Can apparent diffusion coefficient values help distinguish between different types of pediatric brain tumors?

Classifying brain tumors is challenging, but recently developed imaging techniques offer the opportunity for neuroradiologists and neurosurgeons to diagnose, differentiate, and manage different types of brain tumors. Such advances will be reflected in improvements in patients' life expectancy and quality of life. Among the newest techniques, the apparent diffusion coefficient (ADC), which tracks the rate of microscopic water diffusion within tissues, has become a focus of investigation. Recently, ADC has been used as a preoperative diffusion-weighted magnetic resonance imaging (MRI) parameter that facilitates tumor diagnosis and grading. Here, we aimed to determine the ADC cutoff values for pediatric brain tumors (PBTs) categorized according to the World Health Organization (WHO) classification of brain tumors.

We retrospectively reviewed 80 cases, and assessed them based on their MRI-derived ADC. These results were compared with those of WHO classification-based histopathology.

Whole-lesion ADC values ranged 0.225-1.240 × 10^-3 mm²/s for ependymal tumors, 0.107-1.571 × 10^-3 mm²/s for embryonal tumors, 0.1065-2.37801 × 10^-3 mm²/s for diffuse astrocytic and oligodendroglial tumors, 0.5220-0.7840 × 10^-3 mm²/s for other astrocytic tumors, and 0.1530-0.8160 × 10^-3 mm²/s for meningiomas. These findings revealed the usefulness of ADC in the differential diagnosis of PBT, as it was able to discriminate between five types of PBTs.

The application of an ADC diagnostic criterion would reduce the need for spectroscopic analysis. However, further research is needed to implement ADC in the differential diagnosis of PBT.