Biologically Reliable White Matter Fiber Tractography: Issues and Solutions

Abstract

Evaluation of: Farquharson S, Tournier JD, Calamante F et al. White matter fiber tractography: why we need to move beyond DTI. J. Neurosurg. 118, 1367–1377 (2013). This study reports on the limitations of diffusion tensor imaging (DTI) to generate fiber orientations and white matter fiber pathways, and the practical consequences for neurosurgical assessment. DTI and constrained spherical deconvolution, a higher-order method for generating fiber orientations that addresses the issue of crossing fibers, were systematically applied to the diffusion-weighted data from 45 healthy controls and ten patients undergoing presurgical imaging assessment. A comparison of the two methods indicated that DTI substantially underestimates the extent of the corticospinal tracts leading to the sensorimotor cortices. In the clinical cases, where tractography is used to assess the risk of neurological deficit from surgery, constrained spherical deconvolution and DTI demonstrated very different apparent safety margins of resection. It is argued that DTI, the most widely used clinical tractography method, provides systematically unreliable and clinically misleading information. The higher-order tractography model, constrained spherical deconvolution, provides a reasonable solution to these problems within a clinically feasible timeframe.

Keywords:

• diffusion tensor imaging
• fiber tracking
• neurosurgery
• white matter tractography

Financial & competing interests disclosure

LM Carey is supported by an Australian Research Council Future Fellowship (no. FT0992299). S Palmer and LM Carey are grateful to the Victorian Government‘s Operational Infrastructure Support Program for support. The authors have no other relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript apart from those disclosed.

No writing assistance was utilized in the production of this manuscript.

Additional information

Funding

LM Carey is supported by an Australian Research Council Future Fellowship (no. FT0992299). S Palmer and LM Carey are grateful to the Victorian Government‘s Operational Infrastructure Support Program for support. The authors have no other relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript apart from those disclosed.