[Study of the pre and post-synaptic dopaminergic system by DaTSCAN/IBZM SPECT in the differential diagnosis of parkinsonism in 75 patients].

Introduction: Essential tremor (ET) may be misdiagnosed as idiopathic Parkinson's disease (PD). In neurodegenerative diseases, structural imaging, such as CT or MRI, is of limited value for differentiating parkinsonian syndromes since structural changes are often only evident by the time the disease is far advanced. Most cases of symptomatic parkinsonism are vascular parkinsonism, but PD may coexist. The differential diagnosis between Alzheimer's disease (AD) and dementia with Lewy bodies (LBD) is often difficult.

Objective: To define the utility of functional neuroimaging test to establish differential diagnosis between PD and ET, drug induced parkinsonism, multiple system atrophy and vascular parkinsonism, and between AD and LBD, when clinical presentation, evolution or treatment response are atypical.

Patients And Methods: A group of 75 patients with parkinsonism was examined by clinical assessment and DaTSCAN (123I-FP-CTI, dopamine transporter protein marker) and/or IBZM SPECT (D2 receptor marker). The patients were recruited from our outpatient clinic.

Results: Correlation between initial clinical diagnosis and functional imaging studies (DaTSCAN and/or IBZM SPECT) in our patients did not reach that described (more than 90 %) for these techniques in previously published studies. Conclusions. According to sensitivity and sensibility reported in previous imaging studies of the pre and/or postsynaptic dopaminergic system using DaTSCAN and/ or IBZM, SPECT may be a new tool in the diagnosis of parkinsonian patients with difficult clinical diagnosis.