The role of contrast enhanced ultrasound in radiofrequency ablation of liver metastasis / 中华超声影像学杂志

ABSTRACT

Objective To evaluate the clinical value of contrast enhanced uhrasound(CEUS)for uhrasoundguided radiofrequency ablation(RFA)of liver metastasis.Methods One hundred and forty-one consecutive patients with liver metastasis asked for RFA treatment in our department.Of them,102 patients with received CEUS with SonoVue before RFA treatment.Eighty-six of the 102 patients were regarded as indications for RFA by CEUS(Group A).During the same period,another 39 patients who received conventional US without contrast before RFA were served as the control group(Group B).In Group A,the RFA protocol for each case was designed according to CEUS finding,which included perfusion feature,lesion number,size,shape,invasive range,location and relationship between tumor and surrounding structures.In Group B.the RFA protocol for each case was designed according to conventional ultrasound and CT/MRI result.Results In 102 patients who intended to receive RFA treatment,1 6 were excluded from RFA after CEUS examination.Of them,3 patients with 10 tumors received 6-10 sessions of chemotherapy and there were no enhancement within or around tumors.Another 13 cases were found that the invasive range being more than 8 cm in size,tumor number more than 7,and tumor location adhered to diaphragm and second hepatic helium by CEUS.In Grou0 A,CEUS detected additional 1-3 tumors in 36 patients(41.9%).The size range of the 58 new tumors was 8-15 mm.Of these,79.4%(46/58 tumors)were visualized in parenchymal phase.A total of 209 liver metastasis tumors were treated by RFA.CEUS before RFA demonstrated 49.7%(75/151 tumors)were 1arger in size compared with conventional US.Of these,69.3%(52/75 tumors)presented larger in arterial phase,the remaining 30.7%(23/75 tumors)presented larger in parenchymal phase,and the increased area was also ablated.On 1-3 months follow up with CT,the tumor necrosisrate in Group A was 94.7%(198/209 tumors),which was significantly higher than 87.6%(99/113 tumors)in Group B ( P=0.013). During follow-up period, local recurrence were found in 15 tumors (7.1 %) 2-17 months after REA and intrahepatic new tumors developed in 32 patients (37.2%) 2-17 months after RFA in group A,While local recurrence were found in 16 tumors (14.1%) and intrahepatic new tumors developed in 17 patients (43.5%) in group B ( P=0. 041, P ＞0.05, respectively). Conclusions CEUS provides important information for selecting candidation and designing optimal protocol for RFA in liver metastasis. The use of CEUS can increase tumor necrosis rate and decrease post-RFA tumor local recurrence,and then improve efficacy of RFA therapy.