Neck Coverage Research Articles

In vitro evaluation of flow diverter performance using a human fibrinogen-based flow model.

Fibrin deposition represents a key step in aneurysm occlusion, promoting endothelization of implants and connective tissue organization as part of the aneurysm-healing mechanism. In this study, the authors introduce a novel in vitro testing platform for flow diverters based on human fibrinogen. A flow diverter was deployed in 4 different glass models. The glass models had the same internal parent artery (4 mm) and aneurysm (8 mm) diameters with varying parent artery angulations (paraophthalmic, sidewall, bifurcation, and slightly curved models). The neck size and area were 4 mm and 25 mm2, respectively. Human fibrinogen (330 mg/dl) was circulated within the glass models at varying flow rates (0, 3, 4, and 5 ml/sec) with or without heparin, calcium chloride, and thrombin for as long as 6 hours or until complete fibrin coverage of the flow diverter's neck was achieved. Aneurysm neck coverage was defined as macroscopic fibrin deposition occluding the flow diverters' pores. Flow characteristics after flow diverter deployment were assessed with computational fluid dynamics analysis. The effects of flow rates, heparin, calcium chloride, and thrombin on fibrin deposition rates were tested using 1-way ANOVA and the Tukey test. A total of 84 replicates were performed. Human fibrin did not accumulate on the flow diverter stents under static conditions. The fibrin deposition rate on the aneurysm neck was significantly greater with the 5 ml/sec flow rate as compared to 3 ml/sec for all models. The paraophthalmic model had the highest inflow velocity of 48.7 cm/sec. The bifurcation model had the highest maximum shear stress (SS) and maximum normalized shear stress values at the device cells at 843.3 dyne/cm2 and 35.1 SS/SSinflow, respectively. The fibrin deposition rates of the paraophthalmic and bifurcation models were significantly higher than those of sidewall and slightly curved models for all additive or flow rate comparisons (p = 0.001 for all comparisons). The incorporation of thrombin significantly increased the fibrin deposition rates across all models (p = 0.001 for all models). Rates of fibrin deposition varied widely across different configurations and additive conditions in this novel in vitro model system. Fibrin accumulation started at the aneurysm inflow zone where flow velocity and shear stress were the highest. The primary factors influencing fibrin deposition included flow velocities, shear stress, and the addition of thrombin at a physiological concentration. Further research is needed to test the clinical utility of fibrinogen-based models for patient-specific aneurysms.

Posterior Neck Coverage in Patients Receiving Regional Nodal Irradiation for Breast Cancer

Patterns-of-failure studies suggest the posterior neck (PN) may harbor microscopic disease in patients with locally advanced breast cancer. We compared target coverage, lung dose, and toxic effects in patients treated with either an anterior oblique field (AO) or opposed oblique fields (OO) to address the superior axillary and supraclavicular nodal (SCV) regions. We identified 119 consecutively treated patients who received regional nodal irradiation, including a "third field," to address the superior axillary and supraclavicular nodal regions with a monoisocentric technique in our institution. Coverage of the axillary clinical target volume (CTV), SCV CTV and PN CTV was determined based on the delivered treatment plan. Wilcoxon rank-sum test and Fisher's exact test were used to compare coverage of the axillary, SCV, and PN CTVs, lung dosimetry, and toxic effects (graded by the Common Terminology Criteria for Adverse Events v4.0) between patients receiving an AO or OO. There were 29 patients in the AO group and 80 in the OO group. All patients in the AO group received conventionally fractionated radiation versus 61% in the OO group. Modestly hypofractionated plans were delivered to 39% of the OO group. The body mass index and anterior-posterior separation at the matchline (measured at the center of the carotid artery) were similar in both groups. The median volume (%) of the SCV CTV receiving at least 90% of the prescription dose (V90%) was 91% (85, 99) in the AO group and 93% (91, 95) in the OO group (P = 0.2). The median V90% of the PN CTV was 30% (12, 49) in the AO group and 100% (100, 100) in the OO group (P<0.001). The median V90% in the axillary levels I, II and III CTVs were 98%, 95% and 90%, respectively, in the AO group and all 100% in the OO group (P<0.001). Maximum dose and heterogeneity in the SCV CTV were similar in both groups. Including only patients who received conventionally fractionated plans, the mean lung dose (cGy) was 1216 in the AO group and 1328 in the OO group (P = 0045). The lung V5 Gy, V10 Gy and V20 Gy were similar in both groups. Ipsilateral upper extremity lymphedema (all grade 1) was 3.4% in the AO group and 2.5% in the OO group (p>0.9). Moist desquamation in the neck was 0% in the AO group and 1.2% in the OO group (p>0.9). Pneumonitis (all grade 1) was 0% in the AO group and 1.2% in the OO group (p>0.9). Compared to a single anterior field, opposed oblique fields provide superior axillary and posterior neck coverage without increasing toxicity.

In vitro flow diversion effect of the ReSolv stent with the shelf technique in a bifurcation aneurysm model

BackgroundFlow-diverting stents are not currently indicated for the treatment of bifurcation aneurysms, and some case series have demonstrated low occlusion rates, possibly due to a lack in neck coverage. The...

Surgical Resection and Intensity Modulated Proton Therapy for Esthesioneuroblastoma

<h3>Purpose/Objective(s)</h3> Esthesioneuroblastoma (ENB) is a rare locally aggressive neuroendocrine sinonasal malignancy commonly presenting with skull base and intracranial invasion, which is often managed using multimodality therapy with surgery and radiotherapy (RT). Advances in surgical techniques as well as RT have improved outcomes for these complex tumors. Proton therapy has dosimetric advantages over conventional X-ray based approaches and may further improve the therapeutic ratio. We report our early experience with intensity modulated proton therapy (IMPT) in the management of ENB. <h3>Materials/Methods</h3> We retrospectively reviewed treatment records of patients with ENB treated at our center with IMPT from 2015-2021. IMPT was delivered with a 2 to 5 field pencil-beam scanning plan, initially with single-field optimization, then multi-field optimization after 2018. All pathology was internally reviewed. Event outcomes were calculated from date of biopsy to time of locoregional recurrence or death. Survival statistics were calculated using the Kaplan-Meier (KM) method using a scientific 2-D graphing and statistics software. <h3>Results</h3> 15 patients were identified, median age 52 (range 32-78), gender (male 12, female 3), Kadish stage (B – 2; C – 12; D – 1), AJCC T classification (T3 – 3, T4b – 12), 2 had nodal metastasis at diagnosis, Hyams (grade 2 – 10; grade 3-4 – 5). Local disease extent included: anterior cranial fossa – 11, middle cranial fossa – 2, dura – 12, brain parenchyma 1, nasopharynx – 2, orbit – 6. The majority (n=14) were managed with surgical resection followed by postoperative RT, and one underwent primary chemoradiation. Surgery included bifrontal craniotomy + extended endoscopic resection (n=7) and extended endoscopic resection alone (n=7). IMPT was delivered in conventional fractionation (n=12) or hyperfractionated accelerated course (n=3), median dose 68 CGE (range 60-72), neck coverage (n=11). Four received concurrent platinum-based chemotherapy. At median follow up of 20 months (IQR 16-51), 2 patients have died, unrelated to disease progression. Three patients have recurred including 1 local, 1 regional, and 1 distant metastasis (out of field dural metastases). Both patients with locoregional recurrence have undergone surgical salvage and have no evidence of disease. IMPT was well tolerated with expected acute toxicities. One patient developed frontal lobe brain necrosis at 3 years post-treatment managed conservatively, and one underwent functional sinus surgery for sinus obstruction. No de novo high grade visual toxicity was observed. KM 2-year locoregional recurrence-free survival was 83% and OS 88%. <h3>Conclusion</h3> IMPT is feasible in ENB with early outcomes demonstrating excellent local control and favorable toxicity profile in this cohort of patients with very locally advanced disease. IMPT may allow for improved coverage of tumor volumes in close proximity to numerous critical structures. Additional follow up is needed to track long term disease control outcomes and late toxicities.

C11 choline PET/CT succeeds when conventional imaging for primary hyperparathyroidism fails

BackgroundFocused parathyroidectomy in primary hyperparathyroidism is possible with accurate preoperative localization. A growing body of data exists regarding the role of radio-labeled C11 choline positron emission tomography/computed tomography. In cases of nonlocalized disease, it may be a useful adjunct to ultrasound, (123)I/(99)Tc-sestamibi (I-123 sestamibi), or 4-dimensional computed tomography imaging. MethodsPatients who received a neck and chest limited coverage C11 choline positron emission tomography/computed tomography for evaluation of primary hyperparathyroidism from 2017 to 2021 at a single institution were retrospectively reviewed. We assessed the sensitivity, positive predictive value, and false negative rate. We also compared these rates to the standard modalities of ultrasound, I-123 sestamibi, 4-dimensional computed tomography, and examined concordance rates. ResultsWe identified 43 patients, of whom 33 had a positive C11 choline positron emission tomography/computed tomography finding. This cohort of patients had failed to localize on multiple standard imaging modalities. Twenty-five patients proceeded to surgery, 72% of whom were reoperative cases. Twenty (80%) achieved an intraoperative cure. Analysis showed that C11 choline positron emission tomography/computed tomography achieved a sensitivity of 64% (95% confidence interval 47%–82%) and positive predictive value of 72% (95% confidence interval 54%–90%). There were 5/25 (20%) false positive positron emission tomography C11 choline results found to be lymph nodes, normal parathyroid, and 1 recurrent laryngeal nerve neuroma. ConclusionC11 choline positron emission tomography/computed tomography is a useful adjunct for parathyroid localization in a complex population of patients who have failed standard localization techniques including ultrasound, I-123 sestamibi, or 4-dimensional computed tomography and/or prior operations. Although routine inclusion of C11 choline positron emission tomography/computed tomography imaging may not be necessary, it may aid in preoperative localization in the reoperative setting.

Characterizing Lymph Node Burden With Elective Unilateral Neck Irradiation in Human Papillomavirus-Positive Tonsil Squamous Cell Carcinoma: Defining the Upper Limits.

ObjectivesElective unilateral neck irradiation in well-lateralized tonsil carcinoma for N2b disease is controversial. Metrics regarding nodal burden beyond the N-stage to define the upper limit of this de-escalation approach remain limited. We investigated the role of nodal number, level, and volume on outcomes in patients with well-lateralized tonsil carcinoma treated with this approach.MethodsA total of 37 patients received radiotherapy (RT) with unilateral neck coverage for well-lateralized tonsil cancer. Of patients, 95% had p16+ disease, and 81% were staged with positron emission tomography/computed tomography. The majority of patients received definitive chemoradiation on prospective de-escalation trials. Ten patients had ipsilateral neck dissections and were treated adjuvantly. The median RT dose to the ipsilateral neck (generally II-IV) was 45 Gy. The effects of nodal number, max dimension, volume, and level on recurrence-free survival (RFS) and overall survival (OS) were to be analyzed via Cox proportional hazards (Cox-PH).ResultsAfter a median follow-up of 3.9 years, two-year RFS and two-year OS were 100% and 97%, respectively. Given the 0% contralateral recurrence rate, Cox-PH analysis was not performed. Of patients, 70% were American Joint Committee on Cancer (AJCC) 7th edition N2b, with a median number of nodes, number of nodal levels, max dimension, and volume of two, one, 3.4 cm, and 15.6 cc, respectively. There were several patients with low-lying nodes; aggregate nodal volume measured was up to 85.4 cc.ConclusionUnilateral neck irradiation in well-lateralized tonsil carcinoma resulted in no contralateral recurrence. Nodal volume, level, and number do not seem to have a significant impact on outcomes.

Chimeric Anterolateral Thigh Flap for One-stage Reconstruction after Cervical Exenteration with Anterior Mediastinal Tracheostomy

Summary:Cervical exenteration with anterior mediastinal tracheostomy is rarely performed for extensive cervicothoracic malignancies. Although it provides effective palliation and occasional cure, reconstruction remains a formidable challenge owing to its complexity and high mortality. The resultant defects usually require an intestinal flap or tubed skin flap to restore the alimentary tract, soft-tissue interposition to separate the relocated trachea from the innominate artery, and another tubed or fenestrated skin flap to create a tension-free tracheocutaneous anastomosis and provide coverage for the exposed vessels, hopefully in one stage. We report a case involving a 60-year-old woman with recurrent medullary thyroid cancer who developed dyspnea and dysphagia. Salvage cervical exenteration and anterior mediastinal tracheostomy were complicated by tissue fibrosis caused by previous surgical and radiation therapies, resulting in complex defects with segmental loss of the esophagus, a short stump of trachea incapable of tracheocutaneous anastomosis, and great-vessel exposure. We used a chimeric anterolateral thigh flap consisting of a tubed skin flap for pharyngoesophageal reconstruction, a fenestrated skin flap for tracheostomy and neck coverage, and a vastus lateralis muscle bulk to separate the innominate artery from the relocated trachea. To our knowledge, this is the first report describing the reconstruction of such a complex defect with a single skin flap in a single stage.

Watchman FLX vs. Watchman 2.5 in a Dual-Center Left Atrial Appendage Closure Cohort: the WATCH-DUAL study.

No studies have compared Watchman 2.5 (W2.5) with Watchman FLX (FLX) devices to date. We aimed at comparing the FLX with W2.5 devices with respect to clinical outcomes, left atrial appendage (LAA) sealing properties and device-related thrombus (DRT). All consecutive left atrial appendage closure (LAAC) procedures performed at two European centres between November 2017 and February 2021 were included. Procedure-related complications and net adverse cardiovascular events (NACE) at 6 months after LAAC were recorded. At 45-day computed tomography (CT) follow-up, intra- (IDL) and peri- (PDL) device leak, residual patent neck area (RPNA), and DRT were assessed by a Corelab. Out of 144 LAAC consecutive procedures, 71 and 73 interventions were performed using W2.5 and FLX devices, respectively. There were no differences in terms of procedure-related complications (4.2% vs. 2.7%, P = 0.626). At 45-day CT, the FLX was associated with lower frequency of IDL [21.3% vs. 40.0%; P = 0.032; odds ratio (OR): 0.375; 95% confidence interval (CI): 0.160-0.876; P = 0.024], similar rate of PDL (29.5% vs. 42.0%; P = 0.170), and smaller RPNA [6 (0-36) vs. 40 (6-115) mm2; P = 0.001; OR: 0.240; 95% CI: 0.100-0.577; P = 0.001] compared with the W2.5 group. At 45 days, rate of DRT as detected by CT and/or transoesophageal echocardiography (TOE), was higher with W2.5 (6.0% vs. 0%, P = 0.045). At 6-month follow-up, NACE did not differ between groups. In this cohort of consecutive LAACs, FLX as compared to W2.5, was associated with similar procedure-related complications and 6-month NACE, but with improved LAA neck coverage, and lower IDL and DRT.

Long-Term Outcomes of Placement of a Single Transverse Stent through the Anterior Communicating Artery via the Nondominant A1 in Coil Embolization of Wide-Necked Anterior Communicating Artery Aneurysms.

ObjectivePlacement of a single transverse stent via the nondominant A1 across the anterior communicating artery (AComA) into the contralateral A2 can provide sufficient neck coverage for wide-necked bifurcation AComA aneurysms. The authors described the feasibility, safety and long-term outcomes of this technique. MethodsBetween January 2015 and February 2018, placement of a single transverse stent via the nondominant A1 was attempted in 17 wide-necked bifurcation AComA aneurysms. The authors reviewed the medical records and radiological studies. ResultsThe technical success rate was 94.1% (16/17). Periprocedural thromboembolic complications occurred in one patient (6.3%) without permanent neurological deficits. The mean clinical follow-up duration was 39.9±9.8 months. No deaths or delayed thromboembolic complications occurred. The mean angiographic follow-up duration was 38.9±9.8 months. The immediate and final follow-up complete occlusion rates were 87.4 and 93.7%, respectively. There was no recanalization during the follow-up period. ConclusionPlacement of a single transverse stent via the nondominant A1 across the AComA into the contralateral A2 is a feasible and relatively safe endovascular technique for the treatment of wide-necked bifurcation AComA aneurysms, with good long-term occlusion rates and a reasonable complication rate, if only the nondominant A1 is applicable.

Flared non-flow diverting ends of the FRED flow diverter for cerebral aneurysms facilitate device anchoring at the arterial bifurcation.

The Flow Redirection Intraluminal Device (FRED) flow diverter has a unique bilayer design, with the outer scaffolding stent extending beyond the inner flow diverting component by about 3 mm at each end. Here, we describe a technique to utilize these unrestrained flared ends for precise flow diverter placement in cases where the aneurysm and an adjacent branch are in close proximity and branch jailing is not desired, such as in posterior communicating artery aneurysms.Technical note: The distal end of the FRED device is pushed out of the microcatheter at the carotid terminus. Once the distal flared ends are fully open and well situated in the terminus, ideally with at least one of the limbs in the A1 segment of the anterior cerebral artery, the device is unsheathed under gentle forward pressure. This technique stabilizes the device at the distal landing zone and prevents unintended foreshortening at the distal end. This is particularly important for aneurysms located adjacent to the carotid terminus in order to assure adequate neck coverage, as well as avoiding jailing one of the branching parent arteries. An illustrative case is provided. The non-flow diverting unrestrained flared ends of the FRED stabilize the distal end of the device when deployed directly into the branches at the arterial bifurcation. The technique is useful to provide adequate neck coverage of cerebral aneurysm located directly adjacent to the bifurcation as is frequently the case with posterior communicating artery aneurysms.

Contralateral nodal spread in human papillomavirus‐associated oropharyngeal cancer: Can more details help guide contralateral neck coverage?

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Outcomes of vascular wall malapposition following Pipeline Flex embolization device implantation for cerebral aneurysms: A retrospective study

BackgroundPipeline Flex embolization device (PLED) is a specific management modality for adults with intracranial aneurysms (IAs). The technical characteristics of the PLED aid in safe as well as extremely efficient usage. We present our experience of attempted and non-attempted resolution of wall malapposition in ICAs and vertebral artery aneurysms with associated cavernous ICA (cICA) tortuosity’s. MethodsWe conducted a retrospective study to identify PLED wall malapposition from April 2018 to July 2019. We assessed various degrees of vascular tortuosity’s, aneurysm characteristics, immediate wall apposition, postoperative resolution of wall malapposition, postoperative follow-up of patients with wall malapposition as well as wall malapposition related complications. The patients were put into two category such as attempt resolution and non-attempted resolution (conservative treatments) groups. ResultsWe treated a total of 118 patients with PLED out of which 22 patients (18.6%) had wall malapposition. All patients were treated with a single PLEDs. Coils were used to obliterate the aneurysms in nine patients. Adequate aneurysm neck coverage was achieved in all cases. Resolution of wall malapposition was attempted in 13 patients while no resolution was attempted in nine patients intraoperatively. Out of the 22 patients with wall malapposition, 14 of them (63.64%) did not resolve in both groups. These 14 patients were put into follow-up sequence category. ConclusionAttempted resolution may not be suitable for certain aneurysms in very angulated ICAs with associated cICA tortuosity. Interestingly, spontaneous resolution of wall malapposition of PLED didn’t occur as we anticipated in most of our conservative treatment category.

Initial Clinical Experience With a New Conformable Abdominal Aortic Endograft: Aortic Neck Coverage and Curvature Analysis in Challenging Aortic Necks

Objectives: Aim of this work was to investigate precision of deployment and conformability of a new generation GORE EXCLUDER Conformable Endoprosthesis with active control system (CEXC Device, W.L. Gore and Associates, Flagstaff, AZ, USA) by analyzing aortic neck coverage and curvature. Methods: All consecutive elective patients affected by abdominal aortic aneurysm or aortoiliac aneurysm treated at our institution between November 2018 and June 2019 with the new CEXC Device were enrolled. Validated software was adopted to determine the available apposition surface area into the aortic neck, apposition of the endograft to the aortic wall, shortest apposition length (SAL), shortest distance between the endograft fabric and the lowest renal arteries (SFD) and between the endograft fabric and the contralateral renal artery (CFD). Pointwise centerline curvature was also computed. Results: Twelve patients (10 men, median age 78 years (71.75, 81.0)) with available pre- and postoperative computed tomography angiography (CTA) were included. Technical success was obtained in all the cases. Preoperative median length of the proximal aortic neck was 16.1 mm (10.7, 21.7) and suprarenal (α) and infrarenal (β) neck angulation were, respectively, 28.9° (15.7°, 47.5°) and 75.0° (66.9°, 81.4°). Postoperative median apposition surface coverage was 79% (69.25%, 90.75%) of the available apposition surface. SFD and CFD were 1.5 mm (0.75, 5.25) and 7 mm (4.5, 21.5), respectively. Average curvature over the infrarenal aorta decreased from 25 m−1 (21.75, 29.0) to 22.5 m−1 (18.75, 24.5) postoperatively (p=0.02). Maximum curvature did not decrease significantly from 64.5 m−1 (54.25, 92.0) to 62 m−1 (41.75, 71.5) (p=0.1). Conclusions: Our early experience showed that deployment of the CEXC Device is safe and effective for patients with challenging proximal aortic necks. Absence of significant changes between pre- and postoperative proximal aortic neck angulations and curvature confirms the high conformability of this endograft.

Placing a Bolus Helps to Lower the RT Dose to Pacemaker in IMRT Treatment of Head and Neck Cancer.

Planning IMRT for Head and Neck cancer (HNC) patients can be challenging if a pacemaker is in the vicinity of treatment field. This study investigated the use of bolus on the pacemaker to reduce RT dose. Three patients with HNC with pacemaker were included in this study. All subjects were planned to receive RT to neck nodes on the same side as pacemaker. Patients were simulated in the supine position with an aquaplast mask for immobilization. Patients were treated with a dose painting technique. Prescriptions were as follows: Patient 1, 70Gy, 63Gy, and 56Gy and bilateral neck coverage, patient 2 to 66Gy, 59.4Gy, and 56Gy to ipsilateral neck, and patient 3, 70Gy, 63Gy, and 58.10Gy and bilateral necks to high, intermediate and low risk regions respectively. Plans were generated with and without 1cm bolus on the skin over the pacemaker. Currently, the commonly accepted dose for a pacemaker is <2Gy. All patients were planned with a volumetric modulated arc therapy (VMAT) technique using 6MV energy and 3 full arcs with varying collimator angles. The use of bolus over the pacemaker throughout the treatment course reduces the dose received by the pacemaker without affecting PTVs coverage. There was a 33.4%, 19.6%, 34.9% reduction in dose to the pacemaker in patients 1, 2 and 3 respectively when bolus was used and placed on the device. Conclusions: This novel technique of using bolus while planning IMRT for HNC patients with pacemakers yields significant dosimetric advantages and helps to reduce the dose to the pacemaker.Tabled 1Abstract 2800; TablePacemaker Patientskin to pacemaker distanceDistance PTV to pacemakerMax dose w/o 1cm bolusMax dose w 1cm bolus19mm6cm311.1cGy207.3cGy27mm2cm401.4cGy322.8cGy36mm6cm248.8cGy162cGy Open table in a new tab

ECLIPs bifurcation remodeling system for treatment of wide neck bifurcation aneurysms with extremely low dome-to-neck and aspect ratios: a multicenter experience

BackgroundWide necked bifurcation aneurysms (WNBA) are among the most difficult aneurysms to treat. Very low dome-to-neck (DTN) and aspect ratios provide an even greater challenge in the management of WNBAs....

Novel Noncrossing Y-Stent Technique Using Tapered Proximal End of a Solitaire AB Stent for Coil Embolization of Wide-Neck Bifurcation Aneurysms.

The crossing Y-stent method is one of the indispensable techniques to achieve sufficient neck coverage during coil embolization of bifurcation aneurysms with a wide neck and/or branch incorporation. However, the inevitable hourglass-like expansion of the second stent at the crossing point can result in insufficient vessel wall apposition, reduced aneurysm neck coverage, delayed endothelialization, and subsequent higher risks of acute or delayed thrombosis. It also interferes with engagement of the microcatheter into the aneurysm after stent installation. We expected to be able to reduce these disadvantages by installing a noncrossing type Y-stent using the Solitaire AB stent, which is fully retrievable with a tapered proximal end. Here we report the techniques and two successful cases.

Optimum concentration of iodine contrast agent injection for best stent visualization using Neuroform Atlas stent during stent-assisted coil embolization: Case reviews based on in vitro experiments.

Background: The present study aimed to evaluate the influence of contrast agent concentration (Conc) on the visibility of Neuroform Atlas in vitro and in clinical cases.Methods: A plastic tube was filled with several Conc. in saline (experiment 1) and blood (experiment 2). Thereafter, the Neuroform Atlas was placed around the plastic tube in an acrylic shield case. In experiment 3, the Neuroform Atlas was placed in the internal carotid artery of the endo vascular evaluator endovascular training system with an injection of several Conc in saline. Five slices of the axial images obtained using the 3D-cone-beam computed tomography (3D-CBCT) with the digital subtraction angiography system were evaluated. A 1-cm2 circular center, which showed the contrast agent in saline or blood, was determined as the region of interest, and its pixels were evaluated.Results: Radiation density (Rd) was directly proportional to the contrast agent in saline and blood (experiment 1: (Rd (pixel)) = 6.8495 × (concentration (%)) + 152.72 (R2 = 0.99), experiment 2: (Rd (pixel)) = 6.2485 × (concentration (%)) + 167.42 (R2 = 0.9966), experiment 3: (Rd (pixel)) = 10.287 × (concentration (%)) + 108.26 (R2 = 0.993)]. Rd calculated similarly in our cases (concentration varied from 5% to 8%) was between the range of “Rd of experiment 2” and “Rd of experiment 3.”Conclusion: Based on our in vitro experiments, with 5–8% concentration, Neuroform Atlas stent deployment with complete neck coverage by the bulging stent and wall apposition was visualized on 3D-CBCT.

Simultaneous neck coverage and branch preservation using the proximal portion of a self-expandable open-cell stent for embolization of distal internal carotid artery aneurysms: multi-center, long-term results.

We report the long-term results of a modified stent-assisted coil embolization technique using the far proximal part of a self-expanding open-cell stent. The technique was used to cover the neck of the aneurysm while simultaneously preserving the branches of the distal internal carotid artery in patients with aneurysms of the posterior communicating (Pcom) and anterior choroidal arteries (AchA). We performed a retrospective review of the prospectively maintained databases at two tertiary neurosurgical centers to identify all patients who underwent embolization of Pcom or AchA aneurysms using this technique between January 2014 and July 2019. Postoperative and follow-up clinical and radiological results for initial (n = 16) or re-do (n = 4) embolizations were analyzed. We identified 19 patients with 20 (16 Pcom and 4 AchA) unruptured (n = 19) or ruptured (n = 1) aneurysms. Eighteen among 20 stents (90.0%) were deployed successfully, and complete occlusions were initially attained in 18 aneurysms (90.0%). At follow-up examinations 8 to 56months later, 6 of 14 aneurysms (42.8%) showed neck remnants. All of the branches were saved and no thromboembolic event, rupture, or sequelae were noted during or after the procedures. These results suggest that this modified stent-assisted technique is a feasible and reasonable alternative to conventional stent deployment for coil embolization of wide-necked sidewall aneurysms in the distal ICA.

Retrograde stenting through anterior communicating artery in coil embolization of the posterior communicating artery aneurysm: contralateral approach

During coil embolization of wide-necked posterior communicating artery (PcomA) aneurysms, stent assistance is sometimes limited if PcomA is acutely angled at its origins from saccular neck. Herein, we present two instances where retrograde stenting was used for coil embolization of PcomA aneurysms. Both procedures involved a contralateral approach via anterior communicating artery (AcomA). To achieve this, the stent-delivery microcatheter was inserted retrograde from contralateral to ipsilateral internal carotid artery (ICA) across AcomA, arriving at ipsilateral PcomA. A separate microcatheter, passed through ipsilateral ICA, was then used to select the aneurysm sac for coil delivery. Coil embolization ultimately took place under protection of a horizontally placed stent extending from PcomA to terminal ICA. Each aneurysm was properly coiled and occluded, without procedural complications. This stenting technique is a reasonable option, offering a means of strategic coil embolization in wide-necked PcomA aneurysms and providing complete neck coverage through contralateral access.

High frequency optical coherence tomography assessment of homogenous neck coverage by intrasaccular devices predicts successful aneurysm occlusion

BackgroundHigh frequency optical coherence tomography (HF-OCT) is a novel intravascular imaging technology developed for use in the cerebral vasculature. We hypothesize that HF-OCT characterization of intrasaccular device neck coverage can...