Diffusion Magnetic Resonance Imaging and Fiber Tractography in Neurosurgery

Diffusion magnetic resonance imaging (dMRI) exploits the directional movement of water molecules within tissue to reveal the architecture of white matter in the brain. By modelling the diffusion signal, fibre tractography reconstructs three-dimensional pathways of axonal bundles, enabling the non-invasive visualisation of critical tracts. In neurosurgery, this approach informs preoperative planning and intraoperative guidance by delineating the relationship between pathological lesions and eloquent pathways. Key clinical applications include mapping the corticospinal tract to preserve motor function, tracing language pathways to avoid aphasia, and identifying cranial nerve complexes at the skull base. Advances in acquisition schemes, post-processing algorithms and quality assurance have improved spatial resolution and anatomical fidelity, yet challenges remain in regions of complex fibre crossings, peritumoural oedema and susceptibility artefacts. Recent developments in high angular resolution diffusion imaging, multi-shell protocols and machine-learning-based segmentation are fostering more robust, reproducible tract reconstructions. Radiomic analysis of tractography metrics is emerging as a means to quantify white matter integrity and link structural features to functional outcomes. By integrating quantitative tract metrics with neuronavigation, neurosurgeons can refine operative strategies, minimise iatrogenic injury and optimise postoperative recovery. The global significance of these innovations spans neurosurgical oncology, epilepsy surgery and functional neurosurgery, underscoring the transformative potential of dMRI-guided fibre mapping.

Research from Nature Portfolio

Analyses of radiomic parameters derived from corticospinal tractography in patients with high-grade glioma have demonstrated that mean and median fractional anisotropy values correlate significantly with preoperative motor deficits. Manual reconstructions using MRTrix3 and automated segmentation with TractSeg were compared, revealing that conventional streamline count lacks functional specificity, whereas selected radiomic features—such as energy and surface-volume ratio—provide quantitative markers of tract integrity. These findings suggest that radiomic metrics may serve as objective, non-invasive biomarkers to assess corticospinal involvement and guide surgical decision-making in brain tumour resections.

Diffusion Magnetic Resonance Imaging and Fiber Tractography in Neurosurgery publication trend

The graph below shows the total number of articles in diffusion magnetic resonance imaging and fiber tractography in neurosurgery across all publications each year (not limited to Nature Index journals).

Technical terms

Diffusion magnetic resonance imaging (dMRI): Imaging technique that measures the anisotropic diffusion of water molecules to infer tissue microstructure.

Diffusion tensor imaging (DTI): Simplest diffusion model that represents water diffusion as an ellipsoid, yielding metrics such as fractional anisotropy.

Fibre tractography: Computational method that reconstructs three-dimensional white matter pathways by following principal diffusion directions.

Constrained spherical deconvolution (CSD): Advanced algorithm that resolves multiple fibre orientations within a voxel, improving tractography in regions of crossing fibres.

Fractional anisotropy (FA): Scalar measure of diffusion directionality ranging from zero (isotropic) to one (highly anisotropic), indicative of fibre integrity.

Track density imaging (TDI): Post-processing technique that generates super-resolution maps by counting the density of tractography streamlines.

Radiomic analysis: Quantitative extraction of a large number of features from medical images to characterise tissue heterogeneity and structure.

Direct electrical stimulation (DES): Intraoperative technique that applies small electrical currents to brain tissue to identify functional sites and validate tractography accuracy.

References

1. Radiomic white matter parameters of functional integrity of the corticospinal tract in high-grade glioma. Scientific Reports (2024).
2. Diffusion MRI of the facial-vestibulocochlear nerve complex: a prospective clinical validation study. European Radiology (2023).
3. Comparative validation of automated presurgical tractography based on constrained spherical deconvolution and diffusion tensor imaging with direct electrical stimulation. Human Brain Mapping (2024).
4. Directionally encoded color track density imaging in brain tumor patients: A potential application to neuro-oncology surgical planning. NeuroImage Clinical (2023).