Abstract
Purpose:
To assess how accurately ex vivo highโresolution magic angle spinning (HRMAS) proton magnetic resonance spectroscopy (^1^H MRS) from small biopsy tissues relate to in vivo ^1^H MRS (from larger tumor volumes) in human astrocytomas.
Materials and Methods:
In vivo (PRESS, TE = 30 msec) and ex vivo (presaturation) ^1^H spectra of 17 human astrocytomas (4 grade II, 1 grade III and 12 glioblastomas) were quantified using LCModel. Concentrations of 11 metabolites and 2 lipid/macromolecules were retrospectively compared, with histogram analysis of the in vivo MRI data used to evaluate tumor heterogeneity.
Results:
For homogeneousโappearing tumors, significant correlations were found between in vivo and ex vivo ^1^H MRS concentrations of those metabolites known to be metabolically stable in postmortem tissues (eg, creatine, myoโinositol, total cholines, and the โ1.3 and 0.9 ppm lipids). Anaerobic glycolysis during biopsy surgical removal depletes the tissue of glucose, increasing alanine and lactate, and resulted in no correlation between these in vivo and ex vivo metabolite concentrations.
Conclusion:
Within defined limitations, ex vivo astrocytoma biopsy HRMAS ^1^H spectra have similar metabolic profiles to that obtained in vivo and therefore detailed ex vivo characterization of glioma biopsies can directly relate to the original tumor. J. Magn. Reson. Imaging 2010; 31: 289โ297. ยฉ 2010 WileyโLiss, Inc.