Cerebral blood volume measurements and proton MR spectroscopy in grading of oligodendroglial tumors.
OBJECTIVE
The purpose of this study was to determine whether perfusion-weighted imaging (PWI) and proton MR spectroscopy (MRS) are useful in differentiating high- and low-grade oligodendroglial tumors.


METHODS
PWI and MRS studies of 22 patients with histologically proven oligodendroglioma or oligoastrocytoma (13 low-grade and nine anaplastic tumors) were retrospectively reviewed. PWI of 14 subjects was performed with a dynamic contrast-enhanced susceptibility-weighted echo-planar technique. Intratumoral relative cerebral blood volume ratio was calculated and normalized to the same value in contralateral normal-appearing white matter. Multivoxel MRS was performed with a point-resolved spectroscopy sequence at a TE of 135 milliseconds in 20 patients and with the addition of a TE of 30 seconds in 17 patients. MRS data were expressed as intratumoral metabolite ratios (choline to creatine [Cho/Cr], choline to N-acetyl aspartate, N-acetyl aspartate to creatine, and myoinositol to creatine).


RESULTS
Relative cerebral blood volume ratios were significantly different (p = 0.004) between low-grade (1.61 +/- 1.20) and high-grade tumors (5.45 +/- 1.96). The optimal relative cerebral blood volume ratio cutoff value in identification of anaplastic oligodendroglial tumors was 2.14. Analysis of MRS data showed significantly higher Cho/Cr ratios (p = 0.002) in high-grade than in low-grade tumors. A Cho/Cr ratio cutoff value of 2.33 had the highest accuracy in identification of high-grade tumors.


CONCLUSIONS
Relative cerebral blood volume measurement and MRS are helpful in differentiating low-grade from anaplastic oligodendroglial tumors.
Spampinato
M Vittoria
MV
Department of Radiology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA.
Smith
J Keith
JK
Kwock
Lester
L
Ewend
Matthew
M
Grimme
John D
JD
Camacho
Daniel L A
DL
Castillo
Mauricio
M
D000328:Adult; D000368:Aged; D001810:Blood Volume; D001811:Blood Volume Determination / Q000379:methods; D001932:Brain Neoplasms / Q000098:blood supply / Q000175:diagnosis*; D003936:Diagnosis, Computer-Assisted / Q000379:methods*; D005260:Female; D006801:Humans; D009682:Magnetic Resonance Spectroscopy / Q000379:methods*; D008297:Male; D008875:Middle Aged; D009837:Oligodendroglioma / Q000098:blood supply / Q000175:diagnosis*; D011522:Protons; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity
D011522:Protons