OBJECTIVETo evaluate the quantitative relationship between white matter tract (WMT) variation resulting from cerebral tumors and shifting of the fractional anisotropy (FA) index in magnetic resonance (MR) diffusion tensor imaging (DTI).

METHODSFour female and 8 male patients aged from 21 to 62 years with brain malignancies (2 malignant lymphomas, 2 low-grade astrocytomas, and 8 high-grade cerebral gliomas) underwent conventional contrast-enhanced MR and DTI examinations before operation. Routine T(2)-weighted image, fractional anisotropic (FA) map, color-coded directional map, three-dimensional white matter tractography (WMT), and the FA index of bilateral internal capsule were obtained in every patient.

RESULTSFiber tractography derived from DTI was consistent with known white matter fiber anatomy. The DTI patterns in WMT altered by the tumor were categorized on the basis of FA1/FA2 ratio as follows: pattern 1, FA1/FA2> or =75% with normal or only slightly decreased FA; pattern 2, 50%< or =FA1/FA2<75% with WMT displacement; pattern 3, 25%< or =FA1/FA2/50% with WMT involvement; pattern 4, FA1/FA2<25% with WMT destruction.

CONCLUSIONSDTI allows for visualization of WMT and benefits surgical planning for patients with intrinsic brain tumor. There is a positive relationship between the bilateral FA ratio (FA1/FA2) variation and WMT alterations resulting from the tumor.