Diffusion Tensor MR Imaging of Cerebral Gliomas: Evaluating Fractional Anisotropy Characteristics

A, T2-weighted (b=0) MR image shows a grade II glioma. B, Postgadolinium axial T1-weighted image shows whole-tumor contrast enhancement. C, FA map shows tumor FA with a homogeneous blue hue. The darker blue (cool color tone) represents low FA and the red and yellow (warm color tones) correspond to high FA. Region-of-interest selection for FA measurement is based on visually inspecting the hue. Maximum FA, minimum FA, FA range, and maximum SD are 0.145, 0.061, 0.084, and 0.0411, respectively. Arrows point to arteries.

A, T2-weighted MR image shows a grade III glioma. B, Postgadolinium axial T1-weighted image does not show obvious tumor contrast enhancement. C, FA map shows that the tumor has a warmer color tone (light green [arrow]) compared with that in Fig 2. Maximum FA, minimum FA, FA range, and maximum SD are 0.170, 0.0794, 0.0906, and 0.0507, respectively. Each value of the measurements for this grade III tumor is correspondingly larger than that for the grade II tumor shown in Fig 2.

A, FLAIR image shows a grade IV glioma. B, Postgadolinium axial T1-weighted image shows inhomogeneous tumor contrast enhancement. C, FA map shows that the tumor has a warmer color tone (dark green and scattered yellow and red) compared with that in Figs 2 and 3. Maximum FA, minimum FA, FA range, and maximum SD are 0.346, 0.0834, 0.2626, and 0.11, respectively. Each value of the measurements for this grade IV tumor is correspondingly larger than that for the grade III tumor shown in Fig 3.

Graphs show the comparisons of FA measurements among tumor grades and components. Boxes represent the range between the first and third quartiles. Median values are shown as horizontal lines within each box. Asterisks indicate the mean value in each group. Vertical lines extending from the top and bottom of each box terminate at the maximum and minimum values, respectively. A, Mean FA for grade II tumors is lower than that for grade IV tumors, nonenhanced components, or enhanced components, respectively, with a significant or approaching significant difference. B, The maximum FA for grade II tumors is significantly lower than that for grade III, IV, or components. C, The FA range for grade II tumors is significantly lower than that for grade III, IV, or enhanced components. D, The maximum SD for grade II tumors is significantly lower than that for grade III, IV, or components. For all measurements, there was no significant difference among any pair of grade III, IV, or components.