Non-invasive assessment of liver fibrosis and prognosis

Abstract

Over the past decade, several advances have been made in the non-invasive assessment of liver fibrosis. Both serum markers and imaging-based tissue elastography predict the presence of advanced fibrosis compared with liver biopsy. Serum markers may be indirect or direct markers of liver structure and function. Imaging-based techniques measure liver stiffness as a surrogate for fibrosis and include ultrasound and MRI-based methods. Most non-invasive techniques work well at identifying subjects at the extremes of fibrosis but may not accurately discern intermediate stages. In addition to being a diagnostic tool, elastography may have an evolving role in prognosis. Increasing stiffness is associated with higher rates of liver decompensation, need for transplantation, hepatocellular carcinoma, and death. There are special populations of patients where elastography may serve as a non-invasive method to impart useful clinical information, such as patients after liver transplantation, those with congenital heart disease and those being treated for chronic viral hepatitis. The role of non-invasive markers in accurately predicting the presence of fibrosis in obese patients needs to be further refined.

Keywords:

• acoustic radiation force impulse
• elastography
• imaging
• liver cirrhosis
• liver stiffness
• magnetic resonance imaging
• shear wave elastography
• transient elastography

Financial & competing interests disclosure

The authors have no relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript. This includes employment, consultancies, honoraria, stock ownership or options, expert testimony, grants or patents received or pending, or royalties.

No writing assistance was utilized in the production of this manuscript.

Key issues

• Elastography is an accurate, non-invasive method to determine the presence of advanced fibrosis.

• There are at least four main methods commonly used to obtain liver stiffness (LS), transient elastography, acoustic radiation force impulse, 2d-Shear wave elastography, and magnetic resonance elastography.

• Elevated LS, as quantified by elastography, is associated with an increased risk of hepatic decompensation, need for transplant, hepatocellular carcinoma, and death.

• Transient elastography can identify patients with ‘subclinical cirrhosis’, defined as normal platelets, normal liver ultrasound, and normal esophagogastroduodenoscopy, but an elevated LS (>13 kPa). These patients are at increased risk for hepatic decompensation.

• Patients with lower LS after treatment for chronic hepatitis B, as well as patients that are post-liver transplant and have lower LS, have improved outcomes.

• The role of tissue elastography is evolving. Currently, elastography is limited in subjects with significant obesity and further studies are needed before its widespread application in patients with NAFLD, especially in patients who are morbidly obese.

Notes

AST: Aspartate aminotransferase; ALT: Alanine transaminase; GGT: Gamma glutamyl transferase; INR: International normalized ratio; NFS: NAFLD fibrosis score.