Infratentorial tumors in children – value of ADC in prediction of grade of neoplasms

BACKGROUND The purpose of this study was to evaluate ADC values in the preoperative grading of primary infratentorial brain tumors in children. MATERIAL /METHODS: We retrospectively reviewed 50 MR examinations of patients with infratentorial tumors. All children were operated on and tumors were histopathologically proved as low-grade - 25 (24 pilocytic astrocytomas, 1 ependymoma) and high-grade lesions - 25 (19 medulloblastomas, 6 anaplastic ependymomas). In all patients with contrast-enhanced tumors, ROIs were placed in the enhanced region. In patients with non-enhancing tumors, ROIs were placed in the solid part of the lesion. Cystic, hemorrhagic and necrotic areas of tumors were excluded. Statistical analysis was performed by using a Student's t-test. RESULTS Statistically significant differences were found in the comparisons of mean ADC of pilocytic astrocytomas (1.54×10(-3)mm(2)/s ±0.2) with medulloblastomas (0.75×10(-3)mm(2)/s ±0.075) and pilocytic astrocytomas (1.54×10(-3)mm(2)/s ±0.2) with anaplastic ependymomas (0.99×10(-3)mm(2)/s ±0.25). Statistical analysis including ependymomas should be discussed, because of small number of these tumors and a non-homogenous group of lesions. CONCLUSIONS DWI imaging and ADC map provide useful information for preoperative grading of infratentorial tumors in children.