Texture analysis of apparent diffusion coefficient (ADC) map for glioma grading: Analysis of whole tumoral and peri-tumoral tissue.

ABSTRACT

PURPOSE: To prospectively investigate the capabilities of texture analysis (TA) based on apparent diffusion coefficient (ADC) map of the entire tumor volume and the whole volume of peri-tumoral edema, in discriminating between high-grade glioma (HGG) and low-grade glioma (LGG). MATERIALS AND METHODS: A total of 33 patients with histopathological proven glioma were prospectively included. There were 20 men and 13 women with a mean age of 54.5±14.7 (standard deviation [SD]) years (range 34-75years). TA parameters of whole tumor and peri-tumoral edema were extracted from the ADC map obtained with diffusion-weighted spin-echo echo-planar magnetic resonance imaging at 1.5-T. TA variables of HGG were compared to those of LGG. The optimum cut-off values of TA variables and their corresponding sensitivity, specificity and accuracy for differentiating between LGG and HGG were calculated using receiver operating characteristic curve analysis. RESULTS: Mean and median tumoral ADC of HGG were significantly lower than those of LGG, at 1.23×10-3 mm2/s and 1.21×10-3 mm2/s cut-off values, yielding 70% sensitivity each (95% CI 59-82% and 61-80%, respectively), 80% (95% CI 79-98%) and 90% (95% CI 82-97%) specificity, and 73% (95% CI 66-91%) and 76% (95% CI 72-90%) accuracy, respectively. Significant differences in tumoral and peri-tumoral kurtosis were found between HGG and LGG at 1.60 and 0.314 cut-off values yielding sensitivities of 74% (95% CI 58-83%) and 70% (95% CI 59-84%), specificities of 90% (95% CI 80-95%) and 70% (95% CI 64-83%) and accuracies of 79% (95% CI 69-89%) and 70% (95% CI 64-77%), respectively. CONCLUSION: Measurements of whole tumoral and peri-tumoral TA, based on ADC maps, provide useful information that helps distinguish between HGG and LGG.