Clinical evaluation of sonoelasticity measurement in liver using ultrasonic imaging of internal forced low-frequency vibration

The aim of this study is to evaluate liver elasticity noninvasively. We hav e already proposed an ultrasonic imaging system that can reconstruct vibrat ion maps inside tissue under forced mechanical vibration. With this system, shear elastic properties of soft tissue can be evaluated as vibration velo cities. Theoretically, these velocities increase with the increase of tissu e elasticity. Sonoelasticity imaging was performed on 236 patients with chr onic hepatitis and liver cirrhosis, and 50 healthy volunteers. The average of the velocities was 598.8 +/- 151.7 cm/s in healthy volunteers, 984.4 +/- 362.5 cm/s in chronic hepatitis and 1189.0 +/- 411.7 cm/s in liver cirrhos is. The average velocity of Child C group was statistically faster than tho se of Child A and B groups. Fibrotic rate from biopsy specimens statistical ly had the strongest positive correlation with velocities. With our system, the degree of liver fibrosis and function can be estimated objectively and noninvasively. (C) 2001 World Federation for Ultrasound in Medicine & Biol ogy.