Table 4. Summary of findings in Parkinson's disease.

PD: Parkinson's disease; PDD: Parkinson's disease with dementia; DLB: dementia with Lewy bodies; PSP: progressive supranuclear palsy; HC: healthy controls; PET: positron emission tomography; FDG-PET: fluorine-18-fluorodeoxyglucose positron emission imaging; PiB-PET: Pittsburgh compound B positron emission tomography; MRI: magnetic resonance imaging; [123I]FP- CIT-SPECT: Iodine 123-radiolabeled 2β-carbomethoxy-3β-(4-iodophenyl)-N-(3-fluoropropyl) nortropane single-photon emission tomography.

Author	Imaging modality	Subjects	Summary of findings
Gomperts et al. [23]	18F-AV-1451, PiB PET	7 DLB, 8 PDD, 9 PD without dementia, 29 HC	Although less than AD, 18F-AV-1451 retention is higher in PDD group compared to the control group.
Smith et al. [25]	18F-AV-1451 PET, MRI	6 DLB, 18 PDD, 11 PD without dementia, 44 HC	Reduced 18F-AV-1451 retention was seen in the substantia nigra of PDD patients.
Hansen et al. [26]	(123)I-FP-CIT SPECT, 18F-AV-1451 PET	17 idiopathic PD, 16 HC	The nigral 18F-AV-1451 volume of distribution was significantly reduced in idiopathic PD patients than in the control group.
Coakeley et al. [27]	18F-AV-1451 PET	12 patients including PD and PSP, 15 HC	Significantly decreased nigral 18F-AV-1451 uptake in both PD and PSP patients compared to the control groups, no remarkable difference observed between PD and PSP patients.
Cho et al. [28]	18F-AV-1451 PET	14 PSP, 15 PD, 15 HC	Raised sub-cortical 18F-AV-1451 retention was seen in PD and PSP patients and reduced nigral 18F-AV-1451 volume of distribution was noticed in PD patients.