Current and emerging techniques that can be utilized to help clinicians diagnose advanced fibrosis due to nonalcoholic steatohepatitis.
Mazen Noureddin, MD: Advanced fibrosis due to NASH [nonalcoholic steatohepatitis] can be diagnosed via multiple methods. The conventional way is with a liver biopsy. We have known this method for many years. Many pathologists are comfortable with it and can stage the disease with it: F0 to F4, F0 having no fibrosis and F4 being cirrhosis. Advanced fibrosis, as you know, starts around F2, F3 and goes to F4, which actually has been associated with morbidities and mortalities of nonalcoholic fatty liver disease and nonalcoholic steatohepatitis.
Nevertheless, given the prevalence of a disease, people have been actively researching new tools that can test patients noninvasively. Some of these tools are imaging tools, such as the transient elastography and MR [magnetic resonance] elastography. Tons of research that has been done on those shows that they can stage fibrosis very accurately.
There are also other noninvasive biomarkers that are serum based. The American Association for the Study of Liver Diseases Practice Guidelines endorse both the FIB-4 [fibrosis 4] and NAFLD (nonalcoholic fatty liver disease) fibrosis score, both of which are formulized to rely on simple tests such as ALT [alanine aminotransferase], AST [aspartate aminotransferase], age, platelet count. One of them relies on diabetes status. There are also other new, promising biomarkers that are serum based that are going to be used in the future. There’s tons of research on that as well.
Norman Sussman, MD: The standard for diagnosing advanced fibrosis in some people’s minds is liver biopsy. The problem is that it is extremely expensive, has some risks, is inconvenient, and is not something you can do repeatedly. I think most people have moved toward noninvasive testing, usually using elastography. And so there are several techniques that allow you to measure elastography. That is, it measures liver stiffness. There is a fairly good correlation between the amount of fibrosis and how stiff the liver is. We can measure stiffness using an ultrasound. There is a specific device that’s designed just for doing that, and that’s called vibration-controlled transient elastography. The company that makes that is Echosens, and the technique has loosely become standard in many practices. That’s called FibroScan.
There are other techniques for measuring liver stiffness. There are some ultrasound machines that allow you to measure liver stiffness using the same physics with a slightly different technique. In some research centers, we’re able to do magnetic resonance elastography, or MRE. That is thought to be the best but is honestly very difficult to get, because it is not available everywhere and is expensive and time consuming.
Viviana Figueroa Diaz, MD: To diagnose advanced fibrosis due to NASH in my practice, we are screening a lot of people who have risk factors for NASH, as I mentioned before. NASH can be pretty silent. When we’re talking about diagnosing NASH, we’re really talking about diagnosing fatty liver. Then we assume that someone has NASH because to diagnose NASH, you really need a liver biopsy. That’s the gold standard. This is a pathology diagnosis.
In terms of diagnostic tools, liver biopsy tends to be a little more invasive and tends to be a little more costly compared with other things we could do, even though it is the gold standard to diagnose NASH. We now have tools we can use to diagnose fibrosis that do not include a liver biopsy. We have noninvasive testing through blood work; through machines that include a transient elastography, or what we call a FibroScan; and even MRIs [magnetic resonance imaging tests] with elastography.