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Purpose Previous studies have shown that arterial spin-labeling (ASL) has high sensitivity and specificity for detecting dural arteriovenous fistulas (DAVFs). However, in case of jugular venous reflux (JVR), the labeled protons in the jugular vein may lead to a venous hypersignal in the jugular vein, sigmoid, and transverse sinus on ASL images and mimic DAVF. Methods To ascertain this hypothesis, two blinded senior neuroradiologists independently and retrospectively reviewed randomized ASL images and graded the likelihood of DAVF on a 5-point Likert scale in 2 groups of patients: (i) 13 patients with angiographically proven type I DAVF; and (ii) 11 patients with typical JVR diagnosed on the basis of clinical and MR imaging data, first using ASL alone, and second using ASL together with all of the sequences including 4D CE MRA. Result A dural venous ASL signal was seen in 11 patients with type I DAVF and in all the 11 patients with JVR, with no distinctive pattern between the two. The mean Likert score was “very likely” in DAVF and JVR patients when using ASL alone ( k  = 0.71), and “very unlikely” for JVR versus “very likely” for DAVF when using all the sequences available ( k  = 0.92). Conclusion Our study shows that JVR can mimic DAVF on ASL images with potential implications for patient care. The detection of DAVFs should be based on additional MR sequences such as TOF-MRA and 4D CE MRA to exclude JVR and to avoid unnecessary DSAs.

Neurovascular dysfunction, including blood–brain barrier (BBB) breakdown and cerebral blood flow (CBF) dysregulation and reduction, are increasingly recognized to contribute to Alzheimer’s disease (AD). The spatial and temporal relationships between different pathophysiological events during preclinical stages of AD, including cerebrovascular dysfunction and pathology, amyloid and tau pathology, and brain structural and functional changes remain, however, still unclear. Recent advances in neuroimaging techniques, i.e., magnetic resonance imaging (MRI) and positron emission tomography (PET), offer new possibilities to understand how the human brain works in health and disease. This includes methods to detect subtle regional changes in the cerebrovascular system integrity. Here, we focus on the neurovascular imaging techniques to evaluate regional BBB permeability (dynamic contrast-enhanced MRI), regional CBF changes (arterial spin labeling- and functional-MRI), vascular pathology (structural MRI), and cerebral metabolism (PET) in the living human brain, and examine how they can inform about neurovascular dysfunction and vascular pathophysiology in dementia and AD. Altogether, these neuroimaging approaches will continue to elucidate the spatio-temporal progression of vascular and neurodegenerative processes in dementia and AD and how they relate to each other.

Background Endovascular embolization is an effective treatment option for cerebral arteriovenous malformations (AVMs) and dural arteriovenous fistulas (DAVFs). A variety of liquid embolic agents have been and are currently used for embolization of AVMs and DAVFs. Knowledge of the special properties of the agent which is used is crucial for an effective and safe embolization procedure. Material and Methods This article describes the properties and indications of the liquid embolic agents which are currently available: cyanoacrylates (also called glues), and the copolymers Onyx, Squid and PHIL, as well as their respective subtypes. Results Cyanoacrylates were the predominantly used agents in the 1980s and 1990s. They are currently still used in specific situations, for example for the occlusion of macro-shunts, for the pressure cooker technique or in cases in which microcatheters are used that are not compatible with dimethyl-sulfoxide. The first broadly used copolymer-based embolic agent Onyx benefits from a large amount of available experience and data, which demonstrated its safety and efficacy in the treatment of cerebral vascular malformations, while its drawbacks include temporary loss of visibility during longer injections and artifacts in cross-sectional imaging. The more recently introduced agents Squid and PHIL aim to overcome these shortcomings and to improve the success rate of endovascular embolization. Novelties of these newer agents with potential advantages include extra-low viscosity versions, more stable visibility, and a lower degree of imaging artifacts. Conclusion All the available liquid embolic agents feature specific potential advantages and disadvantages over each other. The choice of the most appropriate embolic agent must be made based on the specific material characteristics of the agent, related to the specific anatomical characteristics of the target pathology.

Abstract OBJECTIVE Dural sinus thrombosis often accompanies or precedes the development of dural arteriovenous fistulas (DAVFs). Because thrombophilic abnormalities can contribute to sinus thrombosis, we investigated the prevalence of such abnormalities and of venous sinus thrombosis in patients with DAVFs. METHODS Thrombophilic factors were measured in 18 patients with DAVFs treated with embolization at our university hospital. Control data were obtained from patients with unruptured intracranial aneurysms. In addition to sinus occlusion, we investigated prothrombin time, activated thromboplastin time, platelet count, and fibrinogen, platelet, antithrombin III, protein C, protein S, anticardiolipin antibody, anti-cardiolipin β2-glycoprotein-I complex antibody, and D-dimer levels. RESULTS Of the 18 patients with DAVFs, 16 had abnormal D-dimer levels, whereas the mean values for other thrombophilic factors were nearly normal. D-dimer levels were significantly higher in preoperative DAVF patients than in controls. Interestingly, the mean value of D-dimer was higher in patients with sinus occlusion than in those without it (3.33 versus 1.19). D-dimer levels rose after embolization in eight out of 10 serially tested patients, but, on average, the change was not significant. In clinically cured patients treated more than 3 months before, D-dimer was lower than in preoperative patients. CONCLUSION D-dimer is a very sensitive indicator of acute venous thrombosis, suggesting that elevations in patients with DAVFs are likely to reflect sinus thrombosis. D-dimer values decreased and nearly normalized in clinically cured patients during a long-term follow-up period, a finding consistent with completion of thrombosis and cure of the disease. To clarify the correlation between DAVF and sinus thrombosis from the aspect of etiology, we should thoroughly check the variation in the concentration of the thrombophilic factors in the patient with chronic sinus occlusion to know the variation in the fistula formation in the further study.

Background The purpose was to clarify diagnostic clues and pitfalls in cranio-cervical junction arteriovenous fistulas (CCJ AVFs) with congestive myelopathy. Methods In a multicenter observational study by the Neurospinal Society of Japan, we described the demographics, clinical courses, imaging findings, and outcomes of consecutive patients with CCJ AVFs presenting with congestive myelopathy between 2009 and 2019. Results Twenty-seven patients were included (mean age, 70 years; male, 96%). Progressive symptoms within one day to one month were more common (63%) than chronic symptoms. Myelopathic symptoms were characterized by ascending paralysis beginning from the legs, involving the trunk and arms, and sometimes ending in the brainstem. Fifteen patients (56%) received a misdiagnosis, including acute transverse myelitis. The most common MRI findings were venous congestive edema of the cervical cord (96%) and the brainstem (63%) and surrounding vascular flow voids (100%). The mean extension of congestive edema was 5.5 ± 2.9 vertebral segments. The most common angiographic findings were a dural AVF (78%) at the C1 level (81%) with descending venous drainage (85%). Seven patients (26%) were administered steroids, which resulted in neurological decline in 3. Neurosurgical obliteration of the AVF led to improvements in MRI findings in 75% and a functional status in 67%; however, 44% remained dependent. Conclusions The myelopathy of CCJ AVFs was characterized by acute ascending paralysis in elderly men. A misdiagnosis was common because of the acute presentation due to a longitudinally extensive spinal cord lesion. Dilated vessels on MRI were a key finding for the correct diagnosis. What is already known on this topic? Slowly progressive myelopathy is a well-known symptom that results from impaired spinal venous drainage due to thoracolumbar AVFs. Although cranio-cervical junction arteriovenous fistulas (CCJ AVFs) constitute a treatable cause of congestive myelopathy, detailed information is not currently available due to their rarity. What does this study add? CCJ AVFs often presented with acute ascending myelopathy in elderly men due to a longitudinally extending cervical cord lesion with surrounding flow voids. Steroid pulse therapy was not effective or even harmful to congestive myelopathy, while neurosurgical treatment effectively obliterated AVFs. How might this study affect research, practice or policy? The results obtained revealed diagnostic clues and pitfalls from the largest dataset of patients with CCJ AVFs in a multicenter cohort.

Abstract BACKGROUND Spinal epidural arteriovenous fistulas (SEDAVFs) are an increasingly recognized form of spinal vascular malformation and are distinct from spinal dural arteriovenous fistulas (SDAVFs). Differentiating between these 2 entities is important as operative strategies often differ based on angioarchitecture. OBJECTIVE To compare demographic, clinical, anatomic, and imaging findings of SDAVFs and SEDAVFs. METHODS Consecutive patients diagnosed and/or treated for SDAVF or SEDAVF at our institution between January 2000 and November 2018 were included. Data were collected on demographics, clinical presentation, and imaging findings. All cross-sectional and angiographic imaging were reviewed. To compare continuous variables, t-test was used Chi-squared was used for categorical variables. RESULTS A total of 169 patients were included. In total 47 patients had SEDAVFs and 122 patients had SDVAFs. Clinical presentation and magnetic resonance imaging (MRI) imaging findings were similar between the 2 groups. SEDAVF patients were significantly more likely to have an epidural venous pouch on gadolinium bolus MR angiography (MRA) (0.0% vs 92.1%, P < .0001). SEDAVFs were more commonly located in the lumbar and sacral spine than SDAVFs (85.1% vs 34.4%, P < .0001). When in the lumbar spine, SEDAVFs unlike SDAVFs were more likely to involve the most caudal segments (L4 and L5, P = .02). CONCLUSION SEDAVF share clinical and radiological findings similar to SDAVFS, including high T2 cord signal, cord enhancement, and perimedullary flow voids on conventional MRI. However, they have a characteristic appearance on spinal MRA and DSA with a pouch of epidural contrast. SEDAVFs are more commonly located in the lumbosacral spine.

A 54-year-old man presented with gait disturbances, urinary incontinence, and headache for 6 months. Head computed tomography indicated several high-density mass lesions in the quadrigeminal cistern, causing occlusive hydrocephalus. Digital subtraction angiography confirmed tentorial dural arteriovenous fistulae (AVF). Transarterial embolization (TAE) achieved complete angiographic resolution. However, acute occlusive hydrocephalus worsened, necessitating endoscopic third ventriculostomy (ETV). The patient was discharged without new symptoms and no hydrocephalus recurrence at six-month follow-up. Hydrocephalus is rare in patients with dural AVF and mostly resolves spontaneously after treatment; however, if thrombosis and enlargement of the varix occur after treatment, acute occlusive hydrocephalus can develop.

A compartmental conceptualization of intracranial arteriovenous malformations (AVMs) allows recognition of feeding arteries, an intervening plexiform nidus, and draining veins. AVM therapy involves eliminating the nidus, which is the source of hemorrhage, without compromising normal arterial and venous drainage of the brain. Traditional methods of AVM therapy through microsurgery and endovascular embolization involve arterial devascularization, with preservation of AVM venous drainage, until the nidus is excluded. The transvenous approach in treating vascular malformations was popularized by successful treatment models for dural arteriovenous fistulas. More recently, high-flow intracranial AVMs are being managed with transvenous endovascular approaches, although this novel technique has its challenges and perils. We review the current literature on transvenous AVM therapy and highlight its role for AVM therapy in the present day. ABBREVIATIONS:AVM, arteriovenous malformationsDAVF, dural arteriovenous fistulaTRENSH, transvenous retrograde nidus sclerotherapy under controlled hypotensionVOG, vein of Galen

BackgroundEndovascular embolization is frequently used for vascular lesions of the head and neck. Newer agents may help to enhance visualization and improve treatment outcomes.MethodsThe CLARIDAD clinical trial was a prospective, single center, first-in-man investigation of neurovascular embolization using the novel embolic agent ihtObtura for a broad indication, covering the need for a liquid embolic agent in head and neck procedures. The primary outcomes assessed were therapeutic efficacy to deliver ihtObtura to embolize the catheterized pedicle and associated angiographic vascularity, and subsequent loss of radiopacity. Safety endpoints included procedural adverse events, modified Rankin Scale (mRS) score, morbidity, and mortality. Radiologic and clinical follow-up evaluations were conducted at 30, 90, 180 days, and 1 year post-treatment.Results65 consecutive patients (mean age 37.8 years, 50.8% women) were treated over 129 sessions. A total of 42 brain arteriovenous malformations (AVMs; 90% grades III and IV), 8 dural arteriovenous fistulas (DAVFs), and 15 hypervascular tumors were treated with ihtObtura using an average of 3.9 mL per session and 7.7 mL per patient. We achieved therapeutic effectiveness in 99% of catheterizations. Radiopacity loss was complete after 74.3% of the sessions at 30 days, 95.6% at 90 days, and 100% at the 1 year follow-up. Serious adverse events (mRS score >2) occurred in two patients (3.1%) with previously ruptured high grade AVMs leading to one death and one permanent disabling morbidity.ConclusionsThe study showed that ihtObtura was a novel, safe, and effective liquid embolic agent for the treatment of AVMs, DAVFs, and hypervascular tumors. Its key property of significant radiopacity loss contributes to improve anatomical understanding, particularly in staged procedures, as well as reduction in post-procedural imaging artifact. There may be additional benefits of eliminating tantalum from the embolic mixture in terms of lesion penetration.