Coil Technology Research Articles

Endovascular treatment of ruptured tiny (⩽3 mm) intracranial aneurysms in the setting of subarachnoid hemorrhage: A case series of 20 patients and literature review

Successful endovascular coiling of ruptured tiny saccular intracranial aneurysms (⩽3mm) is technically challenging and traditionally has been associated with technical failures, as well as morbidity related to thromboembolic events and high intraoperative rupture rates. This study analyzes the feasibility, technical efficacy, and clinical outcomes of coil embolization of ruptured tiny intracranial aneurysms using current coil and microcatheter technology and techniques. We performed a retrospective review of 20 patients with 20 ruptured tiny aneurysms treated with endovascular coil embolization from 2013 to 2016 at a single high-volume academic tertiary care practice. The mean aneurysm size was 2.4mm (median 2.5mm, 1–3). Complete occlusion was achieved in 12 of 20 patients (60%), the remaining 7 of 20 patients (35%) had a small neck remnant, and there was 1 failure (5%) converted to microsurgical clipping. Two patients had a failed attempted surgical clip reconstruction and were subsequently coiled. There was 1 intraprocedural rupture (5%) and 1 severe parent artery vasospasm (5%) during coiling. At discharge, 60% of patients were living independently. At follow-up three patients were deceased. Mean angiographic follow-up was 139days (SD 120). There were no aneurysm recurrences among occluded patients and there were no retreatments among those with neck remnants. Coiling of ruptured aneurysms ⩽3mm is feasible with high occlusion rates and low complication rates. The availability of softer coils with flexible detachment zones has led to safe and effective endovascular treatment of tiny ruptured aneurysms.

Microstructure observations on butt joint composed of Nb3Sn CIC conductors

To precisely evaluate a butt joint technology for the JT-60SA CS coils, microstructure observations on the butt joint composed of Nb3Sn CIC conductors were conducted using a FE-SEM. As a sample for the observations, the butt joint sample utilized in the joint resistance measurement was used. During the sample fabrication, the butt joint sample was heated up to about 920K from room temperature for diffusion bonding after heat treatment for Nb3Sn production. Then, the sample was subjected to the cycles of electromagnetic force in the joint measurement.The observation results indicated that Nb3Sn strands and a copper sheet were butted properly at the interface of the butt joint. In addition, there were hairline cracks in the Nb3Sn layers of the strands near the interface. To investigate a cause of the crack initiation, the stresses generated in the butt joint under same conditions were analyzed using a simple model. As a result, the cracks would occur with an axial compressive stress generated by the butt joint fabrication.

Initial Technical Experience with the SMART Coil for the Embolization of Intracranial Aneurysms

Traditional platinum coils used for cerebral aneurysm embolization have a uniform degree of softness throughout an individual coil's length. Recently, SMART Coils (Penumbra Inc., Alameda, California, USA) have been developed, which transition in softness along the length of their coils. We report the initial clinical results with this technology. A retrospective study of all patients undergoing aneurysm coiling with SMART Coils at 2 centers was performed to evaluate the safety and efficacy of this new technology. Outcome and angiographic data were self-reported by individual treatment centers. Fifty-nine patients underwent treatment for cerebral aneurysms with SMART Coils (44% in the setting of subarachnoid hemorrhage). Mean aneurysm size was 5.9 ± 2 mm× 4.5 ± 2 mm. Mean neck size was 3.4 ± 1 mm. More than half (54.2%) of the patients underwent coiling exclusively with SMART Coils. The remainder used either framing or finishing coils of another type. About one third (33.9%) underwent balloon-assisted coiling, and 47.5% underwent stent-assisted coiling. There were no device malfunctions in any of the patients. Six (10.1%) minor complications without clinical sequelae occurred. Raymond I or II occlusion was achieved in 71.2%. Our results demonstrate adequate device safety in a variety of both ruptured and unruptured aneurysm locations. This design enables progressive changes in softness along the length of an individual coil, which offers several potential advantages in the clinical use. This initial investigation of SMART Coil technology demonstrates safety and efficacy in the treatment of a wide range of aneurysm sizes, locations, and morphologies in both ruptured and unruptured settings.

Performance correlation between YBa2Cu3O7−δ coils and short samples for coil technology development

A robust fabrication technology is critical to achieve the high performance in YBa2Cu3O (YBCO) coils as the critical current of the brittle YBCO layer is subject to the strain-induced degradation during coil fabrication. The expected current-carrying capability of the magnet and its temperature dependence are two key inputs to the coil technology development. However, the expected magnet performance is not straightforward to determine because the short-sample critical current depends on both the amplitude and orientation of the applied magnetic field with respect to the broad surface of the tape-form conductor. In this paper, we present an approach to calculate the self-field performance limit for YBCO racetrack coils at 77 and 4.2 K. Critical current of short YBCO samples was measured as a function of the applied field perpendicular to the conductor surface from 0 to 15 T. This field direction limited the conductor critical current. Two double-layer racetrack coils, one with three turns and the other with 10 turns, were wound and tested at 77 and 4.2 K. The test coils reached at least 80% of the expected critical current. The ratio between the coil critical currents at 77 and 4.2 K agreed well with the calculation. We conclude that the presented approach can determine the performance limit in YBCO racetrack coils based on the short-sample critical current and provide a useful guideline for assessing the coil performance and fabrication technology. The correlation of the coil critical current between 77 K and 4.2 K was also observed, allowing the 77 K test to be a cost-effective tool for the development of coil technology.

Emergency abdominal MRI: current uses and trends.

When evaluating the abdomen in the emergency setting, CT and ultrasound are the imaging modalities of choice, mainly because of accessibility, speed and lower relative cost. CT has the added benefit of assessing the whole abdomen for a wide spectrum of gastrointestinal disease, whereas ultrasound has the benefit of avoiding ionizing radiation. MRI is another tool that has demonstrated increasing utility in the emergency setting and also avoids the use of ionizing radiation. MRI also has the additional advantage of excellent soft-tissue contrast. However, widespread use of MRI in the emergency setting is limited by availability and relative cost. Despite such limitations, advances in MRI technology, including improved pulse sequences and coil technology and increasing clinician awareness of MRI, have led to an increased demand in abdominal MRI in the emergency setting. This is particularly true in the evaluation of acute pancreatitis; choledocholithiasis with or without cholecystitis; acute appendicitis, particularly in pregnant patients; and, in some cases, Crohn's disease. In cases of pancreatitis and Crohn's disease, MRI also plays a role in subsequent follow-up examinations.

Advancing Cardiovascular, Neurovascular, and Renal Magnetic Resonance Imaging in Small Rodents Using Cryogenic Radiofrequency Coil Technology.

Research in pathologies of the brain, heart and kidney have gained immensely from the plethora of studies that have helped shape new methods in magnetic resonance (MR) for characterizing preclinical disease models. Methodical probing into preclinical animal models by MR is invaluable since it allows a careful interpretation and extrapolation of data derived from these models to human disease. In this review we will focus on the applications of cryogenic radiofrequency (RF) coils in small animal MR as a means of boosting image quality (e.g., by supporting MR microscopy) and making data acquisition more efficient (e.g., by reducing measuring time); both being important constituents for thorough investigational studies on animal models of disease. This review attempts to make the (bio)medical imaging, molecular medicine, and pharmaceutical communities aware of this productive ferment and its outstanding significance for anatomical and functional MR in small rodents. The goal is to inspire a more intense interdisciplinary collaboration across the fields to further advance and progress non-invasive MR methods that ultimately support thorough (patho)physiological characterization of animal disease models. In this review, current and potential future applications for the RF coil technology in cardiovascular, neurovascular, and renal disease will be discussed.

Enhanced environmental performance of fiber optic gyroscope by an adhesive potting technology

An adhesive potting technology for fiber coils of a fiber optic gyroscope (FOG) is proposed. The fiber coil is immersed in liquid adhesive with superior mechanical properties. The internal air is first removed completely by vacuum pumping, and the adhesive is then evenly pressed into the fiber coil under pressure. The potted fiber core is prepared by ladder-type temperature curing and a stress-release process. With this potting technology, the vibration performance of an FOG is greatly improved and, at the same time, will not lead to degradation of its temperature performance. Using this potting technique of adhesive impregnation, the adaptability of FOGs will be enhanced.

Treatment of emphysema using bronchoscopic lung volume reduction coil technology: an update on efficacy and safety.

In the last decade several promising bronchoscopic lung volume reduction (BLVR) treatments were developed and investigated. One of these treatments is BLVR treatment with coils. The advantage of this specific treatment is that it works independently of collateral flow, and also shows promise for patients with a more homogeneous emphysema disease distribution. Seven years ago, the very first patients were treated with BLVR coil treatment and currently large randomized, controlled trials are underway. The aim of this article is to review the available literature and provide an update on the current knowledge on the efficacy and safety of BLVR treatment with coils.

Bi-2212 Canted-Cosine-Theta Coils for High-Field Accelerator Magnets

report on wind-and-react (W&R) Bi <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> Sr <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> CaCu <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> O <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">8+x</sub> (Bi-2212) insert coils that were fabricated using a Canted-Cosine-Theta (CCT) coil technology. In the CCT technology, a conductor is wound into canted helical channels that are machined into cylindrical coil winding mandrels, thereby creating a cosine-theta current distribution and providing stress support at the conductor level. The prevention of stress accumulations by the internal structure of winding mandrels is considered an enabling technology for high field Bi-2212 insert coils that target the 20 T magnetic field range. We report on the fabrication and reaction of coils for two proof-of-principle Bi-2212 inserts, BIN1 and BIN2, each consisting of two CCT coils. The BIN1 coils use insulated 0.8 mm diameter wires and INCONEL 600 coil winding mandrels with a stainless steel 316 shell, an overall diameter of 50.0 mm and a clear bore of 35.3 mm. The BIN2 coils use insulated 6-around-1 cables from 0.8-mm diameter wires, and aluminum-bronze mandrels with an aluminum alloy 6061 shell, an overall outer diameter of 68.6 mm, and a clear bore of 38.8 mm. The coils are designed to study the fabrication, reaction, and impregnation in Bi-2212 CCT technology, and provide a baseline for a Rutherford cable-wound coil set (BIN3). These latter coils target an insert-coil set with optimized current density in the windings, to enable the construction of an 18 T Nb <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> Sn-Bi-2212 hybrid dipole magnet.

Risk factors for coil protrusion into the parent artery and associated thrombo-embolic events following unruptured cerebral aneurysm embolization.

Advances in vascular reconstruction devices and coil technologies have made coil embolization a popular and effective strategy for treatment of relatively wide-neck cerebral aneurysms. However, coil protrusion occurs occasionally, and little is known about the frequency, the risk factors and the risk of thrombo-embolic complications. We assessed the frequency and the risk factors for coil protrusion in 330 unruptured aneurysm embolization cases, and examined the occurrence of cerebral infarction by diffusion-weighted magnetic resonance imaging (DW-MRI). Forty-four instances of coil protrusion were encountered during coil embolization (13.3% of cases), but incidence was reduced to 33 (10% of cases) by balloon press or insertion of the next coil. Coil protrusion occurred more frequently during the last phase of the procedure, and both a wide neck (large fundus to neck ratio) (OR = 1.84, P = 0.03) and an inadequately stable neck frame (OR = 5.49, P = 0.0007) increased protrusion risk. Coil protrusions did not increase the incidence of high-intensity lesions (infarcts) on DW-MRI (33.3% vs 29% of cases with no coil protrusion). However, longer operation time did increase infarct risk (P = 0.0003). Thus, tail or loop type coil protrusion did not increase the risk of thrombo-embolic complications, if adequate blood flow was maintained. Coil protrusion tended to occur more frequently in cases of wide-neck aneurysms with loose neck framing. Moderate and less coil protrusion carries no additional thrombo-embolic risk, if blood flow is maintained, which can be aided by additional post-operative antiplatelet therapy.

Calculation of electromagnetic quantities of permanent magnet synchronous machines with tooth coil windings using finite elements and frozen permeabilities

Permanent magnet synchronous machines with fractional slot stator windings using the tooth coil technology require detailed investigations on the electromagnetic parameters due to a very low number of slots per pole and phase. Finite element analyses of such machines can provide many results and even allow for a comparison of both Y- and Δ-connected stator windings. However, a subsequent application of the frozen permeabilities method allows for a more detailed discussion of effects caused by both permanent magnets and armature stator currents in conjunction with angular rotor position and also different saturation levels. In particular, such detailed analyses are required for high performance electrical drive systems which operate under very fast changing load conditions and run in deep field weakening ranges additionally.

Periprocedural safety of aneurysm embolization with the Medina Coil System: the early human experience

IntroductionIntracranial saccular aneurysms, if untreated, carry a high risk of morbidity and mortality from intracranial bleeding. Embolization coils are the most common treatment. We describe the periprocedural safety and performance...

Construction and test of a non-insulated insert coil using coated conductor tape

A small coated conductor coil (central field 1 T at 200 A) was constructed and tested in order to evaluate the benefit and the possible disadvantages of non insulated, double pancake construction, in particular regarding quench protection. The insert coil consists of three double pancakes without turn to turn insulation, and it was impregnated with beeswax. The coil was equipped with voltage taps on each pancake, thermocouples and a quench heater. Quench tests were carried out because quench protection is one of the main issues in developing coil technology for coated conductors. Quenches were induced either by a heater or by exceeding the coil critical current; in all cases the quench protection system was able to detect the quench.

Magnetic resonance imaging and foot lameness. Problem solved? Or do we know we know less now that we know more?

Magnetic resonance imaging and foot lameness. Problem solved? Or do we know we know less now that we know more?

Use of Hydrocoil in Small Aneurysms: Procedural Safety, Treatment Efficacy and Factors Predicting Complete Occlusion

Coil technology has been directed to reduce recurrence rates and we have seen the introduction of trials comparing the efficacy of surface modified versus bare platinum coils (BPC). This article reports on one treatment strategy in the treatment of small aneurysms by the placement of Hydrocoil across the neck of the aneurysm. Procedural safety, treatment efficacy and factors which predict complete occlusion are evaluated. We retrospectively identified a subgroup of small aneurysms treated over a four-year period. Analysis comparing aneurysms treated with Hydrocoil and BPC versus Hydrocoil alone was undertaken. Eighty-five aneurysms were coiled; 62% with Hydrocoil alone, 38% in combination with BPC. At six-month follow-up, overall 50% were completely occluded, 39.5% had a neck remnant and 10.5% had a residual aneurysm. Complete occlusion was identified in 39% in the Hydrocoil and BPC group compared to 56% in the Hydrocoil alone group. In 56/76 (74%) cases analysed, Hydrocoil loop successfully bridged the neck of the aneurysm in which 38/76 (68%) of these were completely occluded at six-month follow-up. Thirteen procedure-related complications occurred. Aneurysms treated with Hydrocoil alone resulted in fewer recurrences compared with a combination of Hydrocoil and BPC. These data suggest that the technique of positioning Hydrocoil at the neck of the aneurysm increases the probability of complete occlusion and is therefore a strong predictor of aneurysm occlusion. In our experience, this technique did not demonstrate an increased risk of intra-procedural rupture or thrombo-embolic complications compared to conventional embolization with BPC.

DESIGN OF A PROTOTYPE HYDRO COIL TURBINE APPLIED AS MICRO HYDRO SOLUTION

This study deals with the effort to release new revolution of renewable energy concept. Key issue in generating hydro power from low head, low flow sources until now has been impractical, expensive in efficient and complex technology. The idea of using Hydro Coil instead of turbine gives an economic advantage that it is relatively cheaper. The apparatus allows us to exploit sides that would not be practical at all for conventional small hydroelectric power.Hydro Coil turbine in experimental prototype has been designed, built and tested. The turbine includes 4 inches acrylic with ribbon-like curved shape insert, which present a gradual curve of approximately 70 degrees from the axial flow of water progressing to a tightly curved angle perpendicular to the flow of water at the exit point. The gradual curve is used to reducing the axial velocity of water, thereby further as consequence of transfer energy from water to ribbon, thus the central axle and ribbon rotated. This rotation is initiated at the low frequency coil, with energy incrementally transferred as water, hitting the low frequency coil, turning the ribbon slowly, progressing gradually to higher frequency, tight coil where maximal energy to the transfer occurs.Characteristics and efficiency of Hydro Coil turbine can be identified after laboratory experimental already finished. Turbine efficiency in 92.93% of this prototype exceeds expectation in the experiments. It thus demonstrates the promising potential of Hydro Coil technology to extract power from incoming water flow in low head sources.

E-040 Initial Multi-Centre Experience with the Penumbra PC 400 Detachable Coil

Introduction/PurposeAneurysm coil technology has changed considerably since the introduction of the GDC coil. We evaluated our initial clinical experience with a novel 0.020 Penumbra PC 400 coil to determine device...

E-037 Initial Multi-Centre Experience with the Penumbra PC 400 Detachable Coil in aneurysms 10 mm or greater

BackgroundAneurysm coil technology has changed considerably since the introduction of the GDC coil. We evaluated our initial clinical experience with a novel 0.020 Penumbra PC 400 coil to determine device...

Endovascular Treatment of Intracranial Aneurysms

In a recent systematic review and meta-analysis, the overall prevalence of unruptured intracranial aneurysms (IAs) is estimated as 3.2%.1 The prevalence of IAs is higher in patients with autosomal dominant polycystic kidney disease or a positive family history of IAs of subarachnoid hemorrhage (SAH).1 From the same review, the size of unruptured IAs is <5 mm in 66%, 5 to 9 mm in 27%, and ≥10 mm in 7%; the site of IAs is internal carotid artery, including posterior communicating artery in 42%, middle cerebral artery in 35%, and anterior cerebral artery and anterior communicating artery in 18%. Most IAs are clinically silent until rupture, which is unpredictable and sometimes associated with SAH, intraparenchymal hematoma, and an intraventricular hemorrhage. The case fatality of IA rupture is high (from 27% to 44%), but has decreased during the past 3 decades because of the introduction of improved management strategies, including neurocritical care.2 The International Study of Unruptured Intracranial Aneurysms (ISUIA) showed an increased risk of IA rupture with aneurysm size and for posterior circulation aneurysms.3 Although treatment of a ruptured aneurysm is accepted as an emergency, indication for treatment of unruptured IAs is still being discussed. Decision for treatment is based on clinical and anatomic factors; among them, the most important being patient’s age, family history of IA(s), associated conditions (autosomal dominant polycystic kidney disease), symptomatic aneurysms, aneurysm size, and location. The randomized International Subarachnoid Aneurysm Trial (ISAT) study has clearly demonstrated the superiority of endovascular treatment (EVT) of ruptured aneurysms using coil technology over surgery.4 Since the publication of these results, EVT has rapidly evolved. Although for unruptured aneurysms a direct comparison between EVT and surgery is not available, EVT has been widely used in this subgroup as well.5 In fact the population presenting with …

SP0027 High Resolution and Advanced MR Imaging of Cartilage

Due to the complex, zonally anisotropic internal structure of cartilage resulting in a short T2 relaxation time and because of its thin layer, MRI of articular cartilage is still challenging....