The ability of diffusion tensor MRI to detect the preferential diffusion of water in cerebral white matter tracts enables neurosurgeons to noninvasively visualize the relationship of lesions to functional neural pathways. Although viewed as a research tool in its infancy, diffusion tractography has evolved into a neurosurgical tool with applications in glioma surgery that are enhanced by evolutions in crossing fiber visualization, edema correction, and automated tract identification. In this paper the current literature supporting the use of tractography in brain tumor surgery is summarized, highlighting important clinical studies on the application of diffusion tensor imaging (DTI) for preoperative planning of glioma resection, and risk assessment to analyze postoperative outcomes. The key methods of tractography in current practice and crucial white matter fiber bundles are summarized. After a review of the physical basis of DTI and post-DTI tractography, the authors discuss the methodologies with which to adapt DT image processing for surgical planning, as well as the potential of connectomic imaging to facilitate a network approach to oncofunctional optimization in glioma surgery.
Keywords: AF = arcuate fasciculus; CSD = constrained spherical deconvolution; CST = corticospinal tract; DSI = diffusion spectrum imaging; DTI; DTI = diffusion tensor imaging; FA = fractional anisotropy; FACT = fiber assignment by continuous tracking; GQI = generalized Q-sampling imaging; GTR = gross-total resection; HARDI = high angular resolution diffusion imaging; HDFT = high-definition fiber tractography; HGG = high-grade glioma; IFOF = inferior fronto-occipital fasciculus; KPS = Karnofsky Performance Scale; LGG = low-grade glioma; ODF = orientation distribution function; QA = quantitative anisotropy; QBI = Q-ball imaging; ROI = region of interest; SDF = spin distribution function; SLF = superior longitudinal fasciculus; UKF = unscented Kalman filter; connectomics; diffusion tensor imaging; fMRI = functional MRI; fiber tractography; glioma surgery.
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