Two recent studies have found that magnetic resonance elastography (MRE), a new imaging technique, is an accurate tool for noninvasive diagnosis of liver disease.

The liver responds to many diseases that damage its cells by developing scar tissue or fibrosis. MRE, developed at the Mayo Clinic (Rochester, MN, USA), uses a modified form of magnetic resonance imaging (MRI) to effectively measure the hardness or elasticity of the liver. By applying vibrations to the liver, MRE obtains images of the mechanical waves passing through the organ. The wave images are then processed to generate a quantitative image of tissue stiffness.

“Healthy liver tissue is very soft, while a liver with fibrosis is firmer, and a liver with cirrhosis is almost rock-hard,” stated Richard Ehman, M.D., lead Mayo Clinic researcher on the MRE project. “If detected early, fibrosis of the liver can be treated, but once the disease has progressed to cirrhosis, the condition is irreversible.”

Dr. Ehman and his imaging research team collaborated with Mayo Clinic gastroenterologists to study whether MRE could provide reliable and accurate diagnoses in patients with varying levels of liver disease. One study involved MRE examinations of 57 individuals with chronic liver disease and 20 healthy volunteers. The researchers confirmed that MRE accurately detects fibrosis with high sensitivity and specificity. Researchers also found that steatosis, which is deposits of fatty acids and triglycerides in liver cells and a common condition in patients with liver disease, did not interfere with detection of fibrosis with MRE.

The second Mayo study looked at whether MRE can accurately measure portal hypertension, or high-blood pressure in the portal vein that carries blood from the digestive track to the liver, typically as a result of cirrhosis of the liver. This study involved 35 individuals with differing degrees of chronic liver disease and 12 healthy volunteers. Researchers assessed MRE examinations of liver and spleen stiffness and discovered that a highly significant correlation exists between liver and spleen stiffness in patients with portal hypertension.

According to Dr. Ehman, many disorders cause the characteristics of tissue to change and will be likely candidates for diagnosis using MRE in the future. His research team is now evaluating the use of MRE in detecting breast cancer and Alzheimer’s disease.

The findings were presented in May 2007 at the International Society for Magnetic Resonance in Medicine annual meeting in Berlin, Germany, and Digestive Disease Week 2007 in Washington, DC, USA.

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