Tumor effects on cerebral white matter as characterized by diffusion tensor tractography.

BACKGROUND: Diffusion tensor MRI fiber tractography (DTT) is the first non-invasive in vivo technique for delineating specific white matter (WM) tracts. In cerebral neoplasm, DTT can be used to illustrate the relationship of the tumor with respect to adjacent WM trajectories.

METHODS: Fiber tractography was used in this study to assess tumor-induced changes in WM trajectories in three cases of cerebral neoplasm: glioblastoma multiforme, meningioma, and anaplastic astrocytoma.

RESULTS: Three patterns of WM alteration were identified: 1) disruption, 2) displacement, and 3) infiltration. Tumor disruption of WM tracts was observed in glioblastoma multiforme, which terminated fibers crossing the corpus callosum. In meningioma, DTT illustrated bulk displacement of the corticospinal tract in the affected hemisphere as well as preservation of the deviated axons. In anaplastic astrocytoma, fiber tracking demonstrated disruption of WM tracts at the tumor origin as well as intact axons through areas of tumor infiltration.

CONCLUSIONS: Fiber tracking results correlated with the clinical and histopathological features of the tumor. Larger case series will be required to determine if fiber tracking can add accuracy to existing imaging methods for grading tumors.