Benefits of MR Diffusion Tensor Imaging and Fiber Tractography Over Conventional MRI in Preoperative Evaluation of Pediatric Brain Tumors

Abstract
Background: Diffusion tensor imaging (DTI) is a nonin-vasive magnetic resonance imaging (MRI) modality which accurately shows the location and orientation of subcortical white matter (WM) tracts. The surgeon benefits from DTI as it depicts the relationship of the intra-axial tumor to local WM tracts in multiple planes.
Aim of Study: The purpose of this study is to evaluate the role of MR diffusion tensor imaging and fiber tractography and its benefits over conventional MRI in accurate preoperative localization of important eloquent areas in pediatric brain tissue and their relation to the brain tumor. The aim of the study is to help the surgeon in planning his surgical corridor which causes the least damage and minimizes the postoperative neurological deficits.
Patients and Methods: A total of fifty patients with brain tumors were included in this study using pre-operative contrast-enhanced magnetic resonance imaging and DTI fiber tractog-raphy for preoperative localization of important white matter tracts. Diffusion tensor imaging, by improving the recognition and characterization of white matter tracts, offers a glimpse into the brain microstructure at a scale that is not easily accessible with other modalities.
Results: The extent of white matter pathway involvement was clearly identified in all patients by using color-coded DT imaging maps and MR Tractography.
The study revealed that the most common tract involve-ment pattern detected was pattern (displacement). It was seen in 36 cases representing 72% of all cases. Pattern I (not affected) was detected in 6 cases representing 12%. Pattern III (edematous) was detected in 11 cases representing 22%. Pattern IV (partially disrupted) was detected in 13 cases representing 26%. Pattern V (destroyed) was detected in 3 cases representing 6%. Combined pattern of affection has been detected in most of the cases.
Conclusion: The effect of cerebral neoplasms on white matter pathways is not precisely understood with the aid of standard diagnostic modalities. Diffusion-tensor imaging allowed for the preoperative identification of white matter pathways involved by tumor but the preoperative planning should be optimally complemented by various intraoperative procedures in order to insure a good neurological outcome of the surgery and valid functional prognosis.