[Usefulness of Cho/Cr ratio in proton MR spectroscopy for differentiating residual/recurrent glioma from non-neoplastic lesions].
OBJECTIVE
We evaluated the clinical usefulness of the Cho/Cr ratio of proton MR spectroscopy(1H-MRS) to differentiate residual/recurrent glioma from non-neoplastic lesions.


METHODS
20 cases of glioma were involved in this study(astrocytoma grade I-II: 7, oligodendroglioma: 1, astrocytoma grade III: 2, glioblastoma: 10). Seven of the patients underwent surgical resection only, 4 underwent surgical resection and radiotherapy(40-60 Gy), and 9 underwent surgical resection and radiotherapy with concurrent chemotherapy(14-60 Gy). 1H-MRS was performed on a 1.5 Tesla clinical MR unit using a 3D-chemical shift imaging sequence(1500 msec/270 msec/1 (TR/TE/excitations), and the Cho/Cr ratio was calculated in the voxel where neoplastic lesion was most suspected on MRI. The presence of lactate + lipid peak was also evaluated. All spectra were obtained after the contrast enhanced study.


RESULTS
Cho/Cr ratios were significantly higher in cases of residual/recurrent tumors(mean +/- SD = 1.70 +/- 0.96) than in non-neoplastic lesions(mean +/- SD = 1.04 +/- 1.16) (Mann-Whitney U-test p = 0.047). If a Cho/Cr ratio of more than 1.5 was used as a marker of tumor presence, its sensitivity was 64%, specificity 83%, and accuracy 70%. One false-positive case that of radiation necrosis whose spectrum showed a high Cho/Cr ratio with markedly elevated lactate + lipid peak.


CONCLUSIONS
The Cho/Cr ratio of 1H-MRS provides additional information to MRI in differentiating residual/recurrent gliomas from non-neoplastic lesions.
Ando
Kumiko
K
Department of Radiology, Hyogo College of Medicine.
Ishikura
Reiichi
R
Nagami
Yuki
Y
Morikawa
Tsutomu
T
Takada
Yoshihiro
Y
Ikeda
Jota
J
Nakao
Norio
N
Matsumoto
Tsuyoshi
T
Arita
Norio
N
D000293:Adolescent; D000328:Adult; D000368:Aged; D001932:Brain Neoplasms / Q000175:diagnosis*; D002648:Child; D002675:Child, Preschool; D002794:Choline / Q000032:analysis*; D003401:Creatine / Q000032:analysis*; D005260:Female; D005910:Glioma / Q000175:diagnosis*; D006801:Humans; D009682:Magnetic Resonance Spectroscopy; D008297:Male; D008875:Middle Aged; D009364:Neoplasm Recurrence, Local; D018365:Neoplasm, Residual; D012680:Sensitivity and Specificity
D003401:Creatine; D002794:Choline