Whitney Palmer

Healthcare. Politics. Family.

MR Elastography Growing as Preferred Modality for Liver Diagnosis

Published on the Jan. 24, 2013 DiagnosticImaging.com website

By Whitney L.J. Howell

Once available only to radiologists who purchased new MRI equipment, MR elastography technology is becoming widely available as an upgrade feature to older machines. This expansion not only greatly improves patient care, industry experts said, but it also impacts costs and efficiency.

MR Elastography (MRE) — now available at 100 locations on five continents — is the industry-preferred method for assessing liver stiffness or elasticity. This condition characterizes liver disease and is most often diagnosed through palpation. However, there is a limit to how much tissue providers can feel. While conventional MRI is a powerful tool, liver disease, such as fibrosis or cirrhosis, creates no anatomical changes to the organ, making identification difficult and often requiring a needle biopsy.

“MR elastography provides a safer, more comfortable, non-invasive alternative to

Richard Ehman

Richard Ehman

liver biopsy for assessing liver disease,” said Richard Ehman, MD, professor and chair of radiology at the Mayo Clinic in Minnesota, noting that needle biopsies are often painful.

Being able to analyze liver health in a faster, more reliable way is particularly important now, he said, as the level of obesity and the associated fatty liver disease is rising in the United States. Currently 1 in 3 Americans lives with fatty liver disease, and within 10 years, he said, this condition will be the leading cause for liver transplant. MRE is also beneficial in diagnosing and treating the 25 percent of Hepatitis C patients who develop liver fibrosis, the large build-up of proteins in the liver that eventually leads to cirrhosis.

What Is MRE and How Does It Work?

Approved by the FDA in 2009, MRE is a non-invasive, highly-sensitive method for determining the level of liver disease through the use of low-frequency mechanical waves. It is designed to facilitate faster diagnosis and avoid potentially dangerous — and often inaccurate — liver biopsies, said Ehman, who pioneered the MRE technology and worked with GE Healthcare to bring it to market.

Once installed, this tool pumps 60 Hz waves through a plastic tube to a small, non-metallic drum placed over the abdomen. Slower wave movement correlates to higher stiffness. Standard MRI imaging captures the miniscule movements of the tissue, and, using a special algorithm, converts the data into a color-scale picture that corresponds to the level of liver stiffness.

MRE differs from ultrasound elastography. With the ultrasound method, a probe is pushed across tissue, and a scanner records how the tissue deforms. However, Ehman said, this doesn’t provide a quantitative measure of the tissue’s actual stiffness.

According to Ehman, an MRE scan can be completed with four breath holds — approximately a minute — and is often conducted and billed as part of other abdominal MRI protocols. Based on the color-scale picture, radiologists can instantaneously know whether the patient has a healthy or diseased liver. Liver tissue stiffness is measured in kiloPascals (kPa), with a normal liver having a stiffness of roughly 2 kPa, the same consistency of fat inside the body. Diseased livers range from 3 kPa to more than 10 kPa.

Since MRE’s FDA approval, GE Healthcare has been the main vendor for the tool with its MR Touch product. Siemens has also worked with the Mayo Clinic to provide MRE on its existing MAGNETOM Aera and Skyra MR machines.

Overall, said Richard Hausmann, GE’s president and CEO officer of global MR business, MRE greatly enhances what MRI studies provide.

“MRE offers an accurate assessment of stiffness in the liver, even for deeper tissues not reached by palpation,” he said. “It’s helped increase confidence in diagnoses in this area, and it’s one piece in an attempt to make overall diagnosis less invasive.”

To read the remainder of the story at its original location: http://www.diagnosticimaging.com/mri/content/article/113619/2124974

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February 4, 2013 - Posted by | Uncategorized | , , , , , , , , , , , , , , , , ,

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