New non-invasive scan for liver disease
Posted on 27 March 2017
In a first for Africa, a groundbreaking, non-invasive screening system offered by Dr Naayil Rajabally, gastroenterologist at Mediclinic Constantiaberg, is now available to monitor liver stiffness – a key early indicator for liver disease.
There’s a general rule of gastroenterology, which states simply: ‘Soft liver, healthy liver’. A hard liver is an unhealthy liver, leading to advanced liver disease. The challenge, then, is to measure how hard, how soft, or how elastic a patient’s liver really is. ‘Thus far the only way we have been able to do this reliably is by a liver biopsy,’ says Dr Rajabally. ‘In other words, we would extract a small piece of the liver and a pathologist would assess the degree of fibrosis by examining it under a microscope.’ Biopsies, however, are invasive – and, as Dr Rajabally points out, ‘They are not without risk.’
Now, after many years of research and evaluation at multiple sites around the world, a non-invasive alternative has emerged, whereby elasticity of a patient’s liver can be measured using vibration-controlled transient elastography (VCTE). The FibroScan VCTE Liver Stiffness Testing System – which Dr Rajabally has been using since early 2016 in his rooms – has been adopted as a first line tool for assessing liver fibrosis by the European Association for the Study of the Liver (EASL) and by the American Association for the Study of Liver Diseases (AASLD). The machine generates a shear wave that travels through the liver and the speed of the shear wave is measured by ultrasonic signals. The stiffness of the liver is proportional to the speed of the shear wave. If the test reveals fibrosis, Dr Rajabally explains, treatment can begin without any need for the liver biopsy in conditions such as viral hepatitis, non-alcoholic fatty liver disease (NAFLD), alcoholic liver disease and cholestatic liver diseases.
‘There are various stages from a normal liver to a cirrhotic liver, and fibrosis is essentially what leads to cirrhosis,’ he says, adding that fibrosis is the sole independent predictor for progression of liver disease. ‘So if we can measure fibrosis, we can attempt to change the natural course that leads to liver disease.’
Quick and painless
From a patient’s perspective, the most striking thing about the FibroScan system is how quick and painless the process is. The scan itself can be done in a single consult and feels much like an ultrasound. Following a three-hour fast the patient lies on their back, the doctor applies a gel to the skin, locates the intercostal space between the ribs and applies the scope. This ‘wand’ sends a series of pulses into the liver, which provide 50Hz shear wave speed measurements. At the same time, the system measures ultrasound attenuation rate in the same 3cm3 region of the liver. This provides a 3.5 MHz ultrasound coefficient of attenuation (Controlled Attenuation Parameter, or CAP), which allows the doctor to quantify how much fat is in the liver (steatosis). ‘A conventional ultrasound would have only been able to tell us if there was steatosis provided there is more than 33% of fat in the liver, but with the FibroScan screen fat infiltration can be detected earlier,’ says Dr Rajabally.
The convenience and accessibility of the VCTE system makes check-ins and follow-ups a viable option as an office test – far more so than with biopsies. ‘The use of VCTE is indicated in a range of fields with more than 1 200 peer review articles to support this,’ says Dr Rajabally. For instance, ‘FibroScan can prove to be a vital tool in assessing for liver fibrosis resulting from the cumulative use of the immune system suppressant methotrexate used in dermatology, and in the treatment of rheumatoid arthritis. Diabetes, which is relatively common in our society, can result in an increased disposition to developing fatty liver. About 60 to 80% of diabetics will have some form of fatty liver disease. Now not all of these patients will end up with progressive liver disease, but a sizeable proportion will end up with some form of liver disease, which can progress,’ adds Dr Rajabally. Identifying these individuals can be extremely valuable, as they may benefit from a more intensive glycaemic control.
In early 2017, Dr Rajabally was still the only South African private sector doctor using the FibroScan machine. He says he continues to have patients from around the country vising his practice at Mediclinic Constantiaberg – and expects this to continue. ‘The FibroScan system lets you advise patients on changes to their lifestyle based on a score that you can follow up on once they’ve applied those changes,’ he says.
Dr Rajabally describes the case of a patient whose father had cirrhosis from NAFLD and had required a liver transplant: ‘He was worried he could have the same problems as his father since he had a similar body profile, so he came in and had a FibroScan. We found that he had an elevated fibrosis score – although not to the extent of cirrhosis. He’s since changed his lifestyle, and his score has improved.’