Oct 2 : Researchers have developed new ultrasound and magnetic resonance (MR) imaging tests which could detect fibrosis (scarring) and cirrhosis of the liver in their initial stage, reducing the need for biopsies.

Two of three new studies evaluated techniques of elastography, tests that evaluate reactions to ultrasound vibrations or energy waves as a means of measuring the means increased fibrosis or scarring.

When fibrosis becomes severe, it indicates the presence of cirrhosis.

The current evidence on ultrasound-based transient elastograph was analyzed by Dr. Jayant A. Talwalkar and colleagues of Mayo Clinic College of Medicine, Rochester, Minn.

According to 18 previous studies, the ultrasound test was highly accurate in identifying 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.

The analysis could not establish the true accuracy of this emerging technology because the studies used differing cut-off points. The researchers highlight the need for additional high-quality studies including patients with liver fibrosis ranging from mild to severe.

The researchers 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.

As a part of the study, 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, the researchers 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 findings of the research revealed 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.

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,” Dr. C. Mel Wilcox, Editor of CGH said.

“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,” Wilcox added.

The studies are published in the October issue of the journal Clinical Gastroenterology and Hepatology. (ANI)