Objective    To explore the clinical value of diffusion weighted imaging (DWI) and apparent diffusion coefficients (ADC) measurement in the diagnosis of glioma and meningioma.     Methods    Seventeen patients with gliomas and twenty patients with meningioma underwent routine MRI scan and DWI. Comparisons of apparent diffusion coefficients (ADC)and exponential diffusion coefficients (eADC) were made among tumor parenchymas

peripheral edema regions and normal tissues.     Results    Of 17 cases of gliomas

tumor parenchymas of 10

4

3 cases exhibited hyper

iso

hypo-intensity on DWI respectively. Of 20 cases of meningioma

18 cases showed iso- and hyper-intensity on DWI. The results from ADC or eADC showed significant statistical difference between glioma

meningioma and normal brain tissue (P0.01); The results of grade Ⅰ-Ⅱ glioma were also statistically different with those of and grade Ⅲ-Ⅳ glioma and meningioma (P0.05). In peripheral edema regions

the results from ADC (eADC) of grade Ⅰ-Ⅱ glioma were significantly lower than those of grade Ⅲ-Ⅳ glioma and meningoma (P0.05).     Conclusion    DWI and ADC may evaluate brain tumors by providing the internal functional information

though ADC itself can not be used to differentiate brain tumors.