Resting-state functional MRI has been increasingly implemented in imaging protocols for the study of functional connectivity in glioma patients as a sequence able to capture the activity of brain networks and to investigate their properties without requiring the patients’ cooperation. The present review aims at describing the most recent results obtained through the analysis of resting-state fMRI data in different contexts of interest for brain gliomas: the identification and localization of functional networks, the characterization of altered functional connectivity, and the evaluation of functional plasticity in relation to the resection of the glioma. An analysis of the literature showed that significant and promising results could be achieved through this technique in all the aspects under investigation. Nevertheless, there is room for improvement, especially in terms of stability and generalizability of the outcomes. Further research should be conducted on homogeneous samples of glioma patients and at fixed time points to reduce the considerable variability in the results obtained across and within studies. Future works should also aim at establishing robust metrics for the assessment of the disruption of functional connectivity and its recovery at the single-subject level.

Tractography based on multishell diffusion-weighted magnetic resonance imaging (DWI) can be used to estimate the course of myelinated white matter tracts and nerves, yielding valuable information regarding normal anatomy and variability. DWI is sensitive to the local tissue microstructure, so tractography can be used to estimate tissue properties within nerve tracts at a resolution of millimeters. This study aimed to test the applicability of the method using a disease with a well-established pattern of myelinated nerve involvement. Eight patients with LHON and 13 age-matched healthy controls underwent tractography of the anterior optic pathway. Diffusion parameters were compared between groups, and for the patient group correlated with clinical/ophthalmological parameters. Tractography established the course of the anterior optic pathway in both patients and controls. Localized changes in fractional anisotropy were observed, and related to estimates of different tissue compartments within the nerve and tract. The proportion of different compartments correlated with markers of disease severity. The method described allows both anatomical localization and tissue characterization in vivo, permitting both visualization of variation at the individual level and statistical inference at the group level. It provides a valuable adjunct to ex vivo anatomical and histological study of normal variation and disease processes.

Compared to conventional morphological MR imaging, diffusion tractography may improve the visualization of the anterior optic pathway (AOP), thus enhancing the understanding of its anatomical relationship with surrounding sellar/parasellar tumors (SPTs). We aimed to develop a diffusion tractography pipeline for automatic and reliable reconstruction of the AOP and to investigate its microstructural alterations in SPT patients. A multishell diffusion protocol (b-values = 0,300,1000,2000 s/mm²; 64 maximum gradient directions; 2-mm isotropic voxel) on a 3T scanner, followed by a fully automated pipeline developed in-house to perform the probabilistic tractography, based on multishell-multitissue constrained spherical deconvolution modeling of the signal, was performed. It was first tested retrospectively in 10 healthy controls, then prospectively applied in 25 additional healthy controls and 35 SPTs patients. Microstructural parameters were compared between patients and controls using an along-tract approach. The study included 70 subjects: 35 healthy controls (18 females, mean age 50.7 ± 14.3 years) and 35 patients with SPTs displacing the optic chiasm (18 females; mean age 53.7 ± 16.4 years). The AOP reconstruction was successfully performed in all normal controls and patients. A correct correspondence with surgical inspection was identified in 84.7 % of patients who underwent surgery. Patients had significantly lower mean diffusivity (MD) values at the level of the chiasm (p < 0.01), that correlated with supero-inferior chiasmatic displacement (R = -0.49, p = 0.01). A novel, fully automated diffusion tractography pipeline for the AOP was developed and validated in patients with sellar/parasellar tumors. Reduced MD values at the chiasm level may indicate compression or gliosis in case of displacement.

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.

Diffusion tensor imaging (DTI) tractography is routinely employed in neurosurgical planning; however, the prognostic significance of quantitative DTI metrics for postoperative functional outcomes remains ambiguous. We conducted a PRISMA-informed systematic review of PubMed (January 2005–December 1, 2025), supplemented by additional indexed sources, to synthesize evidence on quantitative DTI measures associated with postoperative motor, language, and cognitive outcomes following intracranial surgery. Thirty-seven studies were included, primarily single-center 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 weakness and poorer recovery. Recovery from supplementary motor area syndrome was associated with interhemispheric callosal connectivity, with greater disconnection predicting prolonged symptom duration. Language outcomes demonstrated reproducible structure–function relationships: higher preoperative integrity of 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; 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 association, limbic, and callosal pathways. Overall, quantitative DTI provides clinically relevant markers of tract and network disruption and postoperative remodeling, but methodological heterogeneity and limited external validation currently preclude universal prognostic thresholds.

The Functionnectome framework enables the projection of task-related fMRI signals onto the underlying white matter pathways, using anatomical priors derived from structural connectivity. However, the existing "standardized" priors are based on averaged tractograms from healthy controls and cannot accurately capture the altered anatomy found in patients with brain lesions. This study extends the Functionnectome framework by generating individualized anatomical priors from subject-specific diffusion MRI tractography, allowing for improved integration of functional and structural data in patients with brain tumors. Twenty-six patients with gliomas (9 females; mean age 43 ± 17 years) underwent 3 T MRI, including a multishell diffusion protocol and task-based fMRI targeting motor and/or language functions. Whole-brain tractography was reconstructed using three methods (TensorDet, PFT, and iFOD2) and converted into voxelwise individualized priors. Functionnectome maps were estimated using both standardized and individualized priors, and Z-statistic activation maps were obtained via GLM analysis. Similarity metrics and atlas-based consistency were used to compare standardized and individualized Functionnectomes. Functionnectomes derived from probabilistic tractography showed moderate correlations with standardized Functionnectomes (average Pearson's r ≈ 0.5), highlighting the influence of individual structural variability while maintaining comparable activation patterns. The PFT-based Functionnectome exhibited superior anatomical plausibility, with consistent overlap with expected motor white matter tracts and identification of relevant bundles in up to 100% of cases, compared to 50-60% with standardized priors. The individualized Functionnectome enhances the anatomical validity and subject specificity of structure-function mapping, advancing precision neuroimaging for clinical and neurosurgical applications.