Noninvasive histologic grading of solid astrocytomas using proton magnetic resonance spectroscopy

Stereotact Funct Neurosurg. 2004;82(2-3):90-7. doi: 10.1159/000077458. Epub 2004 Mar 25.


Background: Proton magnetic resonance spectroscopy (1H MRS) constitutes a promising modality to assess intracranial pathology. We present our experience using this method in grading solid brain astrocytomas.

Material and methods: Using a 1.5-Tesla MRI unit, 71 patients with the radiographic diagnosis of astrocytoma were examined. Water-suppressed single-voxel 1H MRS was employed in all of our patients. The concentrations of choline (Cho), N-acetyl-aspartate (NAA), phosphocreatine-creatine (Pcr-Cr), myo-inositol (MI), lactate (Lac), lipids (Lip) as well as the metabolite ratios of Cho/Pcr-Cr, NAA/PCr-Cr and NAA/Cho were calculated. An appropriate surgical biopsy was performed. Standard pathology examination was employed in a double-blinded fashion.

Results: An increased concentration of Cho and decreased concentrations of Pcr-Cr and NAA were detected. The concentrations of Lac, Lip and MI varied inconsistently, even among tumors of the same histologic grade. The Cho/Pcr-Cr ratio was calculated. This ratio was found to be 2.15 +/- 0.26 in 27 patients with astrocytomas grade I and II, 2.78 +/- 0.09 in 18 patients with grade III, and 5.40 +/- 0.16 in 26 patients with grade IV.

Discussion: The increased concentration of Cho is due to the increased cellularity and a relatively increased number of membranous structures in highly malignant tumors. In abnormal anaerobic metabolic tumor states there is relatively less phosphorylization of creatine. By using the Cho/Pcr-Cr ratio the concomitant effects of structural and metabolic alteration can thereby be emphasized for diagnostic advantage.

Conclusion: The Cho/Pcr-Cr is a very important and statistically significant marker (p = 0.043) determining the degree of intracranial astrocytoma malignancy.

Publication types

  • Comparative Study

MeSH terms

  • Adult
  • Aged
  • Analysis of Variance
  • Astrocytoma / classification
  • Astrocytoma / diagnosis*
  • Astrocytoma / metabolism
  • Brain Neoplasms / classification
  • Brain Neoplasms / diagnosis*
  • Brain Neoplasms / metabolism
  • Double-Blind Method
  • Female
  • Humans
  • Magnetic Resonance Spectroscopy / methods*
  • Male
  • Middle Aged
  • Protons


  • Protons