Can imaging replace liver biopsy for NASH diagnosis?

Last Updated: 2015-12-17

By Megan Brooks

NEW YORK (Reuters Health) - Magnetic resonance imaging-based elastrography (MRE) more accurately classifies liver fibrosis and steatosis in patients with nonalcoholic fatty liver disease (NAFLD) than transient elastography (TE), according to a study from Japan.

"In our paper, we have demonstrated that both MRE and TE are useful diagnostic methods for non-alcoholic steatohepatitis (NASH) in comparison to liver biopsy, (but) MRE is more accurate than TE for liver fat content and fibrosis," Dr. Atsushi Nakajima of the Division of Gastroenterology, Yokohama City University Graduate School of Medicine, told Reuters Health by email.

NAFLD, Dr. Nakajima explained, is the most common liver disease worldwide and 20% to 30% of NAFLD will progress to NASH and liver cancer. Liver biopsy is the gold standard diagnostic method for NASH, but is "painful" and costly, requires hospital admission, and may have complications such as bleeding. "To establish a noninvasive and simple diagnostic method for NASH from NAFLD instead of liver biopsy is a very important issue in clinical settings."

With that goal in mind, the research team did a cross-sectional study of 142 Japanese patients with NAFLD identified by liver biopsy and 10 comparable subjects without NAFLD. All 152 were evaluated by TE using the M probe (including controlled attenuation parameter (CAP) measurements), MRI using MRE and proton density fat fraction (PDFF) measurements, and five different clinical scoring systems.

"To our knowledge, this is the first study that provides a head-to-head comparison of liver stiffness measurement (LSM) measured using TE and MRE, fat accumulation evaluated using CAP measured by means of TE, and PDFF measured using MRI for liver fibrosis and steatosis in biopsy-proven NAFLD," they point out in Gastroenterology online December 8.

They observed a "significant positive correlation" between LSM obtained using MRE and the severity of liver fibrosis in patients with NAFLD. The diagnostic accuracy of MRE for liver fibrosis was higher than that of clinical scoring systems and TE, they report.

TE identified patients with fibrosis stage >2 with an area under the receiver operating characteristic (AUROC) curve value of 0.82, whereas MRE identified these patients with an AUROC curve value of 0.91 (p<0.001).

TE-based CAP measurements identified patients with hepatic steatosis grade >2 with an AUROC curve value of 0.73, while MRI PDFF methods identified these patients with an AUROC curve value of 0.90 (p<0.001).

Obtaining serum K18 fragments or alanine amino transferase measurements did not add value to TE or MRI in identifying NASH, the researchers say.

They conclude based on their findings that "MRE and PDFF methods have higher diagnostic performance in noninvasive detection of liver fibrosis and steatosis in patients with NAFLD than TE and CAP methods. MRI-based noninvasive assessment of liver fibrosis and steatosis is a potential alternative to liver biopsy in clinical practice."

"Further studies must be conducted to explore the prognostic value of the results of these diagnostic techniques to determine the long-term outcome of patients with NAFLD," they add.

The study had no commercial funding and the authors have no disclosures.

SOURCE: http://bit.ly/1JeOSUn

Gastroenterol 2015.