Dopaminergic Pathway Imaging: A Visual and Educational Guide

Dopaminergic molecular imaging has evolved from an esoteric research tool to an indispensable adjunct in the diagnosis, management, and teaching of movement and neuropsychiatric disorders. Despite its clinical relevance, many neurology trainees encounter dopamine transporter (DAT) SPECT, [18F]FDOPA PET, and emerging vesicular monoamine transporter-2 (VMAT2) tracers only sporadically and often without a cohesive interpretive framework. This narrative review aims to provide a visually driven, clinically grounded roadmap that links dopaminergic neurochemistry and pathway anatomy to in vivo molecular imaging, with a specific focus on education and bedside application.

Advances in dopaminergic imaging now allow in vivo interrogation of dopamine synthesis, vesicular storage, synaptic reuptake, postsynaptic receptor signaling, and metabolism using complementary SPECT and PET radiotracers. Presynaptic techniques (FDOPA PET, VMAT2 PET, or DAT SPECT/PET) reliably detect nigrostriatal degeneration, clarify equivocal parkinsonian presentations, and highlight phenotypic variants, including genetic and drug-related mimics. Postsynaptic D₂/D₃ receptor imaging refines differentiation between neurodegenerative and drug-induced parkinsonism, whereas myocardial [123I]-MIBG scintigraphy adds autonomic context that strengthens separation of synucleinopathies from tauopathies. Educational strategies increasingly emphasize pathway-based interpretation, recognition of common pitfalls (such as false-negative DAT scans), and the integration of semiquantitative metrics. Emerging machine learning approaches and standardized quantification pipelines are improving reproducibility and scalability across centers.

By integrating dopaminergic pathway anatomy, molecular neurotransmission, and tracer-specific imaging patterns, dopaminergic scans can be transformed from isolated diagnostic tests into powerful clinical and educational tools. A visually anchored, circuit-based teaching approach-supported by schematic figures, comparative tables, and case-based discussion-enhances trainee understanding and clinical confidence. This guide aims to equip neurologists and trainees with a coherent framework for deploying dopaminergic imaging effectively at the bedside and in the classroom, while preparing the field for quantitative and theragnostic advances.