Non-invasive evaluation of hepatic fibrosis: don’t count your chickens before they’re hatched
- Correspondence to:
Professor M Pinzani
Dipartimento di Medicina Interna, Università degli Studi di Firenze, Viale G B Morgagni, 85, 50134 Firenze, Italy;
- human immunodeficiency virus
- hepatitis C virus
- liver biopsy
- liver fibrosis
- predictive models
There is an increasing desire for non-invasive tests to assess both the stage of liver fibrosis and the rate of progression of fibrogenic chronic liver diseases and so reduce the need for repeated liver biopsies. However, higher quality non-invasive diagnostic procedures are still needed
Cost pressures and recognition of the limitations of liver biopsy have led to an increasing desire for non-invasive tests to assess both the stage of liver fibrosis and, more importantly, the rate of progression of fibrogenic chronic liver diseases (CLD). In addition, the increase in knowledge of the mechanisms regulating the fibrogenic process in CLD and the consequent knowledge of its dynamic features (that is, scarring as the net result of extracellular matrix deposition and degradation) have led to the need for diagnostic tools with higher prognostic value and flexibility for longitudinal follow up.
There are two main groups of non-invasive methodologies for the evaluation of hepatic fibrosis and its progression. The first group, defined “serum markers”, is aimed at predicting fibrosis stage and, possibly, other prognostic information, using parameters measurable in serum. The second group includes methodologies derived from elaboration of parameters obtainable with the current liver imaging techniques (ultrasound, computed tomography (CT) scan, magnetic resonance) or to the innovative use of principles of physics (that is, transient elastography).
Among serum markers we can distinguish indirect and direct markers.1 Indirect markers are based on single or algorhythmic elaboration of commonly observed alterations in liver function that do not necessarily reflect extracellular matrix metabolism (that is, platelet count, aspartate aminotransferase (AST), and total cholesterol) (table 1). Assessment through indirect markers is in general easy to obtain as it is based on routine laboratory tests or tests easily available in a hospital general laboratory. The best known tests based on indirect markers include: the PGA (prothrombin …