Ultrasound Attenuation Measurements of the Liver in Vivo Using a Commercial Sector Scanner

Abstract

Attenuation measurements of various tissue minicking phantoms and three different groups of patients were obtained using a modified commercial sector scanner. Estimates of attenuation were made using the spectral shift method with mean frequencies at different depths of a region of interest being obtained by both zero crossing and fast Fourier transform techniques. The accuracy and precision of both techiques was compared in phantoms and it was found that the FFT technique yielded less day-to-day variation (SD=3 percent) than the zero crossing technique (5 percent). For larger regions of interest, the range of variation in both techniques was more similar. Day-to-day variation in livers of normal patients was much larger than that seen in phantoms (10 to 15 percent) suggesting that in vivo measurements may be less precise due to actual daily changes in patients' livers. Attenuation estimates of phantoms were high by approximately 0.16 dB/Mllz/cm compared to values obtained by transmission techniques. The attenuation values of livers in a group of 31 normal patients ranged from 0.214 dB/cm/MHz to 0.849 dB/cm/MHz with a mean of 0.627 ± 0.126 dB/cm/MHz for the zero crossing technique while the mean value using the FFT technique was 0.86 ± 0.168 dB/cm/MHz. A group of 26 Gauchers disease patients also showed wide variation with a mean attenuation value of 0.768 ± 0.21 dB/cm/MHz using the FFT technique. This was significantly different than that of the normal group (p<.05). Also, a group of 22 chronic B hepatitis patients was examined, having a mean attenuation value of 0.823 ± 0.21 dB/cm/MHz, not significantly different from those of the normal patients. Highly significant differences were found between the three groups when the power spectrum bandwidths of signals received were compared. These differences may be due to differences in the dependence of attenuation as a function of frequency between the groups and may represent a useful tissue characterization parameter.

Keywords

Attenuation power spectrum spectral shift tissue characterization ultrasound

Get full access to this article

View all access options for this article.

References

Taylor

K.J.W.

Gorelick

F.S.

Rosenfield

A.T.

Riely

C.A.

, Ultrasonography of alcoholic liver disease with histological correlation, Radiology 141, 157–161 (1931).

Gosink

B.B.

Lemon

S.K.

Scheible

Leopold

G.R.

, Accuracy of ultrasonography in diagnosis of hepatocellular disease, Am. J. Roentgenol. 133, 19–23 (1979).

Kuc

Schwartz

Finby

Dain

, Statistical Estimation of Acoustic Attenuation Coefficient Slope for Liver Tissue from Reflected Ultrasonic Signals, in Ultrasonic Tissue Characterization II, Linzer

, ed, National Bureau of Standards Spec. Publ. 525 (U.S. Government Printing Office, Washington, DC, 1979).

Flax

S.W.

Pelc

N.J.

Glover

G.H.

Gutman

F.D.

McLachlan

, Spectral characterization and attenuation measurements in ultrasound, Ultrasonic Imaging 5, 95–116 (1983).

Ophir

Maklad

N.F.

Bigelow

R.H.

, Ultrasonic attenuation measurements of in vivo human muscle, Ultrasonic Imaging 4, 290–295 (1982).

Kuc

, Estimating acoustic attenuation from reflected ultrasound signals: comparison of spectral shift and spectral-difference approaches, IEEE Trans. Acoust. Speech, Signal Processing, ASSP-32, 1–6 (1984).

Maklad

N.F.

Ophir

Balsara

, Attenuation of ultrasound in normal liver and diffuse liver disease in vivo, Ultrasonic Imaging 6, 117–125 (1984).

Novick

G.S.

Flax

S.W.

Taylor

K.J.W.

Brennan

P.A.

, Sonographic estimation of tissue attenuation using the method of zero crossings, J. Ultrasound Med., p. 204 (1983) (Abstract only).

Kuc

, Clinical application of an ultrasound attenuation coefficient estimation technique for liver pathology characterization, IEEE Trans. Biomed. Engin. BME-27, 312–319 (1980).

10.

Levi

Keuwez

, Tissue Characterization In Vivo by Differential Attenuation Measurements, in Ultrasonic tissue characterization II, Linzer

, ed., National Bureau of Standards Spec. Publ. 525 (U.S. Government Printing Office, Washington, D.C., 1979).

11.

Kuc

, Estimating Acoustic Attenuation from Reflected Ultrasound, in Proc. 34th Ann Conf. Engin. Med. Biol., p. 142, (1981) (Abstract only).

12.

Shaffer

Pettibone

D.W.

Havlice

J.F.

Nassi

, Estimation of the Slope of the Acoustic Attenuation coefficient, Ultrasonic Imaging 6, 126–138 (1984).

13.

Atkinson

Woodcock

J.P.

, Doppler Ultrasound and its Use in Clinical Measurement, (Academic Press, New York, 1982).

14.

Kuc

Schwartz

Von Micsky

, Parametric Estimation of the Acoustic Attenuation Coefficient Slope for Soft Tissue, in 1976 IEEE Ultrasonic Symposium Proceedings, pp 44–47 (IEEE Cat. No. 76 CH 1120-5SU).

15.

Insana

Zagzebski

Madsen

, Improvements in the spectral difference method for measuring ultrasonic attenuation, Ultrasonic Imaging 5, 331–345 (1983).