Increased Multispectral CT Iodine Concentrations in Patients With Transient Neurological Deterioration Following Endovascular Neurointerventional Procedures: an Argument in Favor of the Elusive Contrast-Induced Encephalopathy?

BACKGROUND AND PURPOSE: So-called contrast-induced encephalopathy (CIE) is a rare but worrying condition occurring after cerebral angiography or neuroendovascular interventions using iodine contrast media. This study aimed to compare cerebral iodine concentrations in patients suspected of having CIE after endovascular procedures to those in matched controls. METHODS: This is a retrospective monocentric study of 25 suspected CIE patients in a tertiary care teaching hospital diagnosed from June 2017 to February 2024. Cerebral multispectral computed tomography (CT) iodine mean concentrations were measured and compared with 1:1 matched controls using the CT constructor's workstation in the whole brain and in specific regions of interest (ROIs) corresponding to a vascular territory downstream of the procedure. Concentration values were compared with paired samples t­test. RESULTS: During the study period, 1097 patients underwent aneurysm embolization and 137 arteriovenous malformation (AVM) embolization procedures. So-called CIE was suspected in 25 patients after aneurysm or AVM embolization (2%). Mean iodine concentrations in the procedure vascular territory ROIs were higher in suspected CIE cases (mean 543 ± 147 µg/cm3) compared to matched controls (mean 463 ± 141 µg/cm3; p = 0.01). Whole brain mean iodine concentrations were modestly higher in CIE patients compared to controls across all subgroups, without reaching statistical significance. CONCLUSIONS: CIE may be associated with modest increase in CT iodine concentration in the procedure vascular territory after neurointerventional procedures. The underlying pathophysiology of this condition remains uncertain and merits further investigation. KEY MESSAGES: Contrast-induced encephalopathy (CIE) is known as a rare neurologic condition following iodine contrast media use in neuroendovascular interventions, with unclear pathophysiology. WHAT THIS STUDY ADDS: This study provides evidence that suspected CIE is associated with higher cerebral iodine concentrations in affected vascular territories, a novel quantifiable change. Implications for research, practice, or policy: These findings suggest the potential for iodine concentration monitoring to refine CIE diagnosis and prevention strategies in clinical practice.

Angiographic Evolution of Brain Arteriovenous Malformation Angioarchitecture After Partial Endovascular Treatment.

BACKGROUND AND OBJECTIVES: Endovascular embolization of brain arteriovenous malformations (AVMs) is sometimes intentionally partial, in the case of staged treatment for instance. Residual AVMs may be prone to angioarchitectural modification during follow-up. The objective of this work is to evaluate the nature and extent of these modifications. METHODS: We performed a retrospective monocentric study on a cohort of adult patients treated by incomplete endovascular embolization for ruptured and unruptured AVMs with an available angiographic follow-up, without any intervening confounding event between the 2 angiographic examinations. AVM angioarchitectural modifications (arterial, nidal, and venous) were analyzed. Clinical and radiological data were tested in univariate analyses for association with the occurrence of AVM regression or progression. RESULTS: Eighty-two partial embolization sessions in 57 patients were included in the study. A 40% (33/82) rate of modification was found on follow-up, with 23/82 (28%) controls showing at least one angioarchitectural regression feature and 15/82 (18.3%) showing at least one angioarchitectural progression item. Nidal growth was the most frequent modification occurring after 12/82 (14.6%) embolizations. The only factor associated with nidal volume growth was a longer time interval between embolization and follow-up (median [IQR]: 190 [250] days vs 89.5[133] days in the subgroup without nidal growth; P = .02). Specific modifications of arterial supply, nidal anatomy, and venous drainage were identified and documented. CONCLUSION: Angioarchitectural modifications (both progression and regression) of brain AVMs are frequent findings after partial embolization. Nidal volume growth is associated with longer time intervals between embolization and follow-up.

Comparison of rescue intracranial stenting versus best medical treatment alone in acute refractory large vessel occlusion: study protocol for the PISTAR multicenter randomized trial.

BACKGROUND: Mechanical thrombectomy (MT) has become a standard treatment for acute ischemic strokes (AIS). However, MT failure occurs in approximately 10-30% of cases, leading to severe repercussions (with mortality rates up to 40% according to observational data). Among the available rescue techniques, rescue intracranial stenting (RIS) appears as a promising option. OBJECTIVE: This trial is poised to demonstrate the superiority of RIS in addition to the best medical treatment (BMT) in comparison with BMT alone, in improving the functional outcomes at 3 months for patients experiencing an AIS due to a large vessel occlusion refractory to MT (rLVO). METHODS: Permanent Intracranial STenting for Acute Refractory large vessel occlusions (PISTAR) is a multicenter prospective randomized open, blinded endpoint trial conducted across 11 French University hospitals. Adult patients (≥18 years) with an acute intracranial occlusion refractory to standard MT techniques will be randomized 1:1 during the procedure to receive either RIS+BMT (intervention arm) or BMT alone (control arm). RESULTS: The primary outcome is the rate of good clinical outcome at 3 months defined as a modified Rankin Scale score ≤2 and evaluated by an independent assessor blinded to the randomization arm. Secondary outcomes include hemorrhagic complications, all adverse events, and death. The number of patients to be included is 346. Two interim analyses are planned with predefined stopping rules. CONCLUSION: The PISTAR trial is the first randomized controlled trial focusing on the benefit of RIS in rLVOs. If positive, this study will open new insights into the management of AIS. TRIAL REGISTRATION NUMBER: NCT06071091.

Intracranial dural arteriovenous fistulas: association with cerebral venous thrombosis, baseline aggressiveness, and clinical outcomes. A retrospective multicenter study on 263 consecutive patients and literature review.

OBJECTIVE: The pathogenesis of intracranial dural arteriovenous fistulas (icDAVFs) is controversial. Cerebral vein thrombosis (CVT) and venous hypertension are recognized predisposing factors. This study aimed to evaluate the incidence of association between icDAVF and CVT and describe baseline aggressiveness and clinical outcomes for icDAVFs associated with CVT. The authors also performed a literature review of studies reporting icDAVF associated with CVT. METHODS: Two hundred sixty-three consecutive patients in two university hospitals with confirmed icDAVFs were included. A double-blind imaging review was performed to determine the presence or absence of CVT close or distant to the icDAVF. Location, type (using the Cognard classification), aggressiveness of the icDAVF, clinical presentation, treatment modality, and clinical and/or angiographic outcomes at 6 months were also collected. All prior brain imaging was analyzed to determine the natural history of onset of the icDAVF. RESULTS: Among the 263 included patients, 75 (28.5%) presented with a CVT concomitant to their icDAVF. For 18 (78.3%) of 23 patients with previous brain imaging available, CVT preceding the icDAVF was proven (6.8% of the overall population). Former/active smoking (OR 2.0, 95% CI 1.079-3.682, p = 0.022) and prothrombogenic status (active inflammation or cancer/coagulation trouble) were risk factors for CVT associated with icDAVF (OR 3.135, 95% CI 1.391-7.108, p = 0.003). One hundred eighty-seven patients (71.1%) had a baseline aggressive icDAVF, not linked to the presence of a CVT (p = 0.546). Of the overall population, 11 patients (4.2%) presented with spontaneous occlusion of their icDAVF at follow-up. Seven patients (2.7%) died during the follow-up period. Intracranial DAVF + CVT was not associated with a worse prognosis (modified Rankin Scale score at 3-6 months: 0 [interquartile range {IQR} 0-1] for icDAVF + CVT vs 0 [IQR 0-0] for icDAVF alone; p = 0.055). CONCLUSIONS: This was one of the largest studies focused on the incidence of CVT associated with icDAVF. For 6.8% of the patients, a natural history of CVT leading to icDAVF was proven, corresponding to 78.3% of patients with previous imaging available. This work offers further insights into icDAVF pathophysiology, aiding in identifying high-risk CVT patients for long-term follow-up imaging. Annual imaging follow-up using noninvasive vascular imaging (CT or MR angiography) for a minimum of 3 years after the diagnosis of CVT should be considered in high-risk patients, i.e., smokers and those with prothrombogenic status.

Evaluation of mechanical thrombectomy in acute ischemic stroke related to a distal arterial occlusion: A randomized controlled trial.

RATIONALE: Mechanical thrombectomy (MT) associated with the best medical treatment (BMT) has recently shown efficacy for the management of acute ischemic stroke (AIS) secondary to a large vessel occlusion. However, evidence is lacking regarding the benefit of MT for more distal occlusions. AIM: To evaluate the efficacy in terms of good clinical outcome at 3 months of MT associated with the BMT over the BMT alone in AIS related to a distal occlusion. METHODS: The DISCOUNT trial is a multicenter open-label randomized controlled trial involving French University hospitals. Adult patients (⩾18 years) with an AIS involving the anterior or posterior circulation secondary to a distal vessel occlusion within 6 h of symptom onset or within 24 h if no hyperintense signal on fluid attenuation inversion recovery acquisition will be randomized 1:1 to receive either MT associated with the BMT (experimental group) or BMT alone (control group). The number of patients to be included is 488. STUDY OUTCOMES: The primary outcome is the rate of good clinical outcome at 3 months defined as a modified Rankin scale (mRS) ⩽2 and evaluated by an independent assessor blinded to the intervention arm. Secondary outcomes include recanalization of the occluded vessel within 48 h, angiographic reperfusion in the experimental group, 3-month excellent clinical outcome (mRS ⩽ 1), all adverse events, and death. A cost utility analysis will estimate the incremental cost per quality-adjusted life year (QALY) gained. DISCUSSION: If positive, this study will open new insights in the management of AISs. TRIAL REGISTRATION: ClinicalTrials.gov: NCT05030142 registered on 1 September 2021.

Evaluation of effectiveness and safety of the CorPath GRX robotic system in endovascular embolization procedures of cerebral aneurysms.

BACKGROUND: Robotic-assisted neurointervention was recently introduced, with implications that it could be used to treat neurovascular diseases. OBJECTIVE: To evaluate the effectiveness and safety of the robotic-assisted platform CorPath GRX for treating cerebral aneurysms. METHODS: This prospective, international, multicenter study enrolled patients with brain aneurysms that required endovascular coiling and/or stent-assisted coiling. The primary effectiveness endpoint was defined as successful completion of the robotic-assisted endovascular procedure without any unplanned conversion to manual treatment with guidewire or microcatheter navigation, embolization coil(s) or intracranial stent(s) deployment, or an inability to navigate vessel anatomy. The primary safety endpoint included intraprocedural and periprocedural events. RESULTS: The study enrolled 117 patients (74.4% female) with mean age of 56.6 years from 10 international sites,. Headache was the most common presenting symptom in 40/117 (34.2%) subjects. Internal carotid artery was the most common location (34/122, 27.9%), and the mean aneurysm height and neck width were 5.7±2.6 mm and 3.5±1.4 mm, respectively. The overall procedure time was 117.3±47.3 min with 59.4±32.6 min robotic procedure time. Primary effectiveness was achieved in 110/117 (94%) subjects with seven subjects requiring conversion to manual for procedure completion. Only four primary safety events were recorded with two intraprocedural aneurysm ruptures and two strokes. A Raymond-Roy Classification Scale score of 1 was achieved in 71/110 (64.5%) subjects, and all subjects were discharged with a modified Rankin Scale score of ≤2. CONCLUSIONS: This first-of-its-kind robotic-assisted neurovascular trial demonstrates the effectiveness and safety of the CorPath GRX System for endovascular embolization of cerebral aneurysm procedures. TRIAL REGISTRATION NUMBER: NCT04236856.

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.

Radial artery occlusion after aneurysm treatment using the rist guide catheter: Single center cohort study.

BACKGROUND AND PURPOSE: Delayed radial artery occlusion (dRAO) is a frequent complication after transradial access (TRA) for neurointervention when using standard large guide catheters. The RIST 079 guide catheter (RIST GC) is the first catheter designed for TRA in neurointervention. We aimed to assess the rate of dRAO after intracranial aneurysm (IA) treatment using the RIST GC. METHODS: Patients treated for an IA using TRA and the RIST GC between June 2021 and November 2022 were referred to a systematic US-doppler assessment of the radial artery patency at 3-month follow-up. Patients with and without dRAO were compared to identify risk factors. RESULTS: Twenty-two patients were included in the analysis. At 3-months follow up, 6 patients (27.3 %) presented with dRAO. Four patients were asymptomatic and 2 experienced post-operative radial hematoma and wrist pain. There was a tendency towards younger age, longer procedure duration and higher rate of forearm hematoma in patients with dRAO. Navigation using the RIST GC was successful in 90.9 % of cases. Intracranial access failures and navigation complications were all related to left internal carotid artery navigation. CONCLUSIONS: At 3-month follow up, 27.3 % of patients treated for IA using TRA with the RIST GC presented dRAO.

Safety and effectiveness of the LVIS and LVIS Jr devices for the treatment of intracranial aneurysms: Final results of the LEPI multicenter cohort study.

BACKGROUND: The Low profile visualized intraluminal support (LVIS)/LVIS Jr is a self-expanding braiding stent for the treatment of intracranial aneurysm. This study is to determine the safety and effectiveness of the LVIS/LVIS Jr for the treatment of intracranial aneurysms in a real-world setting. METHODS: This prospective, observational, multicenter study enrolled patients with unruptured, ruptured and recanalized intracranial aneurysms treated with the LVIS stents, between February 2018 to December 2019. Primary endpoint was the cumulative morbidity and mortality rate (CMMR) assessed at 12 months follow-up (FU). RESULTS: A total of 130 patients were included (62.3 % women, mean age 55.9 ± 11.4) on an intention-to-treat basis. Four patients (3.1 %) had 2 target aneurysms; 134 total aneurysms were treated. The aneurysms were mainly located on the middle cerebral artery (41/134; 30.6 %) and the anterior communicating artery (31/134; 23.1 %). The CMMR at 1 year linked to the procedure and/or device was 4.6 % (6/130). The overall mortality was 1.5 % (2/130), none of these deaths adjudged as being linked to the procedure and/or device. All aneurysms (134/134, 100 %) were successfully treated with LVIS stent and/or other devices. At a mean FU of 16.8 months post-procedure, complete/nearly complete occlusion was achieved in 112 aneurysms (92.6 %), and only 3 patients (2.5 %) required aneurysm retreatment. CONCLUSION: This study provides evidence that the LVIS/LVIS Jr devices are safe and effective in the treatment of complex intracranial aneurysms, with very high rates of adequate occlusion at FU. These angiographic results are stable over time with an acceptable complication rate. TRIAL REGISTRATION: ClinicalTrial.gov under NCT03553771.

Location specific rupture risk of intracranial aneurysms: case of ophthalmic aneurysms.

BACKGROUND: Aneurysm location is a key element in predicting the rupture risk of an intracranial aneurysm. A common impression suggests that pure ophthalmic aneurysms are under-represented in ruptured intracranial aneurysms (RIAs). The purpose of this study was to specifically evaluate the risk of rupture of ophthalmic aneurysms compared with other aneurysm locations. METHODS: This multicenter study compared the frequency of ophthalmic aneurysms in a prospective cohort of RIAs admitted to 13 neuroradiology centers between January 2021 and March 2021, with a retrospective cohort of patients with unruptured intracranial aneurysms (UIAs) who underwent cerebral angiography at the same neuroradiology centers during the same time period. RESULTS: 604 intracranial aneurysms were included in this study (355 UIAs and 249 RIAs; mean age 57 years (IQR 49-65); women 309/486, 64%). Mean aneurysm size was 6.0 mm (5.3 mm for UIAs, 7.0 mm for RIAs; P<0.0001). Aneurysm shape was irregular for 37% UIAs and 73% RIAs (P<0.0001). Ophthalmic aneurysms frequency was 14.9% of UIAs (second most common aneurysm location) and 1.2% of RIAs (second least common aneurysm location; OR 0.07 (95% CI 0.02 to 0.23), P<0.0001). CONCLUSIONS: Ophthalmic aneurysms seem to have a low risk of rupture compared with other intracranial aneurysm locations. This calls for a re-evaluation of the benefit-risk balance when considering preventive treatment for ophthalmic aneurysms.

Longitudinal radiological follow-up of individual level non-ischemic cerebral enhancing lesions following endovascular aneurysm treatment.

BACKGROUND: Non-ischemic cerebral enhancing (NICE) lesions following aneurysm endovascular therapy are exceptionally rare, with unknown longitudinal evolution. OBJECTIVE: To evaluate the radiological behavior of individual NICE lesions over time. METHODS: Patients included in a retrospective national multicentric inception cohort were analyzed. NICE lesions were defined, using MRI, as delayed onset punctate, nodular, or annular foci enhancements with peri-lesion edema, distributed in the vascular territory of the aneurysm treatment, with no other confounding disease. Lesion burden and the longitudinal behavior of individual lesions were assessed. RESULTS: Twenty-two patients were included, with a median initial lesion burden of 36 (IQR 17-54) on the first MRI scan. Of the 22 patients with at least one follow-up MRI scan, 16 (73%) had new lesions occurring mainly within the first 200 weeks after the date of the procedure. The median number of new lesions per MRI was 6 (IQR 2-16). Among the same 22 patients, 7 (32%) had recurrent lesions. The median persistent enhancement of a NICE lesion was 13 weeks (IQR 6-30). No factor was predictive of early regression of enhancement activity with lesion regression kinetics mainly being patient-dependent. CONCLUSIONS: The behavior of individual NICE lesions was found to be highly variable with an overall patient-dependent regression velocity.

'Pressure cooker' and 'balloon pressure' techniques significantly increase 3-month complete occlusion rate after spinal arteriovenous fistula embolization as compared to glue: single center evaluation on 38 consecutive patients.

BACKGROUND: Spinal arteriovenous fistulas can be treated either by surgery or by endovascular means, using different strategies. The main drawback of embolization is the risk of recurrence. Our objective is to evaluate the angiographic occlusion rate and the predictive factors of angiographic cure of spinal arteriovenous fistulas at 3 months or more after embolization. METHODS: This is a retrospective single-center study including 38 consecutive patients with spinal arteriovenous fistulas treated by embolization as first-line treatment. We reviewed clinical and imaging data, complications, and the immediate angiographic occlusion rate of the fistulas, and at 3 months or more after the embolization. RESULTS: A total of 45 embolization procedures were performed: 30 procedures using glue, 15 using Onyx by 'pressure cooker' or 'balloon pressure' techniques. We observed no statistically significant difference between the two groups concerning the immediate angiographic occlusion rate (87% in both groups; P>0.9), as well as for periprocedural complication rates. The angiographic occlusion rate at 3 months or more was higher in the Onyx 'combined' techniques treated group (87% vs 40%, P=0.007). The use of Onyx 'combined' techniques was independently associated with angiographic cure at 3 months after embolization (P=0.029). No other factors were identified as predictive of angiographic cure and clinical recovery after embolization procedures, nor were any predictive factors identified for the occurrence of periprocedural complications. CONCLUSION: Embolization of spinal arteriovenous fistulas with Onyx using 'combined' techniques appears to be safe and associated with a higher rate of angiographic occlusion at 3 months than regular embolization with glue.

Balloon Pressure Technique with the Scepter Mini Balloon as Part of the Endovascular Strategy for Brain Arteriovenous Malformations Embolization : Preliminary Multicenter Experience.

BACKGROUND: The balloon pressure technique (BPT) is an alternative to the pressure cooker technique. A dual lumen balloon (DLB) is used to inject the liquid embolic agent through the working lumen while the balloon is inflated. The purpose of our study was to report our early experience using the Scepter Mini dual lumen balloons for BPT in brain arteriovenous malformation (bAVM) embolization. MATERIAL AND METHODS: Consecutive patients treated from July 2020 to July 2021 in 3 tertiary centers using the BPT with low-profile dual lumen balloons (Scepter Mini, Microvention, Tustin, CA, USA) by endovascular means for bAVMs were retrospectively reviewed. Patient demographics and bAVM angio-architectural features were collected. The feasibility of Scepter Mini balloon navigation close to the nidus was evaluated. Technical as well as clinical (ischemic and/or hemorrhagic) complications were also systematically assessed. The occlusion rate was evaluated on follow-up DSA. RESULTS: A total of 19 patients (10 females; mean age = 38.2 years) consecutively treated for a bAVM (8 ruptured/11 unruptured) using the BPT with a Scepter Mini through 23 embolization sessions were included in our series. Navigation of the Scepter Mini was feasible in all cases. Of the patients 3 (16%) had procedure-related ischemic stroke and 2 patients (10.5%) had late hemorrhages. None of these complications led to severe permanent sequela. Complete occlusion of bAVM embolized with intention to cure was recorded in 11/13 cases (84.6%). CONCLUSION: The BPT using low-profile dual lumen balloons is feasible and seems safe for embolization of bAVMs. It may help to reach high occlusion rates, especially when performed in the intent to cure by embolization only.

Nidus Compacity Determined by Semi-Automated Segmentation is a Strong Quantitative Predictor of Brain Arterio-Venous Malformation Cure.

BACKGROUND AND OBJECTIVE: A compact nidus is a well-known feature of good outcome after treatment in brain arteriovenous malformations (bAVM). This item, included in the "Supplementary AVM grading system" by Lawton, is subjectively evaluated on DSA. The present study aimed to assess whether quantitative nidus compacity along with other angio-architectural bAVM features were predictive of angiographic cure or the occurrence of procedure-related complications. MATERIALS AND METHODS: Retrospective analysis of 83 patients prospectively collected data base between 2003 to 2018 having underwent digital subtraction 3D rotation angiography (3D-RA) for pre-therapeutic assessment of bAVM. Angio-architectural features were analyzed. Nidus compacity was measured with a dedicated segmentation tool. Univariate and multivariate analyses were performed to test the association between these factors and complete obliteration or complication. RESULTS: Compacity was the only significant factor associated with complete obliteration in our predictive model using logistic multivariate regression; the area under the curve for compacity predicting complete obliteration was excellent (0.82; 95% CI 0.71-0.90; p < 0.0001). The threshold value maximizing the Youden index was a compacity > 23% (sensitivity 97%; specificity 52%; 95% CI 85.1-99.9; p = 0.055). No angio-architectural factor was associated with the occurrence of a complication. CONCLUSION: Nidus high compacity quantitatively measured on 3D-RA, using a dedicated segmentation tool is predictive of bAVM cure. Further investigation and prospective studies are warranted to confirm these preliminary results.

The Egyptian Escalator: Gaining access to distal parent vessel in giant and large aneurysms.

Flow-diverter stents have become the mainstay of endovascular treatment for giant and large intracranial aneurysms. However, the local aneurysmal hemodynamics, the incorporation of the parent vessel and the frequent wide-neck configuration render gaining stable distal parent artery access difficult. In this technical video, we present three cases in which we employed the so called "Egyptian Escalator technique" for obtaining and maintaining stable distal access: after looping the microwire and microcatheter inside the aneurysmal sac and exiting in the distal parent artery, we deployed a stent-retriever and utilized a gentle traction on the microcatheter in order to straighten the intra-aneurysmal loop. Afterwards, a flow-diverter stent was deployed, with optimal coverage of the aneurysmal neck. The "Egyptian Escalator" technique provides a useful approach for obtaining stable distal access for flow-diverter deployment in giant and large aneurysm (supplementary mmc1 (Video 1)).

Endovascular treatment as first-line therapy in Spetzler-Martin grade III brain arteriovenous malformations: a multicenter retrospective study.

OBJECTIVE: The management of Spetzler-Martin grade (SMG) III brain arteriovenous malformations (bAVMs) may be challenging, whatever the exclusion treatment modality chosen. The purpose of this study was to evaluate the safety and effectiveness of endovascular treatment (EVT) as a first-line treatment of SMG III bAVMs. METHODS: The authors performed a retrospective, two-center, observational cohort study. Cases recorded in institutional databases between January 1998 and June 2021 were reviewed. Patients who were ≥ 18 years of age, had ruptured or unruptured SMG III bAVMs, and received EVT as first-line therapy were included. Baseline characteristics of patients and bAVMs, procedure-related complications, clinical outcome according to the modified Rankin Scale, and angiographic follow-up were assessed. The independent risk factors of procedure-related complications and poor clinical outcome were assessed using binary logistic regression. RESULTS: One hundred sixteen patients with 116 SMG III bAVMs were included. The mean age of the patients was 41.9 ± 14.0 years. The most common presentation was hemorrhage (66.4%). Forty-nine (42.2%) bAVMs were found to be completely obliterated by EVT alone at follow-up. Complications occurred in 39 patients (33.6%), including 5 (4.3%) major procedure-related complications. There was no independent predictor of procedure-related complication. Age > 40 years and poor preoperative modified Rankin Scale score were the independent predictors of poor clinical outcome. CONCLUSIONS: EVT of SMG III bAVMs provides encouraging results but needs further improvement. When the embolization procedure performed with intent to cure appears difficult and/or risky, a combined technique (with microsurgery or radiosurgery) may be a safer and more effective strategy. In terms of safety and effectiveness, the benefit of EVT (alone or included in a multimodal management strategy) for SMG III bAVMs needs to be confirmed by randomized controlled trials.

Superselective 3D digital subtraction angiography and magnetic resonance fusion imaging for the management of micro-arteriovenous malformations.

Cerebral micro-arteriovenous malformations (AVM) are defined by an infracentimetric nidus or a nidus solely visible on superselective digital subtraction angiography (DSA).12 While representing a minority of brain AVMs, intracerebral hemorrhage is a frequent manifestation in this subset of AMVs.2 Micro-AVMs are often occult lesions, with superselective DSA being instrumental for increasing diagnostic yield.13 While superselective three-dimensional DSA (3D-DSA)/MR fusion imaging has been employed to better delineate anatomical proximity in cerebral AVMs with a visible nidus on MRI,4 this fusion algorithm has not yet been used for describing the relationship of micro-AVMs nidus and afferent arteries with neighboring structures, in order to guide endovascular and microsurgical procedures. In this technical video (Video 1), we present 3 cases regarding micro-AVM embolization, in which superselective 3D-DSA/MR fusion imaging aided therapeutic decision, by defining the local anatomy and allowing a safer procedure.

'Balloon pressure technique' for endovascular treatment of spinal cord arteriovenous fistulas: preliminary results in 10 cases.

BACKGROUND: Spinal arteriovenous fistulas (SAVFs) are challenging lesions to treat by endovascular means. Our purpose was to report our early experience with dual lumen balloons (DLBs) for embolization of SAVFs using ethylene vinyl alcohol (EVOH) (the so-called 'balloon pressure technique' (BPT)). MATERIALS AND METHODS: During the inclusion period, 10 consecutive patients (nine men, mean age 61.6 years) underwent endovascular treatment of a SAVF (seven dural SAVFs and three epidural SAVFs) at a single institution using the BPT. DLBs were used in all cases. In seven cases (70%), a regular DLB was used, while in three cases (30%), low profile DLBs were used. EVOH was used as the liquid embolic agent in all cases. Technical and clinical complications were systematically recorded. Clinical and angiographic outcomes were systematically evaluated more than 3 months after the procedure. RESULTS: Complete cure of the SAVF by endovascular means alone was obtained in 80% of cases (8/10). For the two patients with incomplete SAVF occlusion, surgery was successfully performed secondarily. No recurrence was found at the 3 month follow-up in the eight patients for whom complete occlusion was obtained at the end of the embolization procedure. No permanent clinical complication was recorded using the BPT. Clinical improvement was observed in 6/10 (60%) cases. CONCLUSION: BPT was a feasible technique, with regular or low profile DLBs, for embolization of SAVFs. Our preliminary results suggest the safety and effectiveness of this technique.

Long-Term Middle Meningeal Artery Caliber Reduction Following Trisacryl Gelatine Microsphere Embolization for the Treatment of Chronic Subdural Hematoma.

PURPOSE: Middle meningeal artery (MMA) particle embolization is a promising treatment of chronic subdural hematomas (CSDH). The main purpose of this study is to measure MMA proximal caliber and assess the visibility of the two main MMA branches as a surrogate for long-term distal arterial patency following MMA CSDH embolization with trisacryl gelatine microspheres (TAGM). METHODS: This is a single-center retrospective study. All patients having undergone MMA TAGM only embolization for CSDH treatment between 15 March 2018 and 6 June 2020 with an interpretable follow-up magnetic resonance imaging (MRI) examination and no confounding factors were included. Patients were compared with controls matched for age, sex and MRI machine. Two independent readers analyzed the MRI images. RESULTS: In this study, 30 patients having undergone embolization procedures using TAGM of 36 MMAs were included. The follow-up MRI scans were performed after a mean delay of 14.8 ± 7.1 months (range 4.9-29.4 months). The mean diameter of TAGM embolized MMAs (1 mm; 95% confidence interval, CI 0.9-1.1) was significantly smaller than the mean diameter of paired control MMAs (1.3 mm; 95% CI 1.3-1.4) (p < 0.001). The mean proximal diameter of the embolized MMAs (0.9 mm; 95% CI 0.7-1.1) was significantly smaller than the mean diameter of the contralateral MMAs in the same patients (1.4 mm; 95% CI 1.3-1.6)(p < 0.001). CONCLUSION: Long-term follow-up MRI demonstrated a significant impact of TAGM embolization on MMA proximal caliber as well as on the visibility of the two main MMA branches. All comparisons indicated that there was a probable lasting impact of embolization on the patency of distal branches.

The human placenta as a model for training and research in mechanical thrombectomy: Clarifications and use of the chorionic plate veins.

Indications for mechanical thrombectomy in acute ischemic stroke are increasing, resulting in the continuous development of new devices and techniques. Therefore, there is a need for a realistic testing and training environment that offers the opportunity to practice different procedures and test the latest devices. Some authors have described the use of the human placenta as a model for neurointerventional surgery, with striking similarities to real-life conditions. This model has many advantages, including its relatively low cost and minimal infrastructure requirements, with fewer ethical concerns compared to animal models. So far, some preparation and set-up details were missing, and only arteries from the chorionic plate were used. This article provides the necessary clarifications and a mapping of the chorionic plate veins, so that the use of this model, which is particularly well suited for mechanical thrombectomy, can be as easy and wide as possible. A video explaining how to prepare the model is provided.