Dopamine transporter imaging in neurodegenerative movement disorders: PET vs. SPECT

Abstract

Purpose The dopamine transporter (DAT) serves as biomarker for parkinsonian syndromes. DAT can be measured in vivo with single-photon emission computed tomography (SPECT) and positron emission tomography (PET). DAT-SPECT is the current clinical molecular imaging standard. However, PET has advantages over SPECT measurements, and PET radioligands with the necessary properties for clinical applications are on the rise. Therefore, it is time to review the role of DAT imaging with SPECT compared to PET. Methods PubMed and Web of Science were searched for relevant literature of the previous 10 years. Four topics for comparison were used: diagnostic accuracy, quantitative accuracy, logistics, and flexibility. Results There are a few studies directly comparing DAT-PET and DAT-SPECT. PET and SPECT both perform well in discriminating neurodegenerative from non-neurodegenerative parkinsonism. Clinical DAT-PET imaging seems feasible only recently, thanks to simplified DAT assessments and better availability of PET radioligands and systems. The higher resolution of PET makes more comprehensive assessments of disease progression in the basal ganglia possible. Additionally, it has the possibility of multimodal target assessment. Conclusion DAT-SPECT is established for differentiating degenerative from non-degenerative parkinsonism. For further differentiation within neurodegenerative Parkinsonian syndromes, DAT-PET has essential benefits. Nowadays, because of wider availability of PET systems and radioligand production centers, and the possibility to use simplified quantification methods, DAT-PET imaging is feasible for clinical use. Therefore, DAT-PET needs to be considered for a more active role in the clinic to take a step forward to a more comprehensive understanding and assessment of Parkinson’s disease.

Synaptic Density and Neuronal Metabolic Function Measured by Positron Emission Tomography in the Unilateral 6-OHDA Rat Model of Parkinson’s Disease

“…Several techniques have been developed to identify disease-related neuronal patterns to aid early detection and differential diagnoses of Parkinson’s disease (PD). Examples of such methods are positron emission tomography (PET) imaging to measure glucose metabolism ( Loane and Politis, 2011 ), dopamine synthesis, transporters, or receptors ( Kerstens and Varrone, 2020 ). In PD, one affected neuronal circuit is the cortico-striato-thalamo-cortical (CSTC) circuit ( Vriend et al, 2014 ).…”

11C- and 18F-Radiotracers for In Vivo Imaging of the Dopamine System: Past, Present and Future

“…Over the decades since introduction of [ 11 C]CFT in the early 1990s, a very large number of analogs have been synthesized which incorporate 11 C or 18 F [ 59 ]. Several of the fluorine-18 labeled 3-phenyltropanes (e.g., [ 18 F]FE-PE2I; Figure 2 ) [ 60 , 61 ] have been translated into human studies, and together with continued use of [ 11 C]CFT, provide DAT radioligands for numerous clinical research studies.…”

“…As there are no uniform methods for evaluation of new radiopharmaceuticals, and seldom any direct comparison of two or more radiotracers, no single PET radiotracer for the DAT has progressed to true widespread use. SPECT (single-photon emission computed tomography) imaging of the DAT is currently approved for clinical use in many countries, employing the radiotracer DaTScan ® (Ioflupane I123 Injection: N-ω-fluoropropyl-2β-carbomethoxy-3β-(4-[ 123 I]iodophenyl) nortropane), but the advantages inherent in PET imaging (resolution, quantification) should encourage the eventual advancement of one or more of the fluorine-18 labeled DAT radioligands into regulatory approval and commercial availability [ 61 ].…”

Synaptic density and neuronal metabolic function measured by PET in the unilateral 6-OHDA rat model of Parkinson’s disease

“…Several techniques have been developed to identify disease-related neuronal patterns to aid early detection and differential diagnoses of Parkinson’s disease (PD). Examples of such methods are positron emission tomography (PET) imaging to measure glucose metabolism, dopamine synthesis, transporters, or receptors (Loane and Politis, 2011; Kerstens and Varrone, 2020). In PD, one affected neuronal circuit is the cortico-striato-thalamo-cortical (CSTC) circuit (Vriend et al, 2014).…”