[Imaging in atherosclerosis: scintigraphy techniques]

Noninvasive detection of atherosclerotic plaques remains a major challenge for clinical diagnosis, therapy and prognosis. Several approaches have been explored as a tool for thrombus imaging, using platelets, antiplatelet antibodies and fibronectin or as a direct metabolic marker as low density lipoproteins or photophrine II. We tested the affinity of a new F(ab')2 monoclonal antibody (TRF1) against human fragment D-dimer of cross-linked fibrin, for atherosclerotic plaques free of detectable thrombi on their surface. Six atherosclerotic segments of carotid and femoral arteries, and (as a control) 5 segments of atherosclerosis-free internal mammary artery, were drawn from 11 male patients undergoing bypass surgery. All segments were carefully washed in order to dissolve and remove possible endoluminal thrombi, and were subsequently cut to obtain couples of fragments of intima of similar weight, containing atherosclerotic plaques (n 16), or fatty streaks (n 12), or normal endothelium (n 20). Each fragment was separately put into a radioimmunoassay vial, and underwent a direct binding test to TRF1, or to an aspecific antibody, which both were labelled with 125I. The activity present in each fragment was measured with a gamma-counter after 3 h of incubation at 37 degrees C, and every hour after washing the fragments in order to remove the unbound antibody. No significant binding difference (expressed as per cent final activity in comparison with initial one) of the aspecific antibody between normal and atherosclerotic fragments was found. By contrast, TRF1 binding was significantly higher (p < 0.001) in atherosclerotic than in normal fragments (26.0 +/- 11.5% in atherosclerotic plaques, versus 9.23 +/- 9% in fatty streaks, versus 1.9 +/- 0.6% in normal endothelium.(ABSTRACT TRUNCATED AT 250 WORDS)