MNI-659

MNI-659 is a **fluorine-18 radiolabeled small molecule** positron emission tomography (PET) ligand developed for imaging **phosphodiesterase 10A (PDE10A)** in the brain. PDE10A is highly expressed in striatal medium spiny neurons, which are affected in neurodegenerative diseases such as **Huntington's disease** and possibly **schizophrenia**. MNI-659 enables quantitative imaging of PDE10A levels as a biomarker of neuronal degeneration or altered neurotransmission in these conditions. The radiotracer shows reduced binding in the striatum of individuals with early Huntington's disease compared to healthy controls, correlating with disease severity and atrophy, and has also been used in schizophrenia patient research[1][3][4][7][8]. The developer is MNI (Molecular NeuroImaging, now part of Invicro).