Table 2.
Mean neuromelanin contrast ratios, 11C-PE2I BPND values, per cent decline and asymmetry indices
| Healthy control (n = 15) | Parkinson’s disease (n = 30) | ||||||||
|---|---|---|---|---|---|---|---|---|---|
| Bilateral | AI | MA | % | LA | % | Bilateral | % | AIa | |
| Neuromelanin contrast ratio | |||||||||
| SNc combined (SNccom) | 0.14 ± 0.03 | −0.17 ± 18.98 | 0.10 ± 0.03 | 71.79 | 0.11 ± 0.04 | 77.99 | 0.10 ± 0.03 | 74.89 | 6.25 ± 19.30 |
| Ventral tier (SNcven) | 0.12 ± 0.03 | 2.24 ± 26.23 | 0.08 ± 0.04 | 66.62 | 0.09 ± 0.04 | 73.32 | 0.09 ± 0.04 | 69.97 | 5.54 ± 32.23 |
| Dorsal tier (SNcdor) | 0.15 ± 0.03 | −3.07 ± 20.44 | 0.11 ± 0.03 | 76.31 | 0.12 ± 0.04 | 80.79 | 0.11 ± 0.03 | 78.55 | 4.43 ± 17.99 |
| 11C-PE2I BPND | |||||||||
| SNc combined (SNccom) | – | – | 0.63 ± 0.13 | – | 0.67 ± 0.14 | – | 0.65 ± 0.13 | – | 5.76 ± 14.50 |
| Ventral tier (SNcven) | – | – | 0.59 ± 0.11 | – | 0.62 ± 0.14 | – | 0.61 ± 0.12 | – | 3.97 ± 18.54 |
| Dorsal tier (SNcdor) | – | – | 0.67 ± 0.15 | – | 0.71 ± 0.16 | – | 0.69 ± 0.14 | – | 5.67 ± 16.57 |
| Striatum | – | – | 1.68 ± 0.49 | – | 2.03 ± 0.61 | – | 1.85 ± 0.52 | – | 20.20 ± 16.49 |
| Putamen | – | – | 1.17 ± 0.37 | – | 1.53 ± 0.53 | – | 1.35 ± 0.41 | – | 27.06 ± 21.79 |
| Pre-commissural dorsal putamen | – | – | 1.04 ± 0.45 | – | 1.46 ± 0.66 | – | 1.23 ± 0.49 | – | 35.22 ± 29.71 |
| Pre-commissural ventral putamen | – | – | 1.94 ± 0.64 | – | 2.47 ± 0.83 | – | 2.19 ± 0.67 | – | 25.45 ± 22.47 |
| Post-commissural putamen | – | – | 0.70 ± 0.16 | – | 0.94 ± 0.36 | – | 0.82 ± 0.25 | – | 26.71 ± 21.97 |
| Caudate | – | – | 2.00 ± 0.68 | – | 2.37 ± 0.76 | – | 2.18 ± 0.69 | – | 19.71 ± 17.33 |
| Pre-commissural caudate | – | – | 2.21 ± 0.78 | – | 2.60 ± 0.87 | – | 2.39 ± 0.79 | – | 19.29 ± 18.08 |
| Post-commissural caudate | – | – | 1.18 ± 0.41 | – | 1.47 ± 0.49 | – | 1.32 ± 0.43 | – | 23.88 ± 23.05 |
Mean (±SD) neuromelanin contrast ratios in the SNc are shown for both the Parkinson’s disease and healthy control groups bilaterally and for the clinically most and least affected sides for the Parkinson’s disease group. Change in neuromelanin contrast ratios for the Parkinson’s disease group is expressed as a percentage relative to the healthy control group. Mean (±SD) asymmetry indices (AI) for both the Parkinson’s disease (most/least affected) and healthy control groups (right/left) and mean (±SD) 11C-PE2I BPND values in the SNc and striatum for the Parkinson’s disease group are also shown.
aRemoval of one outlier for asymmetry indices >3 SD away from the mean.
AI = asymmetry index; BPND = non-displaceable binding potential; LA = least affected; MA = most affected.