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Hendrikus H Boersma
Posters-Accepted Abstracts: J Clin Exp Cardiolog
PET, SPECT and fluorescence tracers can be used to identify vulnerable plaques in atherosclerotic disease. Clinical PET/ SPECT camera systems are restricted in terms of resolution for the visualization of detailed inflammation patterns in smaller vascular structures. This paper reviews the possible added value of a high-resolution molecular imaging in excised human carotid artery plaques using several tracers representing the pathogenesis of vulnerable plaques, such as folate ([99mTc]- or FITC-folate), [89Zr]-bevacizumab, Na[18F]F, and [18F]RGD-K5 (targeting avb3-integrins) and [18F]-fluorodesoxymannose (FDM).In our studies patients with a planned carotid endarterectomy were included. Excised plaques were incubated in one of the tracer solutions and imaged with either microPET, microSPECT or a fluorescence camera. Tracer uptake was confirmed using relevant immunohistochemical methods. Plaque calcification was assessed additionally with microCT and correlated to tracer uptake. Furthermore, we were able to investigate FDM imaging to evaluate plaque vulnerability in vivo in rabbits.Tracer uptake from [99mTc]-or FITC-folate, [89Zr]-bevacizumab, Na[18F]F, [18F]RGD-K5 and FDM indicative for plaque vulnerability and histology were compared with symptomatology. Heterogeneous distributions and variable intensities of uptake were found within the plaques with good resolution. A positive correlation between the distribution of macrophages and uptake of the tracers was demonstrated for most of the investigated tracers. These studies demonstrate that carotid artery plaques can be visualized in detail using nuclear and optical micro-imaging systems. Enhancement of the resolution in clinical imaging of these tracers, either nuclear or optical, is needed for translation into the clinic.