SLC6A3 and Lewy body dementia: Significantly lower SBR in the α-syn + group than that in the α-syn – group (1.35 ± 0.42 versus 1.55 ± 0.41; p = 0.047), and a high negative correlation coefficient of plasma α-synuclein level with SBR (−0.36; p = 0.002) indicated a good correlation of the plasma α-synuclein level with reduced dopamine transporter uptake in the striatal areas, which is currently the hallmark of brain imaging study for the diagnosis of DLB.