Role of dopamine transporter imaging in routine clinical practice.
Functional imaging of the dopamine transporter (DAT) defines integrity of the dopaminergic system and has its main clinical application in patients with mild, incomplete, or uncertain parkinsonism. Imaging with specific single positron emission computerised tomography ligands for DAT (FP-CIT, beta-CIT, IPT, TRODAT) provides a marker for presynaptic neuronal degeneration. Striatal uptake correlates with disease severity, in particular bradykinesia and rigidity, and monitoring of progression assists in clinical trials of potential neuroprotective drugs. DAT imaging is abnormal in idiopathic Parkinson's disease, multiple system atrophy and progressive supranuclear palsy and does not distinguish between these disorders. Dopamine loss is seen even in the earliest clinical presentations of true parkinsonism; a normal scan suggests an alternative diagnosis such as essential tremor, vascular parkinsonism (unless there is focal basal ganglia infarction), drug-induced parkinsonism, or psychogenic parkinsonism. Congruence between working clinical diagnosis and DAT imaging increases over time in favour of baseline DAT imaging results. Additional applications are characterising dementia with parkinsonian features (abnormal results in dementia with Lewy bodies, normal in Alzheimer's disease); and differentiating juvenile-onset Parkinson's disease (abnormal DAT) from dopa-responsive dystonia (normal DAT).
Marshall
Vicky
V
Institute of Neurological Sciences, Glasgow, United Kingdom. v.marshall@clinmed.gla.ac.uk
Grosset
Donald
D
D000544:Alzheimer Disease / Q000175:diagnosis / Q000378:metabolism* / Q000503:physiopathology; D001921:Brain / Q000378:metabolism* / Q000473:pathology / Q000503:physiopathology; D003042:Cocaine / Q000031:analogs & derivatives / Q000493:pharmacokinetics; D050483:Dopamine Plasma Membrane Transport Proteins; D020329:Essential Tremor / Q000175:diagnosis / Q000378:metabolism / Q000503:physiopathology; D006801:Humans; D007457:Iodine Radioisotopes / Q000493:pharmacokinetics; D020961:Lewy Body Disease / Q000175:diagnosis / Q000378:metabolism* / Q000503:physiopathology; D008562:Membrane Glycoproteins; D026901:Membrane Transport Proteins / Q000378:metabolism / Q000502:physiology*; D009419:Nerve Tissue Proteins; D015609:Organotechnetium Compounds / Q000493:pharmacokinetics; D010300:Parkinson Disease / Q000175:diagnosis / Q000378:metabolism* / Q000503:physiopathology; D010818:Practice Patterns, Physicians'; D019275:Radiopharmaceuticals / Q000493:pharmacokinetics; D015899:Tomography, Emission-Computed, Single-Photon; D014057:Tomography, X-Ray Computed; D014326:Tropanes / Q000493:pharmacokinetics
D050483:Dopamine Plasma Membrane Transport Proteins; D007457:Iodine Radioisotopes; D008562:Membrane Glycoproteins; D026901:Membrane Transport Proteins; D009419:Nerve Tissue Proteins; D015609:Organotechnetium Compounds; D019275:Radiopharmaceuticals; C493214:SLC6A3 protein, human; D014326:Tropanes; C104196:technetium Tc 99m TRODAT-1; C087552:2-carbomethoxy-8-(3-fluoropropyl)-3-(4-iodophenyl)tropane; C069723:2beta-carbomethoxy-3beta-(4-iodophenyl)tropane; D003042:Cocaine