Lab Soft News: PAD as a Future Focus for Integrated Diagnostics

In a previous note (see: Informatics as the "Secret Sauce" in the Integration of Pathology and Radiology), I discussed a new Siemens Healthcare integrated diagnostics project at Hospital Clinic in Barcelona. One of the three diseases that will be studied in this initiative is liver fibrosis. In a previous note, I discussed the use of a biomarker to assist in the diagnosis of hepatic fibrosis (see: Serum Biomarkers for Hepatic Fibrosis). This test could potentially be used in collaboration with hepatic MR elastography (see: In a Clinical Trial, Hepatic MR Elastography Delivers Encouraging Results) as a non-invasive approach to this diagnosis. The alternative is a needle biopsy of the liver with its associated risk and morbidity.

It occurred to me that there might be other diseases that could be used to test the theory that serum biomarkers plus medical imaging could be a used to accurately diagnosis disease. In this context, peripheral arterial disease (PAD) immediately comes to mind. PAD affects about 8 million Americans and increases with age such that by 65 about 12 to 20 percent of the population has evidence of the disease. Early diagnosis is important because individuals with PAD have a 4-5 times greater risk of heart attack or stroke. One biomarker that is currently being studies to diagnose PAD is beta-2-microglobulin (B2M) (see: ß2-Microglobulin as a Biomarker in Peripheral Arterial Disease).

Relevant for this discussion of integrated diagnostics for PAD is that the FDA has just approved a contrast agent used in connection with magnetic resonance angiography (MRA) to assess blood flow (see: FDA Approves First Imaging Agent to Enhance Scans of Blood Flow). This agent plus MRA could be used with PAD biomarkers as a new type of integrated diagnostics. Below is an excerpt from the article with boldface emphasis mine:

The U.S. Food and Drug Administration [has]...approved Vasovist Injection..., the first contrast imaging agent for use in patients undergoing magnetic resonance angiography, or MRA, a minimally invasive test for examining blood vessels. Although MRA can be performed without the use of a contrast imaging agent, Vasovist administration provides a clearer image in patients who are suspected of having blockages or other problems with the blood vessels in their abdomen or limbs...."This MRA contrast imaging agent provides clinicians with a much clearer scan of blood vessels, compared to MRA without contrast, even in vessels that are difficult to scan because they twist and turn in the body," said [an FDA spokesman]. When blood vessels are scanned using MRA without any contrast, radiologists are unable to interpret the images about 10 percent to 30 percent of the time. As a result, radiologists have typically used X-rays to detect blood vessel abnormalities. But this is a lengthy procedure and requires sticking a needle into an artery to inject the X-ray dye, a procedure that may result in injury to vessel walls, blood clots, allergic reactions and potential kidney damage. Vasovist is injected into a peripheral vein and no artery is punctured, thus the potential risks are fewer.

I am going to keep an eye out in the future for candidate diseases that may lend themselves to rapid diagnosis by the combination of serum biomarkers and medical imaging, particularly when this approach yields special benefits over current diagnostic methods.