Application of edema ring around the ablation zone on FS-T2WI of early phase in effect evaluation of radiofrequency ablation for malignant hepatic tumors / 中国介入影像与治疗学

ABSTRACT

Objective: To explore the value of edema ring around the ablation zone on FS-T2WI for early phase effect evaluation of radiofrequency ablation (RFA) for treatment of malignant hepatic tumors. Methods: Totally 18 patients with liver cancer and 4 with liver metastasis who underwent RFA therapy were enrolled. Plain MR images were obtained to observe the morphological features of the edema ring around the ablation zone on FS-T2WI on the third day after RFA. Plain and multiphase enhanced MRI were obtained after RFA to observe the effect, as well as tumor markers. The value of continuity of edema ring on FS-T2WI for evaluating the effect of RFA was assessed. Results: High-signal edema ring was seen around the ablation zone on FS-T2WI in all 22 cases. The edema rings were continuous in 19 cases, among them the thickness of the edema rings were uniform in 11 cases, while were uneven but with regular shape and clear boundary in the other 8 cases. No abnormal enhancement was detected on the following enhanced MRI after RFA, and the tumor markers were stable in above 19 cases, both suggesting completed ablation. The edema rings were discontinuous in 3 cases of liver cancer, with protruding slightly high signal nodule which enhanced on MRI 1 month after RFA, and the serum alpha-fetoprotein were elevated, suggesting that the ablation area did not completely cover the tumor area, and the ablations were not complete. Conclusion: The edema ring around the ablation zone on plain FS-T2WI early phase after RFA has certain value in assessing the effect of RF for malignant liver tumors, especially for short-term effect of RFA.