Hepatocellular carcinoma treated with radio frequency ablation: An early evaluation with magnetic resonance imaging

Abstract

Purpose:To determine the usefulness of nonenhanced T1-weighted spoiled gradient-recalled acquisition in the steady-state (SPGR) MRI in the early assessment of the efficacy of radio frequency (RF) therapy for hepatocellular carcinoma (HCC). Materials and Methods:A total of 23 patients with 28 HCC nodules treated with percutaneous RF ablation underwent nonenhanced MRI within two days after the RF procedure and contrast-enhanced computed tomography (CT) one week after. MR assessment of ablation efficacy according to the concentric zonal pattern on T1-weighted SPGR imaging was compared with the one-week CT and presence of local recurrence by means of follow-up study for 12 months or more. Results:In 18 of 28 ablated nodules, SPGR images revealed a central hyperintense zone covering the entire tumor, CT showed a nonenhanced area covering the entire tumor, and no local recurrence was demonstrated in the follow-up studies. In nine of 28 nodules, the central hyperintense zone did not cover the entire tumor; and local recurrence was demonstrated in three nodules. In the remaining one nodule, no signal change was seen in the treated area on SPGR images and CT showed the presence of residual viable tumor. Conclusion:Nonenhanced T1-weighted MRI was considered useful for early assessment of the efficacy of RF therapy for HCC.

Imaging Modalities for Assessment of Treatment Response to Nonsurgical Hepatocellular Carcinoma Therapy: Contrast-Enhanced US, CT, and MRI

“…MRI evaluation of the absence of tumor enhancement and the safety margin is also based on a visual comparison of the pre-and post-RFA images by referring to specific landmarks of the liver. A hyperintense zone on non-enhanced T1WI within 2 days after RFA reflects the extent of the ablated region [50]. Functional imaging including diffusion-weighted MRI has the ability to provide unique insights into molecular water distribution within a tumor, and therefore indicate tumor viability at a cellular level [51].…”

Correlation between High Field MR Images and Histopathological Findings of Rat Transplanted Cancer Immediately after Partial Microwave Coagulation

“…In many studies for evaluating thermal ablation at the acute phase, MR images are acquired several days after treatment. 22 In our case, however, MR images were acquired within 2 hours after treatment, so tissue responses to ablation may be slight and MR ndings may diŠer from those in other studies. The groups of Lee 23 and Onishi 24 also reported MR images of the liver in animal models from 2 hours after radiofrequency (RF) ablation.…”

Radiofrequency ablation of hepatocellular carcinoma: The feasibility of magnetic resonance imaging with gadolinium ethoxybenzyl diethylene triamine pentaacetic acid for evaluating the ablative margin

“…Regarding an early evaluation with MRI after RF ablation, Khankan et al . reported that a hyperintense zone on non‐enhanced T 1 ‐weighted MRI within 2 days after ablation reflected the extent of the ablated region 16 . Accordingly, blurring of the hyperintense rim on T 1 ‐weighted images can be attributed to a hemorrhage or a proteinaceous material within the ablated area 17,18 .…”