Correlations between in vivo (1)H MRS and ex vivo (1)H HRMAS metabolite measurements in adult human gliomas.
OBJECTIVE
To assess how accurately ex vivo high-resolution 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.


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 homogeneous-appearing 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, myo-inositol, total cholines, and the approximately 1.3 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.


CONCLUSIONS
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.
Opstad
Kirstie S
KS
Division of Cardiac and Vascular Sciences, St George's, University of London, London, UK. kopstad@sgul.ac.uk
Wright
Alan J
AJ
Bell
B Anthony
BA
Griffiths
John R
JR
Howe
Franklyn A
FA
D000465:Algorithms; D001254:Astrocytoma / Q000175:diagnosis* / Q000378:metabolism*; D014408:Biomarkers, Tumor / Q000032:analysis*; D001932:Brain Neoplasms / Q000175:diagnosis* / Q000378:metabolism*; D003936:Diagnosis, Computer-Assisted / Q000379:methods; D006801:Humans; D009682:Magnetic Resonance Spectroscopy / Q000379:methods*; D011522:Protons; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013223:Statistics as Topic
D014408:Biomarkers, Tumor; D011522:Protons