Relation between dopamine synthesis capacity and cell-level structure in human striatum: a multi-modal study with positron emission tomography and diffusion tensor imaging.
Positron emission tomography (PET) study has shown that dopamine synthesis capacity varied among healthy individuals. This interindividual difference might be due to a difference in the cell-level structure of presynaptic dopaminergic neurons, i.e., cellular density and/or number. In this study, the relations between the dopamine synthesis capacity measured by PET and the parameter estimates in diffusion tensor imaging (DTI) in striatal subregions were investigated in healthy human subjects. DTI and PET studies with carbon-11 labeled L-DOPA were performed in ten healthy subjects. Age-related changes in the above parameters were also considered. Fractional anisotropy showed a significant positive correlation with age in the posterior caudate. There was significant negative correlation between dopamine synthesis capacity and mean diffusivity in the posterior caudate and putamen. Assuming that mean diffusivity reflects the density of wide-spreading axonal terminals in the striatum, the result suggests that dopamine synthesis may be related to the density of dopaminergic neuronal fibers. It is evident that PET/DTI combined measurements can contribute to investigations of the pathophysiology of neuropsychiatric diseases involving malfunction of dopaminergic neurons.
Molecular Imaging Center, National Institute of Radiological Sciences, Chiba, Japan.
Hiroshi
H
Kawaguchi
Molecular Imaging Center, National Institute of Radiological Sciences, Chiba, Japan ; Research Center for Charged Particle Therapy, National Institute of Radiological Sciences, Chiba, Japan.
Takayuki
T
Obata
Molecular Imaging Center, National Institute of Radiological Sciences, Chiba, Japan.
Harumasa
H
Takano
Molecular Imaging Center, National Institute of Radiological Sciences, Chiba, Japan.
Tsuyoshi
T
Nogami
Molecular Imaging Center, National Institute of Radiological Sciences, Chiba, Japan.
Tetsuya
T
Suhara
Molecular Imaging Center, National Institute of Radiological Sciences, Chiba, Japan.
Hiroshi
H
Ito
D000328:Adult; D000368:Aged; D001369:Axons / Q000000981:diagnostic imaging / Q000378:metabolism; D002247:Carbon Isotopes / Q000008:administration & dosage; D003342:Corpus Striatum / Q000000981:diagnostic imaging / Q000378:metabolism; D056324:Diffusion Tensor Imaging; D004298:Dopamine / Q000096:biosynthesis*; D015259:Dopamine Agents / Q000494:pharmacology; D059290:Dopaminergic Neurons / Q000000981:diagnostic imaging / Q000378:metabolism; D005260:Female; D006801:Humans; D007980:Levodopa / Q000008:administration & dosage; D008297:Male; D008875:Middle Aged; D049268:Positron-Emission Tomography; D011859:Radiography
D002247:Carbon Isotopes; D015259:Dopamine Agents; D007980:Levodopa; D004298:Dopamine