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.