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

Vera S Kerstens,A Varrone

doi:10.1007/s40336-020-00386-w

Abstract

PurposeThe 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.MethodsPubMed 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.ResultsThere 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.ConclusionDAT-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.

Highlights

dopamine transporter (DAT) as imaging markerParkinson’s disease (PD) is the most common neurodegenerative movement disorder, with approximately 1 out of 1000 people age 50 and older having the disease
The aim of this review is to critically address this question by giving an overview of how DAT imaging with positron emission tomography (PET) and single-photon emission computed tomography (SPECT) compare in the following four aspects: 1. Diagnostic accuracy, 2
Findings on correlations between DAT availability and motor and non-motor symptoms vary, with the majority finding no or weak correlations [6, 29, 30]. This might be because the outcomes applied, use generalized clinical outcomes and generalized regions in the brain, instead of sub-scales and sub-regions

Summary

Introduction

DAT as imaging markerParkinson’s disease (PD) is the most common neurodegenerative movement disorder, with approximately 1 out of 1000 people age 50 and older having the disease. To be able to assess the effectiveness of a new treatment, a reliable outcome measure. The decline of DAT density is secondary to the neurodegeneration of the dopaminergic nerve terminals, and to functional adaptation of the dopaminergic system; compensatory DAT downregulation might occur in earlier stages. At symptom onset, already 50% of dopaminergic terminals are lost, a flooring effect of DAT measurements might occur later on in the disease. Taking these two things into account, the measured DAT decline is most likely non-linear [6, 7], and DAT imaging might be useful in early stages of the disease, both for diagnostic purposes and for assessment of treatment effects

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