between May2012and March2013, from the first affiliated hospital,Guangxi medical university. BUS, RTE, CEUS were performed in34HCClesions before RFA and24h after RFA to evaluate the ablative lesions,respectively. In order to compare with each other, care should be taken thatusing the same imaging plane (we defined the plane where RFA electrodecould be identified) on BUS, RTE and CEUS imaging to gain the long andshort axis of ablation zone. Quantitative data in this survey were showed asmean±standard deviation. Randomized block design analysis of variance wasused to compare the diameters of BUS, RTE and CEUS imaging, and personcorrelation coefficients were calculated between these three methods. SPSS16.0software was using to performing the statistical analyses. All statisticalsignificance was set at P <0.05(2-tailed).Results On BUS imaging24h after ablation, all ablative areas showed asheterogeneous echoexture. On RTE imaging24h after ablation, blue dominatedthe ablative area and distinguished from peripheral liver tissue in32(94.1%)lesions, and blue and green dominated the ablative area and undistinguishedfrom peripheral liver tissue in2(5.9%) lesions. On CEUS imaging24h afterablation, ablative area showed non-enhancement in three phases, whereas thesurrounding congestive liver parenchyma displayed hyper-enhancement inarterial phase, iso-enhancement or hypor-enhancement in portal and late phases.The long axis and short axis of ablative lesions on BUS, RTE and CEUSimaging were demonstrated statistic difference(P<0.01), and there weresignificant difference between BUS and RTE imaging, and between BUS andCEUS imaging too(both P<0.05), but there were no significant differencebetween RTE and CEUS imaging(P＞0.05). Pearson correlation analysisshowed that the correlation coefficient of long axis and short axis of ablative lesions measured on RTE and CEUS imaging were0.878and0.788,respectively.Conclusion RTE may be a promising tool for estimating the ablativezone.