# Diffusion Tensor Imaging Biomarkers to Predict Neurological Outcomes in Brain Surgery: A Systematic Review

## TL;DR

This systematic review explores how diffusion tensor imaging (DTI) metrics can predict neurological outcomes after brain surgery, focusing on motor, language, and cognitive functions.

## Contribution

The study systematically reviews evidence linking quantitative DTI measures to postoperative neurological outcomes, identifying specific associations for motor, language, and cognitive functions.

## Key findings

- Reduced corticospinal tract integrity correlates with muscle weakness and poor recovery after surgery.
- Higher preoperative dorsal language pathway integrity is linked to milder aphasia and better recovery.
- Postoperative tract disruption and diffusivity changes predict persistent language deficits.

## Abstract

Diffusion tensor imaging (DTI) tractography is routinely employed in neurosurgical planning; however, the prognostic significance of quantitative DTI metrics for postoperative functional outcomes remains unclear. We conducted a PRISMA-informed systematic review of PubMed (January 2005–1 December 2025), supplemented by additional indexed sources, to synthesize the evidence on quantitative DTI measures associated with postoperative motor, language, and cognitive outcomes following intracranial surgery. Thirty-seven studies were included, primarily single-center studies, and predominantly focused on glioma surgery. Motor outcomes exhibited the most consistent associations, with reduced corticospinal tract integrity and adverse postoperative diffusion changes correlating with muscle weakness and poorer recovery. Recovery from supplementary motor area syndrome was associated with interhemispheric callosal connectivity, with greater disconnection predicting a prolonged symptom duration. Language outcomes demonstrated reproducible structure–function relationships: higher preoperative integrity of the dorsal language pathways was associated with milder postoperative aphasia and better recovery, whereas postoperative tract disruption and diffusivity changes predicted persistent naming and fluency deficits, and ventral pathway alterations were specifically linked to lexico-semantic impairment. In epilepsy surgery, language performance correlated with contralateral and distributed network diffusion changes, consistent with reorganization. Evidence for cognition and gait outcomes was limited and mainly involved the association, limbic, and callosal pathways. Overall, quantitative DTI provides clinically relevant markers of tract and network disruption and postoperative remodeling; however, methodological heterogeneity and limited external validation currently preclude universal prognostic thresholds.