Researchers in Germany have developed a fluorine-based tracer compound that can bind with high affinity to small clots, allowing doctors to image them using positron emission tomography (PET).
Blood clots can cause heart attacks and strokes. Doctors often need to find clots using imaging techniques, so that they can treat them or identify where thrombi are causing problems. At the moment, imaging techniques frequently rely on spotting changes in blood flow, rather than imaging the clots themselves. Depending on the suspected location of a clot, different imaging techniques are needed, and it can be difficult to spot smaller clots, or damaged areas in blood vessels where there is a risk of clots forming.
“Currently available diagnostic techniques for blood clot imaging rely on different modalities depending on the vascular territory,” says Andrew Stephens of Piramal Imaging, a researcher who was involved in the study, which was recently published in The Journal of Nuclear Medicine. “A single imaging modality that could visualize clots from various sources in different anatomic regions would be very valuable.”
The team developed a fluorine-18 (18F) labeled tracer that can bind with high affinity to GPIIb/IIIa receptors on platelets. Platelets are cell fragments in blood that help to form blood clots, and GPIIb/IIIa receptors are involved in platelet clumping at the site of a clot. The tracer can be injected into the blood stream and will bind to clots, which can then be imaged using PET. When testing their system in monkeys, the researchers could visualize small clots in arteries and veins in the brain, and even see damage to the blood vessel lining where clots might form in the future.
“Although the current studies are preliminary, the tracer may provide not only more accurate anatomic localization, but also information of the risk of the clot growth or embolization,” says Stephens.
Image: PET scans of three Cynomolgus monkeys. Strong signals are detected at the sites where inserted catheters had roughened surfaces of blood vessels. Credit: Piramal Imaging GmbH, Berlin Germany.
Study in The Journal of Nuclear Medicine: 18F-GP1, a Novel PET Tracer Designed for High-Sensitivity, Low-Background Detection of Thrombi…
