福田 浩之¹, 沼田 和司¹, 田中 克明¹, 前田 愼², 伊藤 龍³

Hiroyuki FUKUDA¹, Kazushi NUMATA¹, Katsuaki TANAKA¹, Shin MAEDA², Ryu ITO³

¹横浜市立大学附属市民総合医療センター消化器病センター, ²横浜市立大学附属病院消化器内科, ³さんむ医療センター内科

¹Gastroenterological Center, Yokohama City University Medical Center, ²Division of Gastroenterology, Yokohama City University Graduate School of Medicine, ³Sanmu Medical Center Hospital

キーワード : high-intensity focused ultrasound, hepatocellular carcinoma, ultrasound

目的：高密度超音波を微小な焦点域に集める集束強力超音波（high-intensity focused ultrasound: HIFU）は，癌組織を熱凝固により壊死させる，穿刺のいらない低侵襲治療法である．現在，最も一般的な治療である経皮的ラジオ波焼灼療法（radiofrequency ablation: RFA）と比較しその長い治療時間が課題である．HIFU治療機のモニターは，画質の点や2次元超音波画像のため，照射や効果判定の立体的把握に限界があった．今回，US（ultrasonography），CTの3次元画像を用い，その有用性を検討した．方法：対象は，3D Dual imagingを施行しHIFUを施行した腫瘍径20 mm以下の肝細胞癌10例である．3次元超音波はAplio（東芝）を用いた．3次元CT（Light Speed Ultra, GE），の立体情報は，3次元画像作成ワークステーション（ZioM900）に入力し，HIFU装置の超音波プローブの角度情報から3次元US，3次元CTの同一断面を作成した．HIFU装置は，重慶Haifu社製JC200．超音波造影剤はレボビストを用いた．成績：集束超音波治療施行の10例について，US，CTの3次元画像のアシストにより完全凝固された．考案：HIFUは，安全で有効な治療であり，US，CTの3次元画像のアシストが有用であった．

High-intensity focused ultrasound (HIFU) is a noninvasive method that can cause complete coagulation necrosis without requiring the insertion of any instruments. The purpose of this study was to evaluate the safety and usefulness of HIFU assisted by ultrasound-computed tomography three-dimensional (US-CT3D) dual imaging for the treatment of hepatocellular carcinoma (HCC). The HIFU system (Chongqing Haifu Tech, Chongqing, China) was used under ultrasound guidance. HIFU ablation was performed in 10 patients with small HCC (≤3 lesions, ≤3 cm in diameter). By transferring the sagittal or axial plane of the 3D US and the CT volume data into a ZioM900 workstation, multiplanar reconstruction images were displayed in a manner resembling conventional US to assist the HIFU treatment. The patients in whom good visualization using B-mode sonography could not be achieved because of the influence of multi-reflections, rib shadows, and unclear tumor margins were successfully treated under the guidance of US-CT 3D dual imaging. The 3D US images obtained as part of the US-CT 3D dual imaging had a high resolution and were useful for examining the area of HCC invasion and for determining the extent of the ablation area. The CT images, which are not influenced by bone shadows or multi-reflections, were useful for detecting the tumors and for visualizing the presence of the intestines in the sonication zone. HIFU treatments were successfully performed in all of the patients with the assistance of US-CT 3D dual imaging.