ARFI elastography is a new method developed in the last 3 years for the noninvasive
evaluation of liver fibrosis, integrated into a Siemens Acuson ultrasound
system. Usually 10 valid measurements are performed in the right liver lobe, a median
value is obtained and the result is expressed in meters/second. In patients with chronic
hepatopathies, the AUROC’s for predicting significant fibrosis range between 0.75-0.85
and for predicting cirrhosis between 0.85-0.95, the diagnostic performances being better
in patients with chronic hepatitis C. Most studies regarding ARFI were performed in
patients with chronic viral hepatitis, but recently data regarding patients with nonalcoholic
fatty-liver disease and post-transplant patients were published. To increase the
accuracy of liver cirrhosis diagnosis, the spleen stiffness (SS) assessed by ARFI can be
used. ARFI it is a reproducible method, the intraclass correlation coefficient for interand
intraobserver measurements ranging from 0.81-0.87, better in patients with severe
fibrosis and cirrhosis. Similar with Transient Elastography (TE), elevated levels of
aminotransferases are associated with the increase of liver stiffness (LS) values assessed
by ARFI. Even if the manufacturer did not recommended the use of technical
parameters IQR (interquartile range interval) and SR (success rate) well-known from
TE, published data proved that the accuracy of the method significantly increased with
the use of these quality parameters. Regarding the prediction of liver cirrhosis
complications, especially portal-hypertension, data regarding the usefulness of LS
and/or SS are not so solid, but ARFI accuracy can be increased by combining different
parameters.
Keywords: ARFI elastography, liver stiffness, chronic hepatitis, liver cirrhosis,
portal hypertension.
