SLC6A3 and Parkinson disease: The diagnostic performance of dopamine transporter imaging in the assessment of nigrostriatal function loss was investigated in 19 studies (32%) in patients with DLB [17, 19, 20, 22, 23, 27, 35–37, 45, 49–57], while the differentiation of DLB from other entities in the Lewy body disease spectrum (DLB, PD, PDD) was assessed in 15 studies (25%) [18, 24, 26, 27, 29, 30, 35, 37–39, 43, 47, 53, 58, 59].