Purpose: Parkinson’s disease (PD) is a neurodegenerative disease characterized by progressive loss of dopaminergic neurons in the brain. To achieve better explorations of dopamine changes both centrally and peripherally, we employed uEXPLORER dynamic [11C]CFT PET/CT imaging combined with voxel-wise kinetic modeling. Methods: Eleven participants (five patients, PD and six healthy volunteers, HC) underwent 75-min dynamic scans were enrolled. Volumes of interest for four nigrostriatal nuclei (caudate, putamen, pallidum and substantial nigra) and three digestive organs (pancreas, stomach and duodenum) were delineated. Total-body parametric images of relative transporter rate constant (R1) and distribution volume ratio (DVR) using the simplified reference tissue model (SRTM2) were quantitatively generated by a linear regression with spatial-constraint algorithm. Standardized uptake value ratio (SUVR) at early and late phase were calculated as the semi-quantitative substitutes. Results: Significant differences between the two groups were identified in DVR and SUVRLP of putamen (P < 0.05) and SUVREP of stomach (P < 0.01). For HC group, negative correlations of R1 were achieved between stomach and both putamen and substantial nigra (all P < 0.05); positive correlations of DVR were identified between pancreas and all four brain nuclei (all P < 0.05). Yet in PD group, correlations of R1 or DVR between the targeted digestive and brain areas were considerably diminished. Similar trends in correlations were also found in SUVR analysis. Conclusions: We introduced a pioneering approach using dynamic total-body [11C]CFT PET/CT imaging to investigate distinctive patterns of potential “brain-GI” interplays, which may provide new insights towards the understanding of PD.

Alzheimers disease (AD) is a common neurodegenerative disease. The histopathological changes of AD include amyloid β-protein (Aβ) deposition, tau tangles, neuroinflammation and neurodegeneration. Some of the pathological changes could be shown in vivo by positron emission tomography (PET) and magnetic resonance imaging (MRI) biomarkers which play a key role in diagnosing AD. Fluorodeoxyglucose positron emission tomography (FDG-PET) can reflect and predict dysfunction. Aβ-PET was sensitive for the diagnosis of early AD but cannot distinguish the severity of AD. Tau-PET can compensate for the deficiency of Aβ-PET. Tau tangles were positively correlated with the severity of AD, and also associated with cognitive impairment. Probes targeting neuroinflammation of AD have been developed, but further study is needed to validate its effectiveness. Conventional MRI performs high tissue contrast that can show structural changes and has been routinely applied in clinical practice, such as evaluation of cerebral atrophy. Advanced MRI sequences (such as DTI、ASL、MRS、BOLD and QSM) that can provide additional information beyond structure that includes brain microstructure, blood perfusion, metabolite concentration, brain activity, connections and networks between brain regions, iron deposition, etc. The integrated PET and MR may improve the diagnostic efficiency of AD.