Pediatric Cerebellar Tumors: Does ADC Analysis of Solid, Contrast-Enhancing Tumor Components Correlate Better with Tumor Grade than ADC Analysis of the Entire Tumor?

BACKGROUND: Apparent diffusion coefficient (ADC) values assist differentiating malignancy grades in pediatric cerebellar tumors. Previous studies reported the significance of ADC measurements within the solid, contrast-enhancing tumor component (SCT). These measurements take into account only a part of the tumor. In this study, we compared ADC measurements of the SCT versus entire tumor (ET). METHODS: ADC values were measured in the SCT and ET. Absolute tumor ADC values and cerebellar and thalamic ratios were compared across tumor grades. RESULTS: Thirty-two children with 16 low-grade and 16 high-grade tumors were included. The median age at presurgical MRI was 7.66 years (range .08-17.38 years). In the SCT, absolute ADC values, cerebellar ratio, and thalamic ratio were higher in low- versus high-grade tumors (P < .001). In the ET, absolute ADC values, cerebellar ratio, and thalamic ratio were also higher in low- versus high-grade tumors (P < .005). Cut-off absolute ADC values of .9 × 10^-3 mm/s² (sensitivity 94%, specificity 100%) and 1.5 × 10^-3 mm/s² (sensitivity 88%, specificity 75%) were calculated for measurement in the SCT and ET, respectively, to differentiate between tumors grades. CONCLUSION: A rigorous ADC measurement of the SCT has a higher sensitivity and specificity in predicting tumor grade compared to ADC measurement of the ET.