Role of proton magnetic resonance spectroscopy in differentiating oligodendrogliomas from astrocytomas.
OBJECTIVE
Preoperative differentiation of astrocytomas from oligodendrogliomas is clinically important, as oligodendrogliomas are more sensitive to chemotherapy. The purpose of this study was to assess the role of proton magnetic resonance spectroscopy in distinguishing astrocytomas from oligodendrogliomas.


METHODS
Forty-six patients [astrocytomas (n= 17) and oligodendrogliomas (n= 29)] underwent magnetic resonance imaging and multi voxel proton magnetic resonance spectroscopic imaging before treatment. Peak areas for N-acetylaspartate (NAA), creatine (Cr), choline (Cho), myo-inositol (mI), glutamate/glutamine (Glx), and lipids + lactate (Lip+Lac) were analyzed from voxels that exhibited hyperintensity on fluid-attenuated inversion recovery images and were normalized to Cr from each voxel. The average metabolite/Cr ratios from these voxels were then compared between astrocytomas and oligodendrogliomas. Receiver-operating curve analyses were used as measures of differentiation accuracy of metabolite ratios. A threshold value for a metabolite ratio was estimated by maximizing the sum of sensitivity and specificity.


RESULTS
A significant difference in mI/Cr was observed between astrocytomas and oligodendrogliomas (.50 +/- .18 vs. 0.66 +/- 0.20, P < .05). Using a threshold value of .56 for mI/Cr ratio, it was possible to differentiate oligodendrogliomas from astrocytomas with a sensitivity of 72.4% and specificity of 76.4%.


CONCLUSIONS
These results suggest that mI/Cr might aid in distinguishing oligodendrogliomas from astrocytomas.
Chawla
Sanjeev
S
Department of Radiology, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA.
Oleaga
Laura
L
Wang
Sumei
S
Krejza
Jaroslaw
J
Wolf
Ronald L
RL
Woo
John H
JH
O'Rourke
Donald M
DM
Judy
Kevin D
KD
Grady
Michael S
MS
Melhem
Elias R
ER
Poptani
Harish
H
D000328:Adult; D000368:Aged; D001254:Astrocytoma / Q000175:diagnosis* / Q000378:metabolism / Q000473:pathology; D001921:Brain / Q000378:metabolism / Q000473:pathology; D001932:Brain Neoplasms / Q000175:diagnosis* / Q000378:metabolism / Q000473:pathology; D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D009682:Magnetic Resonance Spectroscopy / Q000379:methods*; D008297:Male; D008875:Middle Aged; D009837:Oligodendroglioma / Q000175:diagnosis* / Q000378:metabolism / Q000473:pathology; D011522:Protons; D012372:ROC Curve; D012680:Sensitivity and Specificity; D055815:Young Adult
D011522:Protons