FEATURE HEPATOLOGY
80% of new cases, the infection becomes chronic. About 30% of individuals progress inexorably to develop cirrhosis over a variable period of up to 20 years after the initial infection, which is usually 5-10 years after initial medical presentation. Current treatment regimens are designed to prevent the progression in disease from mild hepatitis through significant fibrosis and subsequently, cirrhosis. Sustained response rates to antiviral treatment with pegylated interferon and ribavirin are variable, but at best are 80%. Hepatic steatosis has been identified
as an independent risk factor for chronic liver disease, with non-alcoholic steatohepatitis (NASH) identified in a subgroup of patients with non-alcoholic fatty liver disease (NAFLD). Hepatic steatosis is also the most common histological abnormality of the liver, affecting about 50% of patients who abuse alcohol. NALFD is part of the metabolic syndrome, associated with obesity, hypertension, type II diabetes mellitus and dyslipidaemia. Some patients with NASH also develop fibrosis and subsequently cirrhosis.
LIVER BIOPSY TECHNIQUES The first liver aspirate was performed by the German physician, Paul Ehrlich in 1883, while percutaneous liver biopsy was first reported in the 1920s. The transjugular approach was pioneered by the radiologist, Charles Dotter, in the 1970s. Several pre- procedural precautions need to be taken, including prior knowledge of the patient’s anatomy with a screening liver ultrasound, an up-to-date platelet count and a clotting screen. Particular situations, such as high bleeding risk, can prohibit standard percutaneous approches, partially or completely. However, liver biopsy remains the gold standard for assessing the severity of chronic liver diseases.
REQUIREMENT FOR BIOMARKERS OF LIVER FIBROSIS Effective antiviral therapies and the advent of antifibrotic drugs have led to an increasing demand for non-invasive, accurate and reliable biomarkers of hepatic disease severity. It is recognised
Arab Health Show Issue 2012 57
«A safe, reliable non- invasive imaging approach for detecting hepatic fibrosis would obviate the hazards associated with liver biopsy»
that the current gold standard for monitoring the severity of fibrosis, histological analysis of liver biopsy, has limitations and engenders risk to the patient with a defined morbidity, including pain, bleeding, time off work and even mortality rate of between one in 1,000 and one in 10,000 cases. The specimen retrieved by standard liver biopsy techniques represents just 1/50,000 of the liver, and typically only 16% of such biopsies exceed the optimal length for adequate histological assessment of 25mm. This leads to sampling variability since
hepatic fibrosis, inflammation and steatosis may all have a patchy spatial distribution within the liver. In addition, as histological scoring systems are semi-quantitative categorical assessments of a continuous process (fibrogenesis), there is appreciable intra- and inter- observer variability. A safe, reliable non-invasive imaging
approach for detecting hepatic fibrosis would obviate the hazards associated with liver biopsy and allow patients to be monitored serially with a view to preventing the slide towards cirrhosis and its complications. Accordingly, there are potential health economic benefits by prevention of end-stage disease and the reversal of less severe fibrosis.
APPROACHES TO THE NON-INVASIVE ASSESSMENT OF CHRONIC LIVER DISEASE The non-invasive assessment of the severity of chronic liver disease includes
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