Ultrasonic liver scanning: the A-scan in the normal and cirrhosis

Abstract

Techniques for the analysis of ultrasonic A-scans of the liver were used to compare the scans of 30 normal livers with those of 13 with cirrhosis. The ultrasonic frequency was approximately 1.5 MHz. Thirty scans of each liver were analysed using a computer. There is no significant difference between the ultrasonic attenuations in the two groups, but the echo amplitudes are significantly greater in the cirrhotics than in the normals. The echo envelope shapes of both groups are similar, apart from the larger amplitudes amongst the cirrhotics. This result is consistent with a model in which the source of the echoes is the hepatic vessel system, the characteristic impedance mismatch being increased in cirrhosis.