Abstract：Objective: To evaluate the usefulness of ADC in differentiating tumor, edema, and normal brain tissue, and in grading the malignancy of cerebral gliomas. Materials and Methods: Using a Philips 1.5T super conduct MR unit, 39 gliomas underwent conventional MR imaging and diffusion weighted imaging. The apparent diffusion coefficients of regions of interest(ROI) were measured with two different b values(b=0s/mm2 and b=1000s/mm2) ADC maps were calculated and ROIs were manually placed over areas of tumor, edema, and normal brain tissue. Results: When ADC values were analyzed as a group, significant differences were found between tumor(1.72±0.78)×10-3(mm2/ｓ), edema(1.44±0.31)×10-3(mm2/ｓ), and normal brain tissues (0.93±0.59)×10-3(mm2/ｓ); but not between tumor and adjacent edema. ADC value of low grade (grade1~2) gliomas is higher than that of high grade(grade3~4) glioma. Conclusion: ADC values helped to distinguish tumor from normal tissue but could not be used to separate tumor and adjacent edema. Individually, ADC values overlapped considerably. The ADC value can reflect cellularity of gliomas, so DWI may predict the degree of malignancy of gliomas.
2007, Vol. 18 
