Clinical Value Of Combination Of Intraoperative CEUS And Postoperative MRI In Evaluation Of Early Posttreatment Efficacy Of Microwave Ablation Procedure In Patients With Renal Tumor

ObjectiveTo discuss the value of intraoperative contrast enhanced ultrasound(CEUS) combinedwith postoperative contrast-enhanced magnetic resonance imaging(CEMRI) in evaluatingthe clinical efficiency of percutaneous microwave ablation procedure in patients withkidney tumor, so as to increase the inactivated rate within a relatively short period oftreatment.Methods20patients with21lesions (11male,9female;age range,30–77years;mean age,59years;5cases in the left kidney,14cases in the right kidney, and1cases in hibateral kidneys;with the range of maximum diameter of tumors from1.0cm to4.8cm,) who were referredto our institution between September2010and September2011underwent microwaveablation guided by ultrasound. All the cases were performed with conventional ultrasound,contrast-enhanced ultrasound and contrast-enhanced MRI or enhanced CT examination, inorder to define kidney mass for tumor staging and grading. All patients underwent biopsybefore operation. The pathological findings revealed17cases with clear-cell carcinoma,1cases with renal anaplastic carcinoma,1case with adencarcinoma, and1case with hepaticmetastatic tumor. All the lesions were examined exactly by intraoperative CEUS aftervenous bolus injection of SonoVue to investigate the treatment effect of microwaveablation. When the suspected lesion was identified, further ablation was performedimmediately. Within24hours, CEMRI was performed to observe the perfusion changes ofcontrast medium in cortex and parenchyma phase and to evaluate the range of lesion withablation. Lesion with no enhancement in CEMRI or contrast-enhanced ultrasound in eachphase was defined as the index of completely inactivated tumors, and irregular enhancement around or inside the treatment zone demonstrated residual tumor remained.The result of CEUS after ablation was compared with MRI images (within6-24hours) toevaluate the curative effect of microwave ablation.If any suspected lesion was detected,further ablation would be performed within48hours.All the cases were followed-up byCEUS,CECT/CEMRI and clinical examination after1-6months. Biopsy was conducted ifnecessary. The final curative effect was evaluated according to the follow up or histologicexamination.ResultsIn the21lesions treated with microwave ablation.19lesions were demonstratedcompletely ablated with immediate CEUS after the ablating procedure.2lesions showedirregular enhancement and underwent further ablation,and final CEUS result showed thelesions with complete ablation.The21lesions were examined by MRI (within6-24hours).19lesions weredemonstrated completely ablated with immediate CEUS.2lesions which showed nodulemargin with enhancement in cortex phase on MRI images which revealed residual tumorremained and was confirmed with puncture biopsy,and the lesions were redeemly ablatedwithin48hours.2lesions which were redeemly ablated in operation were demonstratedcompleted ablated on MRI images.There was good consistency in investigating curative effect between immediate CEUSand synchronal MRI with the coincidence of90.4%(19/21) and100%(21/21) respectively.The results of curative effect investigation revealed there was no significant differencebetween CEUS and MRI (P＞0.05).There was no significant difference in comparison oftreatment extent of those lesions between CEUS and MRI (P＞0.05).Combined applicationof CEUS and MRI could shorten treatment cycles and increase the inactivated rate.ConclusionBoth intraoperative CEUS and synchronal CEMRI can exactly detect the renal tumorinactivated degree and evaluate the treatment extent of microwave ablation. Both of themhave their advantages.The combination of the two imaging modalities is proved to beeffective for detection and assessment of post-treatment effect of microwave ablation.