Figure 8.

⁶⁸Ga-DOTATATE Ligand Binding to Macrophage SST₂ in Carotid Plaque

In vivo CT angiography views of culprit carotid artery (hatched oval = internal carotid artery) in axial (A) and sagittal (E) views, with corresponding fused ⁶⁸Ga-DOTATATE PET-CT (B). Ex vivo views of macrographic images of the explanted carotid specimen (I, hatched line signifies location of carotid section); phosphor autoradiographic image shows the total binding of ⁶⁸Ga-DOTATATE to SST₂ receptors in macrophages within a transverse carotid section (C) corresponding to the level shown in clinical images. Adjacent section was incubated with ⁶⁸Ga-DOTATATE and cold competing ligand (D) showing very low levels of nonspecific binding. Brightfield photomicrographs show brown immunoreactive SST₂ staining (G, J, M) of macrophages identified with the panmacrophage marker CD68 (H, K, N), colocalized SST₂(brown), and CD68 (blue) staining in the same section (L); Movat’s pentachrome stain (F).