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Enlarged perivascular spaces (EPVS) are common in older adults, but their neuropathologic correlates are unclear mainly because most work to date has relied on visual rating scales and/or clinical cohorts. The present study first developed a deep-learning model for automatic segmentation, localization and quantification of EPVS in ex vivo brain MRI, and then used this model to investigate the neuropathologic, clinical and cognitive correlates of EPVS in 817 community-based older adults that underwent autopsy. The new method exhibited high sensitivity in detecting EPVS as small as 3 mm 3 , good segmentation accuracy and consistency. Most EPVS were located in the frontal lobe, but the highest density was observed in the basal ganglia. EPVS in the cerebrum and specifically in the frontal lobe were associated with infarcts independent of other neuropathologies, while temporal and occipital EPVS were associated with cerebral amyloid angiopathy. EPVS in most brain lobes were also associated with diabetes mellitus independently of neuropathologies, while basal ganglia EPVS were independently associated with hypertension, supporting the notion of independent pathways from diabetes and hypertension to EPVS. Finally, EPVS were associated with lower cognitive performance independently of neuropathologies and clinical variables, suggesting that EPVS represent additional abnormalities contributing to lower cognition., Competing Interests: The authors report no competing interests., (© The Author(s) 2024. Published by Oxford University Press on behalf of the Guarantors of Brain.)

Meningiomas are the most common primary intracranial tumors and can be associated with significant morbidity and mortality. Radiologists, neurosurgeons, neuro-oncologists, and radiation oncologists rely on brain MRI for diagnosis, treatment planning, and longitudinal treatment monitoring. However, automated, objective, and quantitative tools for non-invasive assessment of meningiomas on multi-sequence MR images are not available. Here we present the BraTS Pre-operative Meningioma Dataset, as the largest multi-institutional expert annotated multilabel meningioma multi-sequence MR image dataset to date. This dataset includes 1,141 multi-sequence MR images from six sites, each with four structural MRI sequences (T2-, T2/FLAIR-, pre-contrast T1-, and post-contrast T1-weighted) accompanied by expert manually refined segmentations of three distinct meningioma sub-compartments: enhancing tumor, non-enhancing tumor, and surrounding non-enhancing T2/FLAIR hyperintensity. Basic demographic data are provided including age at time of initial imaging, sex, and CNS WHO grade. The goal of releasing this dataset is to facilitate the development of automated computational methods for meningioma segmentation and expedite their incorporation into clinical practice, ultimately targeting improvement in the care of meningioma patients., (© 2024. The Author(s).)

Competing Interests: The author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Purpose of Review: Tumor-like brain lesions are rare and commonly suggest a neoplastic etiology. Failure to rapidly identify non-neoplastic causes can lead to increased morbidity and mortality. In this review, we describe 10 patients who presented with atypical, non-neoplastic tumor-like brain lesions in which brain biopsy was essential for a correct diagnosis and treatment., Recent Findings: There has been increasing recognition of autoimmune conditions affecting the nervous system, and many of those diseases can cause tumor-like brain lesions. Currently available reports of non-neoplastic tumor-like brain lesions are scarce. Most case series focus on tumefactive demyelinating lesions, and a comprehensive review including other neuroimmunological conditions such as CNS vasculitis, neurosarcoidosis, histiocytic and infectious etiologies is lacking., Summary: We review the literature on tumor-like brain lesions intending to increase the awareness and differential diagnosis of non-neoplastic brain tumor mimics. We advocate for earlier brain biopsies, which, in our case series, significantly changed diagnosis, management, and outcomes., Competing Interests: G.S. Perez reports no disclosures relevant to the manuscript; L. Singer reports no disclosures relevant to the manuscript; T. Cao reports no disclosures relevant to the manuscript; P. Jamshidi reports no disclosures relevant to the manuscript; K. Dixit reports no disclosures relevant to the manuscript; M. Kontzialis reports no disclosures relevant to the manuscript; R. Castellani reports no disclosures relevant to the manuscript; P. Pytel reports no disclosures relevant to the manuscript; N. Anadani reports no disclosures relevant to the manuscript; C. Bevan has participated in an ad board for Genentech; E. Grebenciucova reports no disclosures relevant to the manuscript; R. Balabanov received honoraria from Biogen, Sanofi, Alexion, and Teva Pharmaceutical and research support from the National Multiple Sclerosis Society, National Institute of Health, Nextcure, and Biogen; B. Cohen reports no disclosures relevant to the manuscript. E. Graham received consulting and advisory board fees from Novartis, Atara Biotherapeutics, Tavistock Life Sciences, Horizon Therapeutics, Roche Genentech. She receives research support from F. Hoffman-La Roche Ltd. She received compensation for question writing from ACP MKSAP. Full disclosure form information provided by the authors is available with the full text of this article at Neurology.org/cp., (© 2023 American Academy of Neurology.)

Introduction: Gruber's ligament (GL), a surgical landmark, extends from the lateral upper clivus to the petrous apex (PA), forming the superior boundary of Dorello's canal (DC). It overlies the interdural segment of the abducens nerve (CN VI). High-resolution 3D skull base MRI (SB-MRI) demonstrates anatomic details visible to the surgeon, but not well seen on traditional cross-sectional imaging. The aim of this study was to demonstrate visualization of the GL and its relationship to CN VI utilizing contrast enhanced high-resolution SB-MRI., Methods: Two neuroradiologists retrospectively reviewed in consensus the SB-MRIs of 27 skull base sides, among 14 patients. GL detection rate, confidence of detection, and GL length were recorded. When GL was successfully identified, the position of the interdural segment of CN VI within DC was recorded., Results: GL was readily identified in 16 skull base sides (59%), identified with some difficulty in 2 skull base sides (7%), and failed to be identified in 9 skull base sides (33%). The mean GL length was 7.1 mm (4.5-9.3 mm). Among the 18 cases where GL was successfully identified, CN VI was readily identified in all cases (100%), coursing the lateral third of DC in 72% of sides, and middle third in the remaining 28% of sides., Conclusion: GL can be identified in approximately two-thirds of cases utilizing 3D high resolution SB-MRI. CN VI passes most commonly along the lateral third of DC. This is the first report demonstrating visualization of GL and its relation to CN VI, on imaging., (© 2022. The Author(s), under exclusive licence to Springer-Verlag France SAS, part of Springer Nature.)

Competing Interests: Declaration of Conflicting Interests: The author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Background: Mechanical thrombectomy (MT) for anterior circulation stroke has been proven to be highly effective. In comparison, MT for basilar artery occlusion (BAO) continues to lack definitive evidence of efficacy. The main MT modalities are stent retriever (SR) and direct aspiration (DA). Several studies have been published comparing the 2 approaches., Objective: We sought to directly compare and synthesize safety and efficacy outcomes with SR versus DA for acute BAO., Methods: A systematic review and meta-analysis was conducted according to the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines., Results: Overall, 8 studies comprising 693 patients with BAO were included (SR: 457; DA: 236). The SR group was associated with statistically significant lower odds of modified Thrombolysis in Cerebral Infarction (mTICI) 2b/3 (odds ratio [OR]: 0.54; 95% confidence interval [CI]: 0.31-0.94) and mTICI3 (OR: 0.47; 95% CI: 0.23-0.95) compared with DA. Favorable outcome rates were similar between the 2 groups (OR: 0.83; 95% CI: 0.60-1.16). The rates of symptomatic intracerebral hemorrhage (OR: 3.57; 95% CI: 0.75-16.95), subarachnoid hemorrhage (SAH) (OR: 4.71; 95% CI: 0.82-26.90), and vessel perforation (OR: 2.64; 95% CI: 0.43-16.33) were higher in the SR group, but statistical significance was not reached. The rates of 90-day mortality were similar between the 2 groups (OR: 1.07; 95% CI: 0.67-1.70). Procedure duration was significantly shorter when DA was used compared with SR (weighted mean difference: 26.10 minutes; 95% CI: 13.28-38.92)., Conclusions: SR is associated with statistically significant lower odds of mTICI 2b/3 and mTICI 3 recanalization rates compared with DA. SR appears to be associated with a higher complication rate, but significance was not reached., (Copyright © 2021 Elsevier Inc. All rights reserved.)

Τhe accuracy of template-based neuroimaging investigations depends on the template's image quality and representativeness of the individuals under study. Yet a thorough, quantitative investigation of how available standardized and study-specific T1-weighted templates perform in studies on older adults has not been conducted. The purpose of this work was to construct a high-quality standardized T1-weighted template specifically designed for the older adult brain, and systematically compare the new template to several other standardized and study-specific templates in terms of image quality, performance in spatial normalization of older adult data and detection of small inter-group morphometric differences, and representativeness of the older adult brain. The new template was constructed with state-of-the-art spatial normalization of high-quality data from 222 older adults. It was shown that the new template (a) exhibited high image sharpness, (b) provided higher inter-subject spatial normalization accuracy and (c) allowed detection of smaller inter-group morphometric differences compared to other standardized templates, (d) had similar performance to that of study-specific templates constructed with the same methodology, and (e) was highly representative of the older adult brain., (© 2020 The Authors. Human Brain Mapping published by Wiley Periodicals LLC.)

Background: The trochlear nerve (the fourth cranial nerve) is the only cranial nerve that arises from the dorsal aspect of the midbrain. The nerve has a lengthy course making it highly susceptible to injury. It is also the smallest cranial nerve and is often difficult to identify on neuroimaging., Evidence Acquisition: High-resolution 3-dimensional skull base MRI allows for submillimeter isotropic acquisition and is optimal for cranial nerve evaluation. In this text, the detailed anatomy of the fourth cranial nerve applicable to imaging will be reviewed., Results: Detailed anatomic knowledge of each segment of the trochlear nerve is necessary in patients with trochlear nerve palsy. A systematic approach to identification and assessment of each trochlear nerve segment is essential. Pathologic cases are provided for each segment., Conclusions: A segmental approach to high-resolution 3-dimensional MRI for the study of the trochlear nerve is suggested., Competing Interests: The authors report no conflicts of interest., (Copyright © 2020 by North American Neuro-Ophthalmology Society.)

Background: Pial arterioles can provide a variable degree of collateral flow to ischemic vascular territories during acute ischemic stroke. This study sought to identify predictive factors of the degree of pial collateral recruitment in acute ischemic stroke., Methods: Clinical information and arteriograms from 62 consecutive patients with stroke due to either middle cerebral artery (MCA) M1 segment or internal carotid artery (ICA) terminus occlusion within 6 h following symptom onset were retrospectively reviewed. Pial collaterals were defined based on the extent of reconstitution of the MCA territory. Patients with slow antegrade flow distal to the occlusion site were excluded and no anesthetics were used prior or during angiography. Results were analyzed using multivariate nominal logistic regression., Results: Better pial collateral recruitment was associated with proximal MCA versus ICA terminus occlusion ( p  = 0.005; odds ratio (OR) = 9.3; 95% confidence interval (CI), 2.16-53.3), lower presenting National Institutes of Health Stroke Scale Score (NIHSSS) ( p  = 0.023; OR = 6.51; 95% CI, 1.49-41.7), and lower diastolic blood pressure ( p  = 0.0411; OR = 5.05; 95% CI, 1.20-29.2). Age, gender, symptom duration, diabetes, laterality, systolic blood pressure, glucose level, hematocrit, platelet level, and white blood cell count at presentation were not found to have a statistically significant association with pial collateral recruitment., Conclusions: Extent of pial collateral recruitment is strongly associated with the occlusion site (MCA M1 segment versus ICA terminus) and less strongly associated with presenting NIHSSS and diastolic blood pressure.

Acute headache is a common symptom and is reported by approximately 2%-4% of patients who present to the emergency department. Many abnormalities manifest with headache as the first symptom, and it is crucial to obtain a patient's complete clinical history for correct diagnosis. Headache onset, duration, and severity; risk factors such as hypertension, immunosuppression, or malignancy; and the presence of focal neurologic deficits or systemic symptoms may aid the radiologist in deciding whether imaging is appropriate and which modality to choose. Imaging findings are more likely to be abnormal in patients with a "thunderclap" headache than in those with headaches of lesser severity. The causes of headache in the emergency setting are various. They may manifest at imaging as subarachnoid hemorrhage (ruptured aneurysm, reversible vasoconstriction syndrome, or pituitary apoplexy), parenchymal hemorrhage (hypertension, ruptured arteriovenous malformation, cerebral amyloid angiopathy, dural arteriovenous fistula, or sinus thrombosis), or parenchymal edema (posterior reversible encephalopathy syndrome, reversible cerebral vasoconstriction syndrome, sinus thrombosis, or encephalitis). Alterations in intracranial pressure that are related to idiopathic intracranial hypertension or spontaneous intracranial hypotension and prior lumbar puncture or epidural injection may manifest with specific imaging findings. With accumulating knowledge of disease pathophysiology, radiologists have started to play a more central role in making the correct diagnosis. This article reviews multiple causes of acute headache and their characteristic appearances at multimodality imaging and familiarizes the reader with current concepts in imaging. Online supplemental material is available for this article. © RSNA, 2019.

There are multiple causes of neurotoxicity in children including medications, extrinsic toxins and insults, illicit drugs, built up of toxic metabolites due to genetic or acquired disorders, and metabolic abnormalities. The review is centered on causes of neurotoxicity affecting the pediatric brain and producing typical and easily recognized imaging manifestations. Early identification of common and less common imaging findings may point toward the correct direction, and may facilitate early diagnosis and institution of appropriate treatment to reverse or at least limit the injury to the developing brain. Two common imaging patterns of neurotoxicity in children are the posterior reversible encephalopathy syndrome and acute toxic leukoencephalopathy that are usually related to chemotherapy and immunosuppression for common pediatric malignancies. Another well-described imaging pattern of injury in children involves reversible splenial lesions with or without associated white matter abnormalities. Multiple additional extrinsic causes of neurotoxicity are presented including radiation and chemoradiation, various medications and treatment regimens, poisoning, illicit drug use or accidental exposure, and the respective characteristic neuroimaging findings are highlighted. Intrinsic neurotoxicity may occur in the setting of inborn errors of metabolism or acquired progressive organ failure leading to build up of toxic metabolites. Additional intrinsic causes of neurotoxicity include metabolic derangements and characteristic imaging findings in all instances are reviewed. The goal of the article is to enhance familiarity of neurologists and neuroradiologists with the imaging appearance of common and less common toxic insults to the pediatric brain., (© 2018 by the American Society of Neuroimaging.)

Trigeminal neuralgia is a debilitating pain syndrome in the sensory distribution of the trigeminal nerve. Compression of the cisternal segment of the trigeminal nerve by a vessel, usually an artery, is considered the most common cause of trigeminal neuralgia. A number of additional lesions may affect the trigeminal nerve anywhere along its course from the trigeminal nuclei to the most peripheral branches to cause facial pain. Relevant differential considerations are reviewed starting proximally at the level of the brainstem., Competing Interests: Conflict of interest: None declared.

A wide variety of conditions may involve the splenium of the corpus callosum on magnetic resonance imaging in children. A single cause may present with different patterns of splenial involvement, and multiple diseases may have similar imaging findings. Keeping this limitation in mind, the goal of this text is to assist in the diagnostic process of pediatric neurological diseases that are characterized by prominent involvement of the splenium of the corpus callosum on imaging. The various pathologies will be reviewed and categorized based on etiology, reversibility, and pattern of additional or associated findings. Transient splenial lesions in children are an uncommon radiologic finding of unknown etiology in a long list of conditions that may present with altered consciousness, and it usually carries a favorable prognosis. The discussion continues with the presentation of diseases inflicting irreversible damage on the splenium. Familiarity with the various causes implicated in splenial injury may assist in the formulation of differential diagnosis in the appropriate clinical setting using an easily recognizable imaging finding., (Copyright © 2017 by the American Society of Neuroimaging.)

Spinal nerve root enhancement in pediatric patients is generally nonspecific, and clinical and laboratory correlation is essential. Nerve root enhancement indicates lack of integrity of the blood-nerve barrier. In this review, we will present a range of pediatric conditions that can present with spinal nerve root enhancement including inflammatory, infectious, hereditary, and neoplastic causes. Familiarity with the various pathologic entities associated with spinal nerve root enhancement is important for a concise differential diagnosis in the appropriate clinical setting. This will avoid unnecessary additional investigations., (Copyright © 2015 by the American Society of Neuroimaging.)

Background and Purpose: To determine if axial T2-weighted imaging can serve as screening tool for pediatric brain imaging., Methods: We retrospectively evaluated consecutive brain magnetic resonance imaging (MRI) data of 161 children (74 girls) with a mean age of 7.44 ± 5.71 years. Standard of reference was the final report of neuroradiology attendings. Three readers with different levels of experience were blinded for clinical diagnoses and study indications. First, readers studied only the axial T2-weighted screening sequence. Second, they studied all available anatomical and functional MRI sequences as performed per standard protocol for each clinical indication. The readings were classified as normal or abnormal. Sensitivity and specificity were measured., Results: Axial T2 screening yielded a sensitivity of 77-88% and a specificity of 92%. The full studies/data sets had a sensitivity of 89-95% and a specificity of 86-93%. Nineteen of 167 studies were acquired for acute and 148 of 167 studies for nonacute clinical indication. Twenty-five false-negative diagnoses paneled in three groups were made by all readers together. Readers misread four of 19 studies with acute and 21 of 148 studies with nonacute clinical indication. Four of 21 misread studies with nonacute indications harbored unexpected findings needing management., Conclusions: Axial T2 screening can detect pediatric brain abnormalities with high sensitivity and specificity and can possibly replace CT as screening tool if the reading physician is aware of possible limitations/pitfalls. The level of experience influences sensitivity and specificity. Adding diffusion-weighted imaging and susceptibility-weighted imaging to a 3-dimensional T2-weighted sequence would most likely further increase sensitivity and specificity., (Copyright © 2015 by the American Society of Neuroimaging.)

The malignant or benign nature of a salivary gland (SG) tumor can be predicted with reasonably high accuracy by imaging. There is some overlap between the imaging findings of benign and malignant tumors, particularly for low-grade malignancies, and tissue diagnosis remains necessary for definitive diagnosis. Magnetic resonance imaging is the modality of choice for the evaluation of salivary neoplasms, as it allows for delineation of local infiltration, perineural spread and intracranial extension. This review will focus on the advanced imaging techniques that help to characterize SG tumors. A brief overview of the conventional imaging features of SG neoplasms is necessary before a discussion of the advanced imaging methods., (© 2016 S. Karger AG, Basel.)

Case reports remain an invaluable resource in the literature, and they continue to serve an equally important role in scientific advancement. They record discoveries, report the unexpected, and spark further research. Preparation of a case report can be a great learning experience, especially for medical students, residents, and young physicians. It serves as an excellent introduction to academic writing, familiarizing them with all aspects of publishing, from a structured case presentation and literature review to submitting and revising a manuscript. It can also stimulate an interest in a specific topic and gradually lead to more involved and complex academic endeavors.

Case reports remain an invaluable resource in the literature, and they continue to serve an equally important role in scientific advancement. They record discoveries, report the unexpected, and spark further research. Preparation of a case report can be a great learning experience, especially for medical students, residents, and young physicians. It serves as an excellent introduction to academic writing, familiarizing them with all aspects of publishing, from a structured case presentation and literature review to submitting and revising a manuscript. It can also stimulate an interest in a specific topic and gradually lead to more involved and complex academic endeavors.

Background: Weakness of the sixth cranial nerve is the most common cause of an ocular motor cranial nerve palsy. It is often difficult to identify a corresponding abnormality on neuroimaging to correlate with the clinical examination., Evidence Acquisition: High-resolution 3D skull base magnetic resonance imaging (MRI) allows for visualization of the sixth nerve along much of its course and may increase sensitivity for abnormalities in regions that previously were challenging to evaluate. In this review, the authors share their experience with high-resolution imaging of the sixth nerve., Results: For each segment, anatomic features visible on high-resolution imaging are described along with relevant pathologic entities., Conclusions: We present a segmental approach to high-resolution 3D MRI for evaluation of the sixth nerve from the nuclear to the orbital segment.

A 15-year-old girl was referred to a dentist complaining of parageusia, bad taste in the mouth, which started 9 months ago. Panoramic X-ray and non-enhanced computed tomography scan revealed multiple bilateral unilocular cysts in the mandible and maxilla, along with calcification of anterior part of the falx cerebri. She was eventually diagnosed with Gorlin-Goltz syndrome based on imaging and histopathologic finding of keratocystic odontogenic tumor.

Scedosporium apiospermum is a deadly fungal infection that can infect the central nervous system, particularly in immunocompromised patients. We present two cases of Scedosporium brain abscesses. The first case was fatal and relevant conventional MRI and MR spectroscopy findings are discussed. To our knowledge, this is the first reported case of MR spectroscopy in Scedosporium apiospermum abscesses. In the second case, the patient recovered and conventional MR findings are followed over several months. In the appropriate clinical setting, conventional MR imaging and MR spectroscopy may facilitate diagnosis, earlier initiation of antifungal pharmacotherapy and surgical intervention in this frequently fatal infection., (Copyright © 2013 Elsevier Inc. All rights reserved.)

Background and Purpose: Because alteplase does not penetrate thrombus effectively, this study examined whether a method thought to maximize surface distribution of alteplase on the offending thrombus during IATT would result in greater reperfusion rates in acute ischemic stroke., Materials and Methods: Clinical information, arteriograms, and CT scans following treatment from 85 consecutive patients who underwent IATT by using alteplase within 6 hours of stroke symptom onset were reviewed. Alteplase was delivered through a microcatheter embedded within the thrombus at 1 mg per minute in all cases, and the delivery never exceeded 100 mg of alteplase. Patients who underwent microcatheter contrast injections confirming that alteplase surrounded the thrombus were compared with patients who did not., Results: Greater than 50% vascular territory reperfusion occurred in 82.2% of patients who underwent IATT with the intention of optimizing alteplase delivery versus 30.0% in patients without this intention (P < .0001, Pearson correlation) with an odds ratio of 15.8 based on nominal regression analysis. Hemorrhagic complication rates between methods were similar. The mRS at 1-3 months, infarct volume, change in NIHSS score by 24 hours, and hospital discharge were positively affected by optimizing alteplase delivery., Conclusions: A method that intends to evenly distribute alteplase around a thrombus resulted in better reperfusion rates and clinical outcomes compared with methods without this intention. Other predictors positively influencing reperfusion included the presence of slow antegrade flow distal to the clot, earlier time to treatment, lower presenting NIHSS score, and proximal occlusion site.

Stroke is currently the third leading cause of death in the United States, with approximately 780,000 Americans affected by a new or recurring stroke each year. Although a variety of therapeutic approaches have shown promise in small-animal models of stroke, the vast majority of clinical trials to test the efficacy of such modalities have failed. To bridge the translational gap between laboratory and clinical research, we developed a preclinical model of acute ischemic stroke in dogs. Using a minimally invasive endovascular approach, a platinum coil was intravascularly guided through the vertebrobasilar system under C-arm fluoroscopy to occlude the M1 segment of the middle cerebral artery (MCA) for 1 h. The approach included femoral artery catheterization to access the MCA and therefore eliminated the occurrence of head trauma associated with other preclinical stroke models relying on transorbital or craniectomy approaches. After 1 h of focal MCA ischemia, the coil was retrieved to cause reperfusion, which was verified by arteriograms. At 24 h, T2-weighted coronal magnetic resonance (MR) images were acquired and processed for three-dimensional reconstruction of the brain and its vasculature. Infarction, limited to the area at risk, was noted. Two independent observers calculated the mean percentage hemispherical lesion volumes as follows: observer 1, 30.9 +/- 2.1%; observer 2, 31.2 +/- 4.3%. Infarct-affected changes in histology were determined by hematoxylin and eosin as well as by Fluoro-Jade staining. This work reports the successful development of a powerful preclinical model of stroke that lends itself to the study of biologic mechanisms as well as to testing experimental therapeutics.