Table 5.
rHC thresholds for each ROI and the optimal point from each ROC curve for type A and non-type A studies. FPR* and TPR* values are the ROC co-ordinates from the type A curves (Figure 5, left) for the corresponding values of rHC thresholds. This allows for comparison with the type A ROC optimal values.
| Front Med. Orb. | Ant. Cing. | Lat. Temp. | Precuneus | Post. Cing. | Parietal | ||
| rHC threshold | SUVR +2 SD | 1.09 | 1.25 | 1.21 | 1.17 | 1.25 | 1.05 |
| FPR* | 15% | 17% | 20% | 22% | 20% | 10% | |
| TPR* | 97% | 97% | 95% | 97% | 95% | 76% | |
| Type A ROC optimum threshold | SUVR | 1.13 | 1.25 | 1.29 | 1.25 | 1.38 | 1.00 |
| FPR | 12% | 17% | 12% | 17% | 7% | 12% | |
| TPR | 97% | 97% | 95% | 95% | 87% | 92% | |
| Non-type A ROC optimum threshold | SUVR | 1.52 | 1.38 | 1.53 | 1.03 | 1.52 | 1.43 |
| FPR | 8% | 0% | 0% | 15% | 0% | 23% | |
| TPR | 25% | 50% | 50% | 75% | 63% | 88% |
Acc, accuracy; Ant. Cing, anterior cingulate; FPR, false positive rate; Front Med. Orb, frontal medial orbital cortex; Lat. Temp, lateral temporal lobes; MCC, Matthews correlation coefficient; Post. Cing, posterior cingulate; ROC, receiver operating characteristic; ROI, region of interest; SUVR, standardised uptake value ratio; TPR, true positive rate.
Single regions are not used to classify scans, the FPR and TPR were used to choose optimum SUVR for each ROI and also for comparison between subgroups and thresholds.