A new brain perfusion imaging agent: [I-123]HIPDM:N,N,N'-trimethyl-N'-[2-hydroxy-3-methyl-5-iodobenzyl]-1,3-propanediamine.

Based on the pH-shift mechanism, a new brain imaging agent I-124 HIPDM (N,N,N'-trimethyl-N'-[2-hydroxy-3-methyl-5-[123I]iodobenzyl]-1,3-propanediamine ) has been developed. This agent can be prepared by a simple exchange reaction suitable for routine clinical use. The physicochemical parameters, partition coefficient vs. pH profile, and protein binding, as well as biodistribution in rats, were very similar to those of I-123 IMP (N-isopropyl-p-iodoamphetamine). High brain uptake was found in animals after i.v. injection. The brain radioactivity persists for at least 1 hr in rats and monkeys. Regional distribution in sections of rat brain appeared to reflect regional perfusion. In conjunction with single-photon emission tomography (SPECT), this agent may provide useful information on local cerebral perfusion in humans.