Figure 6. Intra-neuronal metabolism and myocardial vesicular uptake of ¹⁸F-DA.

(A) Mean (±SEM) arterial plasma concentrations of ¹⁸F-DOPAC as a function of time. (B) Vesicular uptake index (initial radioactivity divided by peak ¹⁸F-DOPAC) for individuals. (C) Group mean values for vesicular uptake index. (D) Group mean values for the ratio of myocardial radioactivity to concurrent plasma ¹⁸F-DOPAC as a function of time. (E) Individual values for rate of loss of radioactivity versus vesicular uptake index. Shaded rectangles highlight regions of (top left) decreased initial radioactivity plus increased loss in patients with Lewy body diseases (pink) or (bottom right) normal initial radioactivity and normal rates of loss in patients with MSA. Dashed line represents the logarithmic equation of best fit. Red, PD+OH; yellow, PD-No-OH Low rad.; blue, MSA; green, PAF; gray, normal control subjects.