Liver needle biopsies played important role in determining the various forms of chronic hepatitis, the activity of inflammation and the degree of fibrosis. A breakthrough in their evaluation was provided by the so-called Knodell Histology Activity Index (HAI) system, which expressed the dynamics of the process and histological characteristics of therapy response. The HAI system underwent several modifications, the most widely used being the Desmet, Ishak modifications as well as the METAVIR scoring system. These systems examine necroinflammation and degree of fibrosis separately, namely the grade and stage of chronic hepatitis. Determination of fibrosis has become the subject of discussion lately, since the amount of connective tissue deposition (collagen fiber, extracellular matrix) is not clearly identifiable with the stage of chronic hepatitis. Histological evaluation of the liver remains decisive in determining the effect of the various new therapeutic drugs, in particular the protease and polymerase inhibitors of certain nonstructural proteins of the hepatitis C virus. It can be established however, that in recent years liver biopsies have become rather a selective than routine technique.
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