Additional Coil Research Articles

Integrated ${LCC} $ Compensation Topology for Wireless Charger in Electric and Plug-in Electric Vehicles

This paper presents an integrated <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$LCC$</tex-math></inline-formula> compensation topology for electric vehicle/plug-in hybrid electric vehicle wireless chargers. The effect of the coupling between the additional coil and the main coil on the <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$LCC$</tex-math></inline-formula> compensation topology is studied. The proposed topology will reduce the size of the additional coil and make the system more compact with extremely high efficiency. The basic characteristics of the proposed topology are analyzed based on fundamental harmonic approximation. Furthermore, based on the steady-state model, three categories of operation modes are presented and analyzed. In order to realize zero-voltage switching, the series capacitor <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$C_{2} $</tex-math></inline-formula> on the secondary side is tuned. A numerical method is used to analyze the impact of different values of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\Delta C_{2}$</tex-math></inline-formula> on the turnoff current, and the best value of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$C_{2}$</tex-math></inline-formula> is chosen to build a prototype to verify the analysis.

Transrenal Antegrade Ureteral Occlusion: Clinical Assessment of Indications, Technique and Outcomes

We describe the indications, technique and outcome of transrenal antegrade ureteral occlusion. An institutional database was used to retrospectively identify patients who underwent image guided transrenal ureteral occlusion between December 1998 and March 2014. Platinum coils were deployed into the distal ureter or 4 to 5 cm proximal to the site of ureteral leak. Gelfoam® pledgets were injected in the ureter at the level of the coils. Additional coils were deployed to trap the pledgets in the distal ureter. Between December 1998 and March 2014, 12 men and 12 women with a mean age of 69 years (range 45 to 87) underwent fluoroscopically guided, transrenal antegrade ureteral occlusion for intractable hematuria in 7 and urinary fistula in 17. A total of 39 ureteral units were occluded, including 3 on the right side, 6 on the left side and 30 that were bilateral. Ureteral occlusion was successful in 35 of 37 renal units (94.6%) as determined by post-procedure antegrade nephrostogram and resolution of clinical symptoms of hematuria and/or urinary leakage. Repeat occlusion was necessary to achieve total ureteral occlusion in 2 of 35 renal units (5.7%). Percutaneous ureteral occlusion with platinum coils and Gelfoam offers a treatment option for patients with refractory urinary fistula and intractable hematuria in whom standard methods of urinary diversion fail.

A Fuzzy-P controller of an active reaction force compensation (RFC) mechanism for a linear motor motion stage

Residual vibration of system base due to high-speed motion of a stage may significantly reduce life span and productivity of the manufacturing equipment. Although a passive reaction force compensation (RFC) mechanism was developed to reduce residual vibration of a linear motor motion stage, the passive RFC mechanism should be redesigned according to variation of motion profiles. In this paper, we develop a fuzzy-P (proportional) controller of an active RFC mechanism to automatically tune the gain according to variation of motion profiles. First, frequency components of motion profiles for a linear motion stage are analyzed and performances of the passive RFC mechanism are approximately evaluated using a motion profile analysis. An active RFC mechanism with an additional control coil is introduced to overcome limitation of the passive RFC mechanism and a fuzzy rule is proposed to automatically tune the P controller of the active RFC mechanism according to variations of motion profiles. Simulations and experiments are performed to show effectiveness of the proposed fuzzy rule for tuning the P control gain of the active RFC mechanism.

AN ANALYSIS OF THE ELECTROMAGNETIC PROCESSES IN THE INDUCTOR SYSTEM – TOOL OF THE STRAIGHTENING OF CAR BODIES

Introduction. One of the promising directions of electromagnetic forming (EMF) is a contactless magnetic-pulse straightening of the automobile bodies. The efficiency and the quality of the straightening depend on design and operating principle of the straightening tool. In the modern technique of EMF a large number of the tools - inductor systems (IS) is used in different configurations with uneven distribution forces on the treatment object that in turn does not meet the needs of the effective process of straightening. There appears the urgent necessity to create IS with high uniformity of the induced field and a high concentration of attracting forces in the working area of the tool. The most effective IS are the Inductor Systems with an Attracting Screen (ISAS). One of the most important considerations when choosing a particular design ISAS is the study of the electrodynamics processes with definition of excited loads. The nature and the course of the electrodynamics processes in accordance with design features determine the effectiveness and the efficiency of the ISAS. Therefore, in ISAS an additional coil for the concentration of the attracting forces in the working area should be entered. Purpose. The numerical analysis of the induced fields and the currents in the experimental models of ISAS with an additional coil was made. Methodology. In the idealization of the «extremely low» frequencies of existing fields, there were received rated dependences for density of the induced currents and distributed attracting force in ISAS and the external additional coil, through the use of the calculated model in the cylindrical coordinate system. Results. Insertion of the additional coil placed over the accessory screen allows to concentrate and increase the amplitude of the attracting forces in the central part of the working area of the inductor system. Practical value. 1. Numerical analysis of fields and currents in experimental models of Induction Systems with Attracting Screen (ISAS) and additional coil, designed to align the metal coatings of vehicles was made. 2. It is shown that if in ISAS they insert additional coil placed over the accessory screen significantly increases the amplitude of excited forces of attraction. 3. It is shown that the parallel connection of the primary and additional coils in ISAS allows to concentrate the forces of attraction in the centre of the working area of the tool for straightening automobile bodies.

Alternate Oscillation between Scissors and Quadrupole Modes in Sodium Bose–Einstein Condensates

Using an additional off-axis Helmholtz coil, we modulated the strength of a magnetic field at the center of a cloverleaf trap for sodium Bose–Einstein condensates so that it passed through zero for a few milliseconds. At a modulation time of 1 ms, a scissors mode and a high-lying quadrupole mode were generated independently, which had the same Landau damping rates of 39(10) 1/s. However, at 2 ms, alternate oscillation between the scissors mode and the high-lying quadrupole mode, whose frequency was twice that of the scissors mode, was observed with the frequency of the low-lying quadrupole mode.

Treatment of male varicoceles by transcatheter polidocanol foam sclerotherapy: evaluation of clinical success, complications, and patients' satisfaction with regard to alternative techniques.

We report our experience with polidocanol foam sclerotherapy with no additional coils, evaluating clinical success, patients' satisfaction, and complications. We conducted a retrospective study of 141 patients with 146 varicoceles (mean age: 29.3 years; range: 13 - 60 years) who underwent foam sclerotherapy with polidocanol 2% (range: 2 - 12 ml) in an outpatient setting between January 2007 and December 2013. For the follow-up, telephone interviews with the patients were conducted (mean follow-up time: 46.4 months, standard deviation: 20.17 months). The technical success rate was 91.8%. There was a 55.8% response rate to the telephone interviews. Follow-up revealed a clinical success rate of 83.9% and a persistence or relapse rate of 16.1%. Of the patients, 81.9% were absolutely satisfied with the outcome. In 94.9% of cases, pain or discomfort resolution was reported, and in 97% of cases, aesthetic issues were no longer a problem. Of partners, 63.2% achieved pregnancy, and in 50% of patients with preprocedural testicular atrophy, catch-up growth was observed. One patient with pampiniform plexus phlebitis received inpatient treatment with no long-term damage recorded. Polidocanol foam varicocele sclerotherapy is a safe and effective procedure, with a high rate of patients' satisfaction, clinical and technical success, and considerable catch-up growth and pregnancy achievement. • Varicocele treatment using polidocanol foam sclerotherapy is a safe and effective procedure. • It is easily feasible in an outpatient setting. • The clinical and technical success rates are high. • It shows a high rate of patients' satisfaction and symptom resolution. • Postinterventional catch-up growth and pregnancy achievement are considerable.

A Viscosity and Density Sensor Based on Diamagnetically Stabilized Levitation

We investigate the feasibility of viscosity and density measurements using diamagnetically stabilized levitation of a floater magnet on pyrolytic graphite. This principle avoids any clamping structures in the measurement chamber and is, therefore, not suffering under unknown mounting conditions and is furthermore easy to integrate into microfluidic systems. The only part that has to be in contact with the liquid is the floater magnet. Immersing it in a liquid, buoyancy forces will come into play. Keeping the levitation height of the floater magnet constant in different liquid surroundings by accordingly adjusting the lifter magnet, the buoyancy force and, therefore, the density of the fluid can be determined from these adjustments. For more accurate results, a magnetic field modeling was used to determine the levitation height of the floater magnet out of the superposed magnetic fields of both magnets. For viscosity measurements, we add an additional ac-driven coil to the setup, which yields a superposed alternating force on the floater magnet causing periodic vibrations of the floater magnet. The vibrations are damped according to the viscosity of the surrounding fluid. By performing a frequency sweep, the frequency response of the damped spring mass resonator can be obtained where the resonance frequency for our setup is around 6 Hz. Furthermore, the influence of the levitation height on the resonance characteristics was examined by studying the resonance frequency and quality factor for different lifter magnet positions.

Simulation and experimental results of hybrid electric machine with a novel flux control strategy

Abstract The paper presents selected simulation and experimental results of a hybrid ECPMS-machine (Electric Controlled Permanent Magnet Synchronous Machine). This permanent magnets (PMs) excited machine offers an extended magnetic field control capability which makes it suitable for battery electric vehicle (BEV) drives. Rotor, stator and the additional direct current control coil of the machine are analyzed in detail. The control system and strategy, the diagram of power supply system and an equivalent circuit model of the ECPMS-machine are presented. Influence of the additional excitation on the performance parameters of the machine, such as: torque, efficiency, speed limits and back-EMF have also been discussed.

A Field Cancellation Signal Extraction Method for Magnetic Particle Imaging

In nowadays Magnetic Particle Imaging (MPI) signal detection and excitation happens at the same time. This concept, however, leads to strong coupling of the drive (excitation) field (DF) with the receive chain. As the induced DF signal is several orders of magnitude higher, special measures have to be taken to suppress this signal portion within the receive signal to keep the required dynamic range of the subsequent analog to digital conversion in a technically feasible range. For "frequency space MPI" high-order band-stop-filters have been successfully used to remove the DF signals, which unfortunately as well removes the fundamental harmonic components of the signal of the magnetic nanoparticles (MNP). According to the Langevin theory the fundamental harmonic component has a large signal contribution and is important for direct reconstruction of the particle concentration. In order to separate the fundamental harmonic component of the MNP from the induced DF signal, different concepts have been proposed using signal cancelation based on additional DF signals, also in combination with additional filtering. In this paper, we propose a field-cancelation (FC) concept in which a receive coil (RC) consists of a series connection of a primary coil in combination with an additional cancelation coil. The geometry of the primary coil was chosen to be sensitive for the MNP signal while the cancelation coil was chosen to minimize the overall inductive coupling of the FC-RC with the DF. Sensitivity plots and mutual coupling coefficients were calculated using a thin-wire approximation. A prototype FC-RC was manufactured and effectiveness of the reduction of the mutual inductive coupling (d) was tested in an existing mouse MPI scanner. The difference between simulations (ds =70 dB) and the measurements (dms =55 dB) indicated the feasibility as well as the need for further investigations.

Bare Metal Stents for Treatment of Extracranial Internal Carotid Artery Aneurysms

Purpose: To examine the long-term outcomes of bare metal stent placement for exclusion of extracranial internal carotid artery (ICA) aneurysms. Methods: From 2006 to 2011, 7 consecutive symptomatic patients (4 men; mean age 52 years) with surgically inaccessible extracranial ICA aneurysms were treated with a bare stent at a single center. Patients received clopidogrel for 3 months after the procedure and aspirin for life. Clinical follow-up with duplex ultrasound and/or computed tomographic angiography was performed at 3, 6, and 12 months and yearly thereafter. Results: All procedures were technically successful; no neurological complications occurred. After 6 months, there was complete thrombosis of the aneurysm in all except one case. In this asymptomatic patient, the residual active flow was successfully obliterated by additional coil embolization. Over a mean follow-up of 57±22 months, all patients were alive and free of local or central neurological symptoms. All stents were patent, and thrombosis of the aneurysms was complete. Conclusion: In this small series, treatment of extracranial ICA aneurysms with a bare stent seems technically feasible and safe. All treated extracranial ICA aneurysms were excluded by primary intervention or secondary coil embolization.

In vivo demonstration of magnetic guidewire steerability in a MRI system with additional gradient coils.

To assess the ability to control the steering of a modified guidewire actuated by the magnetic force of a magnetic resonance imaging system with additional gradient coils for selective arterial catheterization in rabbits. Selective catheterizations of the right renal artery, left renal artery, superior mesenteric artery, and iliac artery were performed on two rabbits. A 3D magnetic force was applied onto a magnetic bead placed at the tip of a guidewire. The ability of the guidewire to advance in the aorta without entering the side branches when the magnetic force was not applied was also evaluated. Steering of the guidewire was combined with a dedicated tracking system and its position was registered on the 3D model of a magnetic resonance angiography (MRA). The magnetic catheterization of the renal arteries was successful and showed reproducibility. Superior mesenteric artery and iliac artery showed that the catheterization was feasible. These two arteries were difficult to visualize on MRA, making catheterization and setting the direction of the force more difficult. There was no inadvertent catheterization of side vessels when the guidewire was advanced with magnetic steering despite the hook shape at the tip of the guidewire caused by the alignment of the bead anisotropy with the permanent magnetic field. This first evaluation of selective catheterization of aortic branches with a magnetic guidewire provided a successful steering in the less angled side branches and this modified guidewire was advanced in the aorta without inadvertent selective catheterization when manipulated without magnetic actuation.

Sensing Physical Fluid Properties in Microcavities Utilizing Diamagnetic Levitation

This contribution presents a concept for the measurement of density and viscosity of fluids in microfluidic systems. To do so, we utilize diamagnetically stabilized levitation of a small floater magnet, which is integrated and confined in a small cavity. When liquid is fed into the microreactor, buoyancy forces act on the floater magnet. Keeping the levitation height of the floater magnet constant in different liquid surroundings by accordingly adjusting the lifter magnet, the buoyancy force and, therefore, the density of the fluid can be determined. For viscosity measurements, we add an additional ac-driven coil to the setup, which yields a superposed alternating force causing periodic vibrations of the floater magnet. The vibrations are damped according to the viscosity of the surrounding fluid. By performing a frequency sweep, the frequency response of the damped spring mass resonator can be obtained.

Analytic quantification of bias and variance of coil sensitivity profile estimators for improved image reconstruction in MRI.

Magnetic resonance (MR) imaging provides a unique in-vivo capability of visualizing tissue in the human brain non-invasively, which has tremendously improved patient care over the past decades. However, there are still prominent artifacts, such as intensity inhomogeneities due to the use of an array of receiving coils (RC) to measure the MR signal or noise amplification due to accelerated imaging strategies. It is critical to mitigate these artifacts for both visual inspection and quantitative analysis. The cornerstone to address this issue pertains to the knowledge of coil sensitivity profiles (CSP) of the RCs, which describe how the measured complex signal decays with the distance to the RC. Existing methods for CSP estimation share a number of limitations: (i) they primarily focus on CSP magnitude, while it is known that the solution to the MR image reconstruction problem involves complex CSPs and (ii) they only provide point estimates of the CSPs, which makes the task of optimizing the parameters and acquisition protocol for their estimation difficult. In this paper, we propose a novel statistical framework for estimating complex-valued CSPs. We define a CSP estimator that uses spatial smoothing and additional body coil data for phase normalization. The main contribution is to provide detailed information on the statistical distribution of the CSP estimator, which yields automatic determination of the optimal degree of smoothing for ensuring minimal bias and provides guidelines to the optimal acquisition strategy.

Covered stents for the endovascular treatment of a direct carotid cavernous fistula : single center experiences with 10 cases.

ObjectiveCovered stent has been recently reported as an effective alternative treatment for direct carotid cavernous fistulas (DCCFs). The purpose of this study is to describe our experiences with the treatment of DCCF with covered stents and to evaluate whether a covered stent has a potential to be used as the first choice in selected cases.MethodsFrom February 2009 through July 2013, 10 patients underwent covered stent placement for a DCCF occlusion. Clinical and angiographic data were retrospectively reviewed.ResultsCovered stent placement was performed for five patients primarily as the first choice and in the other five as an alternative option. Access and deployment of a covered stent was successful in all patients (100%) and total occlusion of the fistula was achieved in nine (90%). Complete occlusion immediately after the procedure was obtained in five patients (50%). Endoleak persisted in five patients and the fistulae were found to be completely occluded by one month control angiography in four. The other patient underwent additional coil embolization by a transvenous approach. Balloon inflation-related arterial dissection during the procedure was noted in two cases; healing was noted at follow-up angiography. One patient suffered an asymptomatic internal carotid artery occlusion noted seven months post-treatment.ConclusionAlthough endoleak is currently a common roadblock, our experience demonstrates that a covered stent has the potential to be used as the first choice in DCCF; this potential is likely to increase as experience with this device accumulates and the materials continue to improve.

Endovascular Treatment of Vertebral Artery Dissecting Aneurysms That Cause Subarachnoid Hemorrhage : Consideration of Therapeutic Approaches Relevant to the Angioarchitecture.

ObjectiveIntracranial ruptured vertebral artery dissecting aneurysms (VADAns) are associated with high morbidity and mortality when left untreated due to the high likelihood of rebleeding. The present study aimed to establish an endovascular therapeutic strategy that focuses specifically on the angioarchitecture of ruptured VADAns.MethodsTwenty-three patients with ruptured VADAn received endovascular treatment (EVT) over 7 years. The patient group included 14 women (60.9%) and 9 men (39.1%) between the ages of 39 and 72 years (mean age 54.2 years). Clinical data and radiologic findings were retrospectively analyzed.ResultsFour patients had aneurysms on the dominant vertebral artery. Fourteen (61%) aneurysms were located distal to the posterior inferior cerebellar artery (PICA). Six (26%) patients had an extracranial origin of the PICA on the ruptured VA, and 2 patients (9%) had bilateral VADAns. Eighteen patients (78%) were treated with internal coil trapping. Two patients (9%) required an adjunctive bypass procedure. Seven patients (30%) required stent-supported endovascular procedures. Two patients experienced intra-procedural rupture during EVT, one of which was associated with a focal medullary infarction. Two patients (9%) exhibited recanalization of the VADAn during follow-up, which required additional coiling. No recurrent hemorrhage was observed during the follow-up period.ConclusionEVT of ruptured VADAns based on angioarchitecture is a feasible and effective armamentarium to prevent fatal hemorrhage recurrence with an acceptable low risk of procedural complications. Clinical outcomes depend mainly on the pre-procedural clinical state of the patient. Radiologic follow-up is necessary to prevent hemorrhage recurrence after EVT.

Plan for Testing High-Current Superconductors for Fusion Reactors with A 15T Test Facility

Fusion power plants need larger scale and higher field superconducting magnets than the ITER magnets. Therefore, higher current superconductors with high strength against strong electromagnetic forces are needed. In order to examine the superconducting properties of such large conductors in real conditions, we are preparing a new test facility that is equipped with a solenoid coil of the highest field of 13 T with the bore of 0.7 m, a pair of temperature-variable current leads, and a vacuum chamber for conductor samples. The highest field can be increased to 15 T by installing an additional coil with the cold bore of 0.6 m. Since the inlet temperature of the samples can be varied from 4.4 K to 50 K, it is possible to examine properties of advanced conductors at actual operating temperatures including high-temperature superconductors. We propose coil-shaped conductor samples instead of straight samples in order to apply electromagnetic hoop forces on the conductors to realize the real condition. A reference design of a sample for a cable-in-conduit conductor is provided.

Oclusão Percutânea da Persistência do Ducto Arterioso

Introducao: A persistencia do ducto arterioso e uma condicao congenita de alta morbidade, especialmente em recem-nascidos prematuros de extremo baixo peso, representando 5 a 10% das cardiopatias congenitas. Nosso objetivo foi descrever as abordagens realizadas em hospital de referencia para o tratamento da persistencia do ducto arterioso com o metodo percutâneo de oclusao. Metodos: Foi realizado estudo retrospectivo do tratamento transcateter da persistencia do ducto arterioso no periodo de abril de 2008 a abril de 2010. Resultados: Foram revisados 47 casos, a maioria (78,8%) tratada com molas Flipper®; os demais tratados com a protese Amplatzer®. A configuracao morfologica ductal foi do tipo A de Krichenko em 89,4% (34 no grupo molas Flipper® e 8 no grupo Amplatzer®), tipo D em 6,4% (2 no grupo molas Flipper® e 1 no grupo Amplatzer®) e tipo E em 4,2% (1 em cada grupo) dos pacientes. Os diâmetros minimos pre-cateterismo foram de 2,6 ± 0,8 mm e 3,8 ± 1,6 mm para os grupos de molas Flipper® e Amplatzer®, respectivamente. Obteve-se oclusao imediata total do defeito na angiografia de controle em 72,3% dos pacientes tratados. Sete pacientes tratados com molas Flipper® receberam molas adicionais e os tratados com protese Amplatzer® mostraram apenas shunts residuais minimos em dois casos. Nao ocorreram complicacoes do procedimento. No acompanhamento apos a alta, um paciente permaneceu com minimo shunt residual a ecografia, 45 dias apos o cateterismo. Conclusoes: A oclusao da persistencia do ducto arterioso por metodo percutâneo tem-se mostrado segura e efetiva na maioria dos casos.

Initial experience with use of hydrogel microcoils in embolization of pulmonary arteriovenous malformations.

The purpose of this study is to describe our initial experience with embolization of pulmonary arteriovenous malformations (PAVMs) using hydrogel microcoils. The technical and radiological outcomes were retrospectively reviewed in seven patients with nine simple-type PAVMs (median feeder size 4 mm, range 3-6 mm) who underwent embolization. Hydrogel microcoils were mainly used, and detachable bare microcoils were combined as needed to occlude the terminal feeding artery just before the sac. Of a total of 43 microcoils, 30 (69.8%) hydrogel microcoils were deployed in eight PAVMs with the median number 3.5 (range 2 to 6) per lesion. All hydrogel microcoils were successfully deployed without microcatheter stuck or malposition. In the remaining one small PAVM, only soft bare microcoils were used, however, resulting in recanalization requiring additional coils in the second session. The venous sac was substantially shrunk in all lesions treated with hydrogel microcoils with the median size reduction rate 95.0% (range 81.8% to 99.0%) during the median follow-up period 10 months (range 6 to 18 months). In conclusion, hydrogel microcoils were safely and effectively applied for occluding PAVMs with relatively small feeders.

EXPERIMENTAL STUDY OF PROCESSES IN AN ATTRACTIVE-SCREEN INDUCTOR SYSTEM UNDER ADDITIONAL COIL INSERTION

The article is devoted to experimental investigations of action of an additional coil inserted inside an inductor system with an attractive screen on induced current distribution in the work-piece and to determination of the coefficient of the solenoid winding current transformation.

Multiple overlapping stent-assisted coiling of complex aneurysms: a single-center experience

Objectives:Coil embolization of wide-necked and fusiform aneurysms is challenging and is frequently associated with recanalization despite assistance of any additional device. The purpose of this study was to evaluate the feasibility and mid-term outcomes of complex aneurysms after multiple overlapping stent-assisted coiling (OSAC).Methods:We retrospectively evaluated 26 wide-necked and fusiform atherosclerotic or dissecting aneurysms that were treated with multiple OSAC. Eight aneurysms (30·8%) presented with subarachnoid hemorrhage and one (3·9%) with intracranial hemorrhage.Results:Complete embolization was achieved in 15 of the 26 aneurysms (57·7%), while remnant neck was identified in nine (34·6%) and remnant aneurysm was noted in two (7·7%). Immediate procedure-related complications were observed in five patients (19·2%) including two with asymptomatic in-stent thrombosis, one with transient right-sided weakness, one with decreased mentality, and one with aphasia and quadriplegia. A procedure-related permanent neurologic deficit (modified Rankin scale scores of 1 and 5) was noted in two patients (7·7%). Angiographic follow-up (mean duration 23·9 months) after OSAC was carried out in 18 patients (69·2%): 11 (61·1%) were stable, 3 (16·7%) improved, 3 (16·7%) had minor compaction, and 1 had major recanalization (5·5%). One recurred aneurysm after OSAC and two recanalized aneurysms after single stenting were re-treated using additional stent-assisted coiling, and there was no recanalization in these three aneurysms during the 25·7 months after re-treatment.Conclusions:Multiple OSAC is feasible and effective for complex aneurysms and recurrent aneurysms after stent-assisted coiling.