Performance of intravascular probe in animal studies

Up to 70% of heart attacks are thought to be caused by vulnerable plaque in arterial walls. We report on the first preclinical tests of an intravascular imaging detector to identify vulnerable coronary artery plaques. The detector identifies plaque by sensing beta emission from radiotracers, which bind to the vulnerable plaque. The detector design consists of a bundle of six 7 mm long scintillating fibers each fused to a 1.5 m plastic fiber. The scintillating fibers are offset from each other longitudinally by 6 mm and arranged spirally around a guide wire in the center of the catheter. To demonstrate the detection performance of this probe, excised arteries of transgenic mice were scanned using a single fiber version of the probe. The distal end of the probe was scanned over the arteries using a micrometer, and 2D images of the beta activity in the arteries were made. The images were later superimposed on autoradiographic images acquired from the same arteries to confirm the uptake in the plaque. The beta imaging probe was able to detect beta labeled plaque and a high degree of correlation with the autoradiography results validated the concept of using such a device to identify vulnerable plaque in-vivo. The future development of the detector will include additional in-vivo studies with animal models, and further development of the intravascular probe for improved sensitivity and miniaturization.