Diffusion tensor MR imaging of glioblastoma multiforme

Objective To evaluate the value of fractional anisotropy (FA) and apparent diffusion coefficients (ADC) measurement in differentiating tumor, edema, and normal white matter regions and whether they are helpful in differentiating tumor invasion. Methods Fourteen patients with glioblastomas multiforme underwent conventional MR, contrast-enhanced structural and diffusion tensor MR imaging before therapy. Tumor, edema, and normal-appearing white matter regions were determined on contrast-enhanced T1-weighted structural images, T2-weighted structural images. FA and ADC were measured in each tissue type in the ADC maps and FA maps. Differences in these values among the tissue types were assessed with a standard analysis of variance. Results ADC was highest in the necrotic tumor core (2.07±0.631)×10-3 mm2/s, followed by edema region (1.39±0.164)×10-3 mm2/s, enhancing tumor core (1.13±0.187)×10-3 mm2/s, enhancing tumor margin (1.04±0.254)×10-3 mm2/s, the normal-appearing white matter adjacent to the tumors (0.779±0.088)×10-3 mm2/s and contralateral normal white matter (0.748±0.082)×10-3 mm2/s. FA was highest in contralateral normal white matter (0.538±0.084)×10-3 mm2/s, and lowest in the necrotic core (0.09±0.028)×10-3 mm2/s. Significant differences of ADC were found in enhancing tumor margins compared with necrotic tumor core, edema region, normal-appearing white matter adjacent to the tumors and contralateral normal white matter, while there was no differences between the normal-appearing white matter adjacent to the tumors and contralateral normal white matter. Significant differences of FA were found in enhancing tumor margins compared with necrotic tumor core; the normal-appearing white matter adjacent to the tumors and contralateral normal white matter, and significant differences of FA were also found in the normal-appearing white matter adjacent to the tumors and contralateral normal white matter, while there was no differences between enhancing tumor margins and edematous brain. Conclusion ADC values can be used to differentiate normal white matter, edema region, and enhancing tumor margins. FA values add no benefit to tissue differentiation. FA value is helpful in detecting tumor invasion.