Coil Packing Density Research Articles

Therapeutic Effect of Targeted Deployment Filling Coils in the Treatment of Intracranial Aneurysms.

Endovascular coil embolization is the primary therapeutic modality for intracranial aneurysms. Substantial reports have been found regarding the coil packing density and inflow jet. However, the hemodynamic effect of increasing the rate of tamponade in the inflow jet area within the aneurysm remains unclear. In this study, individualized geometries of six intracranial aneurysms were recruited: all six aneurysms were located in the internal carotid artery. Two groups were created by changing the position and orientation of the microcatheter for the release of the third segment of the filling coil. The finite element method was used to simulate coil deployment. Computational fluid dynamics was used to characterize hemodynamics in post-deployment aneurysms. The parameters evaluated included velocity reduction, wall shear stress (WSS), low WSS (LWSS), relative residence time (RRT), flow kinetic energy in the neck region of the aneurysms, and residual flow volume (RFV) in the aneurysms. At the peak time (t = 0.17 s), the targeted deployment group has similar proportion of LWSS area to conventional deployment groups: targeted 78.13% ± 34.59% versus normal 74.20% ± 36.94% (mean ± SD, p = 0.583). The targeted deployment group has a higher RRT area (targeted 16.84% ± 5.58% vs. normal 6.42% ± 5.67% [mean ± SD, p = 0.009]), smaller flow kinetic energy (targeted 9.43 ± 4.33 vs. normal 16.23 ± 5.92 [mean ± SD, p = 0.047]), and a larger RFV in the aneurysms (targeted 35.97 ± 24.35 mm3 vs. normal 25.80 ± 18.94 mm3 [mean ± SD, p = 0.44]). Inflow jets play an important role in the treatment of aneurysms, and deploying filling coils in accordance with inflow jets may result in a better hemodynamic environment.

Hemodynamic analysis of coil filled patient-specific middle cerebral artery aneurysm using porous medium approach

Cerebral aneurysms are bulges of an artery, which could be life-threatening when ruptured. Depending on their size, shape, and location, they need to be managed either through clipping or an endovascular coiling intervention. When coiled, reduced hemodynamic activity enables the coil to get thrombosed and achieve flow stasis. However, some coils delivered into the aneurysm tend to prolapse into the parent vessel and cause stroke due to obstruction and embolization. The recurrence of an aneurysm after endovascular coiling is of concern in the treatment of wide necked aneurysms. The initial packing density or improper coiling of the aneurysm and its relation to recurrence remains uncertain. This study investigates the influence of reduction in coil fill volume and packing density on the aneurysm recurrence using hemodynamic parameters by analyzing its flow features. Finite element method based commercial computational fluid dynamics solver is employed for performing patient-specific simulations for the coil filled aneurysm. The present approach uses porous medium based formulation. The numerical simulations show that any reduction below the optimal coil fill volume and packing density inside the aneurysm increases the velocity magnitude, wall shear stress, time-averaged wall shear stress, and spatial gradient of wall shear stress and reduces the relative residence time. The hemodynamic parameters and flow features suggest that a reduction in the coil packing density inside the aneurysm increases the chances of aneurysm recurrence. Hence, an assessment on how to achieve optimal coil fill volume and packing density is critical in reducing the risk of aneurysm recurrence.

Abstract 180: A Prospective, Single‐Center Study Appraising Aneurysm Embolization using the Balt Optima™ Coil System (APPLY Study)

Introduction Intracranial aneurysms, both ruptured and unruptured, pose a significant risk to the general population. Cases of unruptured intracranial aneurysms (UIA) are estimated to affect roughly 3% of the general population and aneurysmal subarachnoid hemorrhage (aSAH) have an incidence of 8 to 9 people per 100,000. With the advancement of endovascular coil devices, aneurysm embolization with coiling is becoming the more preferred treatment approach compared to craniotomy with microsurgical clipping. The purpose of this study was to assess the safety and efficacy of endovascular coiling using the novel Balt Optima™ Coil System. Methods This study was an investigator‐initiated, prospective, real‐world, single‐center, post‐market study conducted in Thousand Oaks, California. Between 2020 and 2023, thirty cerebral aneurysms were treated with at least 80% utilization of the Balt Optima™ Coil System. The subjects were followed for 6 months (‐4 months/+6 months). Data points were obtained at baseline, procedure, discharge or postoperative day 7, and 6 months follow‐up (‐4 months/+6 months). Primary outcomes were functional status recorded as modified Rankin scores (mRS) and radiographic occlusion rates documented as Raymond‐Roy scores. Serious adverse events including, but not limited to, groin hematoma, periprocedural stroke, intraoperative aneurysm rupture, coil herniation requiring stent placement, and mortality were recorded. Secondary outcomes included coil packing densities, minor complications, procedure duration, disposition after hospitalization, and antithrombotic medication adjustments. Results 30 intracranial aneurysms in 29 individual subjects were included in the study and were treated by a total of 4 neurointerventionalists with at least 80% use of the Balt Optima™ Coil System. One subject had two aneurysms which were treated at two separate occasions, and the subject was consented for both aneurysms to be included in the study. 60% of aneurysms were located along the right anterior circulation and vessels involved mirrored epidemiological data in the literature. 83% of subjects were female, and 50% of aneurysms presented as ruptured. All subjects had a baseline mRS 0‐2. 83% of aneurysms were treated with utilization of an assist device as well. At 6 months follow‐up (‐4 months/+6 months), 80% of subjects had mRS 0‐2. Of the 21 patients with 6 month (‐4 months/+6 months) follow‐up imaging, 15 (71%) had complete aneurysm occlusion (Raymond‐Roy score of 1) and 6 (29%) patients had residual aneurysm neck filling (Raymond‐Roy score of 2). One subject (3%) expired during the hospitalization due to complications unrelated to the aneurysm or coil system, and one subject (3%) was lost to follow‐up. One subject (3%) developed a groin hematoma, one subject (3%) had an intraoperative rupture with no significant clinical consequence, and two subjects (7%) experienced coil herniation requiring stent placement with no clinical sequelae. No subjects (0%) had periprocedural strokes. Conclusion This study demonstrates that the Balt Optima™ Coil System is safe and effective for endovascular treatment of both unruptured and ruptured intracranial aneurysms. Additional data is needed to validate these results and compare to other coil devices on the market.

The safety and efficacy of double microcatheter technique in small and tiny ruptured aneurysms: A single center study.

Double microcatheter technique (dMC) can be the alternative to Single microcatheter technique (sMC) for challenging cases, but there is lack of studies comparing dMC to sMC especifically for small ruptured aneurysms. Our objective was to compare the safety and efficacy of dMC to sMC in treating small (≤5 mm) and tiny (≤3 mm) ruptured aneurysms. This study focused on 91 out of 280 patients who had ruptured aneurysms and underwent either single or double microcatheter coil embolization. These patients were treated with either single or double microcatheter coil embolization. We divided the patients into two groups based on the procedural method and evaluated clinical features and outcomes. Subgroup analyses were conducted specifically for tiny aneurysms, comparing the two methods, and within the dMC group, we also examined whether the aneurysm was tiny or not. In addition, univariate logistic regression analysis was performed to assess the impact of coil packing density. The mean values for most outcome measures in the dMC group were higher than those in the sMC group, but these differences did not reach statistical significance (coil packing density, 45.739% vs. 39.943%; procedural complication, 4.17% vs. 11.94%; recanalization, 8.3% vs. 10.45%; discharge discharge modified Rankin Scale (mRS), 1.83 vs. 1.97). The comparison between tiny aneurysms and other sizes within the dMC group did not reveal any significant differences in terms of worse outcomes or increased risk. The only factor that significantly influenced coil packing density in the univariate logistic regression analysis was the size of the aneurysm (OR 0.309, 95% CI 0.169-0.566, p=0.000). The dMC proved to be a safe and viable alternative to the sMC for treating small ruptured aneurysms in challenging cases.

Hemodynamic nature of black-blood enhancement in long-term coiled cerebral aneurysms.

Vessel wall imaging (VWI) with black-blood (BB) technique can demonstrate aneurysmal enhancement preluding to growth/rupture in treatment-naive cerebral aneurysms. Interestingly, recent works showed that BB enhancement may also occur in endovascularly treated aneurysms, though its meaning is controversial. Hypothesizing a flow-related mechanism of BB enhancement, we explored its relationship with incomplete occlusion status and coil packing density at DSA. We analyzed the subjects undergoing 3T MRI between January 2017 and October 2020 for a previous aneurysmal coiling. All the MRI studies included pre- and post-contrast 3D BB sequences. The presence of intra-aneurysmal pre-contrast BB signal was assessed. BB enhancement (when present) was classified as follows: (1) enhancement at the neck, (2) intrasaccular/intra-coil enhancement, and (3) peripheral enhancement. Coil packing density and aneurysmal occlusion status (according to the modified Raymond-Roy classification, MRRC) were determined on post-treatment DSA and compared with BB findings using generalized linear mixed-effect model and ANOVA. Significant p values were <0.05. Forty-eight aneurysms from 44 patients were eligible for analysis. Pre-contrast BB signal was observed in 50% of the aneurysms and showed a relationship with baseline aneurysmal size. BB enhancement was detectable in 31 aneurysms (65%), being significantly associated with incomplete aneurysmal occlusion and reduced coil packing density at DSA. BB enhancement of coiled aneurysms is related with increasing degrees of post-coiling aneurysmal remnants and with loose coil packing density at DSA. This supports a hemodynamic interpretation of BB enhancement in long-term coiled aneurysms.

A comparison of endovascular coil systems for the treatment of small intracranial aneurysms.

Endovascular coiling of small, intracranial aneurysms remains controversial and difficult, despite advances in technology. We retrospectively reviewed data for 62 small aneurysms (<3.99 mm) in 59 patients. Occlusion rates, complications rates, and coil packing densities were compared between subgroups based upon coil type and rupture status. Ruptured aneurysms predominated (67.7%). Aneurysms measured 2.99 ± 0.63 mm by 2.51 ± 0.61 mm with an aspect ratio of 1.21 ± 0.34 mm. Brands included Optima (Balt) (29%), MicroVention Hydrogel (24.2%), and Penumbra SMART (19.4%) coil systems. Average packing density was 34.3 ± 13.5 mm3. Occlusion rate was 100% in unruptured aneurysms; 84% utilized adjuvant devices. For ruptured aneurysms, complete occlusion or stable neck remnant was achieved in 88.6% while recanalization occurred in 11.4%. No rebleeding occurred. Average packing density (p = 0.919) and coil type (p = 0.056) did not impact occlusion. Aspect ratio was smaller in aneurysms with technical complications (p = 0.281), and aneurysm volume was significantly smaller in those with coil protrusion (p = 0.018). Complication rates did not differ between ruptured and unruptured aneurysms (22.6 vs. 15.8%, p = 0.308) or coil types (p = 0.830). Despite advances in embolization devices, coiling of small intracranial aneurysms is still scrutinized. High occlusion rates are achievable, especially in unruptured aneurysms, with coil type and packing density suggesting association with complete occlusion. Technical complications may be influenced by aneurysm geometry. Advances in endovascular technologies have revolutionized small aneurysm treatment, with this series demonstrating excellent aneurysm occlusion especially in unruptured aneurysms.

Modeling the Mechanical Microenvironment of Coiled Cerebral Aneurysms.

Successful occlusion of cerebral aneurysms using coil embolization is contingent upon stable thrombus formation, and the quality of the thrombus depends upon the biomechanical environment. The goal of this study was to investigate how coil embolization alters the mechanical micro-environment within the aneurysm dome. Inertialess particles were injected in three-dimensional, computational simulations of flow inside patient aneurysms using patient-specific boundary conditions. Coil embolization was simulated as a homogenous porous medium of known permeability and inertial constant. Lagrangian particle tracking was used to calculate the residence time and shear stress history for particles in the flow before and after treatment. The percentage of particles entering the aneurysm dome correlated with the neck surface area before and after treatment (pretreatment: R2 = 0.831, P < 0.001; post-treatment: R2 = 0.638, P < 0.001). There was an inverse relationship between the change in particles entering the dome and coil packing density (R2 = 0.600, P < 0.001). Following treatment, the particles with the longest residence times tended to remain within the dome even longer while accumulating lower shear stress. A significant correlation was observed between the treatment effect on residence time and the ratio of the neck surface area to porosity (R2 = 0.390, P = 0.007). The results of this study suggest that coil embolization triggers clot formation within the aneurysm dome via a low shear stress-mediated pathway. This hypothesis links independently observed findings from several benchtop and clinical studies, furthering our understanding of this treatment strategy.

A novel self-expanding shape memory polymer coil for intracranial aneurysm embolization: 1 year follow-up in Chile

BackgroundAneurysm recurrence remains a challenge when coiling cerebral aneurysms. Development of next generation coils has focused on accelerating thrombus maturation and increasing coil packing density. Ultra low density shape memory...

Commentary: Coil Packing Density – Not Just for Cerebral Aneurysms

Coil packing density (CPD) has been recognized as a factor related to coil compaction or recanalization in the treatment of visceral and intracranial aneurysms ( 1 Yasumoto T. Osuga K. Yamamoto H. et al. Long-term outcomes of coil packing for visceral aneurysms: correlation between packing density and incidence of coil compaction or recanalization. J Vasc Interv Radiol. 2013; 24: 1798-1807 Abstract Full Text Full Text PDF PubMed Scopus (58) Google Scholar , 2 Kawanabe Y. Sadato A. Taki W. Hashimoto N. Endovascular occlusion of intracranial aneurysms with Guglielmi detachable coils: correlation between coil packing density and coil compaction. Acta Neurochir (Wien). 2001; 143: 451-455 Crossref PubMed Scopus (186) Google Scholar ). Simple coiling (SC), balloon remodeling (BR), and stent-assisted coiling are 3 commonly used techniques for percutaneously treating aneurysms. In the article by Kesim et al ( 3 Kesim Ç. Özcan Ü.C. Yildirim E. Effects of the cerebral aneurysm treatment method on coil packing density and its relationship with the ostium area. J Vasc Interv Radiol. 2022; 33: 631-638 Abstract Full Text Full Text PDF Scopus (1) Google Scholar ) titled “Effects of the Aneurysm Treatment Method on Coil Packing Density and Its Relationship with the Ostium Area,” the authors demonstrated that it is possible to achieve similar CPDs using these 3 coiling techniques while treating intracranial aneurysms and concluded that “in cerebral aneurysms treated with balloon- or stent-assisted coiling, the CPD value does not differ from that in aneurysms treated with simple coiling.” The authors noted that coiling technique is influenced by aneurysm neck size, with BR and stent-assisted coiling used for aneurysms with unfavorable neck morphology. Another possible conclusion is that for aneurysms with unfavorable neck morphology, BR and stent-assisted coiling make it possible to achieve CPDs similar to those achieved with SC in “simple” aneurysms. Effects of the Cerebral Aneurysm Treatment Method on Coil Packing Density and Its Relationship with the Ostium AreaJournal of Vascular and Interventional RadiologyVol. 33Issue 6PreviewTo test the following hypotheses: (a) balloon or stent assistance increases coil packing density (CPD) in the endovascular treatment of intracranial aneurysms, and (b) CPD correlates to ostium area (OA) and aneurysm volume (AV). Full-Text PDF

Effects of the Cerebral Aneurysm Treatment Method on Coil Packing Density and Its Relationship with the Ostium Area

PurposeTo test the following hypotheses: (a) balloon or stent assistance increases coil packing density (CPD) in the endovascular treatment of intracranial aneurysms, and (b) CPD correlates to ostium area (OA) and aneurysm volume (AV). Materials and MethodsThis retrospective study included 60 aneurysms (54 ruptured and 6 unruptured) treated with simple coiling (SC) (n = 18), balloon-assisted coiling (BAC) (n = 7), or stent-assisted coiling (SAC) (n = 35) at the authors’ institution between August 2017 and December 2019. AV and OA measurements were obtained from 3-dimensional digital subtraction angiography images using commercial software. Coil sizes were retrieved from patient files, and coil volume (CV) measurements were obtained from https://www.angiocalc.com/. Analysis of covariance, multivariate covariance analysis, and Pearson correlation analyses were performed. ResultsThe median value for AV, CV, CPD, and OA was 63.4 mm3 (range, 5.5–1,771.4 mm3), 23.13 mm3 (range, 2.03–296.95 mm3), 33.29% (range, 13.41%–81.02%), and 10.7 mm2 (range, 2.7–49.9 mm2), respectively. Multivariate analysis showed that the CPD values were not significantly different among the treatment groups, although OA significantly differed between the SC and SAC groups (P < .05). Pearson correlations showed that similar to AV, OA was negatively correlated with CPD (r = −0.321, P < .05). ConclusionsThe CPD value in cerebral aneurysms treated with BAC or SAC did not differ from that in aneurysms treated with SC.

How to perform intra-aneurysmal coil embolization after Pipeline deployment: a study from a hemodynamic viewpoint

BackgroundPipeline embolization device (PED) deployment combined with coil therapy for large complex intracranial aneurysms is effective and considered superior to PED deployment alone. However, the optimal strategy for use of...

Risk factors of recurrence after endovascular embolization of posterior communicating artery aneurysms.

To determine the risk factors for recurrence after endovascular embolization of posterior communicating artery aneurysms (PcomA). We retrospectively analyzed a cohort of 163 patients harboring 172 PocmAs who were treated with endovascular embolization from January 2019 to December 2020. The patients were divided into recurrence and stable groups depending on outcome. Univariate and logistic regression analyses were performed to determine the potential risk factors of recurrence during follow-up. Of the total 163 patients harboring 172 aneurysms, 107 were treated with simple coil occlusion and 65 were treated with stent-assisted coil embolization. There were significant differences in aneurysm sizes and use of non-stent-assisted coil embolizations between the groups (P < 0.05). The incidence of saccular aneurysm and Raymond grade were significantly higher in the recurrent group than in the stable group (P < 0.01). After variable selection, Raymond grade, aneurysm size, saccular aneurysm and non-stent-assisted coil embolization were included in further analysis. Binary logistic regression analysis revealed significant associations with non-stent-assisted coil embolization (P = 0.007), packing density (P < 0.001) and Raymond grades II (P < 0.001) and III (P = 0.002). Non-stent-assisted coil embolization, as well as packing density and Raymond grades II grade III are associated with recurrence after endovascular treatment of PcomA.

Fast virtual coiling algorithm for intracranial aneurysms using pre-shape path planning

To aid in predicting and improving treatment outcome of endovascular coiling of intracranial aneurysms, simulation of patient-specific coil deployment should be both accurate and fast. We developed a fast virtual coiling algorithm called Pre-shape Path Planning (P3). It captures the mechanical propensity of a released coil to restore its pre-shape for bending energy minimization, producing coils without unrealistic kinks and bends. A coil is discretized into finite-length segments and extruded from the delivery catheter segment-by-segment following a generic coil pre-shape. With the release of each segment, coil-wall and coil-coil collisions are detected and resolved. Modeling of each case took seconds to minutes. To test the algorithm, we evaluated its output against the literature, experiments, and patient angiograms. The periphery-to-core ratio of coils deployed by P3 decreased with increasing coil packing density, consistent with observations in the literature. Coils deployed by P3 compared well with in vitro experiments, free from unphysical kinks and loops that arose from previous virtual coiling algorithms. Simulations of coiling in four patient-specific aneurysms agreed well with the patient angiograms. To test the influence of coil pre-shape on P3, we performed hemodynamic simulations in aneurysms with coils deployed by P3 using the generic pre-shape, P3 using a coil-specific pre-shape, and full finite-element-method simulation. We found that the generic pre-shape was sufficient to produce results comparable to virtual coiling by finite element modeling. Based on these findings, P3 can rapidly simulate coiling in patient-specific aneurysms with good accuracy and is thus a potential candidate for clinical treatment planning.

Three-dimensional aneurysm volume measurements show no correlation between coil packing density and recurrence

ObjectiveEndovascular treatment is the mainstay therapy for brain aneurysms. About 15% of patients need re-treatment within six months due to early recanalization. In this study, we investigate risk factors associated with treatment failure. MethodsThis retrospective cohort study includes endovascularly treated aneurysm cases between July 2012 and December 2015 at the University of California Davis Medical Center with pre-treatment and early post-treatment imaging. Thin cut 3D aneurysm volume rendering was used for morphologic analyses. Univariate and bivariate analyses were conducted to evaluate differences between patients and clinical factors by treatment failure. ResultsOf the 50 patients who met the inclusion criteria, 41 (82.0%) were female, with an average age of 61 years. Most aneurysms were on the anterior communicating artery (40%) or posterior communicating artery (22.0%), and 34 (68%) aneurysms were ruptured. Early treatment failure was observed in 14 (28.0%) of endovascularly treated patients. Raymond-Roy class (RRC) was significantly associated with treatment failure (p = 0.0052), with 10 out of the 14 cases (71.4%) with early recanalization having an RRC of 3. Coil packing density did not associate with aneurysm recanalization (p = 0.61). ConclusionIn our single institution series, patient characteristics, aneurysm characteristics, or coil packing density did not affect early aneurysm recanalization. RRC was the best predictor of early recanalization; however, further confirmation with additional studies are required. Although this study focused on early treatment failure, late recanalization has been shown with longer follow up. Further investigation into factors associated with late treatment failure will need further investigation. New intrasaccular devices and flow diverters will also likely play a role in reducing recurrence in the future as these treatments gain usage.

Endovascular treatment of wide-necked aneurysms of the visceral and renal arteries using the double microcatheter technique via a single access route

We aimed to evaluate the utility of and complications associated with the double microcatheter technique for the treatment of wide-necked visceral and renal artery aneurysms (VRAAs). Nine patients (mean age, 58 years; age range, 42-69 years; 4 men, 5 women) with wide-necked VRAAs who underwent treatment with the double microcatheter technique from January 2016 to July 2018 were included in the study. For all patients, anatomical features were confirmed using cone-beam computed tomography (CT) with rotational angiography. The aneurysmal location, size, volume, neck-to-dome ratio, number of coils used, and coil packing density were investigated. Technical success, complications (coil migration and organ ischemia), changes in the complete blood count or serum creatine level, and recurrence were also evaluated. Three renal artery aneurysms and 6 splenic artery aneurysms were treated by the double microcatheter technique. The mean size of the aneurysms was 26.09±4.76 mm, mean volume was 6.19±3.69 cm3, and mean neck-to-dome ratio was 1.53±0.24. The number of coils used ranged from 7 to 16. The mean packing density was 11.32%±3.72%. Technical success was achieved in all 9 patients. Renal ischemia occurred in two patients with renal artery aneurysm, one of whom showed minimal scar formation on follow-up CT after infarction. No coil migrations or disease recurrences were observed. The double microcatheter technique for the treatment of wide-necked VRAAs appears to be relatively safe and useful. However, complex renal artery aneurysm should be carefully managed in order to prevent infarction.

Initial Raymond\u2013Roy Occlusion Classification but not Packing Density Defines Risk for Recurrence after Aneurysm Coiling

PurposeAfter coil embolization of intracranial aneurysms, it is currently not well understood whether the initial coil packing density or the type of aneurysm residual perfusion, depicted by the modified Raymond-Roy occlusion classification, primarily effects the rate of aneurysm recurrence. We hypothesized that these factors interact and only one remains an independent risk factor.MethodsIn this single center retrospective study, 440 patients with intracranial ruptured and unruptured aneurysms between 2010 and 2017 were screened. A total of 267 patients treated with stand-alone coiling, with or without stent or balloon assistance were included (age 54.1 ± 12.2 years, sex 70.4% female). Flow diverter or Woven EndoBridge (WEB) device implantation were exclusion criteria.ResultsUsing a binary logistic regression model, independent risk factors for aneurysm recurrence were postinterventional modified Raymond-Roy occlusion classification class (Odds ratio [OR] 1.747, 95% confidence interval [CI] 1.231–2.480) and aneurysm diameter (OR 1.145, CI 1.032–1.271). A trend towards a higher recurrence in ruptured aneurysms did not reach significance (OR 1.656, CI 0.863–3.179). Aneurysm localization, packing density, and neck width were not independently associated with aneurysm recurrence.ConclusionIndependent risk factors for aneurysm recurrence after coil embolization with and without stent or balloon assistance were aneurysm diameter and postinterventional grading within the modified Raymond-Roy occlusion classification. Packing density interacted with the latter and was not independently associated to recurrence.

The role of coil packing density in stable occlusion of intracranial aneurysms treated with balloon or stent-assistance

Amaç: Koil paket dansitesinin (KPD) intraktaniyal anevrizma nüksünde önemli bir prediktif faktör olduğu ile ilgili birçok çalışma vardır. Çalışmamızda KPD yoğunluğunun tedavide kullanılan endovasküler tekniğe göre, anevrizma stabil okluzyonundaki rolünü göstermeyi amaçladık.Gereç ve Yöntem: 2018-2019 tarihleri arasında balon ya da stent yardımlı koil embolizasyon ile tedavi edilmiş anevrizmaların retrospektif analizi yapıldı. Tedavi sonrası anevrizma okluzyon değerlendirmesinde Raymond-Roy sınıflaması, anevrizmaların paketleme yoğunluğu için ise AngioCalc serebral ve periferik anevrizma hesaplayıcısı kullanıldı.Bulgular: Çalışmaya 30 hastadaki 31intraserebral anevrizma dahil edildi. Balon yardımlı koil embolizasyon yapılan anevrizma sayısı 18 iken, stent yardımlı embolizasyon yapılan anevrizma sayısı ise 13 idi. Yapılan kontrol görüntülemede balon yardımı kullanılan hastaların %38.8’inde, stent yardımı kullanılan hastaların ise %7.7’sinde rekanalizasyon saptandı. Çalışmamızda mortalite izlenmemiş olup, morbidite oranı %3.3 idi. Sonuç: KPD yoğunluğu, Raymond-Roy Class 1 anevrizma okluzyonu sağlamak için oldukça önemli bir faktördür. Bununla birlikte, anevrizma hacmi arttıkça, yüksek KPD sağlamak zorlaşmakta ve bu durum rekanalizasyon riskini arttırmaktadır. Daha büyük hasta grupları ve daha uzun süreli takipler ile yapılacak çalışmalar, stent yardımlı tedavi edilen anevrizmalarda, stent kullanımının da nüks riskini azalttığını gösterilebilir.

Application of High-Resolution C-Arm CT Combined with Streak Metal Artifact Removal Technology for the Stent-Assisted Embolization of Intracranial Aneurysms.

Metal artifacts from coils and stents limit the level of detail in C-arm CT images of stent attachment and coiling attenuation in the aneurysm neck. We evaluated the utility of high-resolution C-arm CT combined with streak metal artifact removal technology for stent-assisted embolization of intracranial aneurysms. From October 2017 to July 2018, the First Affiliated Hospital of Zhengzhou University treated 107 patients with intracranial aneurysms (118 aneurysms in total) with stent-assisted embolization. Conventional C-arm CT and high-resolution C-arm CT scanning of the stented area were performed during and after treatment. 3D images were reconstructed with and without streak metal artifact removal techniques. Subsequently, the image quality was compared. The reconstructed images indicated the stent deployment degree and packing density. Follow-up assessments included clinical and angiographic outcomes and complications. In total, 118 aneurysms were successfully embolized using 118 stents. Image quality was significantly higher (P < .05) with high-resolution C-arm CT combined with streak metal artifact removal reconstruction. Streak metal artifact removal reconstruction and 2D angiography at working angles showed incomplete deployment of 6 stents and incomplete aneurysm embolization of 15 patients, which were subsequently resolved. One case of hemorrhage was noted postoperatively. Follow-up of 93 patients at 6-13 months indicated 3 cases of aneurysm recurrence. High-resolution C-arm CT combined with the streak metal artifact removal technique effectively reduced metal artifacts from stents and coils during aneurysm embolization. This method can help physicians determine the extent of stent deployment and the packing density of coils and thus potentially reduce complications and aneurysm recurrence.

Cerebral Aneurysm Wall Stress After Coiling Depends on Morphology and Coil Packing Density.

Endovascular coil embolization is now widely used to treat cerebral aneurysms (CA) as an alternative to surgical clipping. It involves filling the aneurysmal sac with metallic coils to reduce flow, induce clotting, and promote the formation of a coil/thrombus mass which protects the aneurysm wall from hemodynamic forces and prevents rupture. However, a significant number of aneurysms are incompletely coiled leading to aneurysm regrowth and/or recanalization. Computational models of aneurysm coiling may provide important new insights into the effects of intrasaccular coil and thrombus on aneurysm wall stresses. Porcine blood and platinum coils were used to construct an in vitro coil thrombus mass (CTM) for mechanical testing. A uniaxial compression test was performed with whole blood clots and CTM, with coil packing densities (CPDs) of 10%, 20%, and 30% to obtain compressive stress/strain responses. A fourth-order polynomial mechanical response function was fit to the experimentally obtained stress/strain responses for each CPD in order to represent their mechanical properties for computational simulations. Patient-specific three-dimensional (3D) geometries of three aneurysms with simple geometry and four with complex geometry were reconstructed from digital subtraction angiography (DSA) images. The CPDs were digitally inserted in the aneurysm geometries and finite element modeling was used to determine transmural peak/mean wall stress (MWS) with and without coil packing. Reproducible stress/strain curves were obtained from compression testing of CTM and the polynomial mechanical response function was found to approximate the experimental stress/strain relationship obtained from mechanical testing to a high degree. An exponential increase in the CTM stiffness was observed with increasing CPD. Elevated wall stresses were found throughout the aneurysm dome, neck, and parent artery in simulations of the CAs with no filling. Complete, 100% filling of the aneurysms with whole blood clot and CPDs of 10%, 20%, and 30% significantly reduced MWS in simple and complex geometry aneurysms. Sequential increases in CPD resulted in significantly greater increases in MWS in simple but not complex geometry aneurysms. This study utilizes finite element analysis to demonstrate the reduction of transmural wall stress following coil embolization in patient-specific computational models of CAs. Our results provide a quantitative measure of the degree to which CPD impacts wall stress and suggest that complex aneurysmal geometries may be more resistant to coil embolization treatment. The computational modeling employed in this study serves as a first step in developing a tool to evaluate the patient-specific efficacy of coil embolization in treating CAs.

Efficacy of LVIS vs. Enterprise Stent for Endovascular Treatment of Medium-Sized Intracranial Aneurysms: A Hemodynamic Comparison Study

Background: We conducted a computational fluid dynamics (CFD) study and compared the treatment of medium-sized intracranial aneurysms with LVIS and Enterprise stent-assisted coil embolization (SACE) to determine the effects of hemodynamic changes caused by different stent and coil packing densities (PDs) in endovascular treatment.Methods: We enrolled 87 consecutive patients, with 87 medium-sized intracranial aneurysms (≥7, ≤ 12 mm), who underwent LVIS or Enterprise SACE. Aneurysms treated with LVIS SACE were allocated to the LVIS group, and the remainder were allocated to the Enterprise group. CFD were performed to assess hemodynamic alterations between before treatment, after stent deployment, and after SACE.Results: One aneurysm recanalized in the LVIS group (n = 42), and five recanalized in the Enterprise group (n = 45) (recanalization rate: 2.4 vs. 11.1%, respectively; P = 0.108). Higher complete obliteration rate (P = 0.069) was found in the LVIS group. Velocity at the neck plane showed a greater reduction ratio than velocity and WSS of the aneurysm in both groups after stent deployment, while velocity and WSS of the aneurysm showed a greater reduction ratio after coil placement. Further, there was a greater reduction in velocity at the neck plane (59.52 vs. 39.81%), aneurysmal velocity (88.46 vs. 69.45%), and wall shear stress (WSS) (85.45 vs. 69.49%) on the aneurysm in the LVIS group (P < 0.001 for all). Specifically, the reduction ratio of velocity at the neck plane showed significant difference between the groups in the multivariate analysis (P = 0.013).Conclusions : LVIS SACE showed a lower recanalization for endovascular treatment of medium-sized intracranial aneurysms, and the greater hemodynamic alterations might be the key factors.