Detection of atherosclerotic plaques in carotid arteries by the use of 123I-fibrinogen.

A non-invasive method for detecting atherosclerotic plaques by the administration of radioactively labelled fibrinogen has been used in a pilot study in one non-atherosclerotic patient and in four patients with unilateral or mainly unilateral atherosclerotic changes. Immediately after 1 mCi 123I-labelled fibrinogen had been given intravenously, the cervical region was examined with a gamma camera and again after 4 h and 20 h. In the control case there was little difference in activity between the left and right carotid regions. The other cases showed a significant increase of activity over the region of the plaque after 4 h. This increased uptake had disappeared after 20 h. Studies to clarify the nature of this uptake and the usefulness of the method are in progress.