[18F]-MFBG Versus [123I]-MIBG and [18F]-PE2I in PD vs. MSA and DLB vs. AD

Study Rationale: This prospective study, to be conducted in two centers (UZ Leuven and UZ Gent), aims to validate cardiac \[18F\]-MFBG PET in distinguishing Parkinson's disease (PD) from multiple system atrophy (MSA-P) and differentiating dementia with Lewy bodies (DLB) from Alzheimer's disease (AD). Both PD and DLB, caused by alpha-synuclein deposits (Lewy bodies), exhibit not only nigrostriatal dopaminergic deficits but also early peripheral changes in myocardial norepinephrine (NE) innervation. These defects can be visualized and quantified using NE transporter tracers. \[18F\]-MFBG was developed several years ago with high-yield production and has already been employed in multiple centers worldwide, mainly in the context of imaging neuroendocrine tumors. \[18F\]-MFBG offers logistical, technical, and pharmacological advantages, including faster scanning, high spatial resolution, and improved quantification compared to the existing method using \[123I\]-MIBG SPECT. Participant Population: The study will include 28 healthy volunteers (CON), of which 3 will participate in \[18F\]-MFBG PET dosimetry (part 1) and 25 in the main study for optimization/age-dependence of cardiac \[18F\]-MFBG parameters (part 2). In part 3, 40 PD, 15 MSA-P, 15 DLB, and 15 AD patients with biomarker-confirmed diagnoses will be included. Total: 113 subjects. Intervention: All subjects will undergo three examinations in the main work packages (parts 2 and 3) dynamic cardiac \[18F\]-MFBG PET, with dynamic \[123I\]-MIBG SPECT as a comparator, as well as cerebral \[18F\]-PE2I PET. Endpoints: Primary: Non-inferiority in discriminating populations using \[18F\]-MFBG; Secondary: effect size, relationship between myocardial uptake and cerebral dopamine active transporter (DAT) changes, autonomic dysfunction, regional myocardial variation. Secondary: 1. Determine the effect size (ES) of the reduction in myocardial uptake of \[18F\]-MFBG in PD and DLB compared to \[123I\]-MIBG SPECT and \[123I\]-MIBG planar scintigraphy. 2. Identify any significant correlation between the reduction in myocardial uptake of \[18F\]-MFBG in PD and DLB and the reduction in \[18F\]-PE2I binding in early to moderate disease stages. 3. Assess the relationship between the reduction in myocardial uptake of \[18F\]-MFBG in PD and DLB and measures of autonomic dysfunction. 4. Examine the regional pattern of reduced \[18F\]-MFBG uptake in PD/DLB compared to controls, with an endpoint considered met if different regional segment scores are evident between PD/MSA-P or DLB/AD or subtypes of PD.