Objective   To investigate the value of proton MR spectroscopy (

l

H-MRS) and diffusion tensor imaging in differentiating benign from malignant intracranial tumors.   Methods   Thirty-three patients with pathological confirmed brain tumor

including 10 meningiomas

4 acoustic neuromas

1 hemangioblastoma

1 mixed glioneuronal tumor

11 gliomas

5 metastasis and 1 primitive neuroectodermal tumor underwent conventional MRI and diffusion tensor imaging

and 22 of them performed proton magnetic resonance spectroscopy in our hospital from September to December 2008. Choine (Cho)

N-acetylaspartate (NAA)

creatine (Cr)

lipid (Lip) and lactate (Lac) level were measured in the tumor masses and peritumor tissues. Mean diffusivity (MD) and fractional anisotropy (FA) was obtained in solid area

necrosis area

peritumor edema area

white matter surrounding the edema and contralateral white matter.   Results   All the patients were divided into benign (n=19) and malignant (n=14) groups according to the pathological results. Both benign and malignant tumors showed low NAA and high Cho. The Cho/NAA and Cho/Cr value in solid area of the benign tumor was  markedly lower than that of the malignant tumor

with a significant difference (P0.01)

while the NAA/Cr ratio in the former group was higher than that of the later

though having no significant difference between them (P0.05). Eight of 13 benign tumors had Lac peak

and 2 had Lip peak. Seven of 9 malignant tumors had Lac peak

and 5 had Lip peak. The FA value in solid area and white matter surrounding the edema of benign tumors was significant higher than that of the malignant (P0.05)

however the difference of FA in the necrosis and peritumor edema area between the 2 groups was not significant (P0.05). FA value in the white matter surrounding edema of benign tumor was significant higher than contralateral white matter (P0.05). Although the FA value in the white matter surrou

nding edema of malignant tumor was lower than the contralateral white matter

though the difference didn’t reach statistical significance (P0.05). The difference of MD in solid area of benign and malignant tumor was significant (P0.05)

but difference of necrosis

peritumor edema and white matter surrounding edema between the 2 groups was not significant (P0.05). For the FA and MD value in solid part of tumor there was linear negative correlation with Cho/Cr ratio.   Conclusion  

I

H-MRS

a noninvasive technique for investigating the metabolic changes in brain tumor

is helpful to differentiate benign from malignant intracranial tumors through Cho/NAA and Cho/Cr ratios. There is negative correlation between Cho/Cr and FA

MD value. Cho/NAA

Cho/Cr and FA

MD value may effectively differentiate benign from malignant intracranial tumor.