A new method for attenuation coefficient measurement in the liver: comparison with the spectral shift central frequency method.
OBJECTIVE
To assess the feasibility of a new method of measuring the attenuation coefficient in the liver, which offers less variability of results than the conventional method.


METHODS
The attenuation coefficient was evaluated on the basis of the following equation with sound field correction: [log(M0 (z)) - tau(z)]. In our system, the attenuation coefficient was also evaluated by the spectral shift central frequency method at the same time. We used 44 cases of normal liver, 40 cases of fatty liver, and 20 cases of cirrhotic liver in the system.


RESULTS
With this new method, attenuation coefficient values were 0.59+/-0.10 dB x cm(-1) x MHz(-1) in normal livers, 0.80+/-0.12 dB x cm(-1) x MHz(-1) in fatty livers, and 0.62+/-0.09 dB x cm(-1) x MHz(-1) in cirrhotic livers. In both methods we recorded a statistically significant difference between normal and fatty livers and between fatty and cirrhotic livers (P < .0001). Only in the fatty liver was any significant difference (P < .0001) found between attenuation coefficients in the new method and those in the spectral shift central frequency method (0.70+/-0.05 dB x cm(-1) x MHz(-1)).


CONCLUSIONS
This new method, which was more sensitive in detecting fatty infiltration than the spectral shift central frequency method, was considered usable for evaluating the attenuation coefficient of the liver in vivo.
Fujii
Yasutomo
Y
Department of Clinical Laboratory Medicine, Jichi Medical School, Tochigi, Japan.
Taniguchi
Nobuyuki
N
Itoh
Kouichi
K
Shigeta
Kouichiro
K
Wang
Yi
Y
Tsao
Jing-Wen
JW
Kumasaki
Kenji
K
Itoh
Takashi
T
D000293:Adolescent; D000328:Adult; D000368:Aged; D005234:Fatty Liver / Q000000981:diagnostic imaging; D005260:Female; D006801:Humans; D008099:Liver / Q000000981:diagnostic imaging*; D008103:Liver Cirrhosis / Q000000981:diagnostic imaging; D008297:Male; D008875:Middle Aged; D019047:Phantoms, Imaging; D014463:Ultrasonography