Transient elastography as measured by the Fibroscan device is used throughout the world, except notably in the U.S.  That may change soon as an application is under review by the FDA (Gastroenterology & Hepatology 2012; 8: 605-7).

• Fibroscan works by measuring shear wave velocity with a 50-MHz wave that is “passed into the liver from a small transducer on the end of an ultrasound probe.”
• “The technology measures the velocity of the sound wave passing through the liver and then converts that measurement into a liver stiffness measurement.”
• Takes 5-7 minutes to perform
• Fibroscan is particularly reliable when showing either no fibrosis or advanced fibrosis.  Less accuracy is noted with moderate fibrosis.
• Technology can be augmented with noninvasive biomarkers of fibrosis
• Not reliable in several groups: morbidly obese & patients with ascites

Additional references:

• Am J Gastroenterol 2011; 106: 2121-22. Staging liver fibrosis for HCV
• Gastroenterol 2005; 128: 343-50.  Comparison of elastography, biomarkers, and liver biopsy for staging fibrosis