Assessment of ablative margin by unenhanced magnetic resonance imaging after radiofrequency ablation for hepatocellular carcinoma

作者：Koda Masahiko^*; Tokunaga Shiho; Miyoshi Kennichi; Kishina Manabu; Fujise Yuki; Kato Jun; Matono Tomomitsu; Okamoto Kinya; Murawaki Yoshikazu; Kakite Suguru

来源：European Journal of Radiology, 2012, 81(10): 2730-2736.

DOI：10.1016/j.ejrad.2011.11.013

• Radiofrequency ablation
• Hepatocellular carcinoma
• Magnetic resonance image
• Ablative margin

Purpose: The aim of this study was to evaluate the feasibility of magnetic resonance imaging (MRI) without a contrast agent to visualize the ablative margin after radiofrequency ablation (RFA) for hepatocellular carcinoma (HCC), compared with enhanced CT. %26lt;br%26gt;Methods: Twenty-five HCCs in 19 patients were treated by RFA. T1-weighted MRI was performed before and after RFA, and the signal intensities of the tumors and surrounding liver tissues were measured. Treatment efficacy was assessed based on three grades: margin (+), a continuous high-intensity rim around the index tumor; margin zero, a partially discontinuous high-intensity rim; margin (-), the tumor extends beyond the high-intensity rim. %26lt;br%26gt;Results: Twelve (86%) of fourteen low-intensity tumors on the pre-MRI were visualized as low-intensity tumors on post-MRI, and the ablative margins were visualized as high-intensity rims. Two (67%) of three high-intensity tumors on pre-MRI were visualized as higher-intensity tumors in the high-intensity ablative margin. Because the signal intensities of tumors and surrounding tissues in 14 tumors that were low- or high-intensity tumors on pre-MRI increased to the same extent, the tumors and ablative margin could be distinguished on post images. In 6 (75%) of the 8 iso-intensity tumors on pre-MRI, the ablative margin and tumor could also not be discriminated on post-MRI. The overall agreement between MRI and CT for the ablative margin was good (kappa coefficient = 0.716, p = 0.00002). %26lt;br%26gt;Conclusion: In 82% of low- or high-intensity tumors on pre-MRI, post-MRI without a contrast agent enabled visualization of the ablative margin as a high-intensity rim, and it was possible to evaluate the ablative margin earlier and easier than with enhanced CT.

• 出版日期2012-10