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Fig 2. Axial FLAIR (top row) and color-coded FA maps (bottom row) demonstrating the proximity of the tumor to corticospinal fibers. The color-coded FA maps hinder visualization of the tumor, which implies preserved FA and function of involved white matter tracts. Thus, comparing FLAIR images to the color-coded FA maps is critical in fully appreciating the proximity of tumor borders to motor fibers. Based on anatomic relationships and DTI data, the white matter arising from lower-extremity M1 cortex wraps around the anterior-medial edge of the mass, whereas white matter descending (blue) from upper- and lower-extremity M1 cortex (arrows) is in proximity to the anterior border of the mass. White matter arising from corresponding postcentral gyrus wraps around the anterior-lateral border of the mass. In light of the results of the intraoperative mapping, it is possible that postcentral gyrus white matter contains motor fibers. T, tumor. White matter orientation color encoding: blue, ascending-descending fiber orientation; red, right-left fiber orientation; green, anteroposterior fiber orientation.
