Category: MRI

Posted on

Ventral Spinal Cord Displacement: A Guide to Differentiating Spinal Cord Herniation From Dorsal Arachnoid Web

Operative Neurosurgery 30:977–984, 2026

This article reviews imaging and operative distinctions between spinal arachnoid webs (SAW) and spinal cord herniation (SCH), using two detailed case illustrations with narrated 2-D operative videos. It highlights diagnostic imaging features, intraoperative findings, and tailored surgical techniques to optimize differentiation and management.

Focusing on technical nuance, the paper contrasts midline-sparing unilateral laminectomy and arachnoid lysis for SAW with bilateral laminectomy, cord mobilization, and ventral alloderm sling reconstruction for SCH, and emphasizes intraoperative ultrasound and neuromonitoring for safe reduction and decompression.

Problem: Spinal arachnoid web (SAW) and spinal cord herniation (SCH) can present similarly (myelopathy/radiculopathy) and both often look like focal anterior cord displacement on MRI, yet require very different operative strategies.

Definitions: SAW is abnormally thickened arachnoid tissue in the subarachnoid space that can tether/compress the cord and disrupt CSF flow (edema/syrinx), while SCH is cord displacement through an opening in the dura/arachnoid (often ventral).

Imaging workup: CT myelography is recommended to evaluate/confirm suspected findings because its resolution can outperform MRI for distinguishing these entities.

Key imaging clues: Visible ventral CSF between cord and ventral dura argues against herniation, while absence of ventral CSF supports SCH; cord twisting at the abnormal level is a more specific sign for SCH; the “scalpel sign” is commonly linked to SAW but can occur in both.

Limits of imaging: Arachnoid webs are below MRI/CT resolution, and diagnostic patterns are imperfect (reported SAWs can lack the scalpel sign or mimic SCH on CT myelogram).

SAW surgery: Definitive treatment is lysis/excision of the thickened arachnoid band, often via laminectomy with ultrasound localization; dentate ligament division can help inspect the ventral compartment to exclude ventral pathology.

SCH surgery: Management typically uses wider exposure (often bilateral laminectomy), spinal cord mobilization/rotation (sectioning dentate ligaments ± dorsal rootlets), reduction of the herniation, and placement/suturing of a ventral alloderm sling to span the dural defect, with close neuromonitoring and ultrasound confirmation.

Outcomes in cases: SAW case showed postoperative normalization of cord position and complete syrinx regression after web excision/lysis; SCH case showed complete reduction of herniation on postoperative MRI with substantial functional improvement (including near-resolution of bowel/bladder symptoms).

Posted on

A novel interpretable classification of lumbar spinal stenosis using a cascade deep learning approach and T2-weighted MRI

J Neurosurg Spine 44:847–857, 2026

This clinical article presents a fully automated, interpretable three-stage deep learning pipeline for detecting and grading lumbar spinal stenosis (LSS) using axial T2-weighted MRI. The framework integrates region classification, YOLO-based ROI detection, and CNN-based severity grading, validated on internal (640 patients, 17,440 slices) and external (515 patients, 8,000 slices) datasets with high accuracy and explainability via Grad-CAM.

The study details dataset curation, model architectures (ResNet-18, RegNetX-400MF, EfficientNet-B0, YOLOv5/8), training protocols, evaluation metrics, and clinical implementation pathways, highlighting strengths, limitations (single-rater labels, class imbalance, 2D slice analysis), and future directions toward volumetric and multi-expert validation.

Objective Standardize and automate lumbar spinal stenosis (LSS) identification, classification, and grading from axial T2-weighted lumbar MRI to reduce diagnostic variability.

Pipeline Three-stage cascade: (1) classify slices into sacral/lumbar/thoracic regions, (2) detect and crop anatomical ROIs, (3) grade LSS as binary or multiclass severity.

Datasets Internal training set: 640 patients with 17,440 retained axial T2 slices; external validation set: 8000 preprocessed, neurosurgeon-graded axial slices from an open-access dataset (515 patients).

Grading scheme Labels follow Schizas central canal stenosis grades A–D; a binary version groups A+B as nonstenotic and C+D as clinically significant stenosis.

Models Lightweight CNN backbones (ResNet-18, RegNetX-400MF, EfficientNet-B0) used for stages 1 and 3; YOLOv5/YOLOv8 used for ROI detection.

Validation approach Patient-level splits with 10-fold cross-validation to reduce overfitting and data leakage; an independent internal test set (62 patients, 1679 slices) reserved for final evaluation.

Performance Achieved 97.87% accuracy for binary LSS grading and 95.52% accuracy for multiclass grading, outperforming prior models in this setting.

Interpretability & clinical aim Grad-CAM heat maps highlight regions influencing predictions to support trust and potential workflow integration as an interpretable decision-support tool.

Posted on

The role of surveillance MRI scans in patients with sporadic cerebral cavernous malformations

J Neurosurg 144:1017–1023, 2026

This clinical study assesses the diagnostic value of routine versus symptom-driven MRI follow-up in patients with sporadic cerebral cavernous malformations (CCMs), analyzing radiographic changes at the first postdiagnosis scan in a prospective single-center cohort. Results show that new or worsening focal neurological deficit (FND) strongly predicts symptomatic hemorrhage, while routine surveillance rarely detects acute hemorrhage.

Imaging progression—including lesion growth, Zabramski classification changes, T1 hyperintensity, and edema—occurred across indications but had limited impact on management when patients were asymptomatic. The authors recommend symptom-driven MRI, reserving routine surveillance for select cases and early posthemorrhage confirmation.

Objective Evaluate whether routine surveillance MRI vs symptom-driven MRI better detects hemorrhage in patients with sporadic, brain-only cerebral cavernous malformations (CCMs), and what radiographic changes appear at first follow-up.

Cohort/Design Prospective single-center registry analysis of 236 sporadic brain-only CCM patients who had ≥1 follow-up MRI after diagnosis; MRI indications categorized as routine vs symptom-driven (e.g., new/worsening focal neurological deficit [FND], headache, seizure).

Hemorrhage yield Radiographic hemorrhage at first follow-up occurred in 19.1% (13/68) of symptom-driven MRIs vs 1.2% (2/168) of routine/non–CCM-related surveillance MRIs.

Routine progression In routine/non–CCM-related surveillance (n=168), 10.1% showed radiologic progression (growth ≥3 mm, more aggressive Zabramski type, or hemorrhage), but acute hemorrhage was only 1.2%; 88.2% of progression events occurred within 2 years.

Imaging correlates of SH Symptomatic hemorrhage (SH) was associated with lesion growth, moderate-to-severe T1-hyperintensity, and edema at follow-up; baseline lesion size and location did not predict hemorrhage.

Symptom predictors New or worsening FND predicted hemorrhage, while seizure or headache alone did not; in multivariate analysis, only new/worsening FND remained independently associated with hemorrhage (OR 13.73, p<0.001).

Clinical implication Follow-up MRI is most justified when there is new or worsening FND; routine surveillance in asymptomatic patients has limited diagnostic yield but may be reasonable in select situations.

Special cases MRI may still be considered for atypical, prolonged headaches distinct from baseline and not responsive to over-the-counter medication, or for changing/new seizure patterns based on clinical judgment.

Posted on

Prediction of Diffuse High-Grade Glioma Survival Outcomes Using Preoperative Whole-Brain Tractography–Based Resectability Metrics

Neurosurgery 98:836–847, 2026

This study presents novel whole-brain tractography (WBT)–derived resectability metrics—resectability index (RI) and unresectable tumor volume (UTV), plus modified versions mRI and mUTV—calculated from preoperative diffusion imaging to estimate how much of diffuse high-grade gliomas (HGG) can be safely resected. Metrics are derived by quantifying tumor overlap with critical white-matter tracts and deep structures, and compared with conventional postoperative measures.

Using retrospective data from 146 tumors (84 with WBT), mRI and mUTV strongly predicted biopsy versus resection and correlated with extent of resection, residual tumor, and overall survival. Accelerated failure time models incorporating mUTV/mRI provided accurate preoperative survival predictions, outperforming conventional metrics in postoperative models.

Problem: Extent of resection (EOR) predicts survival in diffuse high-grade glioma but is only measurable postoperatively, limiting preoperative decision-making.

Approach: Preoperative whole-brain tractography (WBT) was used to quantify tumor overlap with eloquent tracts and deep structures to estimate resectability before surgery.

Metrics: Unresectable tumor volume (UTV) = tumor overlap with eloquent tracts + deep structures; Resectability index (RI) = (preop tumor volume − UTV) / preop tumor volume.

Modified metrics: mUTV/mRI focused only on corticospinal tract and left arcuate fasciculus, and performed better than unmodified metrics in several analyses.

Surgical decision prediction: mRI (AUROC 0.953) and mUTV (AUROC 0.854) accurately predicted biopsy vs resection, with optimal cutoffs mRI 0.75 and mUTV 2.5 cm³.

Survival separation: Tumors with mRI > 0.65 vs ≤ 0.65 showed the largest median overall survival difference (not reached vs 82 days, P < .0001).

Best preop survival model: A log-logistic accelerated failure time (AFT) model using only preoperative covariates achieved validated C-index 0.788, with mUTV an independent predictor of overall survival (P = .008).

Overall conclusion: Preoperative WBT-based resectability metrics approximate postoperative EOR/residual tumor volume and can strongly predict survival outcomes after biopsy or resection.

Posted on

Quantitative MRI Tractography of White Matter Tracts After Tumor Craniotomy Surgery: Comparative Analysis Between Tubular Retractor and Open Craniotomy Surgery

Operative Neurosurgery 30:525–532, 2026

This study compares quantitative diffusion MRI tractography outcomes after deep-seated brain tumor resections using tubular retraction (TR) versus open craniotomy (OC) with spatula/cottonoid retraction. In a matched cohort of 20 patients, TR achieved comparable extent of resection with improved postoperative fractional and geodesic anisotropy metrics and a greater mean increase in Karnofsky Performance Score.

Methods include pre/postoperative 1.5T DTI, autosegmented tractography of ipsilateral tracts, and statistical comparison of FA, GA, diffusivity metrics, and tract volume. Results suggest TR reduces certain retraction-related white matter distortion without worsening diffusivity markers, supporting TR as a viable technique for deep subcortical lesions with potential functional benefit.

Goal Quantitatively compare cerebral retraction–related white matter tract changes after deep-seated tumor surgery using tubular retraction (TR) vs open craniotomy (OC) with spatula retraction via diffusion MRI tractography metrics.

Design Retrospective matched-pair analysis of 20 patients (10 TR vs 10 OC), matched by tumor size, depth, and age; all surgeries performed by a single surgeon.

Tractography process/metrics Pre- and postoperative DTI tractography (1.5T MRI) autosegmented ipsilateral supratentorial tracts; quantified FA, GA, MD, RD, AD, and tract volume across specified tracts (e.g., corticospinal, arcuate/SLF, ILF, IFOF, fornix, uncinate, optic radiations).

Extent of resection Resection was comparable between groups (TR 90.4% vs OC 94.8%, P = .395).

Functional outcome Change in Karnofsky Performance Score (KPS) favored TR (mean +11 points) vs OC (no change), P = .035.

Key quantitative findings Postoperative FA and GA differed significantly in favor of TR (FA 0.322 TR vs 0.029 OC, P = .011; GA increased in TR 0.441 vs decreased in OC 0.411, P = .012).

Other imaging metrics Postoperative tract volume was higher in TR than OC (14.9 cm³ vs 10.6 cm³, P = .036), while diffusivity metrics (MD, RD, AD) were broadly comparable between cohorts.

Conclusion TR offers a viable approach for deep-seated tumors with similar resection extent while mitigating some components of retraction injury as reflected by quantitative tractography changes and improved KPS.

Posted on

Lumbar Multifidus Intramuscular Fat Concentrations are Associated With Recovery Following Decompressive Surgery for Lumbar Spinal Stenosis

Spine 2026;51:25–33

This longitudinal cohort study investigates whether preoperative intramuscular fat (IMF) in lumbar paraspinal muscles predicts five-year recovery and surgical success after decompressive surgery for lumbar spinal stenosis causing intermittent neurogenic claudication. Using automated MRI segmentation and quantitative IMF thresholds, outcomes included global perceived effect, Zurich Claudication Questionnaire-based surgical success, pain VAS, and disability scores.

Key findings show lower preoperative multifidus IMF (but not erector spinae IMF) was associated with higher rates of perceived recovery, surgical success, and reduced long-term disability over five years. No consistent relationship was found between IMF and leg or back pain trajectories; results were adjusted for age, BMI, sex, smoking, reoperation, and surgical technique.

Lumbar multifidus intramuscular fat (IMF): Lower preoperative IMF in the lumbar multifidus muscle is associated with higher rates of perceived recovery and surgical success after decompression surgery for lumbar spinal stenosis (LSS) over a five-year period.

Erector spinae IMF: Preoperative IMF levels in the erector spinae muscle are not significantly associated with recovery or surgical success following LSS surgery.

Disability outcomes: Patients with nonsevere IMF in the right lumbar multifidus experience less postoperative disability for up to five years compared to those with severe IMF.

Pain outcomes: No significant association exists between preoperative paraspinal IMF (either muscle) and the clinical course of leg or back pain intensity after surgery.

IMF quantification method: Automated MRI-based quantification and categorization of IMF (<50% = nonsevere, ≥50% = severe) using computer vision models enables objective assessment of paraspinal muscle health.

Prognostic value: Assessing lumbar multifidus IMF preoperatively can improve prediction of which patients are at risk for poor recovery and help tailor individual interventions.

Study limitations: Missing data (up to 32% at five years), dichotomized IMF classification, and limited field-of-view for some muscles may affect precision; more detailed and larger studies are needed.

Clinical implication: Routine IMF assessment may enhance clinical decision-making and rehabilitation strategies for patients undergoing lumbar decompressive surgery.

Posted on

Multi-institutional recommendations on the use of 7T MRI in deep brain stimulation

J Neurosurg 143:1165–1175, 2025

This multi-institutional review presents consensus recommendations for integrating 7T ultrahigh-field MRI into deep brain stimulation (DBS) workflows, drawing on experience from over 1,000 procedures. It summarizes technical challenges—B1+ heterogeneity, susceptibility and gradient nonlinear distortions—and practical solutions for acquisition, distortion correction, and coregistration to ensure stereotactic accuracy.

The document details optimized sequences and target-specific imaging strategies (STN, GPi, thalamic nuclei, ANT, CM), advanced modalities (DTI/DiMANI, QSM, tractography), and multidisciplinary workflow considerations to improve patient-specific anatomical and connectivity-based DBS targeting and programming.

• 7T MRI Advantages: Ultrahigh-field 7T MRI provides superior spatial resolution, signal-to-noise ratio, and tissue contrast, enabling clearer visualization of deep brain structures critical for deep brain stimulation (DBS) targeting compared to 1.5T and 3T MRI.

• Improved DBS Targeting: 7T MRI enhances direct anatomical and connectivity-based targeting for DBS, supporting more precise, patient-specific electrode placement for Parkinson’s disease, essential tremor, and epilepsy.

• Key Technical Challenges: 7T MRI introduces unique challenges including B1+ transmit field inhomogeneity, increased image distortions (gradient nonlinearity and susceptibility), and chemical shift artifacts, all of which require specialized correction and protocol optimization.

• Distortion Correction and Coregistration: Accurate DBS planning with 7T MRI demands robust correction for gradient and susceptibility distortions, careful coregistration with stereotactic CT, and often manual or nonlinear registration adjustments for optimal anatomical alignment.

• Recommended Imaging Sequences: Specific 7T MRI sequences, such as T2-weighted, FGATIR, MP2RAGE, SWI, QSM, and advanced diffusion imaging (DTI/DiMANI), are recommended for visualizing common DBS targets (STN, GPi, thalamic nuclei), each offering distinct advantages for different structures.

• Connectivity and Tractography: Advanced diffusion MRI at 7T allows submillimetric tractography, enabling functional parcellation of DBS targets (e.g., STN, GPi, DRTT), which can improve patient outcomes by supporting symptom- and network-specific targeting.

• Clinical Impact: Implementation of 7T MRI in over 1000 DBS procedures across multiple centers has demonstrated that, with appropriate workflow and expertise, technical challenges can be managed and targeting accuracy and patient outcomes can be improved.

• Multidisciplinary Collaboration: Effective use of 7T MRI for DBS requires close collaboration between neurosurgeons, MR technicians, physicists, and neuroradiologists to optimize protocols and address the complexity of ultrahigh-field imaging

Posted on

Indirect cognitive mapping in glioma surgery in patients not eligible for awake craniotomy

Acta Neurochirurgica (2025) 167:289

This article presents a neurosurgical technique for indirectly mapping cognitive subcortical white matter pathways during glioma resection in patients who cannot undergo awake craniotomy. Using preoperative DTI and fMRI to create a 3D functional map, the team employs intraoperative monopolar subcortical motor stimulation as a live landmark to infer and protect nearby cognitive tracts like the arcuate fasciculus and IFOF.

Three illustrative cases demonstrate planning limits based on measured motor stimulation thresholds (approx. 1 mA ≈ 1 mm) and show safe resections with preserved cognitive and motor function. The report discusses indications, limitations versus awake mapping, importance of patient counselling about transient deficits, and integration of neuronavigation, tractography, and intraoperative motor mapping.

Posted on

Does the Presence of Preoperative Myelomalacia Impact Outcomes Following ACDF?

Spine 2025;50:1539–1546

This retrospective cohort study examines whether preoperative cervical myelomalacia on MRI influences patient-reported outcomes after anterior cervical discectomy and fusion (ACDF) in 518 adults. Results show similar modified JOA (mJOA) recovery between groups, with myelomalacia not independently predicting worse mJOA up to one year postoperatively.

Secondary findings reveal myelomalacia patients had lower baseline pain/disability and less frequent NDI MCID achievement, but multivariable analysis attributed those differences to baseline scores, smoking, and demographics rather than myelomalacia itself. Multilevel myelomalacia correlated with worse baseline mJOA but did not independently affect long-term improvement.

• Preoperative Myelomalacia: Presence of myelomalacia on MRI before anterior cervical discectomy and fusion (ACDF) in patients with mild-moderate myelopathy does not predict worse postoperative mJOA scores or overall patient-reported outcomes at any time point up to one year after surgery.

• Functional Outcomes: Both patients with and without preoperative myelomalacia achieve similar improvements in functional outcomes (mJOA), with no significant difference in the likelihood of reaching the minimum clinically important difference (MCID) for mJOA.

• Neck Disability Index (NDI): Patients with myelomalacia less commonly achieve MCID for NDI at one year, but this is attributable to less severe baseline symptoms and higher rates of current smoking, not the presence of myelomalacia itself.

• Multilevel Myelomalacia: Patients with two or more levels of myelomalacia have worse preoperative mJOA scores but show greater short-term improvement, resulting in similar one-year outcomes compared to single-level myelomalacia; preoperative severity, not the extent of myelomalacia, predicts improvement.

• Baseline Differences: Patients with myelomalacia tend to have lower baseline pain and disability, possibly due to earlier surgical intervention prompted by MRI findings rather than symptom severity.

• Other Patient-Reported Outcomes: Myelomalacia patients may have better physical component scores (SF-12 PCS) and lower neck pain (VAS neck) at one year, but these differences are small and likely reflect baseline characteristics rather than effects of myelomalacia.

• Prognostic Value: Myelomalacia seen on MRI should not be used as a binary prognostic indicator for surgical outcomes in mild-moderate myelopathy; clinical decision-making should consider baseline function and other patient factors.

• Research Implications: Further studies are needed to clarify the impact of myelomalacia severity, chronicity, and timing on outcomes, especially in patients with more severe myelopathy or more extensive cord signal changes

Posted on

Afferent and efferent fiber systems of the human amygdala: anatomical, pathophysiological, and clinical significance

J Neurosurg 143:1202–1216, 2025

This paper presents a comprehensive neuroanatomical and radiological analysis of the human amygdala, detailing its nuclei, major afferent and efferent fiber systems, and spatial relationships using white matter fiber dissection and diffusion tensor tractography. The authors synthesize structural descriptions with functional roles in emotion, memory, olfaction, and seizure propagation, emphasizing clinical relevance for neuroclinicians.

The study maps key pathways—the ansa peduncularis, ventral and dorsal amygdalofugal routes, stria terminalis, medial forebrain bundle, olfactory striae, and stria medullaris thalami—correlating anatomy with neurosurgical applications such as deep brain stimulation and lesion resection. Anatomical findings are supported by illustrative dissections, tractography, and a clinical cavernoma case demonstrating surgical implications.

Posted on

Volume of parasagittal dura is associated with blood markers of systemic inflammation

Acta Neurochirurgica (2025) 167:255

Higher blood C-reactive protein (CRP), a marker of systemic inflammation, is significantly correlated with lower volume of the parasagittal dura (PSD). This suggests PSD volume may serve as a potential imaging marker of systemic inflammation. No significant association was found between PSD volume and subjective sleep quality.

• The study investigated the relationship between the volume of the parasagittal dura (PSD) and blood markers of systemic inflammation, mainly C-reactive protein (CRP).

• 76 patients underwent intrathecal contrast-enhanced MRI to measure PSD volume and CSF clearance, alongside blood tests for inflammatory markers.

• Higher CRP levels were significantly correlated with lower PSD volume, suggesting an association between systemic inflammation and PSD morphology.

• This inverse relationship was significant even after adjusting for confounders such as age, sex, and diagnosis.

• Other blood markers (hemoglobin, erythrocyte volume fraction) showed initial correlations with PSD volume, but these were not significant after accounting for confounders.

• Impaired sleep quality was associated with higher CRP but not with PSD volume.

• The findings suggest PSD volume may serve as a potential imaging marker of systemic inflammation, but causality remains unclear.

• Further research is needed to clarify mechanisms and clinical implications of the PSD-inflammation link.

Posted on

The neuronal reserve in glioma surgery: functional reorganization of the motor network examined by navigated transcranial magnetic stimulation and diffusion tensor imaging tractography

J Neurosurg 143:793–804, 2025

This study demonstrates that glioma-induced reorganization of the motor cortex, measured by navigated transcranial magnetic stimulation and diffusion tensor imaging, is linked to functional recovery. Individual neuronal reserve—reflected in motor area resizing, excitability, and tract integrity—may explain differences in disease progression and surgical outcomes.

• Glioma surgery outcomes vary due to individual differences in motor network compensation and adaptation.

• This study used navigated transcranial magnetic stimulation (nTMS) and diffusion tensor imaging (DTI) tractography to measure motor cortex reorganization in glioma patients.

• Motor area relocation, resizing, and changes in excitability were observed in both affected and unaffected hemispheres, indicating bilateral reorganization.

• Greater preoperative motor area size and excitability were associated with better postoperative motor function and recovery.

• Reduced integrity of the corticospinal tract correlated with motor impairment and limited reorganization capacity.

• Functional recovery was linked to increased motor area size, excitability, and area relocation, supporting the concept of an individual neuronal reserve.

• Reorganization patterns were independent of tumor grade, highlighting the importance of personalized risk stratification and treatment planning.

• The study recommends using nTMS data for tailored preoperative risk assessment and patient counseling in glioma surgery.

Posted on

Stratifying trigeminal neuralgia and characterizing an abnormal property of brain functional organization: a resting-state fMRI and machine learning study

J Neurosurg 143:74–82, 2025

Resting-state fMRI and machine learning revealed distinct brain connectivity and activity differences between classical and idiopathic trigeminal neuralgia (TN) and controls. These findings identify potential neuroimaging biomarkers for TN subtypes, aiding diagnosis and understanding of TN pathophysiology.

Primary trigeminal neuralgia (TN) includes classical (CTN) and idiopathic (ITN) types, sharing clinical features but differing in neurovascular compression (NVC) presence.

• Resting-state fMRI and machine learning were used to analyze brain functional connectivity and spontaneous activity in 50 TN patients (28 CTN, 22 ITN) and 43 controls.

• TN patients showed increased connectivity between the medial prefrontal cortex (mPFC) and left planum temporale, and decreased connectivity between mPFC and left superior frontal gyrus.

• CTN patients had further reduced connectivity between the left insula and left occipital pole, and decreased activity in the right temporal pole compared to ITN.

• TN patients exhibited heightened neural activity in frontal regions compared to controls.

• Machine learning (support vector machine) distinguished TN patients from controls with moderate accuracy (AUC 0.80).

• Findings suggest potential fMRI biomarkers for TN subtypes, aiding understanding of pathophysiology and improving diagnosis.

• Study limitations include small sample size and exclusion of bilateral/secondary TN, warranting further research.

Posted on

Deep learning–based segmentation of the trigeminal nerve and surrounding vasculature in trigeminal neuralgia

J Neurosurg 143:83–91, 2025

This study developed and validated deep learning U-Net models for automated 3D segmentation of the trigeminal nerve and surrounding vasculature in MRI of trigeminal neuralgia patients, enabling objective quantification of neurovascular conflict features and potentially improving preoperative evaluation and treatment planning.

• Deep learning (U-Net) models were used to segment the trigeminal nerve and surrounding vasculature in patients with trigeminal neuralgia using high-resolution CISS MRI.

• Six U-Net variants with different encoder backbones were tested; SE-ResNet50 performed best overall (Dice score = 0.775, IoU = 0.681).

• The models quantified anatomical features such as the surface area of neurovascular contact and distance to the contact point, showing no significant difference from manual segmentations.

• The best model achieved 100% sensitivity and specificity in detecting neurovascular conflict in the testing set.

• Automated 3D segmentation allows for objective, quantitative evaluation, improving on subjective and time-intensive manual methods.

• Limitations include inability to distinguish vessel type (artery vs. vein) and data from a single institution; future work should address these.

• The method may help standardize neurovascular conflict assessment and improve treatment selection for trigeminal neuralgia.

Posted on

Navigated Transcranial Magnetic Stimulation and Diffusion Tensor Imaging Tractography in Insular Glioma Surgery

Operative Neurosurgery 29:62–70, 2025

Navigated transcranial magnetic stimulation (nTMS) and DTI tractography enable precise preoperative risk stratification in insular glioma surgery, identifying patients at higher risk for postoperative motor deficits by assessing resting motor threshold, tumor proximity to the corticospinal tract, and fiber tract integrity, thus improving surgical planning and outcomes.

• Navigated transcranial magnetic stimulation (nTMS) and nTMS-based DTI tractography were evaluated for preoperative risk stratification in insular glioma surgery.

• Thirty-two patients with insular gliomas underwent preoperative nTMS mapping and DTI tractography to assess motor cortex and corticospinal tract (CST) involvement.

• Higher resting motor threshold (RMT) ratios, CST-tumor distances <3 mm, and decreased peritumoral fractional anisotropy (pFA) ratios were significantly associated with new postoperative motor deficits.

• All patients with new postoperative motor deficits had a CST-tumor distance below 3 mm; lower pFA ratios also correlated with deficits.

• One-third of patients with intraoperative ischemic events developed permanent motor deficits, suggesting additional mediating factors such as CST integrity and cortical excitability.

• A risk model combining RMT ratio, CST distance <3 mm, and low pFA ratio predicted an 82% risk for new motor deficits.

• Preoperative nTMS-based DTI tractography may improve individual risk stratification and surgical planning for insular glioma patients.

Posted on

Prediction of Shunt Malfunction Using Automated Ventricular Volume Analysis and Radiomics

Neurosurgery 97:242–249, 2025

Automated ventricular volume analysis using convolutional neural networks and radiomics, combined with clinical features, improves accuracy in diagnosing hydrocephalus and shunt malfunction from CT scans, outperforming traditional 2D methods and enabling earlier, more reliable detection without requiring prior imaging.

• Automated ventricular volume analysis and radiomics were used to predict shunt malfunction and diagnose hydrocephalus from CT scans.

• Traditional 2D measurements are less sensitive than 3D volumetric analysis for detecting ventricular changes.

• A convolutional neural network (CNN) segmented ventricles, and volumes were compared to age- and sex-matched normative data.

• Volumetric analysis alone achieved up to 73% accuracy (AUC 0.772) for detecting pathology; combining radiomics and clinical data improved accuracy significantly.

• The best model (support vector machine) using selected radiomics features and clinical data reached an AUC of 0.92–0.93 and F1-score of 0.848.

• Automated segmentation is time-efficient, reduces observer variability, and may improve early and accurate diagnosis.

• Limitations include single-institution data, scanner variability, and need for external validation.

• Future work should expand datasets and improve model generalizability, including to MRI and other manufacturers.

Posted on

Advances of MR imaging in glioma: what the neurosurgeon needs to know

Acta Neurochirurgica (2025) 167:174

Advanced MRI techniques—including perfusion, diffusion, spectroscopy, and functional imaging—are critical in glioma diagnosis, surgical planning, and treatment monitoring. These modalities improve tumor characterization, guide safer resections, and help distinguish tumor progression from treatment effects, supporting precision neurosurgical oncology and personalized care.

• High-grade gliomas are aggressive brain tumors with poor prognosis, requiring advanced imaging for diagnosis and management.

• MRI is central throughout the patient journey, from initial detection and differential diagnosis to surgical planning, treatment response, and surveillance.

• Advanced MRI techniques—perfusion, diffusion, spectroscopy, fMRI, and DTI—improve tumor characterization, surgical planning, and assessment of infiltration and eloquent cortex involvement.

• Perfusion MRI (DSC, DCE, ASL) and DWI help distinguish high-grade gliomas from mimics and guide biopsy or surgery.

• MR spectroscopy provides metabolic information, aiding in differentiating gliomas from metastases and guiding surgical margins.

• Postoperative MRI is crucial for assessing residual tumor, complications, and radiotherapy planning.

• MRI during treatment surveillance helps differentiate true progression from pseudoprogression or radiation necrosis.

• Future advances include higher field strengths, molecular imaging, and AI integration for precision neuro-oncology.

Posted on

Decoding Glioblastoma Heterogeneity: Neuroimaging Meets Machine Learning

Neurosurgery 96:1181–1192, 2025

This review highlights how advanced neuroimaging and machine learning, especially radiomics and deep learning models, are transforming the noninvasive diagnosis, molecular characterization, and prognosis prediction in IDH-wildtype glioblastoma, offering improved patient stratification and personalized treatment strategies while emphasizing the need for further clinical integration.

• Neuroimaging and machine learning have greatly improved diagnosis, classification, and prognosis of IDH-wildtype glioblastoma, a highly heterogeneous and aggressive brain tumor.

• Advanced MRI techniques, including diffusion tensor imaging (DTI) and radiomics, provide noninvasive insights into tumor infiltration, metabolic profiles, and microstructural changes.

• Machine learning algorithms, especially CNNs, enhance glioblastoma characterization, enabling accurate prediction of genetic mutations, IDH status, tumor subtypes, and survival outcomes.

• Radiomics extracts quantitative features from neuroimages, serving as potential biomarkers for tumor classification, prognosis, and guiding treatment strategies.

• Integration of radiomics and machine learning helps differentiate pseudoprogression from true tumor progression and predicts patterns of tumor invasion and recurrence.

• Imaging biomarkers and machine learning models are promising but remain complementary to molecular diagnostics and are not yet standard in clinical practice.

• Ongoing research aims to refine models, integrate emerging imaging techniques, and better link imaging features to underlying molecular processes for personalized therapy.

• The synergy of neuroimaging and AI is expected to enable noninvasive, precision management and better outcomes for glioblastoma patients.

Posted on

Efficacy and safety of intraoperative MRI in glioma surgery: a systematic review and meta-analysis of prospective randomized controlled trials

J Neurosurg 142:1319–1330, 2025

This meta-analysis of randomized controlled trials found that intraoperative MRI significantly increases gross-total resection rates and progression-free survival in glioma surgery, without increasing neurological deficits or most complications, though it prolongs surgery and may raise infection risk. iMRI is effective and generally safe for maximizing tumor removal.

• Intraoperative MRI (iMRI) significantly increases the rate of gross-total resection (GTR) in glioma surgery compared to conventional neuronavigation.

• Greater extent of resection (EOR) with iMRI leads to improved progression-free survival (PFS), especially in high-grade gliomas.

• No significant difference in overall survival (OS) was observed between iMRI and conventional surgery groups.

• Rates of postoperative neurological deterioration, motor, and language decline are similar between iMRI and control groups.

• iMRI does not increase the risk of postoperative intracranial hemorrhage, but may be associated with higher rates of wound infections in some studies.

• Use of iMRI prolongs surgery time by an average of 42 minutes.

• Only three randomized controlled trials with a total of 384 patients met inclusion criteria for this meta-analysis.

• Combined use of iMRI and 5-ALA may further enhance EOR, but more randomized studies are needed for definitive conclusions.

Posted on

Comparative analysis of intraoperative MRI and early postoperative MRI findings in glioma surgery patients

J Neurosurg 142:1289–1297, 2025

The study compares intraoperative MRI (iMRI) and early postoperative MRI (epMRI) in glioma surgery, highlighting iMRI’s accuracy in extent of resection (EOR) and reduced surgically induced contrast enhancement (SICE). iMRI better detects postoperative neurological deficits, with fewer diffusion-weighted imaging abnormalities than epMRI.

• Objective: The study compares intraoperative MRI (iMRI) and early postoperative MRI (epMRI) findings in glioma surgery to assess the extent of resection (EOR) and postoperative neurological deficits.

• Methods: A retrospective analysis of 43 glioma patients who underwent surgery with iMRI, with no additional resection after iMRI, was conducted.

• Results: Discrepancies in EOR were found in 11.1% of nonenhanced and 4.0% of enhanced lesions. iMRI showed more accurate EOR and less surgically induced contrast enhancement (SICE) compared to epMRI.

• Findings: The positive rate of SICE was higher on epMRI (67.9%) than iMRI (25.0%). The positive rate of diffusion-weighted imaging (DWI) abnormality was also higher on epMRI (89.2%) compared to iMRI (73%).

• Clinical Outcomes: Two patients developed new neurological deficits postoperatively, both showing DWI abnormality on both iMRI and epMRI. No deficits were observed in the late-developing group.

• Conclusion: iMRI is more reliable for assessing accurate EOR and detecting postoperative neurological deficits than epMRI, despite higher late-developing DWI abnormalities on epMRI.

• Significance: The study underscores the importance of iMRI in optimizing glioma surgery outcomes and minimizing misinterpretation of residual tumors.

Proudly powered by WordPress