Only all the values of sensitivity/specificity pairs plotted in the roc curve provides a complete picture of test accuracy and
the area under the ROC curve (Az) is the measure . A computer software packages NCSS (Release NCSS2007, Kaysville, Utah) Entinostat in vivo was used to determine the statistical significance (p-values) of the difference between the areas under ROC curves with the relative standard error and 95% confidence interval. In addition to ROC curves, parametric (mTOR inhibitor t-test for independent and paired samples) and non-parametric tests (Wilcoxon Signed Ranks test) were also used to investigate the statistically significant differences between diseased and normal regions. Results Before evaluating the parametric maps, an analysis of the tumor size was made for the patient population included in this study. In Fig. 3 the histogram of the areas outlined by the radiologist for each patient as malignant region has been displayed. The average area being 157.0 mm2 and the range was 48.6–520.0 mm2. This analysis was performed on the evidence that the great variability in ROI size surely has a great impact on the mean perfusional values and their variability inside ROIs (see also Fig. 1, 2). Figure 3 Histogram of the areas outlined by the radiologist, for each patient, as malignant regions. Using perfusion
maps to find the possible predictors of malignancy, an analysis was performed on 22 patients affected by a malignant glioma or metastases. The mean values and the standard deviations of all the parameters inside the GF120918 ROIs delineated by the radiologist as lesions and inside the contralateral ROIs were calculated and shown in Table 2 (Tstart was not included being considered of minor interest for the
aim of the study). Table 2 Average values and standard deviations of all the perfusional parameters for malignant and normal tissue. Pat Res (1:1000) Pat Rsq (1:100) PS(0.5 ml/100 ml/min) PBV(%) T peak (s) Normal Tissue 9.0 ± 5.7 8.5 ± 9.0 4.2 ± 6.9 3.3 ± 1.6 5.4 ± 2.2 Lesion 10 ± 5.3 34.6 ± 29.3 14.2 ± 12.6 4.0 ± 1.8 7.5 ± 2.7 CBV(%) Peak enh (a.u.) CBF(ml/100 ml/min) P mean (a.u.) Casein kinase 1 MIP(a.u.) Normal Tissue 4.3 ± 3.2 7.8 ± 8.3 30.9 ± 24.7 35.8 ± 15.0 50.0 ± 16.2 Lesion 6.3 ± 5.0 10.9 ± 8.0 38.8 ± 40.0 42.9 ± 15.0 55.7 ± 12.5 The relative units are indicated in brackets (a.u. is an abbreviation for arbitrary units). Both parametric (t-test) and non-parametric tests (Wilcoxon Signed Ranks test) were used to perform the study, and the t-test was executed with the hypothesis of both independent and paired samples to exclude the possibility that the values obtained inside the contralateral ROIs could be affected by the presence of a tumor on the other hemisphere (Tab. 3).