高橋 政義, 飯田 和成, 和久井 紀貴, 高山 竜司, 塩澤 一恵, 住野 泰清

Masayoshi TAKAHASHI, Kazunari IIDA, Noritaka WAKUI, Ryuji TAKAYAMA, Kazue SHIOZAWA, Yasukiyo SUMINO

東邦大学医療センター大森病院消化器センター内科

Division of Gastroenterology and Hepatology, Department of Internal Medicine, Toho University Omori Medical Center

キーワード : hepatocellular carcinoma, radiofrequency ablation, Sonazoid, ablation zone, flash-replenishment sequence

目的：肝細胞癌（hepatocellular Carcinoma: HCC）患者において，Sonazoid^®造影超音波後血管相（Kupffer phase）の肝実質内micro bubble（MB）に高音圧超音波ビームを照射した際の崩壊距離と，ラジオ波焼灼療法（radio frequency ablation: RFA）における焼灼範囲を比較しその関係を明らかにする．対象：2008年1月から2009年12月までの間にCool-tip 20 mm針でRFA単独治療を行ったウイルス性慢性肝疾患を伴うHCC48症例48結節．方法：RFA施行前にSonazoid^®造影超音波検査を施行．造影開始10分後の後血管相（Kupffer phase）において，flash-replenishment sequenceで肝右葉のMBを崩壊させ，肝表面からの崩壊距離を測定した．その後，RFA治療を行い，治療後の造影CTで焼灼範囲を測定し崩壊距離と比較した．さらに，治療前の各種肝線維化マーカーと崩壊距離を比較した．結果：崩壊距離が深くなるに従い，RFA焼灼範囲は有意に狭くなった（P＝0.0001）．また，IV型コラーゲン 7SはMB崩壊距離が深くなるに従い，有意に増加し，崩壊距離に肝線維化が関与している可能性が示唆された．結論：Sonazoid^®造影超音波の後血管相（Kupffer phase）におけるMB崩壊距離が深くなればなるほど，RFA焼灼範囲は狭くなることが判明した．RFAの術前に焼灼範囲を推測する方法として有用と考える．

Purpose: To compare the length of microbubble (MB) collapse of liver parenchyma brought about by repeated strong pulses in the post-vascular phase (Kupffer phase) of Sonazoid^® enhanced ultrasonography with ablation zone radiofrequency ablation (RFA) in patients with hepatocellular carcinoma. Subjects: This study was performed on 48 nodules of 48 patients with viral chronic hepatic diseases who had undergone RFA treatment using 20-mm cool-tip needles for HCC from January 2008 through December 2009. Methods: Ultrasonography with Sonazoid^® was carried out before RFA. The post-vascular phase (Kupffer phase) MB within the right hepatic lobe were collapsed by a flash-replenishment sequence 10 minutes after initiation of ultrasonography, and the length of the collapse was measured from the hepatic surface. RFA treatment was then performed and the ablation zone was measured by computed tomography (CT) after treatment and compared with the length of the collapse. Moreover, length of collapse was compared with various markers of hepatic fibrosis. Results: The width of the RFA ablation zone decreased significantly with increase in length of collapse (P=0.0001). Further, IV type collagen 7S increased significantly with length of MB collapse, suggesting a possible role of hepatic fibrosis in the length of collapse. Conclusion: The width of the RFA ablation zone decreased with increase in the length of post-vascular phase (Kupffer phase) MB collapse after ultrasonography with Sonazoid^®. This method is useful for estimating the ablation zone before RFA.