Detection of experimental carotid ulceration by radionucleotide labelled particles

An animal model has been set up to study the adherence of various radionucleotide particles to experimental carotid ulcers. 6 animals were used in all, 4 dogs and 2 sheep. Carotid angiography was performed in 2 animals and in 1 of these the conventional mode of angiography failed to detect the carotid ulcer. Intra-arterial injection of technetium labelled macroaggregates in both of these cases showed the position of the lesion in vitro. In the remaining 4 cases, intravenous radionucleotide 99m technetium labelled pyrophosphate was used and in all cases in vitro the position of the experimental carotid ulceration was revealed. Our studies show that both technetium labelled macroaggregates and technetium labelled pyrophosphate are suitable particles for use in this model. Further research is required to establish the mode of their adherence to the experimental area of ulceration. A further extension of this work would be to demonstrate the ulceration in vivo. Encouraging work in this regard has been done by Mettinger et al. (1978) in humans demonstrating, by substraction methods, increased uptake over ulcerated carotid plaques as compared to controls.