scholarly journals Bench-Top Comparison of Three Different Types of Stents Used for Treatment of Intracranial Atherosclerotic Stenosis

2020 ◽  
Vol 15 (3) ◽  
pp. 117-125
Author(s):  
Jung-soo Park ◽  
Hyo Sung Kwak ◽  
Jin-Woo Kim
Keyword(s):  
Kinetic Energy ◽  
Vessel Wall ◽  
Mechanical Characteristics ◽  
Bending Stiffness ◽  
Bending Test ◽  
Intracranial Atherosclerotic Stenosis ◽  
Atherosclerotic Stenosis ◽  
Different Types ◽  
Wall Apposition ◽  
Curved Vessels

Purpose: Four key bench-top tests, including trackability, conformability, wall-apposition, and bending stiffness, were performed to understand the mechanical characteristics in 3 different types of stents applicable for treatment of intracranial atherosclerotic stenosis: Balloon-expandable D<sup>+</sup>Storm, Pro-Kinetic Energy, and self-expandable Wingspan stents.Materials and Methods: Trackability was assessed by measuring the tracking forces of each stent with its delivery systems. Conformability and wall apposition were quantified and analyzed using curved vessel models. A 3-point bending test was employed to evaluate bending stiffness.Results: D<sup>+</sup>Storm showed the lowest tracking forces while the conformability of the Wingspan stent was superior to that of the tested stents. Pro-Kinetic Energy and D<sup>+</sup>Storm had better wall apposition in curved vessels than the Wingspan stent. Bending stiffness of the Wingspan stent was notably lower, whereas no significant differences were found between D<sup>+</sup>Storm and Energy. Pro-Kinetic Energy and D<sup>+</sup>Storm not only indicated lower gap ratios between the struts and the vessel wall but also maintained good wall apposition even in the curved model.Conclusion: These bench-top measurements may provide clinicians with useful information in regard to selecting suitable stents for treatment of intracranial atherosclerotic stenosis.

scholarly journals Comparison of time-of-flight MR angiography and intracranial vessel wall MRI for luminal measurements relative to CT angiography

2020 ◽  
pp. 20200743
Author(s):  
Basar Sarikaya ◽  
Charles Colip ◽  
William D Hwang ◽  
Daniel S Hippe ◽  
Chengcheng Zhu ◽  
...  
Keyword(s):  
Vessel Wall ◽  
Measurement Accuracy ◽  
Random Order ◽  
Concordance Correlation ◽  
Tof Mra ◽  
Intracranial Vessel ◽  
Significant Bias ◽  
Intracranial Atherosclerotic Stenosis ◽  
Atherosclerotic Stenosis ◽  
Made In

Objective: To assess whether intracranial vessel wall (IVW) MRI luminal measurements are more accurate than non-contrast 3D-TOF-MRA measurements for intracranial atherosclerotic stenosis, relative to CTA. Methods: Consecutive patients with non-calcified intracranial atherosclerotic stenosis seen on CTA, who had non-contrast 3D-TOF-MRA and IVW performed between 1 January 2013 and 20 April 2014 were selected, and images with stenosis were pre-selected by a single independent rater. The pre-selected CTA, MRA, and IVW (T1-weighted) images were then reviewed by two independent raters blinded to the other measurements in random order. Measurements were made in a plane perpendicular to the lumen on each modality. MRA and IVW measurements were compared to CTA, to determine which more accurately matched the degree of stenosis. Results: 18 patients with 33 intracranial atherosclerotic stenoses were included. Relative to CTA, IVW had 40% less variance than MRA (p = .004). IVW had a significantly higher concordance correlation coefficient (CCC) relative to CTA than MRA (.87 vs .68, p = .002). IVW and MRA did not have significant bias relative to CTA, however, 8/33 lesions showed >20% overestimation of the degree of stenosis on MRA, compared to 1/33 for IVW. CCC between raters were 0.84 (95% CI 0.67–0.93) for CTA, 0.83 (0.67–0.93) for TOF-MRA, and 0.85 (0.71–0.94) for IVW. For stenosis >50% sensitivity was 82% for IVW and 64% for MRA, while specificity was 73% for both. Conclusion: IVW provides more accurate stenosis measurements than MRA when compared to CTA. Advances in knowledge: Considering higher stenosis measurement accuracy of IVW, it can be more reliably used for quantitative evaluation relative to MRA.

The Research and Analysis of the Body Structure Based on the Experiment of Bending Stiffness

2013 ◽  
Vol 631-632 ◽  
pp. 947-950
Author(s):  
Sheng Hui Peng ◽  
Qing Zhang Liu
Keyword(s):  
Sensitivity Analysis ◽  
Experimental Model ◽  
Structural Dynamics ◽  
Mechanical Characteristics ◽  
Bending Stiffness ◽  
The Body ◽  
Bending Test ◽  
Body Structure ◽  
Static Characteristics

According to the mechanical characteristics of the body structure, the experimental model and the bending test of the body is constructed to understand the static characteristics of the body structure, laying the foundation for the sensitivity analysis and the modification of structural dynamics .

Periprocedural risk and long-term outcome of intracranial angioplasty based on a single-centre experience

VASA ◽  
2013 ◽  
Vol 42 (4) ◽  
pp. 264-274
Author(s):  
Dagmar Krajíčková ◽  
Antonín Krajina ◽  
Miroslav Lojík ◽  
Martina Mulačová ◽  
Martin Vališ
Keyword(s):  
Death Rate ◽  
Long Term Outcomes ◽  
Single Centre ◽  
Intracranial Atherosclerotic Stenosis ◽  
Atherosclerotic Stenosis ◽  
Angioplasty And Stenting ◽  
Aggressive Medical Management ◽  
Stroke Death

Background: Intracranial atherosclerotic stenosis is a major cause of stroke and yet there are currently no proven effective treatments for it. The SAMMPRIS trial, comparing aggressive medical management alone with aggressive medical management combined with intracranial angioplasty and stenting, was prematurely halted when an unexpectedly high rate of periprocedural events was found in the endovascular arm. The goal of our study is to report the immediate and long-term outcomes of patients with ≥ 70 % symptomatic intracranial atherosclerotic stenosis treated with balloon angioplasty and stent placement in a single centre. Patients and methods: This is a retrospective review of 37 consecutive patients with 42 procedures of ballon angioplasty and stenting for intracranial atherosclerotic stenosis (≥ 70 % stenosis) treated between 1999 and 2012. Technical success (residual stenosis ≤ 50 %), periprocedural success (no vascular complications within 72 hours), and long-term outcomes are reported. Results: Technical and periprocedural success was achieved in 90.5 % of patients. The within 72 hours periprocedural stroke/death rate was 7.1 % (4.8 % intracranial haemorrhage), and the 30-day stroke/death rate was 9.5 %. Thirty patients (81 %) had clinical follow-up at ≥ 6 months. During follow-up, 5 patients developed 6 ischemic events; 5 of them (17 %) were ipsilateral. The restenosis rate was 27 %, and the retreatment rate was 12 %. Conclusions: Our outcomes of the balloon angioplasty/stent placement for intracranial atherosclerotic stenosis are better than those in the SAMMPRIS study and compare favourably with those in large registries and observational studies.

Symptomatic and asymptomatic intracranial atherosclerotic stenosis: 3 years’ prospective study

2020 ◽  
Vol 267 (6) ◽  
pp. 1687-1698 ◽  
Author(s):  
Urs Fischer ◽  
Kety Hsieh-Meister ◽  
Frauke Kellner-Weldon ◽  
Aikaterini Galimanis ◽  
Xin Yan ◽  
...  
Keyword(s):  
Prospective Study ◽  
Intracranial Atherosclerotic Stenosis ◽  
Atherosclerotic Stenosis

scholarly journals Motion Planning for a Mobile Humanoid Manipulator Working in an Industrial Environment

2021 ◽  
Vol 11 (13) ◽  
pp. 6209
Author(s):  
Iwona Pajak ◽  
Grzegorz Pajak
Keyword(s):  
Kinetic Energy ◽  
Collision Avoidance ◽  
Industry 4.0 ◽  
Degrees Of Freedom ◽  
Industrial Environment ◽  
Acceleration Level ◽  
Different Types ◽  
Manipulability Measure ◽  
Robotic Tasks ◽  
Primary Problem

This paper presents the usage of holonomic mobile humanoid manipulators to carry out autonomous tasks in industrial environments, according to the smart factory concept and the Industry 4.0 philosophy. The problem of transporting lengthy objects, taking into account mechanical limitations, the conditions for avoiding collisions, as well as the dexterity of the manipulator arms was considered. The primary problem was divided into three phases, leading to three different types of robotic tasks. In the proposed approach, the pseudoinverse Jacobian method at the acceleration level to solve each of the tasks was used. The redundant degrees of freedom were used to satisfy secondary objectives such as robot kinetic energy, the maximization of the manipulability measure, and the fulfillment mechanical and collision-avoidance limitations. A computer example involving a mobile humanoid manipulator, operating in an industrial environment, illustrated the effectiveness of the proposed method.

Bending stiffness of circular multilayer van der Waals material sheets

2022 ◽  
pp. 1-36
Author(s):  
Xiaojie Ma ◽  
Luqi Liu ◽  
Zhong Zhang ◽  
Yueguang Wei
Keyword(s):  
Lattice Structure ◽  
Van Der Waals ◽  
Bending Stiffness ◽  
Quantitative Prediction ◽  
Young’S Moduli ◽  
Different Types ◽  
Interlayer Shear Strength ◽  
Isometric Deformations ◽  
Good Agreement ◽  
Sinusoidal Function

Abstract We study the bending stiffness of symmetrically bent circular multilayer van der Waals (vdW) material sheets, which corresponds to the non-isometric configuration in bulge tests. Frenkel sinusoidal function is employed to describe the periodic interlayer tractions due to the lattice structure nature and the bending stiffness of sheets is theoretically extracted via an energetic consideration. Our quantitative prediction shows good agreement with recent experimental results, where the bending stiffness of different types of sheets with the comparable thickness could follow a trend opposite to their Young's moduli. Based on our model, we propose that this trend may experience a transition as the thickness decreases. Apart from the apparent effects of Young's modulus and interlayer shear strength, the interlayer distance is also found to have an important impact on the bending stiffness. In addition, according to our analysis on the size effect, the bending stiffness of such symmetrically bent circular sheets can steadily own a relatively large value, in contrast to the cases of isometric deformations.

Noninvasive fractional flow in intracranial atherosclerotic stenosis: Reproducibility, limitations, and perspectives

2017 ◽  
Vol 381 ◽  
pp. 150-152 ◽  
Author(s):  
Xinyi Leng ◽  
Linfang Lan ◽  
Vincent H.L. Ip ◽  
Haipeng Liu ◽  
Jill Abrigo ◽  
...  
Keyword(s):  
Fractional Flow ◽  
Intracranial Atherosclerotic Stenosis ◽  
Atherosclerotic Stenosis
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