Imaging of adenosine A1 receptors in the human brain by positron emission tomography with [11C]MPDX

We report the first clinical PET study using [1-methyl-C-11]8-dicyclopropylmethyl-1-methyl-3-propylxanthine ([C-11]MPDX) for imaging adenosine A(1) receptors in the human brain. The binding of [C-11]MPDX evaluated quantitatively as the distribution volume by a graphical analysis was high in the striatum and thalamus, and low in the cerebellum. The distribution pattern of [C-11]MPDX was coincident with that of adenosine A(1) receptors in vitro reported previously, and was different from those of blood flow and [F-18]FDG. The [C-11]MPDX PET has the potential for mapping adenosine A(1) receptors in the human brain.