Imaging technology, developed by Mayo Clinic researchers, can identify liver fibrosis with high accuracy and help eliminate the need for liver biopsies, according to a study presented today at the Liver Meeting, an annual meeting of the American Association for the Study of Liver Disease, in San Francisco.
The technology, called MR elastography (MRE), produces color-coded images known as elastograms that indicate how internal organs, muscles and tissues would feel to the touch. Red is the stiffest; purple, the softest. Other imaging techniques do not provide this information, according to the researchers.
"Knowing the liver's elasticity or stiffness is invaluable in diagnosing liver disease," said study co-investigator Jayant Talwalkar, MD, a Mayo Clinic hepatologist. "A healthy liver is very soft, while a liver with early disease begins to stiffen. A liver with cirrhosis, advanced liver disease, can be rock hard."
The study included 113 patients, who had undergone liver biopsy in the year preceding the study and had a wide variety of liver diseases, including nonalcoholic and alcoholic fatty liver disease, hepatitis C, hepatitis B, autoimmune hepatitis, primary biliary cirrhosis and primary sclerosing cholangitis. Patients ranged in age from 19 to 78, and their body weight ranged from normal to severely obese.
“Results showed that elastography was highly accurate in detecting moderate-to-severe hepatic fibrosis even with the variety in age, types of liver disease and body size," Talwalkar said.
Among the study's findings:
- The detection of cirrhosis by MRE when compared to liver biopsy results was 88 percent accurate; and
- Patients with nonalcoholic fatty liver disease and no significant inflammation or fibrosis were identified with 97 percent accuracy.
“Using MRE, we can confidently avoid liver biopsies for patients with no evidence of advanced fibrosis, as well as for patients with cirrhosis,” Talwalkar said.
Liver biopsies, conducted by extracting tissue samples with a needle, can underestimate the degree of hepatic fibrosis about 20 to 30 percent of the time because of the patchy distribution of fibrosis that occurs in the liver. Another drawback is that since liver biopsy is invasive, patients may be reluctant to have a biopsy performed and sometimes delay the procedure when liver disease is first suspected, according to Talwalkar.
"Our goal in hepatology is to be able to diagnose liver disease early so that novel as well as established therapies can be provided to our patients," said Talwalkar. Treatment and lifestyle changes can help stop the progression of hepatic fibrosis to liver cirrhosis and liver failure, which would eventually require a liver transplant.
MRE measures low-frequency acoustic waves transmitted into the abdomen.