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Purpose: The purpose of this study was to evaluate molecular evidence of nigrostriatal pathway involvement in Japanese encephalitis (JE) survivors with movement complications.Methods: Three JE patients were recruited. All had cranial magnetic resonance imaging (MRI) and single-photon emission computed tomography (SPECT) studies with (99m)Tc-TRODAT-1 and (123)I-IBZM.Results: Cranial MRI revealed involvement of bilateral thalami, substantia nigra, and medial temporal lobes in all three patients, but only case 1 had additional bilateral basal ganglia involvement. The (99m)Tc-TRODAT-1 SPECT for presynaptic dopamine transporter imaging disclosed asymmetrical decreases in bilateral striatal uptake in all three patients. However, the (123)I-IBZM SPECT imaging for postsynaptic D2 dopamine receptors (D2Rs) revealed inconsistent abnormalities including asymmetrical bilateral decreases (case 1), unilateral decrease (case 2), and bilateral increases (case 3) in striatal uptakes.Conclusion: Data have suggested that presynaptic dopaminergic neurons in JE patients are more susceptible to JE virus than postsynaptic striatal neurons. The degree of movement impairment was more closely correlated to the degree of D2Rs disruption seen in (123)I-IBZM SPECT imaging. [ABSTRACT FROM AUTHOR]

Nigral dopaminergic projections to the striatum are targeted in Parkinson’s disease (PD). The extent of the degeneration of the dopaminergic system in PD can be visualised by dopamine transporter imaging using single-photon emission tomography (SPET). In this study in 188 patients with PD, we analysed the image patterns and compared them with the clinical features in order to verify the usefulness of technetium-99m TRODAT-1 brain SPET in the evaluation of patients with PD. Two independent readers visually assessed SPET slices from three brain axes according to a “fine” visual scale; results were also grouped according to a “rough” visual scale. Results of both visual and semi-quantitative analyses were compared among patients with different stages of PD and healthy controls. There was good agreement between the readers in the interpretation of the image patterns [kappa statistic (κ)=0.85 for the presence of PD; κ=0.88 for the rough scale and 0.81 for the fine scale]. Good concordance was obtained when visual interpretation was used to evaluate the presence of PD (sensitivity =98%, specificity =86%, κ=0.85). Semi-quantitative analyses revealed significant negative correlations between both striatal and putaminal uptake and disease severity as assessed using the Hoehn and Yahr scale (ρ=-0.89 and -0.93 respectively). An apparent decrease in striatal uptake in early PD, hardly discernible from the uptake level in advanced PD, was commonly found in visual analyses. The results suggest that both visual and semi-quantitative analyses of [sup 99m]Tc-TRODAT-1 SPET images reflect neurodegeneration in PD, and that [sup 99m]Tc-TRODAT-1 SPET represents an adequate means for evaluation of the status of patients with PD. [ABSTRACT FROM AUTHOR]