SHEAR WAVE ELASTOGRAPHY of LIVER FIBROSIS

Sonography is a noninvasive and inexpensive procedure for diagnosis of diffuse liver disease; however, the value of sonography for distinguishing a low degree of liver fibrosis from cirrhosis is limited. In a study by Colli et al, 28 of 107 patients with severe fibrosis or definite cirrhosis (26%) had negative results for liver surface nodularity and caudate lobe hypertrophy and had normal hepatic venous flow. In this regard, elastography integrated into ultrasound systems is an effective adjunctive tool for quantifying liverfibrosis.

Conclusions

In patients with chronic viral hepatitis, particularly in patients with hepatitis C virus infection, all noninvasive methods are ready to be used for detecting and staging liver fibrosis before therapy at a safe level of predictability.

As with transient elastography, elastographic techniques based on shear waves generated by the acoustic beam are more accurate in detecting cirrhosis than significant fibrosis. They have the advantage of B-mode guidance, which allows one to choose an area of liver parenchyma better suited for stiffness assessment (ie, free of large vessels and focal lesions).

These methods are all valid when information about fibrosis is needed. Liver biopsy should still be performed when biochemical tests and imaging studies are inconclusive or information other than liver fibrosis is required.