Gluing blood into gel by electrostatic interaction using a water-soluble polymer as an embolic agent.

Liquid embolic agents are widely used for the endovascular embolization of vascular conditions. However, embolization based on phase transition is limited by the adhesion of the microcatheter to the embolic agent, use of an organic solvent, unintentional catheter retention, and other complications. By mimicking thrombus formation, a water-soluble polymer that rapidly glues blood into a gel without triggering coagulation was developed. The polymer, which consists of cationic and aromatic residues with adjacent sequences, shows electrostatic adhesion with negatively charged blood substances in a physiological environment, while common polycations cannot. Aqueous polymer solutions are injectable through clinical microcatheters and needles. The formed blood gel neither adhered to the catheter nor blocked the port. Postoperative computed tomography imaging showed that the polymer can block the rat femoral artery in vivo and remain at the injection site without nontarget embolization. This study provides an alternative for the development of waterborne embolic agents.

Most Promising Approaches to Improve Brain AVM Management: ARISE I Consensus Recommendations.

Brain arteriovenous malformations (bAVMs) are complex, and rare arteriovenous shunts that present with a wide range of signs and symptoms, with intracerebral hemorrhage being the most severe. Despite prior societal position statements, there is no consensus on the management of these lesions. ARISE (Aneurysm/bAVM/cSDH Roundtable Discussion With Industry and Stroke Experts) was convened to discuss evidence-based approaches and enhance our understanding of these complex lesions. ARISE identified the need to develop scales to predict the risk of rupture of bAVMs, and the use of common data elements to perform prospective registries and clinical studies. Additionally, the group underscored the need for comprehensive patient management with specialized centers with expertise in cranial and spinal microsurgery, neurological endovascular surgery, and stereotactic radiosurgery. The collection of prospective multicenter data and gross specimens was deemed essential for improving bAVM characterization, genetic evaluation, and phenotyping. Finally, bAVMs should be managed within a multidisciplinary framework, with clinical studies and research conducted collaboratively across multiple centers, harnessing the collective expertise and centralization of resources.

Long-term outcome of endovascular treatment for indirect carotid-cavernous fistulas.

OBJECTIVE: Endovascular treatment (EVT) is the primary approach used to treat indirect carotid-cavernous fistulas (CCFs). In this study, the authors evaluated the immediate and long-term efficacy and safety of different endovascular techniques for indirect CCFs. METHODS: The databases of two endovascular centers were retrospectively reviewed to collect the patients with indirect CCFs treated using endovascular techniques between 2013 and 2023. Demographics, clinical presentation, CCF features, EVT characteristics, and clinical and radiological outcomes were evaluated and analyzed. The analysis was performed to compare the clinical and radiological data between different endovascular approaches and different embolic materials. RESULTS: Ninety-eight patients were included in the study. EVT was successful in 95 patients (96.9%). Immediate complete obliteration of the CCF was achieved in 93.9% of patients, with 98% undergoing embolization with liquid embolic agents (LEAs) and 95.6% undergoing coiling alone. Complete CCF obliteration was higher in the transvenous than in the transarterial approach (94.3% vs 75%, p = 0.010). At ≥ 6 months follow-up, complete CCF obliteration was achieved in all patients (100%). The rate of procedure-related complications was higher following LEAs than with coiling alone (32.0% vs 15.6%). New cranial nerve (CN) palsy was diagnosed in 26.0% and 2.2% after embolization with LEAs and coiling alone, respectively (p = 0.001), with complete CN palsy recovery in 78.6%. Procedure-related intracranial hemorrhage occurred in 3 patients (3.1%). Two patients experienced an ischemic stroke following Onyx migration into the internal carotid artery. Ocular symptoms improved in 93% (83/89) of the patients who were followed. CONCLUSIONS: In this study, complete obliteration of an indirect CCF was achieved in more than 90% of patients. Despite the occurrence of some new postprocedural ocular CN palsy, ocular symptoms improved in most patients in long-term follow-up. The transvenous approach was the most effective method for treating the indirect CCF. Coiling was safer than LEAs for the embolization of the indirect CCF.

Direct puncture embolization of a medulla oblongata hemangioblastoma.

Hemangioblastoma is a rare tumor of vascular origin, most commonly located in the posterior fossa, which presents with severe symptoms and usually very hard to resect without remarkable operative blood loss.1-2 Pre-operative embolization may decrease the amount of intra-operative bleeding, but the endovascular treatment of such tumor may be very challenging due to the high risk of infarction of the surrounding tissues. Direct puncture embolization has been developed to overcome many of the limitations of endovascular techniques for many hypervascular lesions, also hemangioblastomas.3-5 We present in this Technical Video (video 1) a direct puncture embolization with balloon-protection of a hemangioblastoma of the medulla oblongata using Onyx 18 (Medtronic, inc.) as sole liquid embolic agent.

Endovascular Treatment of Visceral Artery Pseudoaneurysms with Ethylene-Vinyl Alcohol (EVOH) Copolymer-Based Non-Adhesive Liquid Embolic Agents (NALEAs).

Background and Objectives: Treatment of visceral artery pseudoaneurysms (VAPs) is always indicated regardless of their diameters, as their risk of rupture is significantly higher than that of visceral artery aneurysms. The invasiveness of surgery and its associated complications have led to a shift in favor of radiological interventions as the initial treatment of choice. However, there are still some unanswered questions on endovascular treatment of VAPs regarding the optimal endovascular technique and the efficacy and safety outcomes. The purpose of this multicenter study was to retrospectively evaluate the effectiveness and safety of endovascular treatment of visceral pseudoaneurysms using Ethylene-Vinyl Alcohol (EVOH) Copolymer-Based Non-Adhesive Liquid Embolic Agents (NALEAs). Materials and Methods: Consecutive patients who underwent endovascular embolization with EVOH-based NALEAs for visceral artery pseudoaneurysms between January 2018 and June 2023 were retrospectively evaluated. Results: 38 embolizations were performed. Technical success was achieved in all patients. The clinical success rate was high (92.1% overall), with no significant differences between ruptured and unruptured VAPs (p = 0.679). Seven patients (18.4%) experienced procedure-related complications, related to one case of non-target embolization, four splenic abscesses due to end-organ infarction, and two femoral pseudoaneurysms. The rates of procedure-related complications, end-organ infarction, and vascular access-site complications did not significantly differ between ruptured and unruptured VAPs (p > 0.05). Conclusions: Both ruptured and unruptured visceral pseudoaneurysms can be effectively and safely treated with NALEA-based endovascular embolization. We suggest considering the use of NALEAs, particularly in specific clinical cases that highlight their advantages, including patients with coagulopathy, fragile vessels, and embolization targets that are located at a considerable distance from the microcatheter tip and are otherwise difficult to reach.

Pre-surgical embolization of carotid body paragangliomas: advantages of direct percutaneous approach and transitory balloon-occlusion at the origin of the external carotid artery.

PURPOSE: Different embolization techniques and materials are available for the pre-operative embolization of carotid body paragangliomas. In this study, we report the first experience of the direct percutaneous puncture technique under fluoroscopic guidance using the low-viscosity formula of SQUID-12. The additional use of a transitory balloon-blockage at the origin of the external carotid artery aims to confer higher protection by limiting the risk of non-target embolization and subsequent neurological sequelae. MATERIALS AND METHODS: We retrospectively reviewed all cases of carotid body paragangliomas that have undergone pre-surgical embolization with a direct puncture technique and balloon-assistance at our institution between 2019 and 2020. The use of the liquid EVOH-based SQUID-12 as the sole embolic agent was the main inclusion criteria. RESULTS: A total of 9 patients with 9 carotid body paragangliomas were enrolled in this case series. The mean volume of the lesion was 309 mm3. The mean embolization-session time amounted to 88 min. The average number of needles inserted was 2, and the mean volume of SQUID-12 used per case was 23 ml. Successful total devascularization was obtained in all cases. No long-term sequelae due to the embolization procedure occurred. CONCLUSIONS: Pre-operative paraganglioma embolization with SQUID-12 using a direct puncture and balloon-assisted technique is a safe and efficient method with few complications.

Comparing N-hexyl cyanoacrylate (Magic Glue) and N-butyl cyanoacrylate (NBCA) for neurovascular embolization using the pressure cooker technique: An experimental study in swine.

BACKGROUND: The pressure cooker (PC) technique uses a second microcatheter to produce a proximal occlusion to prevent the reflux of liquid embolic agent (LEA) injected through a more distal microcatheter, and can be used to treat arteriovenous malformations and dural arteriovenous fistulae. The liquid embolic Magic Glue (MG) (N-hexyl cyanoacrylate (NHCA)) has been introduced as an alternative to N-butyl cyanoacrylate (NBCA). Our goals were to compare the extent of embolization of rete mirabile with or without the PC technique using NBCA or MG, and to compare the proximal occlusions obtained with MG or NBCA while using the PC technique in a renal arterial model. METHODS: Rete mirabile were embolized with (n = 4) and without (n = 4) the PC technique, using MG (n = 4) or NBCA (n = 4). A renal arterial model was then used to study the characteristics of the MG plug (n = 10) used for the PC technique, and resistance to catheter withdrawal as compared to NBCA (n = 4). Specimens were analyzed macro- and microscopically and compared to angiographic results. RESULTS: Extent of rete embolization with CYA agents was not significantly greater when using the PC technique. Results were similar with both types of cyanoacrylate (p = 0.657). The force necessary to withdraw the microcatheter was less with MG than with NBCA (p = 0.035). CONCLUSION: MG was similar to NBCA in extent of rete embolization. Less traction force was necessary to withdraw trapped non-detachable microcatheters using MG compared to NBCA.

Preparation and evaluation of phytantriol liquid crystal as a liquid embolic agent.

Transcatheter arterial chemoembolization (TACE) is the preferred treatment for patients with advanced hepatocellular carcinoma (HCC), but it lacks safe and effective embolic agents. 5-Fluorouracil (5-FU) is a broad-spectrum anticancer drug, but its clinical application is limited due to drug resistance and toxic side effects. Therefore, in this study, we developed a new liquid embolic agent with 5-FU as the model drug. We found that this liquid embolic agent possesses good gelling properties and embolic effects. An in vitro drug release model of the agent conformed to the Weibull model. Cumulative release of the drug over 7 d was ∼90%, consisting of an initial burst followed by sustained release. Cytotoxicity testing showed that each liquid embolic composition is cytocompatible and only mildly cytotoxic. Pharmacokinetic experiments showed that the formulation significantly prolongs the t1/2 of 5-FU (approximately five times that of 5-FU solution) and 5-FU residence time in the body (approximately three times that of 5-FU solution). These results indicate that the liquid embolic agent has embolic capacity and could be used as a potential therapeutic method for TACE.

Onyx embolization of a ruptured anterior inferior cerebellar artery in a neonate.

Aneurysmal subarachnoid hemorrhage (SAH) is rare in neonates. The authors present a unique report of a neonate with SAH from anterior inferior cerebellar artery (AICA) aneurysm rupture that was successfully treated with Onyx embolization. This case report demonstrates the utility of Onyx embolization for posterior circulation aneurysms in neonates and the successful management of SAH in this population.

Complete embolization of jugular paragangliomas by direct puncture. Technical note.

Objective: Intra-arterial embolization of jugular paragangliomas is an established endovascular technique. Intratumoral embolization by direct puncture has been proposed, prior to surgical treatment or radiosurgery to reduce the risk of cranial nerve deficits. Methods: We examined the technical aspects of two patients with jugular paragangliomas embolized with liquid embolic agent by direct puncture of the lesion, as sole treatment. Results: Two patients with jugular paragangliomas presented with lower cranial nerve deficits. The first patient showed an extended lesion (55-mm) and was treated with partial intra-arterial embolization plus direct puncture and injection of Squid 18 and a second staged embolization by direct puncture and filling of the remainder of the lesion. The second patient with a smaller jugular paraganglioma (33-mm) was treated by single embolization by direct puncture of the tumor and injection of Squid 12 and Squid 18 obtaining complete filling of the lesion. No procedural complications were observed. Both patients showed no residual and initial improvement of the neurological deficits. Conclusion: The intratumoral embolization by direct puncture of jugular paragangliomas, under accurate radiological control is a safe procedure, and complete exclusion of the lesion can be obtained in selected cases. A staged particle embolization of the lesion by direct puncture can be proposed for large lesions. Only further studies with larger series and long-term follow-up will be able to define, if this strategy can be curative avoiding additional surgical or radio-surgical treatment.

[Rheological properties of sinomenine in situ liquid crystal as liquid embolic agent].

Three different kinds of sinomenine in situ liquid crystal were prepared for different prescriptions, to investigate the rheological properties before and after in situ treatment and evaluate its feasibility for embolization. Rheological experiments were carried out with cone plate fixtures. Both the steady-state rheological and non-steady-state rheological properties of in-situ gels and the swelling gels were studied and compared. Steady-state rheological study results showed that all the three liquid embolic agents were non-newtonian fluid before and after in situ treatment, which would become less ropy when they were pressed with shear stress; their viscosities differed by 2-5 orders of magnitude. It had a yield value of about 10 Pa before in situ treatment and about 4 500 Pa after in situ treatment. All the six systems had thixotropy while their dynamic viscosities were not influenced by the shear rate, all less than 0.3 Pa·s before in situ treatment more than 1 Pa·s after in situ treatment, differing by an order of magnitude. The results of temperature sweeping showed a slight decrease with a steady rate in viscosity within the range of 10-50 °C, differing by 3-4 orders of magnitude. The results of unsteady rheology showed that there was no obvious linear viscoelastic region in the three kinds of agents, indicating the properties of liquid. After in situ treatment, their linear viscoelastic range γ<1% (No.3 was 5%), and their elastic modulus G' was larger than the viscous modulus G", indicating the properties of solid. Frequency scanning results showed that for the systems at low frequencies, G">G', system viscosity in a dominant position; while at high frequencies, G'>G", system elasticity in a dominant position. The results of compound viscosity test also proved that the liquid embolic agent in situ can form a cubic liquid crystal (the structure of No. 3 was destroyed after in situ treatment). The DHR-2 rheometer was used to investigate the rheological properties of in situ gels with three different prescriptions. The method is simple and the result is reliable, which can provide more theoretical reference for the in vitro evaluation and practical application of the product.

A novel, non-adhesive, precipitating liquid embolic implant with intrinsic radiopacity: feasibility and safety animal study.

OBJECTIVES: To evaluate a novel, ready-to-use, iodinated polyvinyl alcohol polymer embolic implant. METHODS: Under good laboratory practice conditions, 26 pigs were investigated. A complex arteriovenous malformation (AVM) model was created in 16 animals, and a simple rete model was used in the remaining 10 animals. The novel material was used for embolization in 22 animals, and a commercially available liquid embolic material in 4 animals as a control group. Animals were killed at 2 days, 3 months and 6 months. Feasibility, efficacy and safety were evaluated radiologically, clinically and histologically. RESULTS: Preparation was easy, without risk of catheter clogging or adhesiveness. Embolic delivery was well controlled under subtracted fluoroscopy. Visibility was homogeneous throughout the injection and the material behaved cohesively upon delivery. Best lesion penetration was obtained with the use of proximal microballoon occlusion. Unforeseen over-dilution of the test material by DMSO prefilled in the microballoon hub changed the material properties and caused inadvertent cerebral embolization leading to death in five animals. This phenomenon was avoided by practical measures. The casts produced no beam-hardening artefacts on CT scans. Histology showed excellent biocompatibility. CONCLUSIONS: Embolization with this novel, iodinated, precipitating polymer was feasible and effective. Care should be taken during delivery to avoid over-dilution of the material by prefilled DMSO. The material is promising for embolization of AVMs and hypervascular lesions. KEY POINTS: • The intrinsically opaque precipitating polymer has adequate fluoroscopic visibility • The polymer does not induce shading or beam-hardening artefacts on CT • The novel liquid embolic material does not require lengthy preparation • Lack of implant adherence reduces the risk of entrapment of the delivery catheter.

In vitro comparison of middle meningeal artery embolization with Squid liquid embolic agent and Contour polyvinyl alcohol particles.

BACKGROUND: Liquid embolic agents and polyvinyl alcohol (PVA) particles have been used for the embolization of the middle meningeal artery (MMA) for the treatment of chronic subdural hematomas. However, the vascular penetration and distribution of these embolic agents have not yet been compared. The current study compares distribution of a liquid embolic agent (Squid) to PVA particles (Contour) in an in vitro model of the MMA. METHODS: MMA models were embolized with Contour PVA particles 45-150 µm, Contour PVA particles 150-250 µm, and Squid-18 liquid embolic agent (n=5 each). The models were scanned and every vascular segment with embolic agent was manually marked on the images. Embolized vascular length as a percentage of control, average embolized vascular diameter, and embolization time were compared between the groups. RESULTS: The 150-250 µm Contour particles primarily accumulated close to the microcatheter tip, yielding proximal branch occlusions. The 45-150 µm Contour particles achieved a more distal distribution, but in a patchy segmental pattern. However, the models embolized with Squid-18 had a consistently distal, near-complete and homogenous distribution. Embolized vascular length was significantly higher (76±13% vs 5±3%, P=0.0007) and average embolized vessel diameter was significantly smaller (405±25 µm vs 775±225 µm, P=0.0006) with Squid than with Contour. Embolization time with Squid was also lower (2.8±2.4 min vs 6.4±2.7 min, P=0.09). CONCLUSIONS: Squid-18 liquid results in a considerably more consistent, distal and homogeneous pattern of embolysate distribution than Contour PVA particles in an anatomical model of the MMA tree.

Novel superficial temporal artery access route for middle meningeal artery embolization and treatment of chronic subdural hematoma.

We describe the use of direct superficial temporal artery puncture to access the left middle meningeal artery for embolization of a recurrent chronic subdural hematoma in a patient with a type A aortic dissection, involving the origin of the left common carotid artery which precluded conventional access from a radial or femoral approach.

CT-guided percutaneous cyanoacrylate injection targeting the spinal cerebrospinal fluid leak: a potential therapeutic option for spontaneous intracranial hypotension.

BACKGROUND: We report the first case series of spontaneous intracranial hypotension (SIH) patients who underwent CT-guided percutaneous cyanoacrylate injection targeting the cerebrospinal fluid (CSF) leak. METHODS: A retrospective analysis was performed for all consecutive cases of SIH patients with CSF leak confirmed on CT myelography, treated by CT-guided percutaneous cyanoacrylate injection at our institution from 2016 to 2022. On pretreatment brain and spine MRIs, we analyzed signs of SIH according to the Bern score, and dichotomized cases into positive/negative for spinal longitudinal extradural CSF collection (SLEC-P or SLEC-N). The leaks detected on CT myelography were classified into three types according to Schievink et al. We collected the Headache Impact Test 6 (HIT-6) scores throughout a 6-month follow-up, with a brain CT scan at each visit. RESULTS: 11 patients were included (mean age 48.4 years, six men). Five SLEC-P type 1, three SLEC-P type 2, and three SLEC-N type 3 leaks were identified. All patients had significant signs of SIH on pretreatment brain MRI (mean Bern score 7.8±1.1). Six patients underwent a foraminal puncture, and five patients had a cervical epidural approach. Two patients experienced mild and transient locoregional pain after cervical epidural injection. Mean HIT-6 score at baseline was 66.8±3.2 and at the 6-month follow-up was 38±3.6 (P<0.001). All patients achieved improvement in their symptoms, with 82% of them (9/11) having complete resolution of headaches and SIH findings on CT scans at 6 months. No clinical worsening or recurrence was observed. CONCLUSIONS: CT-guided percutaneous cyanoacrylate injection may be a potential therapeutic option for the different types of CSF leak causing SIH.

Polymerisation of cyanoacrylates: The effect of sclero-embolic and contrast agents.

OBJECTIVES: The objective is to investigate the interaction of sclero-embolic and contrast agents with the polymerisation of medical grade n-butyl-cyanoacrylates. METHODS: An in vitro spectrophotometric absorbance method was developed to detect changes in light transmission to measure n-BCA polymerisation. The initiation and the rate-of-polymerisation of mixtures of n-BCA with sclero-embolic and contrast agents were investigated. RESULTS: Initiation of polymerisation: VENABLOCK™ and HISTOACRYL® were the fastest agents to polymerise, while VENASEAL™ was the slowest. Rate of polymerisation: Hypertonic saline inhibited the polymerisation of all n-BCAs, while hypertonic glucose prolonged the polymerisation rate. ETHANOL and detergent sclerosants had no effect. Contrast agents OMNIPAQUE™ and ULTRAVIST® initiated and prolonged the polymerisation of n-BCA, but in contrast, LIPIODOL® failed to initiate the process. CONCLUSIONS: The commercially available medical cyanoacrylates differ in their polymerisation rates. These polymerisation rates are further affected when these products are used in conjunction with other compounds, such as sclero-embolic and contrast agents.

Stereotactic-guided direct orbital puncture for treatment of orbital arteriovenous fistula.

The patient presented with left-sided chemosis, exophthalmos, and progressive visual loss. Cerebral angiography ed a left orbital arteriovenous malformation and an associated hematoma, with the point of fistulation between the left ophthalmic artery and the anterior section of the inferior ophthalmic vein, with retrograde flow through the superior ophthalmic vein. Transvenous embolization through the anterior facial and angular veins was unsuccessful, with residual shunting. Stereotactic-guided direct venous puncture and Onyx embolization was subsequently performed in the hybrid operating room (OR) to cure the fistula. A subciliary incision allowed for retraction of the orbital contents, creating an optimal trajectory. An endonasal endoscopic approach was performed after the embolization to decompress the orbit. This procedure is shown in video 11-11 neurintsurg;16/4/429/V1F1V1Video 1 .

ihtObtura: A novel liquid embolic agent with post-embolization radiopacity loss, in endovascular treatment of brain arteriovenous malformations, dural arteriovenous fistulas, and tumors: CLARIDAD trial.

BACKGROUND: Endovascular embolization is frequently used for vascular lesions of the head and neck. Newer agents may help to enhance visualization and improve treatment outcomes. METHODS: The 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. RESULTS: 65 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. CONCLUSIONS: The 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.

Adenosine-assisted embolization of cerebral arteriovenous malformations: a systematic review and meta-analysis.

BACKGROUND: Cerebral arteriovenous malformations (AVMs) are complex lesions that can cause hemorrhagic stroke and significant neurological disability. Adenosine induces cardiac standstill and hypotension, which are thought to be useful during cerebral AVM embolization. Herein, we conducted a systematic review and meta-analysis of the technique's safety. METHODS: Following PRISMA guidelines, four databases were queried for studies describing the use of adenosine-assisted embolization of cerebral AVMs. Adenosine-related intraoperative complications, permanent neurological outcomes, morbidity, and mortality assessed the technique's safety. Single proportion analysis under a random-effects model was performed. Heterogeneity was assessed using I² statistics, and publication bias was evaluated through funnel plot analysis and Egger's regression test. RESULTS: Ten studies were included, involving 79 patients (55.7% male) with 79 AVMs (54.4% unruptured and 70.9% Spetzler-Martin grade III-V) who underwent 123 embolizations (80.4% and 5.9% under transarterial and transvenous approaches, respectively) with n-butyl cyanoacrylate (80.4%), ethylene vinyl alcohol (14.4%), or both (5.2%). The incidence of transient adenosine-related intraoperative complications was 0% (95% CI 0% to 3%, I2=24%). Besides, the incidence of adenosine-related morbidity, mortality, and permanent outcomes was 0% (95% CI 0% to 3%, I2=0%). During follow-up, good functional outcomes were reported for 64 patients (81%). CONCLUSIONS: Adenosine's effects on blood flow control can facilitate embolization and mitigate the risk of AVM rupture and embolic agent migration. Although current evidence stems from observational studies, the results of this meta-analysis suggest a safe drug profile due to minimal associated morbidity and mortality. Further research from larger randomized and controlled studies is warranted to attain a higher level of evidence. PROSPERO REGISTRY NUMBER: CRD42023494116.

Pioneering artificial intelligence-based real time assistance for intracranial liquid embolization in humans: an initial experience.

BACKGROUND: Liquid embolization in neuroendovascular procedures carries the risk of embolizing an inappropriate vessel. Operators must pay close attention to multiple vessels during the procedure to avoid ischemic complications. We report our experience with real time artificial intelligence (AI) assisted liquid embolization and evaluate its performance. METHODS: An AI-based system (Neuro-Vascular Assist, iMed technologies, Tokyo, Japan) was used in eight endovascular liquid embolization procedures in two institutions. The software automatically detects liquid embolic agent on biplane fluoroscopy images in real time and notifies operators when the agent reaches a predefined area. Safety, efficacy, and accuracy of the notifications were evaluated using recorded videos. RESULTS: Onyx or n-butyl-2-cyanoacrylate (NBCA) was used in the treatment of arteriovenous malformation, dural arteriovenous fistula, meningioma, and chronic subdural hematoma. The mean number of true positive and false negative notifications per case was 31.8 and 2.8, respectively. No false positive notifications occurred. The precision and recall of the notifications were 100% and 92.0%, respectively. In 28.3% of the true positive notifications, the operator immediately paused agent injection after receiving the notification, which demonstrates the potential effectiveness of the AI-based system. No adverse events were associated with the notifications. CONCLUSIONS: To the best of our knowledge, this is the first report of real time AI assistance with liquid embolization procedures in humans. The system demonstrated high notification accuracy, safety, and potential clinical usefulness in liquid embolization procedures. Further research is warranted to validate its impact on clinical outcomes. AI-based real time surgical support has the potential to advance neuroendovascular treatment.