Ultrasound plays a key role in the diagnosis of liver disease, which affects hundreds of millions of people. ShearWave Elastography, which quantifies tissue stiffness, is gaining in use for non-invasively evaluating the liver for these diseases. DOTmed News recently interviewed Alex Exposito, SuperSonic Imagine's Director for North America, to find out about this technology.

DOTmed News: How has ultrasound traditionally been used for treating and caring for liver disease patients?

Alex Exposito: Ultrasound would normally be used for an abdominal exam and part of that would be looking at the liver. Ultrasound generates a 2-D image and with that you can see tissue contrast, texture and resolution of the liver. It enables the evaluation of liver vascularity and identification of lesions and suspicious areas.

As ultrasound has improved over time, its sensitivity and specificity has also increased. Subtle lesions now more evident in the liver. With even more advanced technologies like ShearWave Elastography there is considerably better specificity.

This particular technology, which measures tissue stiffness, is designed to measure the elasticity of tissue. Ultrasound is also used with disease staging when guiding a biopsy needle.

DOTmed News: Why are hospitals and health systems interested in alternatives to liver biopsy these days?

AE: Hospitals want to reduce costs, lower infection rates and improve the patient experience. Anytime you can avoid an invasive method outcomes are improved and costs fall. There is a lot of focus on hepatitis C these days. HCV [hepatitis C virus] patients have to be followed routinely and over time. And with new drugs that can now treat hepatitis C, having an alternative to liver biopsy is even more relevant.

DOTmed News: Are there any examples of health systems that have been effective in using an alternative to liver biopsy?

AE: Dr. James Trotter, who is the medical director for general and transplant hepatology at Baylor Health Care System in Dallas, has been very involved in clinical trials for the hepatitis C drug Sovaldi. Now that the drug has been approved, he's followed several hundred of the patients being treated with it.

He's been able to reduced the biopsy rate in those HCV patients by 90 percent using ShearWave Elastography he reports is quick, reliable and reproducible. With a color-coded map, he can see and quantify the stiffness of the liver and this has become an everyday tool for his liver patients. Without this tool he would not be able to evaluate patients as often, and in some patients with advanced stage disease an invasive biopsy can be very risky.

DOTmed News: Let's follow that, what are some of the risks of liver biopsy?

AE: There are complications around putting a needle in anyone, especially liver disease patients. With any biopsy or interventional procedure, there is always risk. If a liver patient has an advanced stage of fibrosis or cirrhosis in the liver, these patients bleed very easily, so you really don't want to run the risk of inserting a needle.

The other thing that happens is as the liver swells, the vessels become compressed and hard to see. Puncturing vessels can cause bleeding and hemostasis in the liver and more complications. The other issue is patient comfort, and needle biopsy is quite painful.

Liver disease patients might go in to get their values checked every 3 to 6 months and a needle biopsy is likely a part of that. Clearly an invasive procedure is much most costly, considers that complications can run into the tens of thousand of dollars.

DOTmed News: Are there other drawbacks of liver biopsy?

AE: Yes, very much so and this has to do with how representative the sample is. The problem is that a sample size of the liver biopsy also has limitations. A sample from one section of the liver can tell you that the whole liver is diseased or not diseased when that may not be the case at all. Let's say a patients ends up with a high liver enzyme test and you go in and get a biopsy and it comes back normal. That biopsy may not correct, may not be targeting the right spot.

DOTmed News: Are new technologies like ShearWave Elastography for liver disease staging reimbursable yet?

AE: Reimbursement is likely on the horizon for ShearWave Elastography. For now, there is a Category I CPT code available for billing in abdominal studies. Of course there is also the out-of-pocket option, which would only run a patient roughly $100 to $150.

It's a pretty minimal cost and most people would probably rather have a non-invasive technique than an invasive one. The bottom line is that this scanning technique saves the healthcare system a lot of money and is repeatable and therefore of great value to clinician.