Diffusion differences between pilocytic astrocytomas and grade II ependymomas

Background. The aim of our study was to differentiate between cerebellar pilocytic astrocytomas and grade II ependymomas on the basis of their diffusion properties. Patients and methods. The study prospectively included 12 patients with pilocytic astrocytomas and 5 with ependymomas. Apparent diffusion coefficients (ADC) were compared between tumour types. Results. ADC values were significantly higher in pilocytic astrocytomas than ependymomas, with almost no overlapping of the range of measured ADCs between the two tumour types. Conclusions. Significant diffusion differences between pilocytic astrocytomas and grade II ependymomas enable their preoperative distinction, in combination with conventional magnetic resonance images.