What is the role of positron emission tomography (PET) scans and magnetic resonance (MR) spectroscopy in the diagnosis of glioblastoma multiforme (GBM)?

Updated: Jul 01, 2019
  • Author: Jeffrey N Bruce, MD; Chief Editor: Herbert H Engelhard, III, MD, PhD, FACS, FAANS  more...
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Answer

Positron emission tomography (PET) scans and magnetic resonance (MR) spectroscopy can be helpful to identify glioblastomas in difficult cases, such as those associated with radiation necrosis or hemorrhage. On PET scans, increased regional glucose metabolism closely correlates with cellularity and reduced survival. MR spectroscopy demonstrates an increase in the choline-to-creatine peak ratio, an increased lactate peak, and decreased N- acetylaspartate (NAA) peak in areas with glioblastomas (see the image below).

Magnetic resonance (MR) spectroscopy is representa Magnetic resonance (MR) spectroscopy is representative of a glioblastoma multiforme (GBM), demonstrating a high peak ratio of choline (CHO) to creatine (CR), a decreased N-acetylaspartate (NAA) peak, and an increased lactate (LAC) peak.

A study by Piroth et al found that O-(2-[(18)F]fluoroethyl-l-tyrosine (FET) PET to measure tumor volume after surgery has a strong prognostic impact. [8]

Cerebral angiograms are not necessary for the diagnosis or clinical management of glioblastomas.


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