Philadelphia, PA, October 1, 2007 – Newer ultrasound and magnetic
resonance (MR) imaging tests yield encouraging initial results in diagnosing
fibrosis (scarring) and cirrhosis of the liver, according to three studies in
the October issue of the journal Clinical Gastroenterology and Hepatology.
With further research, these and other non-invasive imaging techniques may
reduce the need for biopsies—procedures done to obtain a tissue sample—to
determine the presence and severity of fibrosis and cirrhosis.
Two of the three new papers evaluated techniques of elastography—tests that
evaluate reactions to ultrasound vibrations or energy waves as a means of
measuring the elasticity or stiffness of the liver tissue. Lower elasticity
(or higher stiffness) corresponds to increased fibrosis or scarring. When
fibrosis becomes severe, it signals the presence of cirrhosis.
Dr. Jayant A. Talwalkar and colleagues of Mayo Clinic College of Medicine,
Rochester, Minn., analyzed the current evidence on ultrasound-based transient
elastography - the approach that has received the most research attention to
date. Based on data from 18 previous studies, the ultrasound test was highly
accurate in identifying patients with cirrhosis, defined as severe (stage IV)
fibrosis of the liver. About 90 percent of patients with cirrhosis were
correctly identified by ultrasound-based transient elastography. The test was
somewhat less accurate in detecting less-severe fibrosis.
Because the studies used differing cutoff points, the analysis could not
establish the true accuracy of this emerging technology. The researchers
highlight the need for additional high-quality studies including patients with
liver fibrosis ranging from mild to severe.
Dr. Meng Yin and colleagues, also of Mayo Clinic College of Medicine,
evaluated a different approach to measuring liver elasticity/stiffness: MR
elastography. Although the principle is the same as with the ultrasound
technique, MR elastography measures reactions to mechanical shear waves,
rather than ultrasound vibrations.
The researchers performed MR elastography in 50 patients with chronic liver
disease and 35 normal volunteers. The test was nearly 100 percent accurate in
identifying patients with any degree of liver fibrosis, including those with
mild fibrosis. With further study, Dr. Yin and colleagues believe MR
elastography could be a useful initial test for fibrosis - avoiding the
discomfort and risks of liver biopsy for many patients, while potentially
increasing the reliability of diagnosis.
Dr. Chen-Hua Liu and colleagues of National Taiwan University Hospital,
Taipei, evaluated a different ultrasound technique for measuring fibrosis.
Using widely available duplex Doppler ultrasound equipment, they measured the
characteristics of blood flow in the vessels in and around the liver in
patients with chronic hepatitis C - an increasingly important cause of
fibrosis and cirrhosis.
The results showed that a specific measure of blood flow in the spleen - the
splenic artery pulsatility index (SAPI) - was highly accurate in identifying
fibrosis and cirrhosis. The authors believe that, with further study, the SAPI
could also be a useful indicator of fibrosis/cirrhosis in other groups of
patients with kidney disease.
Cirrhosis and related complications are responsible for over 40,000 deaths per
year in the United States, with direct health care costs of more than $1
billion. Several trends are likely to produce further increases in death and
disease from cirrhosis, including the aging of the population; the epidemic of
obesity, which leads to nonalcoholic fatty liver diseases; and the emergence
of liver disease among patients with chronic hepatitis C.
Traditionally, liver biopsy has been the "gold standard" technique for
diagnosing fibrosis and cirrhosis. However, in addition to pain and a risk of
bleeding and other complications, liver biopsy is a costly technique that is
prone to sampling errors. The new non-invasive imaging techniques may provide
a useful new set of tools not only for diagnosing liver fibrosis and
cirrhosis, but also for evaluating the effectiveness of new treatments for
early-stage fibrosis.
"Application of current imaging modalities may help to define the presence of
cirrhosis and even fibrosis in patients with suspected liver disease,"
commented Dr. C. Mel Wilcox, Editor of CGH. "Using Doppler ultrasound and MRI,
these investigators found these modalities to be accurate and reproducible in
detecting fibrosis and cirrhosis. Look for more studies using these
non-invasive imaging studies, and perhaps others in the future."
# # #
Notes to Editors:
Full text of the articles mentioned above are
available upon request. Contact Jayne M. Dawkins at (215) 239-3674 or ja.dawkins@elsevier.com
to obtain a copy or to schedule an interview. The articles appear in Clinical
Gastroenterology and Hepatology, October 1, 2007, published by Elsevier.
About Clinical Gastroenterology and Hepatology
Clinical
Gastroenterology and Hepatology
, the official clinical practice
journal of the AGA Institute, is the go-to resource for readers interested in
a broad spectrum of themes in clinical gastroenterology and hepatology. CGH
offers original articles, scholarly reviews, and key information on
endoscopy/practice-based technology and health policy/practice management.
About the AGA Institute
The American Gastroenterological
Association (AGA) is dedicated to the mission of advancing the science and
practice of gastroenterology. Founded in 1897, the AGA is one of the oldest
medical-specialty societies in the United States. Comprised of two non-profit
organizations - the AGA and the AGA Institute - our more than 16,000 members
include physicians and scientists who research, diagnose and treat disorders
of the gastrointestinal tract and liver. The AGA, a 501(c6) organization,
administers all membership and public policy activities, while the AGA
Institute, a 501(c3) organization, runs the organization’s practice, research
and educational programs. On a monthly basis, the AGA Institute publishes two
highly respected journals, Gastroenterology and Clinical Gastroenterology and
Hepatology. The organization's annual meeting is Digestive Disease Week®,
which is held each May and is the largest international gathering of
physicians, researchers and academics in the fields of gastroenterology,
hepatology, endoscopy, and gastrointestinal surgery. For more information,
please visit www.gastro.org.
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Media Contact:
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Elsevier
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