Image by Andre E.X. Brown
BALTIMORE—Scientists say they have synthesized an imaging agent that allows them to detect blood clots throughout the body and estimate the fibrin content of those clots.
In murine experiments, the fibrin-specific PET probe FBP8 detected arterial and venous thrombi with high accuracy.
The tracer also proved sensitive to changes in the fibrin content of clots, which correlated with their age.
Francesco Blasi, PhD, of Massachusetts General Hospital in Charlestown, presented these findings at the 2015 SNMMI Annual Meeting (abstract 78).
Dr Blasi and his colleagues synthesized FBP8 by conjugating a short cyclic peptide with high affinity for fibrin to a macrocyclic chelator (NODAGA) and labeling it with 64Cu.
The researchers then performed FBP8-PET 1, 3, or 7 days after inducing thrombosis in 30 Sprague-Dawley rats (by applying ferric chloride on the carotid artery and femoral vein). The team also performed FBP8-PET in an animal model of deep vein thrombosis and pulmonary embolism.
FBP8-PET was more than 97% accurate for pinpointing arterial and venous thrombi in the rats. It also detected lung and venous thrombi in the model of deep vein thrombosis and pulmonary embolism. And probe uptake was significantly greater in fresh blood clots than in older ones (P<0.01).
“If approved, fibrin-specific PET could facilitate diagnosis, guide therapeutic choices, and help physicians monitor their patients’ treatment,” said study investigator Peter Caravan, PhD, of Massachusetts General Hospital.
“This technique also offers full-body detection of thrombi with a single injection of probe, instead of the current imaging standards, which are limited to specific parts of the body. A one-time, whole-body scan could prevent unnecessary procedures and uncover hidden thrombi before they generate a deadly embolism.”
Contingent on approval by the US Food and Drug Administration, the researchers expect to conduct a first-in-human study of FBP8-PET as soon as this fall.
