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BACKGROUND Studies on the routine clinical use of dopamine transporter (DAT) imaging have largely been conducted in Europe and the United States. In this real-world study, we investigated the use of cerebral 99mTc-TRODAT-1 SPECT imaging of DAT in patients with Parkinson disease (PD) at a tertiary hospital in Brazil. MATERIAL AND METHODS We included 119 patients with suspected PD or clinically unclear parkinsonism who underwent brain scintigraphy with 99mTc-TRODAT-1 during a 3-year period. Additionally, a brief interview was conducted with the physician who requested the scan to determine the usefulness of the method in clinical decision-making. RESULTS Regarding the scan requests, most were intended to evaluate or confirm dopaminergic denervation (69%), distinguish PD from essential tremor (10%), or distinguish degenerative parkinsonism from drug-induced parkinsonism (6%). Data analysis showed that scintigraphy with 99mTc-TRODAT-1 was useful in 85% of cases, changing the management of 75% of the patients who underwent a scan. The majority of physicians who requested the scan were neurologists, and 54% were self-reported movement disorder specialists. An inappropriate use of DAT imaging was seen in 5% of cases. CONCLUSIONS This study demonstrated that brain scintigraphy with the DAT ligand 99mTc-TRODAT-1 may influence diagnostic or therapeutic interventions, meaning that Brazilian physicians who requested the exam have taken in vivo DAT results into account at the time of clinical decision-making.

Purpose: "Chemobrain" is a medical secondary effect of cancer chemotherapy treatment characterized by a general decline in cognition affecting visual and verbal memory, attention, complex problem-solving skills, and motor function. Dopamine (DA) central nervous system neurotransmitters serve an important role in cognition, and changes in DA could potentially explain impaired cognition associated with chemotherapy. Therefore, our objective was to assess in vivo dopaminergic dysfunction in the central nervous system (CNS) of a group of female breast cancer survivors with cognitive impairment following chemotherapy., Methods: Twenty-eight women reporting chemobrain were recruited for this study and compared to 22 healthy reference women. Striatal dopamine transporter (DAT) binding ratio was determined by 99m Tc-TRODAT-1 (a highly selective radiotracer for DAT in the dorsal striatum) single-photon emission computed tomography and a quantitative evaluation was obtained by DatQUANT™ software (GE Healthcare). The DAT binding ratio (BR DAT ) in the patient and control groups was compared using the Student's t test, a multivariate analysis of variance (MANOVA) was used to compare age, years of schooling and BR DAT . The relationship between continuous variables, such as cognitive impairment and BR DAT was assessed using Pearson correlation test., Results: There was a difference in BR DAT between the chemobrain patients and control group. Patients had statistically significant (p < 0.05) lower concentrations of the radiopharmaceutical in the striatum., Conclusions: We identified a significant dopaminergic decrease in all regions of the dorsal striatum within the patients reporting cognitive dysfunction after chemotherapy. Therefore, our results indicate a possible role of dopamine transporter in the physiopathology of chemobrain, even out of the acute phase of symptoms.

Rationale: Depression is a frequent non-motor symptom in Parkinson's disease (PD) with increasing rates with the progression of the disease. Molecular imaging studies have shown a reduction of dopamine transporter (DAT) density in depressed PD patients (dPD); however, DAT role in the pathophysiology of PD depression is not clear since clinical matching was inappropriate and DAT reduction could be attributed to PD severity., Objectives: To further examine the role of DAT in PD depression, this study compared thoroughly matched depressed vs. non-depressed PD patients (ndPD)., Materials and Methods: Twenty PD patients (n = 10 ndPD; n = 10 dPD) matched for age and disease severity were submitted to brain SPECT imaging with [(99m)Tc]-TRODAT-1, a DAT radioligand. DAT-binding potential was calculated using regions of interest bilaterally drawn in the striatum, caudate, and putamen. Depression was defined according to Beck Depression Inventory (BDI; cut-off >18)., Results: Mean BDI scores were higher in dPD (25.0 +/- 5.6) than in ndPD patients (8.0 +/- 1.9, p < 0.0001). DAT density was greater on dPD especially in the left caudate (dPD 0.87 +/- 0.19 vs. ndDP 0.69 +/- 0.18, p = 0.02) and right putamen (dPD 0.37 +/- 0.07 vs. ndPD 0.28 +/- 0.13, p = 0.03) than in ndPD patients., Conclusion: Our results suggest that in vivo DAT density is increased in dPD patients as compared to ndPD, suggesting that DAT is implicated in the pathophysiology of PD depression.

Despite its relatively high prevalence Parkinson's Disease (PD) is still misdiagnosed in approximately 25% of cases. In this study our aim was to evaluate patients with Clinically Unclear Parkinsonian Syndromes (CUPS) submitted to brain SPECT imaging using the technetium-99m labeled Dopamine Transporter (DAT) tracer TRODAT-1. We recruited 15 subjects with CUPS and matched them with 13 patients with probable PD and 13 healthy control subjects (HCS). A SPECT with TRODAT-1 was performed at the baseline evaluation and patients from the CUPS were followed-up for 2-years to ensure or not PD diagnosis ("gold-standard"). The mean+/-SD results from Right and Left striatum Binding Potential (BP) were, respectively, 1.08+/-0.20 and 1.04+/-0.16 in the HCS group, 0.47+/-0.16 and 0.53+/-0.17 in the PD group, and 0.68+/-0.11 and 0.84+/-0.17 in the CUPS group. The rate of disagreement between baseline SPECT in the CUPS group as compared to the "gold standard" diagnosis (clinical diagnosis of PD on follow-up) was of 20%. The sensitivity of the SPECT with TRODAT-1 was 100%, while specificity was 70%. In conclusion, our data provided further information about the role of the technetium-99m labeled tracer TRODAT-1 as a biomarker of DAT reduction that can also be used in the diagnosis of patients with CUPS., (Copyright 2010 Elsevier B.V. All rights reserved.)

The development of in vivo molecular imaging to evaluate the dopamine (DA) system with positron-emission tomography and single photon emission computed tomography has been of key importance on monitoring in vivo nigrostriatal neuronal loss in Parkinson's disease (PD), mostly through assessments of pre- and post-synaptic DA receptors. The discoveries of genes related to hereditary forms of parkinsonism (PARK1, PARK2, PARK6, PARK7 and PARK8) have increased our understanding either of distinct subtypes of clinical expression in PD or its etiology. This article revises current data on molecular neuroimaging of genetic forms of parkinsonism comparing and contrasting its main features with the classical sporadic forms. Awareness of the spectrum variance in the genotype and its respective PD phenotype are useful to distinguish different pathophysiological mechanisms of PD.