Ultrasound/MRI elastography: non-invasive test for liver fibrosis and cirrhosis

While looking for papers about "small-for-size" liver syndrome, I just stumbled upon a relatively new test called FibroScan^©. This is an interesting approach in determine the stiffness of the tissue as this reflects a possible fibrosis/cirrhosis of the liver.

The test is performed by Ultra Sound (US) or MRI (the term "FibroScan^©" is the commercial name of the US way only). Both methods rely on measuring the response of the liver tissue to an external vibration.

Here is a nice and short description of the tests. Rowen Zetterman points out some possible limitations:

• "Advanced fibrosis may be underestimated and patients with macronodular cirrhosis may be classified as noncirrhotic.": I don't see this as a problem in real life because macronodular cirrhosis is easily diagnosed just by plain imaging.
• "Fibrosis may be overestimated in patients with extrahepatic cholestasis or acute hepatocellular injury due to the effects of these conditions on liver stiffness.": I would add here also CHF as it makes a liver stiff as well.
• "Ultrasound elastography does not distinguish patients with no fibrosis from patients with minimal fibrosis.": Yes, this is understandable. But there is probably no clinical relevance of this distinction.
• "Ascites can interfere with the generation of a shear wave through the liver.": At the stage of significant ascites, the patients usually have some sort of diagnosis. But I agree that this is a real limitation of the test.

Having those limitations in mind, I think that overall this is a very nice idea. We are challenged now to get some sensitivity and specificity so that we could find the group of patients who could avoid the biopsy.