林 信成¹, 玉木 長良¹, 米倉 義晴¹, 山本 和高¹, 中島 言子¹, 鳥塚 莞爾¹, 小川 俊雄², 片倉 景義², 梅村 晋一郎², 児玉 真塩³

Nobushige HAYASHI¹, Nagara TAMAKI¹, Yoshiharu YONEKURA¹, Kazutaka YAMAMOTO¹, Kotoko NAKAJIMA¹, Kanji TORIZUKA¹, Toshio OGAWA², Kageyoshi KATAKURA², Shinichiro UMEMURA², Mashio KODAMA³

¹京都大学医学部附属病院放射線核医学科, ²日立中央研究所第9部, ³日立メディコ柏工場

¹Department of Radiology and Nuclear Medicine, Kyoto University Hospital, ²9th Department, Central Research Laboratory, Hitachi Ltd., ³Hitachi Medical Co.,Kashiwa

キーワード : IN VIVO measurement, Sound speed, Fatty liver, Liver cirrhosis, Tissue characterization

　A new system to measure sound speed IN VIVO was developed and applied to normal, cirrhotic and fatty livers.
　Sound speed was measured in 26 normal, 27 cirrhotic and 15 fatty livers. Mean speed was determined at 1538 m/s in normal, 1610 m/s in cirrhotic and 1423 m/s in fatty livers. The difference in speed between the three groups was significant (P values less than 0.001).
　It was considered that sound travels faster in cirrhotic livers because of their relative hardness over normal livers, and further, that the reduction in sound speed in fatty livers reflected the fact that sound travels more slowly through fat tissue.
　The method used to measure sound speed through tissue scanned IN VIVO clearly distinguished normal, cirrhotic and fatty livers. This technique would be an important tool for use in the objective and quantitative evaluation of diffuse liver diseases.