Human aorta treated with mono-l-asparatylchlorin e6 (NPe6) or hematoporphyrin derivative (HpD) as photosensitizer, was examined by fluorescence microscopy and fluorescence spectram detector. To compare in vitro with in vivo photosensitizer uptake by plaques, aorota in rabbit was examined by the same methods. The accumulation of fluorescent NPe6 and HpD, was observed selectively within the thickened intima of each atheromatous plaques. Characteristic emission of those was obtained from each atheroma, but not from normal vessel walls. These results suggest that human atheromatous plaques should take up HpD and NPe6 in vivo, and, therefore, be able to diagnose by detecting those fluorescences.
