A thrombus, or blood clot, is made up of aggregated platelets forming a platelet plug, and a cross-linked mesh made of fibrin protein. While a thrombus can be a good response to injury – as when a scab forms to prevent bleeding, a condition called thrombosis causes clots to obstruct blood flow through blood vessels.
Blood clots are a leading cause of death and illness, primarily when a clot breaks free and travels to the heart, lungs, or brain. Yet current imaging techniques for finding them only work for specific areas of the body. There’s currently no whole-body imaging format that can find clots in all parts of the body with one scan. But that may change, as researchers from Massachusetts General Hospital, Perelman School of Medicine, University of Pennsylvania, and the University of Torino in Italy have developed a new whole-body PET scan that can find hidden blood clots in rats.
New Whole-Body PET Seeks Out Hidden Blood Clots
Currently, when a person experiences a stroke caused by a blood clot, identifying the source of the clot can involve many imaging studies, including ultrasound, magnetic resonance imaging (MRI) or computed tomography angiography (CTA). Not only can the cost of these imaging studies add up significantly, they take time, and depending on how long it takes to locate the source of a clot, use of therapies that can prevent a second stroke may be delayed.
But scientists at Massachusetts General have developed a new radiopharmaceutical clot-finding probe named 64Cu-FBP8 that has the potential to save lives. This radiopharmaceutical probe is a chemical that targets fibrin, one of the main components of blood clots. When used with Positron Emission Tomography (PET) scans, it may find hidden blood clots throughout the body with one imaging study.
Testing PET Scans in Animals
To test the ability to find clots throughout the body, researchers induced clot formation in the femoral veins and carotid arteries in rats. They then conducted whole-body imaging with 64Cu-FBP8 PET scans coupled with CT one, three, or seven days after clot formation. Research team members who had not been told of the locations of the clots were assigned to read the images, and they accurately detected blood clot location 97% of the time.
Furthermore, the intensity of the signal that the 64Cu-FBP8 generated decreased as clots aged, corresponding to clot fibrin content. So not only could nuclear radiologists be able to locate hidden clots throughout the body, they may eventually be able to get a better idea of how old those clots are.
What Whole-Body PET Could Mean for Stroke Patients
When a clot causes a stroke, it may have formed any number of places in the body. It’s important for doctors to know if any pieces of the clot or other clots remain in the originating location, because if they do, the risk for a second stroke is higher. How the patient is treated may be different if a “parent” clot is located than if no clot remains elsewhere in the body.
The age of the remaining clot(s) is important because older clots are more stable and less likely to be the source of a stroke-causing clot. Drugs used to dissolve clots target fibrin, and “younger” clots are richer in fibrin, so they are better candidates for treatments with these drugs.
The new imaging technique also holds promise for people with suspected pulmonary embolism. It could determine whether a patient with shortness of breath is experiencing a pulmonary embolism, identifying both the source of the pulmonary embolism and the location of the “parent” clot in deep veins.
PET Scans to Find Blood Clots in Human Volunteers
Initial tests of the 64Cu-FBP8 PET scans in rats were promising, and the research team plans to test it in human volunteers to see how it is distributed in the human body and how long it remains useful after injection. Once researchers know these things, they will have more information with which to design studies for effectiveness of 64Cu-FBP8 PET scans in humans.
High Quality PET Scans Require Radiology Expertise
Effective PET imaging requires the expertise of experienced nuclear medicine radiologists like Charles C. Cole, MD of SteleRAD. SteleRAD is owned and operated by Board-certified radiologists and offers expertise and experience in all radiology subspecialties to imaging centers, hospitals, and physician practices throughout South Florida. If you would like to know more, we encourage you to call 954-358-5250 or contact SteleRAD online.