The most important diagnostic procedure is magnetic resonance imaging (MRI). Occasionally, outside of routine diagnostics, the metabolism in the tissue is shown using positron emission tomography (PET). The diagnosis is confirmed by a fine tissue examination following an operation.<unk> s often show a loss of genetic material. About 50 to 70% of WHO grade III<unk> s have combined allele losses on the short arm of chromosome 1 (1p) and the long arm of chromosome 19 (19q). This change is mostly referred to as "1p / 19q Co Deletion". It can be seen as favorable for the patient and makes a response to radiation or chemotherapy more likely. The designation of grade III<unk>  (high grade) generally subsumes the previous diagnoses of anaplastic or malignant<unk> .<unk>  (1).Histopathological image of<unk>  in cerebrum. Hematoxylin & eosin stain.<unk>  (3).Zooming, note the irregular cell- and nucleus-shapes. File:IDH1 R132H in<unk> .IDH1 R132H in<unk>
Anaplastic oligodendroglioma
Anaplastic astrocytoma
Neurothekeoma
Oligodendroglioma
Giant-cell glioblastoma
Subependymal giant cell astrocytoma
Fibrillary astrocytoma
Pilocytic astrocytoma