Rehearsals using patient-specific 3d-printed aneurysm models for simulation of endovascular embolization of complex intracranial aneurysms: 3D SIM Study

2021 ◽  
Author(s):  
Anthony LE BRAS ◽  
Fakhreddine BOUSTIA ◽  
Kevin JANOT ◽  
Estelle LE PABIC ◽  
Mathilde OUVRARD ◽  
...  
Keyword(s):  
Intracranial Aneurysms ◽  
Endovascular Embolization ◽  
Patient Specific ◽  
3D Printed

Techniques for Virtual Stenting of Intracranial Aneurysms

2007 ◽  
Author(s):  
Sunil Appanaboyina ◽  
Fernando Mut ◽  
Rainald Löhner ◽  
Christopher M. Putman ◽  
Juan R. Cebral
Keyword(s):  
Intracranial Aneurysms ◽  
Numerical Models ◽  
Thrombus Formation ◽  
Endovascular Embolization ◽  
Computational Grids ◽  
Patient Specific ◽  
Parent Vessel ◽  
Invasive Approach ◽  
Aneurysm Neck

Intracranial aneurysms are pathological dilations of the arteries in the brain, whose rupture is often fatal. Surgery and endovascular embolization are the two most common methods of treatment. Surgery involves opening a portion of the skull and placing metallic clips at the aneurysm neck thereby preventing blood flow into the aneurysm. In the case of embolization, a catheter is used to pack platinum coils in the aneurysm reducing the inflow and promoting thrombus formation. Due to its less invasive approach endovascular embolization is preferred over surgery. Nevertheless this approach also has some serious aftereffects. Coil compaction followed by the re-growth or the formation of the secondary aneurysm is the most common problem. The endovascular embolization approach also has a serious shortcoming that the coils alone cannot be used to block every type of aneurysm. Wide neck or fusiform aneurysms are coiled with the help of stents. Recent studies show that stent, which is a hollow cylindrical mesh, can be successfully used to limit the flow of blood into the aneurysm. However these studies have been conducted using idealized in-vitro and numerical models. Studies conducted using patient-specific models generated from medical images will provide a more realistic approach to computationally investigate the effects of stents on intra-aneurysmal flow patterns. However generation of computational grids inside the parent vessel and around these stents is a challenging task. In this paper an algorithm to map the stent to a patient-specific vascular model and an adaptive unstructured embedded gridding technique to model flow around stents are presented. Finally these techniques are demonstrated on patient-specific cases to prove their feasibility.

scholarly journals Quality Control in 3D Printing: Accuracy Analysis of 3D-Printed Models of Patient-Specific Anatomy

Materials ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 1021
Author(s):  
Bernhard Dorweiler ◽  
Pia Elisabeth Baqué ◽  
Rayan Chaban ◽  
Ahmed Ghazy ◽  
Oroa Salem
Keyword(s):  
Wall Thickness ◽  
Large Scale ◽  
Fused Deposition Modeling ◽  
Vascular Anatomy ◽  
3D Models ◽  
Patient Specific ◽  
Stl File ◽  
Fused Deposition ◽  
3D Printed ◽  
The Mean

As comparative data on the precision of 3D-printed anatomical models are sparse, the aim of this study was to evaluate the accuracy of 3D-printed models of vascular anatomy generated by two commonly used printing technologies. Thirty-five 3D models of large (aortic, wall thickness of 2 mm, n = 30) and small (coronary, wall thickness of 1.25 mm, n = 5) vessels printed with fused deposition modeling (FDM) (rigid, n = 20) and PolyJet (flexible, n = 15) technology were subjected to high-resolution CT scans. From the resulting DICOM (Digital Imaging and Communications in Medicine) dataset, an STL file was generated and wall thickness as well as surface congruency were compared with the original STL file using dedicated 3D engineering software. The mean wall thickness for the large-scale aortic models was 2.11 µm (+5%), and 1.26 µm (+0.8%) for the coronary models, resulting in an overall mean wall thickness of +5% for all 35 3D models when compared to the original STL file. The mean surface deviation was found to be +120 µm for all models, with +100 µm for the aortic and +180 µm for the coronary 3D models, respectively. Both printing technologies were found to conform with the currently set standards of accuracy (<1 mm), demonstrating that accurate 3D models of large and small vessel anatomy can be generated by both FDM and PolyJet printing technology using rigid and flexible polymers.

scholarly journals Complex wall modeling for hemodynamic simulations of intracranial aneurysms based on histologic images

2021 ◽  
Vol 16 (4) ◽  
pp. 597-607
Author(s):  
Annika Niemann ◽  
Samuel Voß ◽  
Riikka Tulamo ◽  
Simon Weigand ◽  
Bernhard Preim ◽  
...  
Keyword(s):  
Wall Thickness ◽  
Vessel Wall ◽  
Intracranial Aneurysms ◽  
Geometric Model ◽  
Image Data ◽  
Outer Wall ◽  
3D Models ◽  
Patient Specific ◽  
Intracranial Vessel ◽  
Hemodynamic Simulations

Abstract Purpose For the evaluation and rupture risk assessment of intracranial aneurysms, clinical, morphological and hemodynamic parameters are analyzed. The reliability of intracranial hemodynamic simulations strongly depends on the underlying models. Due to the missing information about the intracranial vessel wall, the patient-specific wall thickness is often neglected as well as the specific physiological and pathological properties of the vessel wall. Methods In this work, we present a model for structural simulations with patient-specific wall thickness including different tissue types based on postmortem histologic image data. Images of histologic 2D slices from intracranial aneurysms were manually segmented in nine tissue classes. After virtual inflation, they were combined into 3D models. This approach yields multiple 3D models of the inner and outer wall and different tissue parts as a prerequisite for subsequent simulations. Result We presented a pipeline to generate 3D models of aneurysms with respect to the different tissue textures occurring in the wall. First experiments show that including the variance of the tissue in the structural simulation affect the simulation result. Especially at the interfaces between neighboring tissue classes, the larger influence of stiffer components on the stability equilibrium became obvious. Conclusion The presented approach enables the creation of a geometric model with differentiated wall tissue. This information can be used for different applications, like hemodynamic simulations, to increase the modeling accuracy.

scholarly journals Total Meniscus Reconstruction Using a Polymeric Hybrid-Scaffold: Combined with 3D-Printed Biomimetic Framework and Micro-Particle

Polymers ◽  
2021 ◽  
Vol 13 (12) ◽  
pp. 1910
Author(s):  
Hun-Jin Jeong ◽  
Se-Won Lee ◽  
Myoung Wha Hong ◽  
Young Yul Kim ◽  
Kyoung Duck Seo ◽  
...  
Keyword(s):  
Shape Matching ◽  
Femoral Condyle ◽  
Immunohistochemical Analysis ◽  
Cartilage Degeneration ◽  
Patient Specific ◽  
Hybrid Scaffold ◽  
Meniscus Tissue ◽  
Cell Source ◽  
3D Printed ◽  
Meniscus Regeneration

The meniscus has poor intrinsic regenerative capability, and its injury inevitably leads to articular cartilage degeneration. Although there are commercialized off-the-shelf alternatives to achieve total meniscus regeneration, each has its own shortcomings such as individualized size matching issues and inappropriate mechanical properties. We manufactured a polycaprolactone-based patient-specific designed framework via a Computed Tomography scan images and 3D-printing technique. Then, we completed the hybrid-scaffold by combining the 3D-printed framework and mixture micro-size composite which consists of polycaprolactone and sodium chloride to create a cell-friendly microenvironment. Based on this hybrid-scaffold with an autograft cell source (fibrochondrocyte), we assessed mechanical and histological results using the rabbit total meniscectomy model. At postoperative 12-week, hybrid-scaffold achieved neo-meniscus tissue formation, and its shape was maintained without rupture or break away from the knee joint. Histological and immunohistochemical analysis results showed obvious ingrowth of the fibroblast-like cells and chondrocyte cells as well as mature lacunae that were embedded in the extracellular matrix. Hybrid-scaffolding resulted in superior shape matching as compared to original meniscus tissue. Histological analysis showed evidence of extensive neo-meniscus cell ingrowth. Additionally, the hybrid-scaffold did not induce osteoarthritis on the femoral condyle surface. The 3D-printed hybrid-scaffold may provide a promising approach that can be applied to those who received total meniscal resection, using patient-specific design and autogenous cell source.

Design, Fabrication, and Accuracy of a Novel Noncovering Lock-Mechanism Bilateral Patient-Specific Drill Guide Template for Nondeformed and Deformed Thoracic Spines

2021 ◽  
pp. 155633162199633
Author(s):  
Mehran Ashouri-Sanjani ◽  
Shima Mohammadi-Moghadam ◽  
Parisa Azimi ◽  
Navid Arjmand
Keyword(s):  
Thoracic Spine ◽  
Sagittal Plane ◽  
Ct Scanning ◽  
Entry Point ◽  
In Vivo Studies ◽  
Patient Specific ◽  
Plane Angle ◽  
Severe Scoliosis ◽  
3D Printed

Background: Pedicle screw (PS) placement has been widely used in fusion surgeries on the thoracic spine. Achieving cost-effective yet accurate placements through nonradiation techniques remains challenging. Questions/Purposes: Novel noncovering lock-mechanism bilateral vertebra-specific drill guides for PS placement were designed/fabricated, and their accuracy for both nondeformed and deformed thoracic spines was tested. Methods: One nondeformed and 1 severe scoliosis human thoracic spine underwent computed tomographic (CT) scanning, and 2 identical proportions of each were 3-dimensional (3D) printed. Pedicle-specific optimal (no perforation) drilling trajectories were determined on the CT images based on the entry point/orientation/diameter/length of each PS. Vertebra-specific templates were designed and 3D printed, assuring minimal yet firm contacts with the vertebrae through a noncovering lock mechanism. One model of each patient was drilled using the freehand and one using the template guides (96 pedicle drillings). Postoperative CT scans from the models with the inserted PSs were obtained and superimposed on the preoperative planned models to evaluate deviations of the PSs. Results: All templates fitted their corresponding vertebra during the simulated operations. As compared with the freehand approach, PS placement deviations from their preplanned positions were significantly reduced: for the nonscoliosis model, from 2.4 to 0.9 mm for the entry point, 5.0° to 3.3° for the transverse plane angle, 7.1° to 2.2° for the sagittal plane angle, and 8.5° to 4.1° for the 3D angle, improving the success rate from 71.7% to 93.5%. Conclusions: These guides are valuable, as the accurate PS trajectory could be customized preoperatively to match the patients’ unique anatomy. In vivo studies will be required to validate this approach.

scholarly journals 3D‐printed, patient‐specific intracranial aneurysm models: From clinical data to flow experiments with endovascular devices

2021 ◽  
Author(s):  
Mariya S. Pravdivtseva ◽  
Eva Peschke ◽  
Thomas Lindner ◽  
Fritz Wodarg ◽  
Johannes Hensler ◽  
...  
Keyword(s):  
Intracranial Aneurysm ◽  
Clinical Data ◽  
Patient Specific ◽  
3D Printed ◽  
Flow Experiments ◽  
Endovascular Devices

scholarly journals Porous Media Computational Fluid Dynamics and the Role of the First Coil in the Embolization of Ruptured Intracranial Aneurysms

2021 ◽  
Vol 10 (7) ◽  
pp. 1348
Author(s):  
Karol Wiśniewski ◽  
Bartłomiej Tomasik ◽  
Zbigniew Tyfa ◽  
Piotr Reorowicz ◽  
Ernest Bobeff ◽  
...  
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Porous Media ◽  
Packing Density ◽  
Coil Embolization ◽  
Intracranial Aneurysms ◽  
Patient Specific ◽  
Computational Fluid Dynamics Analysis ◽  
Ruptured Intracranial Aneurysms ◽  
Statistical Results

Background: The objective of our project was to identify a late recanalization predictor in ruptured intracranial aneurysms treated with coil embolization. This goal was achieved by means of a statistical analysis followed by a computational fluid dynamics (CFD) with porous media modelling approach. Porous media CFD simulated the hemodynamics within the aneurysmal dome after coiling. Methods: Firstly, a retrospective single center analysis of 66 aneurysmal subarachnoid hemorrhage patients was conducted. The authors assessed morphometric parameters, packing density, first coil volume packing density (1st VPD) and recanalization rate on digital subtraction angiograms (DSA). The effectiveness of initial endovascular treatment was visually determined using the modified Raymond–Roy classification directly after the embolization and in a 6- and 12-month follow-up DSA. In the next step, a comparison between porous media CFD analyses and our statistical results was performed. A geometry used during numerical simulations based on a patient-specific anatomy, where the aneurysm dome was modelled as a separate, porous domain. To evaluate hemodynamic changes, CFD was utilized for a control case (without any porosity) and for a wide range of porosities that resembled 1–30% of VPD. Numerical analyses were performed in Ansys CFX solver. Results: A multivariate analysis showed that 1st VPD affected the late recanalization rate (p < 0.001). Its value was significantly greater in all patients without recanalization (p < 0.001). Receiver operating characteristic curves governed by the univariate analysis showed that the model for late recanalization prediction based on 1st VPD (AUC 0.94 (95%CI: 0.86–1.00) is the most important predictor of late recanalization (p < 0.001). A cut-off point of 10.56% (sensitivity—0.722; specificity—0.979) was confirmed as optimal in a computational fluid dynamics analysis. The CFD results indicate that pressure at the aneurysm wall and residual flow volume (blood volume with mean fluid velocity > 0.01 m/s) within the aneurysmal dome tended to asymptotically decrease when VPD exceeded 10%. Conclusions: High 1st VPD decreases the late recanalization rate in ruptured intracranial aneurysms treated with coil embolization (according to our statistical results > 10.56%). We present an easy intraoperatively calculable predictor which has the potential to be used in clinical practice as a tip to improve clinical outcomes.

scholarly journals Custom, spray coated receive coils for magnetic resonance imaging

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
A. M. Zamarayeva ◽  
K. Gopalan ◽  
J. R. Corea ◽  
M. Z. Liu ◽  
K. Pang ◽  
...  
Keyword(s):  
Magnetic Resonance Imaging ◽  
Magnetic Resonance ◽  
Silver Nanoparticle ◽  
Material Selection ◽  
Spray Deposition ◽  
Dielectric Materials ◽  
Patient Specific ◽  
High Signal ◽  
Resonance Imaging ◽  
3D Printed

AbstractWe have developed a process for fabricating patient specific Magnetic Resonance Imaging (MRI) Radio-frequency (RF) receive coil arrays using additive manufacturing. Our process involves spray deposition of silver nanoparticle inks and dielectric materials onto 3D printed substrates to form high-quality resonant circuits. In this paper, we describe the material selection and characterization, process optimization, and design and testing of a prototype 4-channel neck array for carotid imaging. We show that sprayed polystyrene can form a low loss dielectric layer in a parallel plate capacitor. We also demonstrate that by using sprayed silver nanoparticle ink as conductive traces, our devices are still dominated by sample noise, rather than material losses. These results are critical for maintaining high Signal-to-Noise-Ratio (SNR) in clinical settings. Finally, our prototype patient specific coil array exhibits higher SNR (5 × in the periphery, 1.4 × in the center) than a commercially available array designed to fit the majority of subjects when tested on our custom neck phantom. 3D printed substrates ensure an optimum fit to complex body parts, improve diagnostic image quality, and enable reproducible placement on subjects.

The Development of Novel 2-in-1 Patient-Specific, 3D-Printed Laminectomy Guides with Integrated Pedicle Screw Drill Guides

2021 ◽  
Author(s):  
Andrew Kanawati ◽  
Renan Jose Rodrigues Fernandes ◽  
Aaron Gee ◽  
Jennifer Urquhart ◽  
Fawaz Siddiqi ◽  
...  
Keyword(s):  
Pedicle Screw ◽  
Patient Specific ◽  
3D Printed
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