Threshold values for Cho/NAA ratio for differentiation between low- and high-grade gliomas
| Description | Cho/NAA | Sensitivity | Specificity | PPV | NPV | C2 Error | C1 Error |
|---|---|---|---|---|---|---|---|
| Minimum C2 Error* | 0.75 | 96.7 | 10.0 | 76.3 | 50.0 | 25.0 | 46.7 |
| Minimum C1 Error† | 1.60 | 74.2 | 62.5 | 85.6 | 44.6 | 28.8 | 31.7 |
| Same sensitivity as cMRI | 1.66 | 72.5 | 62.5 | 85.3 | 43.1 | 30.0 | 32.5 |
| Same specificity as cMRI | 1.78 | 67.5 | 65.0 | 85.3 | 40.0 | 33.1 | 33.8 |
Note.—Conventional MR imaging (cMRI) sensitivity 72.5%, specificity 65.0%, PPV 86.1%, NPV 44.1%, C2 error 29.4%, and C1 error 31.8%.
* C2 = the percentage of observed data points misclassified.
† C1 = 1 − (sensitivity + specificity)/2. This maximizes the average of sensitivity and specificity.