In order to make an adequate decision on the further treatment of a glioma cancer patient a tissue sample from the tumour is microscopically analysed and classified on a malignancy scale set by the WHO. In this project a software program with a graphical user interface is developed, where the malignancy grade of a tumour could be found by image analysis of susceptibility-weighted MR images. The parameters examined are the local image variance and intratumoural susceptibility signal and the results show the possibility of distinguishing high grade from low grade astrocytoma by image analysis only.