Diagnostic group differences in putamen and caudate dopamine transporter concentrations. (A) Unadjusted putamen dopamine transporter (DAT) concentration was similar in the PD and DLB groups, and was significantly lower than HCS (ANOVA, P<0.0001). (B) Unadjusted caudate DAT concentration was also similar in PD and DLB subjects, and was significantly lower than HCS (ANOVA, P=0.0002). (C) The adjusted caudate DAT concentration was significantly higher in the PD group than in the HCS (P=0.018) and DLB (P=0.041) groups. ANOVA, analysis of variance; DLB, dementia with Lewy bodies; HCS, healthy control subjects; PD, Parkinson disease without dementia.