谷口 信行, 伊東 紘一, 中澤 成公, 中村 みちる, 森 博昭

Nobuyuki TANIGUCHI, Kouichi ITOH, Yoshitaka NAKAZAWA, Michiru NAKAMURA, Hiroaki MORI

自治医科大学臨床病理学教室

Department of Clinical Pathology Jichi Medical School

キーワード : Echo level, Fatty liver, Attenuation, Thorax, Ultrasound

Because of the difficulty of measuring attenuation in skin and subcutaneous tissue in vivo, we estimated attenuation indirectly by using mean frequency shifts in the liver. This method can readily measure attenuation by correlating depth and mean frequency shift in the liver. The attenuation coefficient (mean±standard deviation) in the right intercostal wall was 1.69±0.61 dB/cm/MHz (n=23); and the wall thickness was 1.9±0.1 cm. Attenuation was inversely correlates with wall thickness. The strength of the liver echo is estimated by using an echo-intensity histogram. The echo level of the liver is then corrected by compensating for thoracic wall attenuation. This method was used on the control group and fatty-liver group. The echo level in the fatty-liver group was high only after it was corrected for wall attenuation, compared with the control group.