北村 宏, 中山 中, 川手 裕義, 久保田 充, 小林 聡, 今村 宏, 島田 良, 宮川 眞一, 川崎 誠治

Hiroshi KITAMURA, Ataru NAKAYAMA, Yoshihiro KAWATE, Mitsuru KUBOTA, Akira KOBAYASHI, Hiroshi IMAMURA, Ryo SHIMADA, Shinichi MIYAGAWA, Seiji KAWASAKI

信州大学第一外科

First Department of Surgery Shinshu University School of Medicine

キーワード : Color Doppler, Sonoelasticity, Tissue stiffness

Objective. To evaluate the stiffness of tumors with respect to the stiffness of the surrounding tissue, shear velocity generated by external compression was visualized using a conventional color Doppler ultrasonograph.
Materials and Methods. Patients with breast carcinoma (n=2), hepatocellular carcinoma (n=6), metastatic liver tumor (n=3), leiomyosarcoma of the small intestine (n=1), and carcinoma of the small intestine (n=1) were subjected to ultrasound examination. The hepatocellular carcinomas were treated by transarterial chemoembolization. Manual compression with the transducer was applied through the body surface, and sonoelasticity images were captured when the strain on the tissue was released by a quick backward movement of the transducer. Velocity range was varied in each examination to obtain the best discrimination between the targets and the adjacent tissue based on their shear speeds. The ultrasound data were confirmed by comparison with CT findings from hepatocellular carcinomas and by histological examination (surgical removal) of the other tumors.
Results. Stiffness of pretreated hepatocellular carcinomas did not differ from that of the surrounding parenchyma. Effectively treated tumors or the necrotic portions of the tumors exhibited less Doppler signal than the surrounding parenchyma or residual viable tumor component. Although two of the metastatic liver tumors presented color-coded images indicating hardness, the others did not. The breast tumor and the intestinal tumors presented significant color-coded images, indicating that the tumors were much harder than the surrounding tissue.
Conclusions. Our technique for visualizing tumor characteristics in terms of stiffness seems to be simpler and practical than methods requiring a vibration apparatus, analog-digital converter for radio frequency signal analysis, or other special equipment.