Al(18)F-NODA Benzothiazole Derivatives as Imaging Agents for Cerebrovascular Amyloid in Cerebral Amyloid Angiopathy

[Image: see text] In this study, we synthesized four novel Al(18/19)F-labeled 2-phenylbenzothiazole derivatives conjugated to 1,4,7-triazacyclononane-1,4-diacetic acid via alkyl linkers and evaluated them as imaging agent targets to amyloid-β (Aβ) plaques deposited in the blood vessels of cerebral amyloid angiopathy (CAA) brain. The four ligands exhibited moderate-to-high binding ability to Aβ(1–42) aggregates, of which complex 17 possessing the most potent affinity (K(i) = 11.3 nM) was selected for further biological evaluations. In vitro fluorescent staining and in vitro autoradiography studies on brain sections from CAA patients proved that this ligand could label Aβ deposits in blood vessels selectively. In biodistribution study, [(18)F]17 can hardly penetrate the blood–brain barrier (brain(2 min) = 0.3% ID/g) and displayed a rapid blood washout rate (blood(2 min)/blood(60 min) = 25.2), which is favorable as CAA imaging agents. In conclusion, this Al(18)F-labeled 2-phenylbenzothiazole complex was developed and proved to be a promising CAA positron emission tomography agent.