Table 3:

Results of ROC analysis of DWIs at b = 1000 and b = 3000 s/mm2

DWIAz*Cutoff ScoreSensitivity (%)Specificity (%)PPV (%)NPV (%)κ-value§
b = 1000 s/mm20.790569.476.994.440.00.56
b = 3000 s/mm20.864483.784.695.357.90.77
  • Note:—ROC indicates receiver operating characteristic; DWI, diffusion-weighted imaging.

  • * Az refers to area under the ROC curve; these were not significantly different with the 2 b-values (P = .08).

  • Cutoff score refers to the optimal cutoff level for high-grade glioma with highest accuracy for obtaining a positive test for high-grade glioma with a minimum C1 error by ROC analysis, where C1 = 1 − (sensitivity+specificity)/2.

  • PPV and NPV are positive and negative predictive values, respectively, for high-grade glioma.

  • § κ-value is the kappa value for interobserver agreement.