Hiroaki MORI¹, Kouichi ITOH¹, Nobuyuki TANIGUCHI¹, Yoshikazu YASUDA²

¹Division of Clinical Physiology, Department of Clinical Pathology, Jichi Medical School, ²Department of Surgery, Jichi Medical School

キーワード : Frequency-dependent attenuation, Liver tumors, Mean frequency, Spectral shift zero crossing

The spectral-shift zero-crossing method was used to determine the frequency-dependent attenuation (FDA) of liver tumors. FDA values of phantoms of known attenuation values were used to obtain a high degree of accuracy with this new system. FDA values were measured in 44 liver tumors; comprising five hemangiomas, 16 hepatocellular carcinomas (HCC), 22 metastatic liver tumors, and one granuloma.
The mean attenuation value for hemangiomas was 0.35 dB/cm/MHz, a lower value than that obtained for other liver tumors.
HCC and metastatic liver tumors gave FDA values slightly lower than did normal liver, and there were no significant differences between FDA values in HCC and metastatic liver tumors. Among the metastatic liver tumors, metastases from lung cancer showed lower values than did metastases from gastrointestinal cancer. Our results suggest that FDA values might be useful in diagnosing liver tumors.