BACKGROUND:Cerebral cavernomas are vascular malformations that can cause neurological problems such as hemorrhage and seizures. MRI is the preferred imaging modality, but hemosiderin deposits in cavernomas often lead to signal loss artifacts, complicating treatment planning. MRI-guided laser interstitial thermal therapy (MRIg-LITT) is an innovative, minimally invasive technique that offers a new approach to treating these lesions, but confirming ablation on MRI may be challenging due to these artifacts. METHODS:We evaluated six patients (4 females, 2 males; median age 29 years old) with symptomatic cerebral cavernomas treated with MRIg-LITT. The procedure involved immediate post-treatment imaging to assess lesion reduction and edema. A volumetric T1-weighted subtraction technique was employed after ablation to enhance visualization of contrast enhancement. RESULTS:Thermal ablation was assessed by diffusion hyperintensity and gadolinium-enhanced peripheral rings, despite susceptibility artifacts. T1-weighted volumetric subtraction sequences effectively minimized artifacts and improved visualization of the lesions. No hemorrhagic complications occurred, and expected post-LITT edema was managed with corticosteroid therapy. CONCLUSION:T1-weighted volumetric subtraction sequences reduce magnetic susceptibility artifacts and improve visualization of the post-ablation enhancing rim in MRIg-LITT for cerebral cavernomas. Their clinical impact on treatment assessment remains to be determined.
BACKGROUND:Endovascular therapy (EVT) improves outcomes in selected patients with large-core acute ischemic stroke (AIS), but concerns remain regarding hemorrhagic transformation (HT). We evaluated the risk of intracranial hemorrhage (ICH) and its subtypes following EVT versus medical management (MM). METHODS:PubMed, Embase, and Scopus were searched through February 2026. Randomized clinical trials (RCTs) enrolling adults with large-core AIS (ASPECTS ≤5 or ischemic core volume ≥70 mL) were included. Risk ratios (RRs) were pooled using random-effects models. RESULTS:Six RCTs (n = 1887) and five post hoc publications from same trials were included. EVT increased the risk of any ICH compared with MM (RR=1.80, 95% CI: 1.40-2.30; P < 0.001). Risks of HI2 (RR=2.23), PH1 (RR=2.42), and subarachnoid hemorrhage (RR=2.21) were significantly higher, whereas PH2 and intraventricular hemorrhage were not. Symptomatic ICH occurred more frequently after EVT (5.0% vs. 3.1%; P = 0.02), but this finding was not robust to sensitivity analyses. In ASPECTS 0-2 neither any ICH nor symptomatic ICH was significantly increased; however, limited sample size and influential studies precluded excluding clinically meaningful risk. CONCLUSION:EVT increased radiographic hemorrhage, primarily HI2 and PH1, without a significant increase in PH2. The modest increase in symptomatic ICH was sensitive to the contributing trial and definition.
BACKGROUND:Middle meningeal artery embolization (MMAE) has emerged as an effective treatment for chronic subdural hematoma (CSDH). Although generally considered safe, rare but potentially devastating visual complications have been reported, most often attributed to embolic migration through angiographically occult anastomoses between the middle meningeal artery (MMA) and the orbital circulation. CASE DESCRIPTION:A 75-year-old man with recurrent left-sided CSDH underwent MMAE using 12.5% n‑butyl cyanoacrylate (NBCA). Preprocedural angiography revealed a rare vascular anatomy in which the ophthalmic artery originated exclusively from the MMA, with complete absence of internal carotid artery-derived ophthalmic flow. The microcatheter was positioned in a wedged configuration within the MMA during embolization. Immediately after NBCA injection, the patient developed a unilateral superior visual field defect. Postprocedural findings were consistent with embolic diversion into the orbital circulation via angiographically occult meningo-orbital microanastomoses. CONCLUSION:This case highlights a rare but clinically important high-risk anatomical and hemodynamic scenario during MMAE. Absence of internal carotid artery-derived ophthalmic flow, together with the use of low-concentration NBCA and local hemodynamic alterations associated with microcatheter wedging, may increase the risk of unintended embolization into occult orbital pathways. Careful preprocedural evaluation of ophthalmic artery origin and individualized embolization strategies are essential, particularly when low-viscosity liquid embolic agents such as low-concentration NBCA are considered.
INTRODUCTION:Cortical laminar necrosis (CLN) is a well-described neuropathological entity typically involving the cerebral cortex and associated with hypoxia, metabolic derangements, and ischemia. Reports of CLN-like imaging patterns within subcortical structures are exceedingly rare. METHODS:Case report. CASE:An 89-year-old woman presented with acute aphasia and right-sided weakness due to a left middle cerebral artery (MCA) occlusion, successfully treated with mechanical thrombectomy. Her clinical course was complicated by metastatic lung adenocarcinoma, pulmonary embolism on anticoagulation, and respiratory failure. Follow-up computed tomography (CT) demonstrated hyperdensity within the left caudate and putamen, initially concerning for hemorrhagic transformation. Subsequent magnetic resonance imaging (MRI), performed approximately three weeks after stroke onset, revealed curvilinear T1 and fluid-attenuated inversion recovery (FLAIR) hyperintensity within the basal ganglia without corresponding susceptibility artifact, findings more consistent with laminar necrosis in an atypical subcortical location. CONCLUSION:While CLN is classically described in the cerebral cortex, this case demonstrates imaging features consistent with laminar necrosis in the basal ganglia. Recognition of this atypical presentation may help avoid misinterpretation as hemorrhagic transformation and expands the radiographic spectrum of laminar necrosis.
INTRODUCTION:Endovascular thrombectomy (EVT) is the standard of care for large vessel occlusion stroke, but the optimal first-line strategy remains debated. Thrombus imaging features may help guide device selection, yet their impact on neurointerventionists' decision-making is unclear. METHODS:We conducted an international anonymous survey distributed through JENI and ESMINT networks (January-April 2025). The questionnaire collected demographic data, imaging availability, and responses to 12 case vignettes illustrating thrombus characteristics. Physicians selected their preferred first-line EVT strategy among six options. Subgroup analyses were performed according to physician's procedural volume. RESULTS:A total of 161 stroke physicians from 35 countries responded (median age 40 years; 58% senior attendings). Both CT and MRI were available in 83% of institutions, but CT was more frequently used for screening. Across 1911 responses, combined stent-retriever plus aspiration (44.6%) and contact aspiration (39.2%) were most often selected. Respondents favored the combined strategy (>70%) for long thrombi, and contact aspiration (>66%) for short thrombi. In bifurcated occlusions, the combined technique was preferred by 47.1% of the respondents. Physicians' annual procedural volume was not significantly associated with the choice of first-line EVT strategy. Over half of respondents considered current imaging insufficient to guide EVT choice, and 88% expressed willingness to use artificial intelligence-based decision support tools. CONCLUSIONS:First-line EVT practices remain heterogeneous worldwide, with thrombus length showing a consistent influence on device selection Interest in AI-based tools underscores the need for translational research integrating advanced imaging biomarkers to optimize EVT decision-making.
BACKGROUND AND PURPOSE:Red blood cell (RBC) content, fibrin/platelet (F/P) composition, and clot length are critical determinants of mechanical thrombectomy (MT) outcomes in acute ischemic stroke. However, clinical evidence remains fragmented due to methodological heterogeneity. We systematically evaluated the association between these histologic features, structural heterogeneity, and angiographic/procedural outcomes. MATERIALS AND METHODS:Following PRISMA guidelines (PROSPERO: CRD20251110596), we searched PubMed and MEDLINE for studies published between January 2013 and July 2024. Inclusion criteria comprised adult studies analyzing histology-derived clot composition or length in relation to MT outcomes. Primary outcomes were successful reperfusion (TICI ≥2b) and first-pass effect (FPE). Quantitative pooling was performed for non-overlapping datasets with low-to-moderate risk of bias using random-effects models. RESULTS:Forty-eight studies (∼7000 patients) were included. Qualitative synthesis revealed that RBC-rich clots are consistently associated with higher rates of successful reperfusion, FPE, fewer passes, and shorter procedure times. Quantitatively, cases achieving successful reperfusion had significantly higher mean RBC content (MD: 11.70%; 95% CI: 4.92%-18.48%). Conversely, F/P-rich and longer clots were linked to lower reperfusion rates and increased distal embolization. F/P-rich clots achieving TICI ≥2b had significantly lower mean content than those failing (MD: -9.02%; 95% CI: -16.72% to -1.33%). Additionally, structural heterogeneity was identified as an independent predictor of reduced FPE. CONCLUSIONS:Clot composition, heterogeneity, and length are significantly associated with mechanical thrombectomy outcomes, although causal relationships cannot be established given the predominantly observational nature of the included studies. Translating these biological insights into clinical practice requires standardized histological definitions and the development of real-time intraprocedural characterization to facilitate adaptive, clot-informed treatment strategies.
BACKGROUND AND PURPOSE:Chronic subdural hematoma (cSDH) affects approximately 20 per 100,000 individuals annually, with surgical recurrence rates of 10-20%. Middle meningeal artery embolization (MMAE) has emerged as a promising minimally invasive treatment, but the optimal timing remains unclear. We evaluated the association between MMAE timing and radiological and functional outcomes in cSDH. METHODS:We conducted a retrospective multicenter international cohort study across 33 centres, including patients who underwent MMAE for cSDH between January 2018 and December 2024. Patients were stratified by timing from diagnosis: Q1 (≤1 day), Q2 (2 days), Q3 (3-6 days), and Q4 (>6 days). The primary composite endpoint required radiological success (hematoma thickness <5 mm at 1-3 months), absence of emergency surgical evacuation, and either functional improvement or good functional outcome (modified Rankin Scale 0-2). Propensity score matching compared Q1 and Q4. RESULTS:Of 1,781 patients screened, 908 met inclusion criteria. Mean age was 73.7 ± 12.2 years, and 70.9% were female. Early embolization (Q1) achieved the primary composite endpoint more frequently than delayed embolization (Q4), with concordant improvements in radiological and functional components and no difference in rescue surgery. Good functional outcome was achieved in 76.0% of Q1 patients versus 63.8% in Q4 (absolute difference, 12.2%; P=.003; number needed to treat approximately 8). Hospital length of stay was 21.0 days shorter in Q1 versus Q4 (P<.001), partly attributable to the timing definition. In 174 propensity score-matched pairs, early embolization was associated with higher odds of achieving the primary endpoint (odds ratio, 6.41; 95% confidence interval, 3.29-12.48; P<.001), with pronounced benefit among patients receiving antithrombotic therapy (odds ratio, 8.06; 95% confidence interval, 3.65-17.80). CONCLUSIONS:Early MMAE (≤1 day from diagnosis) was overall associated with better outcomes compared with delayed intervention, particularly among patients receiving antithrombotic therapy. Prospective confirmation is warranted.
OBJECTIVE:To demonstrate the feasibility of threshold-based three-dimensional CT (T3D-CT) for visualizing attenuation patterns in the endolymphatic sac. METHODS:High-resolution temporal bone CT datasets from healthy adults and patients with benign paroxysmal positional vertigo or Ménière's disease were retrospectively analyzed using predefined attenuation thresholds (140-400 HU, >600 HU). Image evaluation was qualitative. RESULTS:Reproducible attenuation patterns were visualized in vestibular structures. Regions corresponding to vestibular organs showed attenuation values of approximately 140-180 HU, whereas higher values were observed in osseous structures. CONCLUSION:T3D-CT enables attenuation-based visualization of vestibular structures. Findings are compatible with calcium-containing materials but are not specific.
Objectives The DTI analysis along the perivascular space (DTI-ALPS) index is widely used to assess water diffusion alterations in Alzheimer's disease (AD), yet its biological interpretation remains debated. We investigated DTI-ALPS associations with regional amyloid-β (Aβ) deposition, glucose metabolism, and cognitive function in Chinese patients with AD and mild cognitive impairment (MCI), offering finer-grained imaging evidence for its pathophysiological interpretation. Methods 34 AD dementia (ADD) patients, 40 MCI patients, and 52 cognitively normal controls (NCs) underwent MRI, 18F-florbetapir (18F-AV45) (standardized uptake value ratio, SUVR; centiloid values, CL), and 18F-FDG (SUVR) imaging. MRI volumetry and PET quantification used Neurophet SCALE PET software. Mediation analysis tested ALPS effects between pathology/metabolism and cognition. Results ALPS differed significantly across groups (ADD:1.152±0.113; MCI:1.247±0.122; NC:1.302±0.121; p<0.001). Adjusted for age, sex, education, and APOE4, ALPS correlated positively with MMSE (r=0.324, p<0.001) and MoCA (r=0.311, p<0.001) and negatively with CL (r=-0.415, p<0.001). The ALPS index showed negative correlations with 18F-AV45 PET SUVR in nearly all brain regions, with the strongest negative associations observed in the posterior cingulate (r=-0.459), paracentral (r=-0.445), superior frontal (r=-0.441), and inferior temporal (r=-0.433) regions. For 18F-FDG PET SUVR, the ALPS index demonstrated bidirectional correlations: positive in regions including the inferior parietal (r=0.396), isthmus of cingulate (r=0.376), and precuneus (r=0.369), but negative in the paracentral (r=-0.418), precentral (r=-0.406), and cerebellar white matter (r=-0.374) (all p<0.001). Mediation analysis revealed that the ALPS index mediates the relationships between glucose metabolism/Aβ accumulation and both abstract thinking and memory. Parietal/cingulate isthmus/precuneus FDG metabolism showed significant ALPS-mediated indirect effects across cognitive domains (p<0.05). Conclusions The ALPS index correlates with Aβ deposition and exhibits region-specific metabolic associations in AD, mediating amyloid-metabolism-cognition pathways and predicting cognitive decline. These findings provide a region-wise correlation map of perivascular water diffusion alterations in AD, informing future research directions, though underlying mechanisms require validation.
OBJECTIVE:To evaluate determinants of first-pass reperfusion and to develop an explainable machine learning framework for intra-procedural decision support in patients undergoing endovascular thrombectomy. MATERIALS AND METHODS:In this retrospective single-center study, 204 consecutive patients with acute ischemic stroke treated with endovascular thrombectomy between June 2021 and June 2025 were included. FPE was defined as achieving mTICI 2c-3 reperfusion after a single device pass. A total of 19 clinical, imaging, and procedural variables were analyzed. Six ML models were developed within a structured preprocessing-feature selection-classification pipeline. Model performance was assessed using repeated nested cross-validation. Discrimination, calibration, and clinical utility were evaluated, and model interpretability was explored using SHAP and partial dependence analyses. The models were designed to reflect real-world intra-procedural conditions. RESULTS:FPE was achieved in 94/204 patients (46.08%). Favorable collateral status, lower systolic blood pressure, absence of hypertension, lower NIHSS, and higher ASPECTS were significantly associated with FPE (all p < 0.05). Among ML models, Random Forest demonstrated the best overall classification profile, with the highest accuracy, specificity, F1 score, and Youden index, whereas AdaBoost achieved the highest ROC-AUC and PR-AUC values. Explainability analyses consistently identified collateral circulation, systolic blood pressure, hypertension, and age as the most influential predictors. A non-linear relationship between systolic blood pressure and FPE was observed. CONCLUSION:Explainable machine learning provided an internally validated framework for estimating the likelihood of first-pass reperfusion using routinely available variables. However, given the limited number of events and absence of external validation, these findings should be considered preliminary and require confirmation in larger independent multicenter cohorts before clinical implementation.
Background and purpose Brain arteriovenous malformations (bAVMs) carry a variable risk of hemorrhage that persists until complete obliteration is achieved. Gamma-knife radiosurgery (GKRS) is an established treatment, yet delayed treatment effects necessitate reliable follow-up imaging. Digital subtraction angiography (DSA) remains the gold standard, but non-invasive alternatives are desirable. Arterial spin labeling (ASL) MRI, which quantifies cerebral blood flow, has shown promise in detecting residual bAVM perfusion. This study aims to assess the diagnostic performance and prognostic value of ASL compared to conventional MRI sequences and DSA for detecting residual bAVM perfusion in adult patients following GKRS. Materials and methods We conducted a retrospective, multicenter study of adult patients with bAVMs treated with GKRS between 2015 and 2024 at two tertiary centers. Patients who underwent at least one follow-up brain MRI including ASL perfusion sequences were eligible. Imaging results were compared to conventional MRI sequences and DSA, used as the reference standard. Diagnostic accuracy metrics were calculated. Quantitative ASL perfusion ratios were analyzed to assess their prognostic value for nidus obliteration over time. Results A total of 99 patients (mean age 49.4 ± 16.3 years, 51% female) underwent 348 follow-up MRI examinations, including 97 with ASL. ASL demonstrated higher sensitivity (88.9%) and specificity (88.6%) than conventional MRI sequences. Quantitative ASL ratios reliably distinguished residual shunting and predicted time to obliteration. Serial reductions in ASL ratios were associated with progressive bAVM involution (p < 0.01). Conclusion ASL outperforms conventional MRI in detecting residual bAVM perfusion after GKRS and provides prognostic information on obliteration. Due to its ability to both identify incomplete obliteration and to predict complete nidal involution ASL may complement standard imaging to optimize DSA timing and reduce invasive procedures.
INTRODUCTION:This study aimed to investigate the relationship between cerebral collateral status and MRI-derived oxygen metabolism in acute ischemic stroke (AIS) patients undergoing mechanical thrombectomy METHODS: The HIBISCUS-STROKE cohort (CoHort of Patients to Identify Biological an Imaging markerS of CardiovascUlar Outcomes in Stroke; NCT: 03149705), a single-center observational study, enrolled AIS patients for thrombectomy following MRI triage due to anterior circulation large vessel occlusion treated with mechanical thrombectomy. Dynamic-Susceptibility Contrast perfusion (DSC perfusion), Diffusion-Weighted Imaging (DWI) and penumbral volume (Tmax ≥ 6 secs) were post-processed to generate oxygen extraction fraction (OEF) and cerebral metabolic rate of oxygen (CMRO2) maps within DWI and penumbral anomalies, compared to contralateral areas. Collateral status, assessed via pretreatment digital subtraction angiography, was categorized as poor (0-2) or good (3-4) based on ASITN/SIR collateral grading system score from Higashida. RESULTS:A total of 137 patients were included (mean age 71 years; 56.2% male). The median National Institutes of Health Stroke Scale (NIHSS) score was 15 (interquartile range [IQR]: 8.0-18.0), and the median time from symptom onset to admission was 96.0 min ([IQR]: 78.0-137.0). 78 patients (57.00%) had good collaterals, while 59 patients (43.10%) had poor collaterals. Good collaterals were independently associated with a smaller baseline infarct core volume and less decrease in CMRO2 within the ischemic penumbra (respectively OR = 0.94; 95% CI: [0.92; 0.96]; (P < 0.0001), and (OR = 1.30; 95% CI: [1.06; 1.82]; P = 0.001). CONCLUSION:Good collateral circulation was independently associated with less severe impairment of cerebral metabolic rate of CMRO2 in the penumbra.
Background and purpose: Because gadolinium-based contrast agents (GBCAs) are almost systematically used in emergency MRI for acute isolated headache, with potential safety and environmental concerns, we aimed to assess their contribution and evaluate the value of non-contrast sequences. Materials and methods: We conducted a retrospective single-center study including 435 outpatients who underwent emergency brain MRI for acute isolated headache between January 2021 and June 2023. Diagnostic yield was calculated, and a subgroup analysis of 50 examinations (including all confirmed cerebral venous thromboses [CVT]) was performed to assess the sensitivity of pre-contrast sequences. Results: Headache-related findings were identified in 10% (45/435) of patients, with sinusitis being the most frequent. CVT was rare, diagnosed in only 3 patients (0.7%). In this cohort, all confirmed CVT cases showed abnormalities on pre-contrast sequences. No diagnosis appeared to rely exclusively on GBCA for initial detection, although contrast-enhanced imaging may still have contributed to diagnostic confirmation or characterization in selected cases. In the 50-case subgroup, a strategy restricted to examinations with suspicious pre-contrast findings would have markedly reduced GBCA administrations while preserving detection of all confirmed CVT cases. Conclusions: In emergency MRI for acute isolated headache, headache-related findings were infrequent and CVT was rare. Our findings support further evaluation of a non-contrast-first MRI strategy in this setting.
