Dopaminergic imaging in drug-induced parkinsonism and dementia with Lewy bodies

Abstract

Dopamine transporter (DAT) imaging is a sensitive method to detect presynaptic dopaminergic neuronal dysfunction, which is a hallmark of neurodegenerative disorders. DAT imaging can be useful for differentiating between conditions with and without presynaptic dopaminergic deficits. Drug-induced parkinsonism (DIP) is the second most common type of parkinsonism after Parkinson’s disease, and their distinction has crucial implications in terms of management and prognosis. A normal DAT single photon emission computed tomography (SPECT) finding is helpful in supporting a diagnosis of drug-induced, psychogenic, and vascular parkinsonism by excluding any underlying true nigral dysfunction. Dementia with Lewy bodies (DLB) is diagnosed on the basis of the presence of dementia and other core clinical features: cognitive fluctuations with marked variation of attention and alertness, recurrent well-formed, detailed visual hallucinations, and spontaneous parkinsonism. Differentiating DLB from Alzheimer’s disease (AD) and other dementia symdromes is important for prognosis and management. DAT-SPECT can be an accate method to differentiate between DLB and other dementia syndromes. Here, we review the usefulness of DAT imaging for the diagnosis of these diseases on the basis of our own cases.