Association between high-risk extracranial carotid plaque and covert brain infarctions and cerebral microbleeds.

PURPOSE: Covert brain infarctions (CBIs) and cerebral microbleeds (CMBs) represent subclinical sequelae of ischemic and hemorrhagic cerebral small vessel disease, respectively. In addition to thromboembolic stroke, carotid atherosclerosis has been associated with downstream vascular brain injury, including inflammation and small vessel disease. The specific plaque features responsible for this are unknown. We aimed to determine the association of specific vulnerable carotid plaque features to CBIs and CMBs to better understand the relation of large and small vessel disease in a single-center retrospective observational study. METHODS: Intraplaque hemorrhage (IPH) and plaque ulceration were recorded on carotid MRA and total, cortical, and lacunar CBIs and CMBs were recorded on brain MR in 349 patients (698 carotid arteries). Multivariable Poisson regression was performed to relate plaque features to CBIs and CMBs. Within-subject analysis in those with unilateral IPH and ulceration was performed with Poisson regression. RESULTS: Both IPH and plaque ulceration were associated with total CBI (prevalence ratios (PR) 3.33, 95% CI: 2.16-5.15 and 1.91, 95% CI: 1.21-3.00, respectively), after adjusting for stenosis, demographic, and vascular risk factors. In subjects with unilateral IPH, PR was 2.83, 95% CI: 1.76-4.55, for CBI in the ipsilateral hemisphere after adjusting for stenosis. Among those with unilateral ulceration, PR was 1.82, 95% CI: 1.18-2.81, for total CBI ipsilateral to ulceration after adjusting for stenosis. No statistically significant association was seen with CMBs. CONCLUSION: Both IPH and plaque ulceration are associated with total, cortical, and lacunar type CBIs but not CMBs suggesting that advanced atherosclerosis contributes predominantly to ischemic markers of subclinical vascular injury.

Hemorrhagic Safety of Magnetic Resonance-Guided Focused Ultrasound Thalamotomy for Tremor without Interruption of Antiplatelet or Anticoagulant Therapy.

INTRODUCTION: Magnetic resonance-guided focused ultrasound (MRgFUS) thalamotomy is an incision-less ablative technique used to treat medically refractory tremor. Although intracerebral hemorrhage has not been reported with MRgFUS thalamotomy for the treatment of movement disorders, clinicians commonly interrupt active blood thinning medications prior to the procedure or offer gamma knife radiosurgery instead. However, MRgFUS uses focal thermoablation, and bleeding risk is likely minimal. This study aimed to evaluate the safety of MRgFUS thalamotomy in patients with essential tremor (ET) and tremor-dominant Parkinson's disease (PD) without interrupting anticoagulant or antiplatelet therapies. METHODS: This was a single-center retrospective case series of all patients with ET or PD undergoing MRgFUS from February 2019 through December 2022 (n = 96). Demographic variables and medications taken at the time of surgery were obtained. Our primary outcome was the type and frequency of hemorrhagic complications noted on the operative report or postoperative imaging. RESULTS: The mean age of patients was 74.2 years, and 26% were female. Forty patients were taking ≥1 antiplatelet or anticoagulant medications. No patient actively taking anticoagulant or antiplatelet therapies had a hemorrhagic complication during or <48 h after the procedure. CONCLUSION: The frequency of intra- or postoperative complications from MRgFUS was not higher in patients actively taking anticoagulant or antiplatelet therapies relative to those who were not. Our findings suggest that MRgFUS thalamotomy does not necessitate interrupting anticoagulant or antiplatelet therapies. However, given the limited number of patients actively taking these therapies in our cohort (n = 40), additional testing in large, prospective studies should be conducted to further establish safety.

MR Angiography Series: Neurovascular MR Angiography.

Neurovascular MR angiography (MRA) is an evolving imaging technique and is crucial for the workup of numerous neurologic disorders. While CT angiography (CTA) provides a more rapid imaging assessment, in select patients it can impart a small risk of contrast material-induced nephrotoxicity or radiation-associated cancers. In addition, MRA offers some advantages over CTA for neurovascular evaluation, including higher temporal resolution and the capability for vessel wall imaging. This module is the third in a series created on behalf of the Society for Magnetic Resonance Angiography (SMRA), a group of researchers and clinicians who are passionate about the benefits of MRA but understand its challenges. The full digital presentation is available online. Work of the U.S. Government published under an exclusive license with the RSNA.

Delayed-Onset Cranial Nerve Palsy After Transvenous Embolization of Indirect Carotid Cavernous Fistulas.

BACKGROUND: Carotid cavernous fistulas (CCF) often present with diplopia secondary to cranial nerve palsy (CNP). Immediate development of postoperative CNP has been described in the literature. This study described delayed-onset of CNP after complete and reconfirmed obliteration of the CCF and resolution of initial CNP. METHODS: A retrospective analysis was performed on patients with indirect CCF between 1987 and 2006 at 4 academic endovascular centers. Details of the endovascular procedures, embolic agents used, and complications were studied. Partial or complete obliteration was determined. Immediate and delayed cranial nerve palsies were independently assessed. RESULTS: A total of 267 patients with symptomatic indirect CCF underwent transvenous endovascular treatment. Four patients (1.5%) developed delayed abducens nerve (VI) palsy after complete resolution of presenting symptoms after embolization. Delayed presentation ranged between 3 and 13 months after complete resolution of initial double vision and cranial nerve palsies. Transvenous coil embolization through the inferior petrosal sinus was performed in all 4 affected patients. All had follow-up angiography confirming durable closure of their CCF. MRI did not show new mass lesions or abnormal soft tissue enhancement. In all 4 patients, their abducens nerve (VI) palsy remained. CONCLUSIONS: Delayed CNP can develop despite complete endovascular obliteration of the CCF. The cause of delayed CNP is not yet determined, but may represent fibrosis and ischemia. Long-term follow-up is needed even after complete neurological and radiological recovery is attained in the immediate perioperative period.

Assessment of quantitative methods for enhancement measurement on vessel wall magnetic resonance imaging evaluation of intracranial atherosclerosis.

PURPOSE: Quantitative measures of vessel wall magnetic resonance imaging (vwMRI) for the evaluation of intracranial atherosclerotic disease (ICAD) offers standardization not available with previously used qualitative approaches that may be difficult to replicate. METHODS: vwMRI studies performed to evaluate ICAD that had caused a stroke were analyzed. Two blinded reviewers qualitatively rated culprit lesions for the presence of enhancement on T1 delay alternating with nutation for tailored excitation (DANTE) SPACE images. At least 3 months later, quantitative analysis was performed of the same images, comparing lesion enhancement to reference structures. Cohen's kappa and intraclass correlation coefficients were calculated to assess agreement. Ratios of enhancement of lesions to references were compared to qualitative ratings. RESULTS: Studies from 54 patients met inclusion criteria. A mean of 49 (90.7%) lesions were qualitatively rated as enhancing, with good inter-rater agreement (κ = 0.783). Among reference structure candidates, low infundibulum demonstrated the highest inter-rater agreement on pre- and post-contrast imaging. The ratio of percentage increase in plaque signal following contrast to the same measure in low infundibulum demonstrated the highest agreement with qualitative assessment, with highest agreement seen with a ratio of 0.8 set as a threshold (κ = 0.675). CONCLUSION: Quantitative metrics can yield objective data to better standardize techniques and acceptance of vwMRI evaluation of ICAD. The low infundibulum had the highest inter-rater agreement on both pre- and post-contrast images and is best suited as a normally enhancing reference structure. Such quantitative techniques should be implemented in future research of vwMRI for the evaluation of ICAD.

Interventional magnetic resonance imaging guided carotid embolectomy using a novel resonant marker catheter: demonstration of preclinical feasibility.

To assess the visualization and efficacy of a wireless resonant circuit (wRC) catheter system for carotid artery occlusion and embolectomy under real-time MRI guidance in vivo, and to compare MR imaging modality with x-ray for analysis of qualitative physiological measures of blood flow at baseline and after embolectomy. The wRC catheter system was constructed using a MR compatible PEEK fiber braided catheter (Penumbra, Inc, Alameda, CA) with a single insulated longitudinal copper loop soldered to a printed circuit board embedded within the catheter wall. In concordance with IACUC protocol (AN103047), in vivo carotid artery navigation and embolectomy were performed in four farm pigs (40-45 kg) under real-time MRI at 1.5T. Industry standard clots were introduced in incremental amounts until adequate arterial occlusion was noted in a total of n=13 arteries. Baseline vasculature and restoration of blood flow were confirmed via MR and x-ray imaging, and graded by the Thrombolysis in Cerebral Infarction (TICI) scale. Wilcoxon signed-rank tests were used to analyze differences in recanalization status between DSA and MRA imaging. Successful recanalizations (TICI 2b/3) were compared to clinical rates reported in literature via binomial tests. The wRC catheter system was visible both on 5° sagittal bSSFP and coronal GRE sequence. Successful recanalization was demonstrated in 11 of 13 occluded arteries by DSA analysis and 8 of 13 by MRA. Recanalization rates based on DSA (0.85) and MRA (0.62) were not significantly different from the clinical rate of mechanical aspiration thrombectomy reported in literature. Lastly, a Wilcoxon signed rank test indicated no significant difference between TICI scores analyzed by DSA and MRA. With demonstrated compatibility and visualization under MRI, the wRC catheter system is effective for in vivo endovascular embolectomy, suggesting progress towards clinical endovascular interventional MRI.

Added Value of Vessel Wall Magnetic Resonance Imaging in the Differentiation of Moyamoya Vasculopathies in a Non-Asian Cohort.

BACKGROUND AND PURPOSE: Although studies have evaluated the differential imaging of moyamoya disease and atherosclerosis, none have investigated the added value of vessel wall magnetic resonance imaging (MRI). This study evaluates the added diagnostic value of vessel wall MRI in differentiating moyamoya disease, atherosclerotic-moyamoya syndrome (A-MMS), and vasculitic-MMS (V-MMS) with a multicontrast protocol. METHODS: We retrospectively reviewed the carotid artery territories of patients with clinically defined vasculopathies (moyamoya disease, atherosclerosis, and vasculitis) and steno-occlusive intracranial carotid disease. Two neuroradiologists, blinded to clinical data reviewed the luminal imaging of each carotid, evaluating collateral extent and making a presumed diagnosis with diagnostic confidence. After 3 weeks, the 2 readers reviewed the luminal imaging+vessel wall MRI for the presence, pattern and intensity of postcontrast enhancement, T2 signal characteristics, pattern of involvement, and presumed diagnosis and confidence. RESULTS: Ten A-MMS, 3 V-MMS, and 8 moyamoya disease cases with 38 affected carotid segments were included. There was significant improvement in diagnostic accuracy with luminal imaging+vessel wall MRI when compared with luminal imaging (87% versus 32%, P<0.001). The most common vessel wall MRI findings for moyamoya disease were nonenhancing, nonremodeling lesions without T2 heterogeneity; for A-MMS eccentric, remodeling, and T2 heterogeneous lesions with mild/moderate and homogeneous/heterogeneous enhancement; and for V-MMS concentric lesions with homogeneous, moderate enhancement. Inter-reader agreement was moderate to substantial for all vessel wall MRI characteristics (κ=0.46-0.86) and fair for collateral grading (κ=0.35). There was 11% inter-reader agreement for diagnosis on luminal imaging when compared with 82% for luminal imaging+vessel wall MRI (P<0.001). CONCLUSIONS: Vessel wall MRI can significantly improve the differentiation of moyamoya vasculopathies when combined with traditional imaging techniques.

High-resolution intracranial vessel wall imaging: imaging beyond the lumen.

Accurate and timely diagnosis of intracranial vasculopathies is important due to significant risk of morbidity with delayed and/or incorrect diagnosis both from the disease process as well as inappropriate therapies. Conventional vascular imaging techniques for analysis of intracranial vascular disease provide limited information since they only identify changes to the vessel lumen. New advanced MR intracranial vessel wall imaging (IVW) techniques can allow direct characterisation of the vessel wall. These techniques can advance diagnostic accuracy and may potentially improve patient outcomes by better guided treatment decisions in comparison to previously available invasive and non-invasive techniques. While neuroradiological expertise is invaluable in accurate examination interpretation, clinician familiarity with the application and findings of the various vasculopathies on IVW can help guide diagnostic and therapeutic decision-making. This review article provides a brief overview of the technical aspects of IVW and discusses the IVW findings of various intracranial vasculopathies, differentiating characteristics and indications for when this technique can be beneficial in patient management.

Quantitative volumetric analysis of head and neck venous and lymphatic malformations to assess response to percutaneous sclerotherapy.

BACKGROUND: Venous and lymphatic malformations of the head and neck can be successfully treated with percutaneous sclerotherapy. PURPOSE: To examine the utility of three-dimensional volumetric analysis to assess these lesions and their response to therapy. MATERIAL AND METHODS: Prospectively maintained procedure records were retrospectively reviewed to identify all patients with vascular malformations who underwent percutaneous sclerotherapy. Clinical data were used to classify lesions by apparent size and degree of visible physical asymmetry due to the lesions. Lesion volume was calculated using magnetic resonance images. Cohen's weighted kappa coefficients were calculated to assess both intra- and inter-rater agreement. Pearson coefficients were calculated to identify correlation between clinical and volumetric measures, both at initial diagnosis and following treatment. RESULTS: Thirty-seven patients with head and neck venous or lymphatic malformations underwent 55 treatment sessions. Cohen's weighted kappa coefficients were 0.84 and 0.77 for intra- and inter-rater agreement, respectively. Clinical size did not significantly correlate with measured volume at diagnosis (ρ = 0.08, P = 0.57). For lymphatic malformations, total lesion volume correlated with volume of macrocystic components (ρ = 0.47, P < 0.01). Total volume reduction significantly correlated with clinical response grade (ρ = 0.46, P = 0.02). For lymphatic malformations, reduction of volume of the macrocystic component significantly correlated with clinical response grade (ρ = 0.44, P = 0.03). CONCLUSION: Changes in calculated volume corresponded to clinical measures of treatment response. Variability of qualitative approaches to lesion analysis may have led to the lack of correlation between initial size of a lesion based on clinical measures and calculated volume. Future research should include quantitative metrics to augment qualitative clinical results.

Imaging in acute ischaemic stroke: assessing findings in light of evolving therapies.

Acute ischaemic stroke (AIS) is a debilitating disease for which effective therapies are now available. Effective identification of candidates for therapy relies heavily on noninvasive imaging that must be interpreted accurately in a short timeframe. This review summarizes the evolution of AIS therapies and the implications for noninvasive imaging. The review concludes with consideration of longstanding assumptions about imaging of ischaemic stroke and potential paradigm shifts on the horizon.

Utility of clinical and radiographic findings in the management of traumatic epidural hematoma.

BACKGROUND: There are currently no clear guidelines for the management and radiological monitoring of pediatric patients with epidural hematomas (EDH). We aim to compare clinical and radiographic characteristics of pediatric EDH patients managed with observation alone versus surgical evacuation and to describe results of repeat head imaging in both groups. METHODS: We performed a retrospective observational study of pediatric patients diagnosed with traumatic EDH at a level II trauma center. RESULTS: Forty-seven cases of EDH were analyzed. Sixty-two percent were managed by observation alone. Patients undergoing surgery were more likely to have an altered mental status (17 vs. 72%, p < 0.001), but there were no other significant clinical differences between the groups. The mean initial EDH thickness and volume were 8.0 mm and 8.6 ml in the observed group and 15.5 mm and 35 ml in the surgery group, respectively (p < 0.001 for both comparisons). Eighty-six percent of the observed and all surgery patients underwent repeat CT imaging. The initial repeat CT scan results led to surgery in 1 patient who was initially treated with observation. CONCLUSIONS: Most pediatric patients with EDH can be managed with observation. Mental status and radiographic findings should guide the need for surgical intervention. Multiple repeat CT scans have minimal utility in changing management.

Spatially resolved transcriptomics for evaluation of intracranial vessels in a rabbit model: Proof of concept.

BACKGROUND: Better understanding of vessel biology and vascular pathophysiology is needed to improve understanding of cerebrovascular disorders. Tissue from diseased vessels can offer the best data. Rabbit models can be effective for studying intracranial vessels, filling gaps resulting from difficulties acquiring human tissue. Spatially-resolved transcriptomics (SRT) in particular hold promise for studying such models as they build on RNA sequencing methods, augmenting such data with histopathology. METHODS: Rabbit brains with intact arteries were flash frozen, cryosectioned, and stained with H&E to confirm adequate inclusion of intracranial vessels before proceeding with tissue optimization and gene expression analysis using the Visium SRT platform. SRT results were analyzed with k-means clustering analysis, and differential gene expression was examined, comparing arteries to veins. RESULTS: Cryosections were successfully mounted on Visium proprietary slides. Quality control thresholds were met. Optimum permeabilization was determined to be 24 min for the tissue optimization step. In analysis of SRT data, k-means clustering distinguished vascular tissue from parenchyma. When comparing gene expression traits, the most differentially expressed genes were those found in smooth muscle cells. These genes were more commonly expressed in arteries compared to veins. CONCLUSIONS: Intracranial vessels from model rabbits can be processed and analyzed with the Visium SRT platform. Face validity is found in the ability of SRT data to distinguish vessels from parenchymal tissue and differential expression analysis accurately distinguishing arteries from veins. SRT should be considered for future animal model investigations into cerebrovascular diseases.

Real-Time Monitoring and Modulation of Blood Pressure in a Rabbit Model of Ischemic Stroke.

Control of blood pressure, in terms of both absolute values and its variability, affects outcomes in ischemic stroke patients. However, it remains challenging to identify the mechanisms that lead to poor outcomes or evaluate measures by which these effects can be mitigated because of the prohibitive limitations inherent to human data. In such cases, animal models can be utilized to conduct rigorous and reproducible evaluations of diseases. Here we report refinement of a previously described model of ischemic stroke in rabbits that is augmented with continuous blood pressure recording to assess the impacts of modulation on blood pressure. Under general anesthesia, femoral arteries are exposed through surgical cutdowns to place arterial sheaths bilaterally. Under fluoroscopic visualization and roadmap guidance, a microcatheter is advanced into an artery of the posterior circulation of the brain. An angiogram is performed by injecting the contralateral vertebral artery to confirm occlusion of the target artery. With the occlusive catheter remaining in position for a fixed duration, blood pressure is continuously recorded to allow for tight titration of blood pressure manipulations, whether through mechanical or pharmacological means. At the completion of the occlusion interval, the microcatheter is removed, and the animal is maintained under general anesthesia for a prescribed length of reperfusion. For acute studies, the animal is then euthanized and decapitated. The brain is harvested and processed to measure the infarct volume under light microscopy and further assessed with various histopathological stains or spatial transcriptomic analysis. This protocol provides a reproducible model that can be utilized for more thorough preclinical studies on the effects of blood pressure parameters during ischemic stroke. It also facilitates effective preclinical evaluation of novel neuroprotective interventions that might improve care for ischemic stroke patients.

Evaluation of methemoglobin as an intravascular contrast agent: T1 relaxation time effect in a rabbit model.

OBJECTIVE: Alternative contrast agents for MRI are needed for individuals who may respond adversely to gadolinium, and need an intravascular agent for specific indications. One potential contrast agent is intracellular methemoglobin, a paramagnetic molecule that is normally present in small amounts in red blood cells. An animal model was used to determine whether methemoglobin modulation with intravenous sodium nitrite transiently changes the T1 relaxation of blood. METHODS: Four adult New Zealand white rabbits were treated with 30 mg intravenous sodium nitrite. 3D TOF and 3D MPRAGE images were acquired before (baseline) and after methemoglobin modulation. T1 of blood was measured with 2D ss EPl acquisitions with inversion recovery preparation performed at two-minute intervals up to 30 min. T1 maps were calculated by fitting the signal recovery curve within major blood vessels. RESULTS: Baseline T1 was 1758 ± 53 ms in carotid arteries and 1716 ± 41 ms in jugular veins. Sodium nitrite significantly changed intravascular T1 relaxation. The mean minimum value of T1 was 1126 ± 28 ms in carotid arteries 8 to 10 min after the injection of sodium nitrite. The mean minimum value of T1 was 1171 ± 52 ms in jugular veins 10 to 14 min after the injection of sodium nitrite. Arterial and venous T1 recovered to baseline after a period of 30 min. CONCLUSION: Methemoglobin modulation produces intravascular contrast on T1-weighted MRI in vivo. Additional studies are needed to safely optimize methemoglobin modulation and sequence parameters for maximal tissue contrast.

Influence of cerebrospinal fluid on power absorption during transcranial magnetic resonance-guided focused ultrasound treatment.

BACKGROUND: Ultrasound beam aberration correction is vital when focusing ultrasound through the skull bone in transcranial magnetic resonance-guided focused ultrasound (tcMRgFUS) applications. Current methods make transducer element phase adjustments to compensate for the variation in skull properties (shape, thickness, and acoustic properties), but do not account for variations in the internal brain anatomy. PURPOSE: Our objective is to investigate the effect of cerebrospinal fluid (CSF) and brain anatomy on beam focusing in tcMRgFUS treatments. METHODS: Simulations were conducted with imaging data from 20 patients previously treated with focused ultrasound for disabling tremor. The Hybrid Angular Spectrum (HAS) method was used to test the effect of including cerebral spinal fluid (CSF) and brain anatomy in determining the element phases used for aberration correction and beam focusing. Computer tomography (CT) and magnetic resonance imaging (MRI) images from patient treatments were used to construct a segmented model of each patient's head. The segmented model for treatment simulation consisted of water, skin, fat, brain, CSF, diploë, and cortical bone. Transducer element phases used for treatment simulation were determined using time reversal from the desired focus, generating a set of phases assuming a homogeneous brain in the intracranial volume, and a second set of phases assigning CSF acoustic properties to regions of CSF. In addition, for three patients, the relative effect of separately including CSF speed of sound values compared to CSF attenuation values was found. RESULTS: We found that including CSF acoustic properties (speed of sound and attenuation) during phase planning compared to phase correction without considering CSF increased the absorbed ultrasound power density ratios at the focus over a range of 1.06 to 1.29 (mean of 17% ± 6%) for 20 patients. Separately considering the CSF speed of sound and CSF attenuation showed that the increase was due almost entirely to including the CSF speed of sound; considering only the CSF attenuation had a negligible effect. CONCLUSIONS: Based on HAS simulations, treatment planning phase determination using morphologically realistic CSF and brain anatomy yielded an increase of up to 29% in the ultrasound focal absorbed power density. Future work will be required to validate the CSF simulations.

Analysis of treatment cost differences in patients undergoing femoral versus radial access in outpatient diagnostic cerebral arteriograms.

BACKGROUND: Outpatient diagnostic cerebral arteriograms are the most common procedure in neuroendovascular surgery, and the use of transradial access for these studies is growing. Although transradial access has been associated with lower hospital costs for elective diagnostic and interventional neuroendovascular procedures, no study has compared transfemoral access and transradial access costs for a homogenous population of patients undergoing outpatient diagnostic cerebral arteriogram. METHODS: In this single-center retrospective study, the Value Driven Outcomes database was used to evaluate treatment costs for patients who underwent outpatient diagnostic cerebral arteriogram from January 2019 to December 2022. Propensity-score matching was performed to reduce confounders. Costs from each encounter were subcategorized into imaging, supplies, pharmacy, procedures, labs, and facility costs. RESULTS: After matching, 337 patients each for transradial access and transfemoral access were available for analysis. A total of 118,992 cost data points were associated with all encounters. Overall, per-visit costs were 15.2% cheaper for patients who underwent transradial access versus transfemoral access (p < 0.001). Most of the cost difference was due to supplies (35.2% cost difference, p < 0.001) and procedure costs (9.3% cost difference, p < 0.001). No statistical differences were observed between the two approaches in imaging, pharmacy, labs, and facility costs (all p > 0.05). CONCLUSIONS: Costs for outpatient diagnostic cerebral arteriogram were lower in patients who underwent transradial access versus transfemoral access because of supply and procedure costs. Understanding reasons for cost differences in common procedures is important for creating strategies to reduce overall healthcare costs. Additionally, addressing the cost differences of newer techniques may increase the likelihood that they are more readily implemented by hospitals and providers.

Idiopathic intracranial hypertension imaging approaches and the implications in patient management.

Idiopathic intracranial hypertension (IIH) represents a clinical disease entity without a clear etiology, that if left untreated, can result in severe outcomes, including permanent vision loss. For this reason, early diagnosis and treatment is necessary. Historically, the role of cross-sectional imaging has been to rule out secondary or emergent causes of increased intracranial pressure, including tumor, infection, hydrocephalus, or venous thrombosis. MRI and MRV, however, can serve as valuable imaging tools to not only rule out causes for secondary intracranial hypertension but can also detect indirect signs of IIH resultant from increased intracranial pressure, and demonstrate potentially treatable sinus venous stenosis. Digital subtraction venographic imaging also plays a central role in both diagnosis and treatment, providing enhanced anatomic delineation and temporal flow evaluation, quantitative assessment of the pressure gradient across a venous stenosis, treatment guidance, and immediate opportunity for endovascular therapy. In this review, we discuss the multiple modalities for imaging IIH, their limitations, and their contributions to the management of IIH.

Balance and cognitive impairments are prevalent and correlated with age in presurgical patients with essential tremor.

INTRODUCTION: Essential tremor (ET) was long considered a monosymptomatic disorder, but this view has given way to a more comprehensive clinical picture that involves consideration of non-tremor symptoms (e.g., balance impairment, cognitive impairment). Recently, the novel designation of "ET-plus" was proposed to reclassify ET patients who demonstrate these non-tremor clinical features, but the prevalence of ET-plus remains poorly defined. The primary aim of our study was to estimate the prevalence of ET-plus among presurgical patients with ET by applying this reclassification scheme. METHODS: We performed a retrospective review of patients with ET being considered for deep brain stimulation or focused ultrasound thalamotomy. Patient demographics and data from their clinical workups were collected. As part of their clinical workup, patients were screened for preexisting balance and cognitive impairment. Patients with ET were designated as ET-plus if they had balance impairment, cognitive impairment, or tremor at rest. We performed a series of Pearson correlations to examine how individual clinical and demographic variables were related. RESULTS: We identified 92 patients who met the study criteria. Our results indicate that 87% of the presurgical patients in our cohort met the criteria for reclassification as ET-plus. In addition, we observed robust correlations between patient age and balance impairment, cognitive impairment, history of falls, family history of tremor, and ET-plus reclassification. CONCLUSION: We propose that balance and gait impairment should be assessed preoperatively alongside neuropsychological evaluation to improve the counseling and treatment of patients with ET-plus.

Neutrophil extracellular traps regulate ischemic stroke brain injury.

Ischemic stroke prompts a strong inflammatory response, which is associated with exacerbated outcomes. In this study, we investigated mechanistic regulators of neutrophil extracellular trap (NET) formation in stroke and whether they contribute to stroke outcomes. NET-forming neutrophils were found throughout brain tissue of ischemic stroke patients, and elevated plasma NET biomarkers correlated with worse stroke outcomes. Additionally, we observed increased plasma and platelet surface-expressed high-mobility group box 1 (HMGB1) in stroke patients. Mechanistically, platelets were identified as the critical source of HMGB1 that caused NETs in the acute phase of stroke. Depletion of platelets or platelet-specific knockout of HMGB1 significantly reduced plasma HMGB1 and NET levels after stroke, and greatly improved stroke outcomes. We subsequently investigated the therapeutic potential of neonatal NET-inhibitory factor (nNIF) in stroke. Mice treated with nNIF had smaller brain infarcts, improved long-term neurological and motor function, and enhanced survival after stroke. nNIF specifically blocked NET formation without affecting neutrophil recruitment after stroke. Importantly, nNIF also improved stroke outcomes in diabetic and aged mice and was still effective when given 1 hour after stroke onset. These results support a pathological role for NETs in ischemic stroke and warrant further investigation of nNIF for stroke therapy.