PANoptosis-like death in acute-on-chronic liver failure injury.

The pathogenesis of Acute-on-chronic liver failure (ACLF) involves several forms of cell death, such as pyroptosis, apoptosis, and necroptosis, which consist of PANoptosis. To explore PANoptosis as a regulated cell death pathway in ACLF. Firstly, a bioinformatic strategy was used to observe the role of the PANoptosis pathway in ACLF and identify differentially expressed genes related to PANoptosis. Enrichment analysis showed that PANoptosis-related pathways were up-regulated in ACLF. We screened out BAX from the intersection of pyroptosis, apoptosis, necroptosis, and DEGs. Secondly, we screened articles from literature databases related to PANoptosis and liver failure, and specific forms of PANoptosis were reported in different experimental models in vitro and in vivo. Secondly, we established a model of ACLF using carbon tetrachloride-induced liver fibrosis, followed by D-galactosamine and lipopolysaccharide joint acute attacks. A substantial release of inflammatory factors(IL-6, IL-18, TNFα, and IFNγ) and the key proteins of PANoptosis (NLRP3, CASP1, GSDMD, BAX, CASP8, CASP3, CASP7, and MLKL) were detected independently in the ACLF rats. Finally, we found that combining TNF-α/INF-γ inflammatory cytokines could induce L02 cells PANoptosis. Our study highlighted the potential role of ACLF and helps drug discovery targeting PANoptosis in the future.

The afterglow of carbon dots shining in inorganic matrices.

Carbon dots (CDs) are a new type of quasi-spherical and zero-dimension carbon nanomaterial with a diameter less than 10 nm. They exhibit a broad absorption spanning from the ultraviolet (UV) to visible light regions and inspire growing interests due to their excellent performance. In recent years, it was identified that the CDs embedded in various inorganic matrices (IMs) can effectively activate afterglow emission by suppressing the nonradiative transitions of molecules and protecting the triplet excitons of CDs, which hold broad application prospects. Herein, recent advances in CDs@IMs are reviewed in detail, and the interaction and luminescence mechanisms between CDs and IMs are also summarized. We highlight the synthetic strategies of constructing composites and the roles of IMs in facilitating the applications of CDs in diverse areas. Finally, some directions and challenges of future research in this field are proposed.

General Synthesis of Carbon Dot-Based Composites with Triple-Mode Luminescence Properties and High Stability.

Carbon dot (CD)-based luminescent materials have attracted great attention in optical anti-counterfeiting due to their excellent photophysical properties in response to ultraviolet-to-visible excitation. Hence, there is an urgent need for the general synthesis of CD-based materials with multimode luminescence properties and high stability; however, their synthesis remains a formidable challenge. Herein, CDs were incorporated into a Yb,Tm-doped YF3 matrix to prepare CDs@YF3:Yb,Tm composites. The YF3 plays a dual role, not only serving as a host for fixing rare earth luminescent centers but also functioning as a rigid matrix to stabilize the triplet state of the CDs. Under the excitation of 365 nm ultraviolet light and 980 nm near-infrared light, CDs@YF3:Yb,Tm exhibited blue fluorescence and green room-temperature phosphorescence of CDs and upconversion luminescence of Tm3+, respectively. Due to the strong protection of the rigid matrix, the stability of CDs@YF3:Yb,Tm is greatly improved. This work provides a general synthesis strategy for achieving multimode luminescence and high stability of CD-based luminescent materials and offers opportunities for their applications in advanced anti-counterfeiting and information encryption.

ImTooth: Neural Implicit Tooth for Dental Augmented Reality.

The combination of augmented reality (AR) and medicine is an important trend in current research. The powerful display and interaction capabilities of the AR system can assist doctors to perform more complex operations. Since the tooth itself is an exposed rigid body structure, dental AR is a relatively hot research direction with application potential. However, none of the existing dental AR solutions are designed for wearable AR devices such as AR glasses. At the same time, these methods rely on high-precision scanning equipment or auxiliary positioning markers, which greatly increases the operational complexity and cost of clinical AR. In this work, we propose a simple and accurate neural-implicit model-driven dental AR system, named ImTooth, and adapted for AR glasses. Based on the modeling capabilities and differentiable optimization properties of state-of-the-art neural implicit representations, our system fuses reconstruction and registration in a single network, greatly simplifying the existing dental AR solutions and enabling reconstruction, registration, and interaction. Specifically, our method learns a scale-preserving voxel-based neural implicit model from multi-view images captured from a textureless plaster model of the tooth. Apart from color and surface, we also learn the consistent edge feature inside our representation. By leveraging the depth and edge information, our system can register the model to real images without additional training. In practice, our system uses a single Microsoft HoloLens 2 as the only sensor and display device. Experiments show that our method can reconstruct high-precision models and accomplish accurate registration. It is also robust to weak, repeating and inconsistent textures. We also show that our system can be easily integrated into dental diagnostic and therapeutic procedures, such as bracket placement guidance.

Electroplating a miniature diamond wheel for grinding of the calcified plaque inside arteries.

A miniature grinding wheel (0.85 mm diameter) was fabricated by nickel (Ni)-diamond electroplating on a thin (0.65 mm outer diameter) flexible hollow stainless steel drive shaft to remove the calcified plaque in coronary and peripheral arteries by atherectomy procedure. To coat electrically nonconductive diamond grits, the drive shaft was submerged in a pile of diamond grit during Ni electroplating. The electroplating current density and temperature were investigated for better surface finishing and Faraday efficiency. The electroplating time to obtain the designed coating thickness was modeled based on Faraday's law of electrolysis and the geometry of drive shaft, wheel, and diamond grit. To validate the miniature wheel performance in atherectomy, grinding experiments were conducted on an atherectomy cardiovascular simulator with a calcified plaque surrogate. The wheel motion, material removal rate, and wheel surface wear were studied via high-speed camera imaging and laser confocal microscopy. The grinding wheel with 80,000 rpm rotational speed had an orbital speed of 14,300 rpm around the 1.5 mm diameter plaque surrogate lumen. After grinding for 120 s, the plaque surrogate inner diameter was enlarged to 3.03 mm, and no wear or loss of diamond abrasive was observed on the grinding wheel. This study demonstrated that the proposed electroplating process for fabricating miniature grinding wheels could effectively remove the calcified plaque surrogate. This research could lead to a more effective and safer atherectomy device with sub-mm miniature diamond wheels to treat lesions deep in coronary and peripheral arteries.

Development of open-source software for free-hand 3D vascular ultrasound: Dialysis fistula application.

BACKGROUND: The arteriovenous fistula (AVF) is the preferred vascular access for End Stage Renal Disease, having superior patency and lower infection risks than prosthetic graft and catheter access. When AVF dysfunction or delayed maturation does occur, the gold standard for diagnosis is the fistula angiogram (a.k.a. fistulogram). 3D ultrasound is available for obstetrical and other specialized uses, but it is cost prohibitive and has a field of view that is too small to cover the region of interest for the dialysis fistula application. We sought to develop a point of care 3D solution using freehand 2D ultrasound data acquisition. METHODS: We developed open-source software for 3D image reconstruction and projection of an angiogram-like image of the vascular access using a 2D freehand ultrasound scanner. We evaluated this software by comparing the ultrasound "sono-angiogram" images to fistulogram images in five subjects, using visual inspection and by applying the Percent of Exact Match (PEM) as a statistic test. RESULTS: The sono-angiograms showed identifiable characteristics that matched the fistulogram results in all five subjects. The PEM ranged between 42.8% and 77.0%, with Doppler and grayscale ultrasound data, showing complementary advantages and disadvantages when used for sono-angiogram image construction. Motion from freehand ultrasound acquisition was a significant source of mismatch. 3D image generation is a potential advantage with ultrasound data. CONCLUSIONS: While further work is needed to improve the accuracy with free hand scanning, fistulogram-like "sono-angiograms" can be generated using point of care 2D ultrasound. Methods such as these may be able to assist in point-of-care diagnosis in the future. The software is open-source, and importantly, the ultrasound data used are non-proprietary and available from any standard ultrasound machine. The simplicity and accessibility of this approach warrant further study.

Unifying theory of carotid plaque disruption based on structural phenotypes and forces expressed at the lumen/wall interface.

OBJECTIVES: To integrate morphological, haemodynamic and mechanical analysis of carotid atheroma driving plaque disruption. MATERIALS AND METHODS: First, we analysed the phenotypes of carotid endarterectomy specimens in a photographic dataset A, and matched them with the likelihood of preoperative stroke. Second, laser angioscopy was used to further define the phenotypes in intact specimens (dataset B) and benchmark with histology. Third, representative vascular geometries for each structural phenotype were analysed with Computational Fluid Dynamics (CFD), and the mechanical strength of the complicated atheroma to resist penetrating forces was quantified (n=14). RESULTS: In dataset A (n=345), ulceration (fibrous cap disruption) was observed in 82% of all plaques, intraplaque haemorrhage in 68% (93% subjacent to an ulcer) and false luminal formation in 48%. At least one of these 'rupture' phenotypes was found in 97% of symptomatic patients (n=69) compared with 61% in asymptomatic patients. In dataset B (n=30), laser angioscopy redemonstrated the structural phenotypes with near-perfect agreement with histology. In CFD, haemodynamic stress showed a large pulse magnitude, highest upstream to the point of maximal stenosis and on ulceration the inflow stream excavates the necrotic core cranially and then recirculates into the true lumen. Based on mechanical testing (n=14), the necrotic core is mechanically weak and penetrated by the blood on fibrous cap disruption. CONCLUSIONS: Fibrous cap ulceration, plaque haemorrhage and excavation are sequential phenotypes of plaque disruption resulting from the chiselling effect of haemodynamic forces over unmatched mechanical tissue strength. This chain of events may result in thromboembolic events independently of the degree of stenosis.

Carbon Dots in Hydroxy Fluorides: Achieving Multicolor Long-Wavelength Room-Temperature Phosphorescence and Excellent Stability via Crystal Confinement.

Carbon dots (CDs) have aroused widespread interest in the construction of room-temperature phosphorescent (RTP) materials. However, it is a great challenge to obtain simultaneous multicolor long-wavelength RTP emission and excellent stability in CD-based RTP materials. Herein, a novel and universal "CDs-in-YOHF" strategy is proposed to generate multicolor and long-wavelength RTP by confining various CDs in the Y(OH)xF3-x (YOHF) matrix. The mechanism of the triplet emission of CDs is related to the space confinement, the formation of hydrogen bonds and C-F bonds, and the electron-withdrawing fluorine atoms. Remarkably, the RTP lifetime of orange-emissive CDs-o@YOHF is the longest among the reported single-CD-matrix composites for emission above 570 nm. Furthermore, CDs-o@YOHF exhibited higher RTP performance at long wavelength in comparison to CDs-o@matrix (matrix = PVA, PU, urea, silica). The resulting CDs@YOHF shows excellent photostability, thermostability, chemical stability, and temporal stability, which is rather favorable for information security, especially in a complex environment.

Semiautomated Software to Improve Stability and Reduce Operator-Induced Variation in Vascular Ultrasound Speckle Tracking.

OBJECTIVES: Ultrasound is useful in predicting arteriovenous fistula (AVF) maturation, which is essential for hemodialysis in end-stage renal disease patients. We developed ultrasound software that measures circumferential vessel wall strain (distensibility) using conventional ultrasound Digital Imaging and Communications in Medicine (DICOM) data. We evaluated user-induced variability in measurement of arterial wall distensibility and upon finding considerable variation we developed and tested 2 methods for semiautomated measurement. METHODS: Ultrasound scanning of arteries of 10 subjects scheduled for AVF surgery were performed. The top and bottom of the vessel wall were tracked using the Kanade-Lucas-Tomasi (KLT) feature-tracking algorithm over the stack of images in the DICOM cine loops. The wall distensibility was calculated from the change of vessel diameter over time. Two semiautomated methods were used for comparison. RESULTS: The location of points selected by users for the cine loops varied significantly, with a maximum spread of up to 120 pixels (7.8 mm) for the top and up to 140 pixels (9.1 mm) for the bottom of the vessel wall. This variation in users' point selection contributed to the variation in distensibility measurements (ranging from 5.63 to 41.04%). Both semiautomated methods substantially reduced variation and were highly correlated with the median distensibility values obtained by the 10 users. CONCLUSIONS: Minimizing user-induced variation by standardizing point selection will increase reproducibility and reliability of distensibility measurements. Our recent semiautomated software may help expand use in clinical studies to better understand the role of vascular wall compliance in predicting the maturation of fistulas.

Ultrasound speckle tracking to detect vascular distensibility changes from angioplasty and branch ligation in a radio-cephalic fistula: Use of novel open source software.

We used novel open source software, based on an ultrasound speckle tracking algorithm, to examine the distensibility of the vessel wall of the inflow artery, anastomosis, and outflow vein before and after two procedures. An 83-year-old white man with a poorly maturing radio-cephalic fistula received an angioplasty at the anastomosis followed by branch ligation 28 days later. Duplex Doppler measurements corroborated the blood flow related changes anticipated from the interventions. The experimental distensibility results showed that it is technically feasible to measure subtle vessel wall motion changes with high resolution (sub-millimeter) using standard Digital Imaging and Communications in Medicine (DICOM) ultrasound data, which are readily available on conventional ultrasound scanners. While this methodology was originally developed using high resolution radiofrequency from ultrasound data, the goal of this study was to use DICOM data, which makes this technology accessible to a wide range of users.

Sono-angiography for dialysis vascular access based on the freehand 2D ultrasound scanning.

INTRODUCTION: Dialysis vascular access, preferably an autogenous arteriovenous fistula, remains an end stage renal disease (ESRD) patient's lifeline providing a means of connecting the patient to the dialysis machine. Once an access is created, the current gold standard of care for maintenance of vascular access is angiography and angioplasty to treat stenosis. While point of care 2D ultrasound has been used to detect access problems, we sought to reproduce angiographic results comparable to the gold standard angiogram (fistulogram) using ultrasound data acquired from a conventional 2D ultrasound scanner. METHODS: A 2D ultrasound probe was used to acquire a series of cross sectional images of the vascular access including arteriovenous anastomosis of a subject with a radio-cephalic fistula. These 2D B-mode images were used for 3D vessel reconstruction by binary thresholding to categorize vascular versus non-vascular structures followed by standard image segmentation to select the structure representative of dialysis vascular access and morphologic filtering. Image processing was done using open source Python Software. RESULTS: The open source software was able to: (1) view the gold standard fistulogram images, (2) reconstruct 2D planar images of the fistula from ultrasound data as viewed from the top, analogous to computerized tomography images, and (3) construct a 2D representation of vascular access similar to the angiogram. CONCLUSION: We present a simple approach to obtain an angiogram-like representation of the vascular access from readily available, non-proprietary 2D ultrasound data in the point of care setting. While the sono-angiogram is not intended to replace angiography, it may be useful in providing 3D imaging at the point of care in the dialysis unit, outpatient clinic, or for pre-operative planning for interventional procedures. Future work will focus on improving the robustness and quality of the imaging data while preserving the straightforward freehand approach used for ultrasound data acquisition.

Ultrasound Measurement of Vascular Distensibility Based on Edge Detection and Speckle Tracking Using Ultrasound DICOM Data.

This study presents an edge detection and speckle tracking (EDST) based algorithm to calculate distensibility as percentage of change of vessel diameter during cardiac cycles. Canny edge detector, Vandermonde matrix representation, Kanade Lucas Tomasi algorithm with pyramidal segmentation, and penalized least squares technique identifies the vessel lumen edge, track the vessel diameter, detrend the signal and find peaks and valleys when the vessel is fully distended or contracted. An upper extremity artery from 10 patients underwent an ultrasound examination as part of preoperative evaluation before arteriovenous fistula surgery. Three studies were performed to evaluate EDST with automatic peak and valley selection versus manual speckle selection of expert users using manual peak and valley selection. Results demonstrate the effectiveness of the proposed methodology, to obtain comparable results as those obtained by expert-users, and considerably reducing the variability associated with external factors such as excessive motion, fluctuations in stroke volume, beat-to-beat blood pressure changes, breathing cycles, and arm-transducer pressure.

Failure modes and effects analysis of mechanical thrombectomy for stroke discovered in human brains.

OBJECTIVE: Despite advancement of thrombectomy technologies for large-vessel occlusion (LVO) stroke and increased user experience, complete recanalization rates linger around 50%, and one-third of patients who have undergone successful recanalization still experience poor neurological outcomes. To enhance the understanding of the biomechanics and failure modes, the authors conducted an experimental analysis of the interaction of emboli/artery/devices in the first human brain test platform for LVO stroke described to date. METHODS: In 12 fresh human brains, 105 LVOs were recreated by embolizing engineered emboli analogs and recanalization was attempted using aspiration catheters and/or stent retrievers. The complex mechanical interaction between diverse emboli (elastic, stiff, and fragment prone), arteries (anterior and posterior circulation), and thrombectomy devices were observed, analyzed, and categorized. The authors systematically evaluated the recanalization process through failure modes and effects analysis, and they identified where and how thrombectomy devices fail and the impact of device failure. RESULTS: The first-pass effect (34%), successful (71%), and complete (60%) recanalization rates in this model were consistent with those in the literature. Failure mode analysis of 184 passes with thrombectomy devices revealed the following. 1) Devices loaded the emboli with tensile forces leading to elongation and intravascular fragmentation. 2) In the presence of anterograde flow, small fragments embolize to the microcirculation and large fragments result in recurrent vessel occlusion. 3) Multiple passes are required due to recurrent (15%) and residual (73%) occlusions, or both (12%). 4) Residual emboli remained in small branching and perforating arteries in cases of alleged complete recanalization (28%). 5) Vacuum caused arterial collapse at physiological pressures (27%). 6) Device withdrawal caused arterial traction (41%), and severe traction provoked avulsion of perforating and small branching arteries. CONCLUSIONS: Biomechanically superior thrombectomy technologies should prevent unrestrained tensional load on emboli, minimize intraluminal embolus fragmentation and release, improve device/embolus integration, recanalize small branching and perforating arteries, prevent arterial collapse, and minimize traction.

Detecting High-Resolution Intramural Vascular Wall Strain Signals Using DICOM Data.

Maintaining dialysis vascular access is a source of considerable morbidity in patients with end-stage renal disease (ESRD). High-resolution radiofrequency (RF) ultrasound vascular strain imaging has been applied experimentally in the vascular access setting to assist in diagnosis and management. Unfortunately, high-resolution RF data are not routinely accessible to clinicians. In contrast, the standard DICOM formatted B-mode ultrasound data are widely accessible. However, B-mode, representing the envelope of the RF signal, is of much lower resolution. If strain imaging could use open-source B-mode data, these imaging techniques could be more broadly investigated. We conducted experiments to detect wall strain signals with submillimeter tracking resolutions ranging from 0.2 mm (3 pixels) to 0.65 mm (10 pixels) using DICOM B-mode data. We compared this submillimeter tracking to the overall vascular distensibility as the reference measurements to see if high-strain resolution strain could be detected using open-source B-Mode data. We measured the best-fit coefficient of determination between signals, expressed as the percentage of strain waveforms that exhibited a correlation with a p value of 0.05 or less. The lowest percentage was 86.7%, and most were 90% and higher. This indicates high-resolution strain signals can be detected within the vessel wall using B-mode DICOM data.

Tele-Operative Low-Cost Robotic Lung Ultrasound Scanning Platform for Triage of COVID-19 Patients.

Novel severe acute respiratory syndrome coronavirus 2 (COVID-19) has become a pandemic of epic proportions, and global response to prepare health systems worldwide is of utmost importance. 2-dimensional (2D) lung ultrasound (LUS) has emerged as a rapid, noninvasive imaging tool for diagnosing COVID-19 infected patients. Concerns surrounding LUS include the disparity of infected patients and healthcare providers, and importantly, the requirement for substantial physical contact between the patient and operator, increasing the risk of transmission. New variants of COVID-19 will continue to emerge; therefore, mitigation of the virus's spread is of paramount importance. A tele-operative robotic ultrasound platform capable of performing LUS in COVID-19 infected patients may be of significant benefit, especially in low- and middle-income countries. The authors address the issues mentioned above surrounding the use of LUS in COVID-19 infected patients and the potential for extension of this technology in a resource-limited environment. Additionally, first-time application, feasibility, and safety were validated in healthy subjects. Preliminary results demonstrate that our platform allows for the successful acquisition and application of robotic LUS in humans.

Angioplasty Induced Changes in Dialysis Vascular Access Compliance.

Dialysis vascular access remains vitally important to maintain life and functional capacity with end stage renal disease. Angioplasty is an integral part of maintaining dialysis access function and patency. To understand the effect of angioplasty balloon dilation on vascular wall mechanics, we conducted a clinical study to evaluate the elastic modulus of the anastomosis in five subjects with anastomosis stenoses, before and after six angioplasty procedures, using B-mode ultrasound DICOM data. A novel and open source vascular ultrasound high-resolution speckle tracking software tool was used. The median lumen diameter increased from 3.4 to 5.5 mm after angioplasty. Meanwhile, the median elastic modulus of the 18 measurements at the anastomosis increased by 52.2%, from 2.24 × 103 to 3.41 × 103 mmHg. The results support our hypothesis that the structural changes induced in the vessel wall by balloon dilation lead to reduced vascular compliance and a higher elastic modulus of the vessel wall.

Near-Infrared-Excited Multicolor Afterglow in Carbon Dots-Based Room-Temperature Afterglow Materials.

Room-temperature afterglow (RTA) materials with long lifetime have shown tremendous application prospects in many fields. However, there is no general design strategy to construct near-infrared (NIR)-excited multicolor RTA materials. Herein, we report a universal approach based on the efficient radiative energy transfer that supports the reabsorption from upconversion materials (UMs) to carbon dots-based RTA materials (CDAMs). Thus, the afterglow emission (blue, cyan, green, and orange) of various CDAMs can be activated by UMs under the NIR continuous-wave laser excitation. The efficient radiative energy transfer ensured the persistent multicolor afterglow up to 7 s, 6 s, 5 s, and 0.5 s by naked eyes, respectively. Given the unusual afterglow properties, we demonstrated preliminary applications in fingerprint recognition and information security. This work provides a new avenue for the activation of NIR-excited afterglow in CDAMs and will greatly expand the applications of RTA materials.

A human brain test bed for research in large vessel occlusion stroke.

OBJECTIVE: Endovascular removal of emboli causing large vessel occlusion (LVO)-related stroke utilizing suction catheter and/or stent retriever technologies or thrombectomy is a new standard of care. Despite high recanalization rates, 40% of stroke patients still experience poor neurological outcomes as many cases cannot be fully reopened after the first attempt. The development of new endovascular technologies and techniques for mechanical thrombectomy requires more sophisticated testing platforms that overcome the limitations of phantom-based simulators. The authors investigated the use of a hybrid platform for LVO stroke constructed with cadaveric human brains. METHODS: A test bed for embolic occlusion of cerebrovascular arteries and mechanical thrombectomy was developed with cadaveric human brains, a customized hydraulic system to generate physiological flow rate and pressure, and three types of embolus analogs (elastic, stiff, and fragment-prone) engineered to match mechanically and phenotypically the emboli causing LVO strokes. LVO cases were replicated in the anterior and posterior circulation, and thrombectomy was attempted using suction catheters and/or stent retrievers. RESULTS: The test bed allowed radiation-free visualization of thrombectomy for LVO stroke in real cerebrovascular anatomy and flow conditions by transmural visualization of the intraluminal elements and procedures. The authors were able to successfully replicate 105 LVO cases with 184 passes in 12 brains (51 LVO cases and 82 passes in the anterior circulation, and 54 LVO cases and 102 passes in the posterior circulation). Observed recanalization rates in this model were graded using a Recanalization in LVO (RELVO) scale analogous to other measures of recanalization outcomes in clinical use. CONCLUSIONS: The human brain platform introduced and validated here enables the analysis of artery-embolus-device interaction under physiological hemodynamic conditions within the unmodified complexity of the cerebral vasculature inside the human brain.

Standardized Fabrication Method of Human-Derived Emboli with Histologic and Mechanical Quantification for Stroke Research.

BACKGROUND: As access to patient emboli is limited, embolus analogs (EAs) have become critical to the research of large vessel occlusion (LVO) stroke and the development of thrombectomy technology. To date, techniques for fabricating standardized human blood-derived EAs are limited in the variety of compositions, and the mechanical properties relevant to thrombectomy are not quantified. METHODS: EAs were made by mixing human banked red blood cells (RBCs), plasma, and platelet concentrate in 10 different volumetric percentage combinations to mimic the broad range of patient emboli causing LVO strokes. The samples underwent histologic analysis and tensile testing to mimic the pulling action of thrombectomy devices, and were compared to patient emboli. RESULTS: EAs had histologic compositions of 0-96% RBCs, 0.78%-92% fibrin, and 2.1%-22% platelets, which can be correlated with the ingredients using a regression model. At fracture, EAs elongated from 81% to 136%, and the ultimate tensile stress ranged from 16 to 949 kPa. These EAs' histologic compositions and tensile properties showed great similarity to those of emboli retrieved from LVO stroke patients, indicating the validity of such EA fabrication methods. EAs with lower RBC and higher fibrin contents are more extensible and can withstand higher tensile stress. CONCLUSIONS: EAs fabricated and tested using the proposed new methods provide a platform for stroke research and pre-clinical development of thrombectomy devices.

Construction of a comprehensive endovascular test bed for research and device development in mechanical thrombectomy in stroke.

OBJECTIVE: The development of new endovascular technologies and techniques for mechanical thrombectomy in stroke has greatly relied on benchtop simulators. This paper presents an affordable, versatile, and realistic benchtop simulation model for stroke. METHODS: A test bed for embolic occlusion of cerebrovascular arteries and mechanical thrombectomy was developed with 3D-printed and commercially available cerebrovascular phantoms, a customized hydraulic system to generate physiological flow rate and pressure, and 2 types of embolus analogs (elastic and fragment-prone) capable of causing embolic occlusions under physiological flow. RESULTS: The test bed was highly versatile and allowed realistic, radiation-free mechanical thrombectomy for stroke due to large-vessel occlusion with rapid exchange of geometries and phantom types. Of the transparent cerebrovascular phantoms tested, the 3D-printed phantom was the easiest to manufacture, the glass model offered the best visibility of the interaction between embolus and thrombectomy device, and the flexible model most accurately mimicked the endovascular system during device navigation. None of the phantoms modeled branches smaller than 1 mm or perforating arteries, and none underwent realistic deformation or luminal collapse from device manipulation or vacuum. The hydraulic system created physiological flow rate and pressure leading to iatrogenic embolization during thrombectomy in all phantoms. Embolus analogs with known fabrication technique, structure, and tensile strength were introduced and consistently occluded the middle cerebral artery bifurcation under physiological flow, and their interaction with the device was accurately visualized. CONCLUSIONS: The test bed presented in this study is a low-cost, comprehensive, realistic, and versatile platform that enabled high-quality analysis of embolus-device interaction in multiple cerebrovascular phantoms and embolus analogs.