Hepatocellular carcinoma treated with transarterial chemoembolization:Evaluation with parametric contrast-enhanced ultrasonography

AIM:To evaluate the response of hepatocellular carcinoma(HCC) to transarterial chemoembolization(TACE) using a simplified protocol of parametric contrastenhanced ultrasound(pCEUS).METHODS:Eighteen patients with HCC(18 target tumors,diameter:2.8-12 cm) were evaluated before,and 20 d after TACE.The distribution and morphology of TACE-induced necrosis in these tumors precluded accurate evaluation by visual assessment or by simple measurements.For pCEUS,a 4.8 mL bolus of SonoVue(Bracco,Milan,Italy) was intravenously administered and analysis of tumor perfusion during the initial phase of enhancement(0-30 s post injection) was performed with dedicated software(Qontrast,Bracco,Milan,Italy).Time-intensity curves were plotted and three parameters were calculated:peak intensity(PI,in percentage %),time to peak(TTP in seconds,s) and area under the curve during wash-in(AUC-WI,in arbitrary units,a.u).Magnetic resonance imaging was the standard imaging modality for post-treatment evaluation.Changes in tumor size were recorded and response was assessed according to response evaluation criteria in solid tumors criteria.RESULTS:A statistically significant decrease in PI and AUC-WI was observed in the treated tumors post TACE;PIpre:21.5% ± 8.7%(mean ± SD),PIpost:12.7% ± 6.7%,P < 0.001,AUC-WI pre:17493 ± 9563 a.u,AUCWI post:9585 ± 5494 a.u,P < 0.001.A slight increase in TTP was noted post TACE,but this was not statistically significant;TTP pre:13.1 ± 4.3 s,TTP post:13.6 ± 4.2 s,P = 0.058).The changes in the aforementioned parameters were not accompanied by significant tumor shrinkage.CONCLUSION:pCEUS,even when limited to the study of the arterial phase of tumoral enhancement,can detect and quantify early perfusional changes in HCC post TACE.