View source for Glioblastoma multiforme

== Diagnostics ==
'''Imaging methods''' are of the greatest importance for the diagnosis of GBM.<ref name="wor">{{Citace
| typ = web
| příjmení1 = Bruce
| jméno1 = Jeffrey N
| url = https://emedicine.medscape.com/article/283252-workup
| název = Glioblastoma Multiforme
| datum_revize = 2011
| citováno = 2012-02-13
}}
</ref>

On CT, glioblastoma appears as a hypodense lesion with a peripheral annular zone of enhanced contrast and a penumbra zone of cerebral edema.

MRI is the method of choice. Typically, the '''T1'''-weighted image shows '''annular hyperintensity''' and the '''T2'''-weighted image shows edema surrounding the lesion. In the T1-weighted image, the interior of the lesion is hypointense due to necrosis. The annular hyperintensity in the contrast examination consists of a tumor mass with rich neovascularization permeable to the contrast agent. Pathological studies have shown that the hyperintense zone does not form the edge of the tumor, but that the tumor cells extend up to two centimeters from this edge, sometimes beyond.

In more complex cases, positron emission tomography (PET) or MR-spectroscopy may help diagnose. PET displays increased glucose metabolism in the area. Measurement of tumor size after surgery with O-2 - [(18) F] fluoroethyl-1-tyrosine (FET) PET is of prognostic significance (Pirotha et al). '''MR-spectroscopy''' shows changes in peaks, such as increased peak ratio for choline and creatinine, increased peak for lactate and decreased for N-acetylspartate.

'''EEG''' changes are non-GBM specific.