Non-invasive radiotracers: A new detection method for acute thrombosis?

By Eike Struck
PhD student at TREC

Heart attack, stroke and blockage of veins are responsible for a quarter of annual deaths worldwide. Common to all those conditions is the development of a blood clot (thrombosis) in the blood vessels before the event occurs. The current detection methods for thrombosis are catheterization, computer tomography, ultrasound and magnetic resonance imaging (MRI). These techniques sometimes fail to detect the clot or incorrectly identify a clot where there is none present, especially in the cases of sudden events.

In a recently published study, Jack Andrews and his colleagues tackle this problem by developing a new detection method for acute thrombosis. Here they use Positron-emission tomography (PET) imaging and a new tracer that recognises one of the “clotting factors” which is involved in clot formation. This newly developed tracer can distinguish between old and newly forming clots.

PET is an imaging technique that observes metabolic processes. Simply put, it detects when a molecule is changed into another molecule. This is analysed using a radioactive molecule called “tracer”. PET imaging is non-invasive but involves exposure to radiation.

Factor XIII is a molecule that is activated in the last step of clotting, right after the clot is formed. It stabilizes the thrombus in a process called “crosslinking” and is very important for wound healing. The activation of the molecule is the metabolic process that is observed using this newly developed tracer.

Andrews and colleagues show that the newly developed tracer is very selective and directed to the crosslinked thrombus. It can be used in different types of thrombosis and distinguish between ongoing and inactive thrombosis. The radioactive tracer is rapidly cleared through the kidneys within some hours. This is an improvement compared to other radioactive tracers, which usually remain in the body for more than one day.

In their study, they show a high potential for PET imaging in the detection of thrombosis. By distinguishing between different types of thrombi, it can help doctors in choosing the right treatment. The new tracer could be useful in the diagnosis of acute thrombosis and in the monitoring of ongoing conditions like post thrombotic syndrome.

Reference: Andrews, Jack P. M., et. al. Non-invasive in vivo imaging of acute thrombosis: development of a novel factor XIIIa radiotracer in European Heart Journal – Cardiovascular Imaging, Published: 13 August 2019.

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