scholarly journals Patient-Specific Aortic Phantom With Tunable Compliance

2019 ◽  
Vol 2 (4) ◽  
Author(s):  
Antonio Gallarello ◽  
Andrea Palombi ◽  
Giacomo Annio ◽  
Shervanthi Homer-Vanniasinkam ◽  
Elena De Momi ◽  
...  
Keyword(s):  
Aortic Arch ◽  
Computational Models ◽  
Three Dimensional ◽  
Complex Interventions ◽  
Patient Specific ◽  
Arch Model ◽  
Magnetic Resonance Imaging Mri ◽  
Variable Wall ◽  
Silicone Model

Abstract Validation of computational models using in vitro phantoms is a nontrivial task, especially in the replication of the mechanical properties of the vessel walls, which varies with age and pathophysiological state. In this paper, we present a novel aortic phantom reconstructed from patient-specific data with variable wall compliance that can be tuned without recreating the phantom. The three-dimensional (3D) geometry of an aortic arch was retrieved from a computed tomography angiography scan. A rubber-like silicone phantom was manufactured and connected to a compliance chamber in order to tune its compliance. A lumped resistance was also coupled with the system. The compliance of the aortic arch model was validated using the Young's modulus and characterized further with respect to clinically relevant indicators. The silicone model demonstrates that compliance can be finely tuned with this system under pulsatile flow conditions. The phantom replicated values of compliance in the physiological range. Both, the pressure curves and the asymmetrical behavior of the expansion, are in agreement with the literature. This novel design approach allows obtaining for the first time a phantom with tunable compliance. Vascular phantoms designed and developed with the methodology proposed in this paper have high potential to be used in diverse conditions. Applications include training of physicians, pre-operative trials for complex interventions, testing of medical devices for cardiovascular diseases (CVDs), and comparative Magnetic-resonance-imaging (MRI)-based computational studies.

In-Vitro Blood Flow and Wall Shear Stress Measurements in Idealised and Patient Specific Models of the Carotid Artery Bifurcation

2008 ◽  
Author(s):  
Nicolas A. Buchmann ◽  
Mark C. Jermy
Keyword(s):  
Shear Stress ◽  
Carotid Artery ◽  
Wall Shear Stress ◽  
Three Dimensional ◽  
Patient Specific ◽  
Specific Geometry ◽  
Wall Shear ◽  
Magnetic Resonance Imaging Mri ◽  
Vitro Model

This work presents Particle Image Velocimetry (PIV) measurements in idealised and patient specific human carotid artery bifurcations (CAB) under steady and pulsatile flow. The geometry and corresponding boundary conditions were obtained by Magnetic Resonance Imaging (MRI) and replicated in an in-vitro model. A complex three-dimensional flow structure exists inside the CAB and vorticity and wall shear stress data are used to quantify the differences between the idealised and patient specific geometry.

Low-Cost Fabrication of Polyvinyl Alcohol-Based Personalized Vascular Phantoms for In Vitro Hemodynamic Studies: Three Applications

2020 ◽  
Vol 3 (3) ◽  
Author(s):  
Giacomo Annio ◽  
Gaia Franzetti ◽  
Mirko Bonfanti ◽  
Antonio Gallarello ◽  
Andrea Palombi ◽  
...  
Keyword(s):  
Polyvinyl Alcohol ◽  
Aortic Arch ◽  
Low Cost ◽  
Three Dimensional ◽  
Patient Specific ◽  
Imaging Research ◽  
Parametric Studies ◽  
Manufacturing Techniques

Abstract Vascular phantoms mimicking human vessels are commonly used to perform in vitro hemodynamic studies for a number of bioengineering applications, such as medical device testing, clinical simulators, and medical imaging research. Simplified geometries are useful to perform parametric studies, but accurate representations of the complexity of the in vivo system are essential in several applications as personalized features have been found to play a crucial role in the management and treatment of many vascular pathologies. Despite numerous studies employing vascular phantoms produced through different manufacturing techniques, an economically viable technique, able to generate large complex patient-specific vascular anatomies, accessible to nonspecialist laboratories, still needs to be identified. In this work, a manufacturing framework to create personalized and complex phantoms with easily accessible and affordable materials and equipment is presented. In particular, three-dimensional (3D) printing with polyvinyl alcohol (PVA) is employed to create the mold, and lost core casting is performed to create the physical model. The applicability and flexibility of the proposed fabrication protocol is demonstrated through three phantom case studies—an idealized aortic arch, a patient-specific aortic arch, and a patient-specific aortic dissection model. The phantoms were successfully manufactured in a rigid silicone, a compliant silicone, and a rigid epoxy resin, respectively; using two different 3D printers and two casting techniques, without the need of specialist equipment.

scholarly journals Distribution of Artificial Thrombi Candidates Through Patient-Specific Aortic-Arch Phantoms under Pulsatile Flow Conditions

2021 ◽  
Author(s):  
Marco Testaguzza ◽  
Mehdi Benhassine ◽  
Haroun Frid ◽  
Laurence Gebhart ◽  
Karim Zouaoui Boudjeltia ◽  
...  
Keyword(s):  
Aortic Arch ◽  
Pulsatile Flow ◽  
Patient Specific ◽  
Flow Profile ◽  
In Vitro Test ◽  
Flow Conditions ◽  
Test Bed ◽  
Arch Models ◽  
Artificial Emboli

Abstract Ischemic Stroke is the most frequent type of stroke and is subject to many studies investigating prevention means. Avoiding the difficulties and ethical problems of experimental in-vivo research, in-vitro testing is a convenient way of studying in controlled conditions the morphological impact and mechanical aspects of emboli dynamics. This in-vitro study was performed with two realistic silicone aortic-arch phantoms submitted to physiological pulsatile flow conditions. In the in-vitro test bed, using automatic image tracking and analysis, it was made possible detecting and tracking artificial spherical emboli candidates circulating in the anatomic aortic-arch models under a realistic based-patient blood flow profile. The emboli trajectories as well as their repartition in the different supra-aortic branches are presented for the two aortic-arch geometries obtained from CT scans. Through a statistical analysis performed with several artificial emboli sizes, the experimental study shows that the repartition percentages of the emboli closely follow the flowrate repartition percentages for both aortic-arch models, suggesting that higher flowrates lead to higher concentrations of emboli in a given artery. Sets of human thrombi were also injected and the repartition percentages have been established, giving the same trend as for artificial emboli.

Impact of image reconstruction parameters when using 3D DSA reconstructions to measure intracranial aneurysms

2017 ◽  
Vol 10 (3) ◽  
pp. 285-289 ◽  
Author(s):  
Katrina L Ruedinger ◽  
David R Rutkowski ◽  
Sebastian Schafer ◽  
Alejandro Roldán-Alzate ◽  
Erick L Oberstar ◽  
...  
Keyword(s):  
Three Dimensional ◽  
Hounsfield Unit ◽  
Ground Truth ◽  
Individual Case ◽  
Dome Height ◽  
Patient Specific ◽  
Analysis Tool ◽  
Accuracy Of Measurements ◽  
Image Characteristic

Background and purposeSafe and effective use of newly developed devices for aneurysm treatment requires the ability to make accurate measurements in the angiographic suite. Our purpose was to determine the parameters that optimize the geometric accuracy of three-dimensional (3D) vascular reconstructions.MethodsAn in vitro flow model consisting of a peristaltic pump, plastic tubing, and 3D printed patient-specific aneurysm models was used to simulate blood flow in an intracranial aneurysm. Flow rates were adjusted to match values reported in the literature for the internal carotid artery. 3D digital subtraction angiography acquisitions were obtained using a commercially available biplane angiographic system. Reconstructions were done using Edge Enhancement (EE) or Hounsfield Unit (HU) kernels and a Normal or Smooth image characteristic. Reconstructed images were analyzed using the vendor's aneurysm analysis tool. Ground truth measurements were derived from metrological scans of the models with a microCT. Aneurysm volume, surface area, dome height, minimum and maximum ostium diameter were determined for the five models.ResultsIn all cases, measurements made with the EE kernel most closely matched ground truth values. Differences in values derived from reconstructions displayed with Smooth or Normal image characteristics were small and had only little impact on the geometric parameters considered.ConclusionsReconstruction parameters impact the accuracy of measurements made using the aneurysm analysis tool of a commercially available angiographic system. Absolute differences between measurements made using reconstruction parameters determined as optimal in this study were, overall, very small. The significance of these differences, if any, will depend on the details of each individual case.

scholarly journals Investigation of the Hemodynamics Influencing Emboli Trajectories Through a Patient-Specific Aortic Arch Model

Stroke ◽  
2019 ◽  
Vol 50 (6) ◽  
pp. 1531-1538 ◽  
Author(s):  
Fiona Malone ◽  
Eugene McCarthy ◽  
Patrick Delassus ◽  
Jan-Hendrick Buhk ◽  
Jens Fiehler ◽  
...  
Keyword(s):  
Aortic Arch ◽  
Patient Specific ◽  
Arch Model

Digital Design and 3D Printing of Aortic Arch Reconstruction in HLHS for Surgical Simulation and Training

2018 ◽  
Vol 9 (4) ◽  
pp. 454-458 ◽  
Author(s):  
Sarah A. Chen ◽  
Chin Siang Ong ◽  
Nagina Malguria ◽  
Luca A. Vricella ◽  
Juan R. Garcia ◽  
...  
Keyword(s):  
3D Printing ◽  
Aortic Arch ◽  
Surgical Simulation ◽  
Three Dimensional ◽  
3D Models ◽  
Digital Design ◽  
Patient Specific ◽  
Aortic Arch Reconstruction ◽  
Arch Reconstruction ◽  
And Training

Purpose: Patients with hypoplastic left heart syndrome (HLHS) present a diverse spectrum of aortic arch morphology. Suboptimal geometry of the reconstructed aortic arch may result from inappropriate size and shape of an implanted patch and may be associated with poor outcomes. Meanwhile, advances in diagnostic imaging, computer-aided design, and three-dimensional (3D) printing technology have enabled the creation of 3D models. The purpose of this study is to create a surgical simulation and training model for aortic arch reconstruction. Description: Specialized segmentation software was used to isolate aortic arch anatomy from HLHS computed tomography scan images to create digital 3D models. Three-dimensional modeling software was used to modify the exported segmented models and digitally design printable customized patches that were optimally sized for arch reconstruction. Evaluation: Life-sized models of HLHS aortic arch anatomy and a digitally derived customized patch were 3D printed to allow simulation of surgical suturing and reconstruction. The patient-specific customized patch was successfully used for surgical simulation. Conclusions: Feasibility of digital design and 3D printing of patient-specific patches for aortic arch reconstruction has been demonstrated. The technology facilitates surgical simulation. Surgical training that leads to an understanding of optimal aortic patch geometry is one element that may potentially influence outcomes for patients with HLHS.

scholarly journals Prediction of Aerosol Deposition in the Human Respiratory Tract via Computational Models: A Review with Recent Updates

Atmosphere ◽  
2020 ◽  
Vol 11 (2) ◽  
pp. 137 ◽  
Author(s):  
Vu Khac Hoang Bui ◽  
Ju-Young Moon ◽  
Minhe Chae ◽  
Duckshin Park ◽  
Young-Chul Lee
Keyword(s):  
Respiratory Tract ◽  
Particle Deposition ◽  
Computational Models ◽  
Aerosol Particles ◽  
Three Dimensional ◽  
Aerosol Deposition ◽  
Research Area ◽  
Human Respiratory Tract

The measurement of deposited aerosol particles in the respiratory tract via in vivo and in vitro approaches is difficult due to those approaches’ many limitations. In order to overcome these obstacles, different computational models have been developed to predict the deposition of aerosol particles inside the lung. Recently, some remarkable models have been developed based on conventional semi-empirical models, one-dimensional whole-lung models, three-dimensional computational fluid dynamics models, and artificial neural networks for the prediction of aerosol-particle deposition with a high accuracy relative to experimental data. However, these models still have some disadvantages that should be overcome shortly. In this paper, we take a closer look at the current research trends as well as the future directions of this research area.

scholarly journals 3D printed patient-specific aortic root models with internal sensors for minimally invasive applications

2020 ◽  
Vol 6 (35) ◽  
pp. eabb4641 ◽  
Author(s):  
Ghazaleh Haghiashtiani ◽  
Kaiyan Qiu ◽  
Jorge D. Zhingre Sanchez ◽  
Zachary J. Fuenning ◽  
Priya Nair ◽  
...  
Keyword(s):  
Minimally Invasive ◽  
Aortic Root ◽  
Three Dimensional ◽  
Sensor Arrays ◽  
Invasive Procedure ◽  
Patient Specific ◽  
Anatomical Site ◽  
Transcatheter Aortic Valve ◽  
Critical Regions

Minimally invasive surgeries have numerous advantages, yet complications may arise from limited knowledge about the anatomical site targeted for the delivery of therapy. Transcatheter aortic valve replacement (TAVR) is a minimally invasive procedure for treating aortic stenosis. Here, we demonstrate multimaterial three-dimensional printing of patient-specific soft aortic root models with internally integrated electronic sensor arrays that can augment testing for TAVR preprocedural planning. We evaluated the efficacies of the models by comparing their geometric fidelities with postoperative data from patients, as well as their in vitro hemodynamic performances in cases with and without leaflet calcifications. Furthermore, we demonstrated that internal sensor arrays can facilitate the optimization of bioprosthetic valve selections and in vitro placements via mapping of the pressures applied on the critical regions of the aortic anatomies. These models may pave exciting avenues for mitigating the risks of postoperative complications and facilitating the development of next-generation medical devices.

scholarly journals A Better, Faster Road From Biological Data to Human Health: A Systems Biology Approach for Engineered Cell Cultures

2017 ◽  
Author(s):  
Brian T. Hawkins ◽  
Sonia Grego
Keyword(s):  
Systems Biology ◽  
Computational Models ◽  
Three Dimensional ◽  
Toxicity Testing ◽  
Biological Data ◽  
Physiological Relevance ◽  
Toxicity Risk ◽  
Therapeutic Development ◽  
Single Cell Type

Traditionally, the interactions of drugs and toxicants with human tissue have been investigated in a reductionist way—for example, by focusing on specific molecular targets and using single-cell-type cultures before testing compounds in whole organisms. More recently, “systems biology” approaches attempt to enhance the predictive value of in vitro biological data by adopting a comprehensive description of biological systems and using computational tools that are sophisticated enough to handle the complexity of these systems. However, the utility of computational models resulting from these efforts completely relies on the quality of the data used to construct them. Here, we propose that recent advances in the development of bioengineered, three-dimensional, multicellular constructs provide in vitro data of sufficient complexity and physiological relevance to be used in predictive systems biology models of human responses. Such predictive models are essential to maximally leveraging these emerging bioengineering technologies to improve both therapeutic development and toxicity risk assessment. This brief outlines the opportunities presented by emerging technologies and approaches for the acceleration of drug development and toxicity testing, as well as the challenges lying ahead for the field.

scholarly journals Meningioma Segmentation in T1-Weighted MRI Leveraging Global Context and Attention Mechanisms

2021 ◽  
Vol 1 ◽  
Author(s):  
David Bouget ◽  
André Pedersen ◽  
Sayied Abdol Mohieb Hosainey ◽  
Ole Solheim ◽  
Ingerid Reinertsen
Keyword(s):  
Three Dimensional ◽  
Specific Treatment ◽  
Primary Brain Tumor ◽  
University Hospital ◽  
Patient Specific ◽  
Entire Volume ◽  
Global Context ◽  
Multi Scale ◽  
Magnetic Resonance Imaging Mri ◽  
The Impact

Purpose: Meningiomas are the most common type of primary brain tumor, accounting for ~30% of all brain tumors. A substantial number of these tumors are never surgically removed but rather monitored over time. Automatic and precise meningioma segmentation is, therefore, beneficial to enable reliable growth estimation and patient-specific treatment planning.Methods: In this study, we propose the inclusion of attention mechanisms on top of a U-Net architecture used as backbone: (i) Attention-gated U-Net (AGUNet) and (ii) Dual Attention U-Net (DAUNet), using a three-dimensional (3D) magnetic resonance imaging (MRI) volume as input. Attention has the potential to leverage the global context and identify features' relationships across the entire volume. To limit spatial resolution degradation and loss of detail inherent to encoder–decoder architectures, we studied the impact of multi-scale input and deep supervision components. The proposed architectures are trainable end-to-end and each concept can be seamlessly disabled for ablation studies.Results: The validation studies were performed using a five-fold cross-validation over 600 T1-weighted MRI volumes from St. Olavs Hospital, Trondheim University Hospital, Norway. Models were evaluated based on segmentation, detection, and speed performances, and results are reported patient-wise after averaging across all folds. For the best-performing architecture, an average Dice score of 81.6% was reached for an F1-score of 95.6%. With an almost perfect precision of 98%, meningiomas smaller than 3 ml were occasionally missed hence reaching an overall recall of 93%.Conclusion: Leveraging global context from a 3D MRI volume provided the best performances, even if the native volume resolution could not be processed directly due to current GPU memory limitations. Overall, near-perfect detection was achieved for meningiomas larger than 3 ml, which is relevant for clinical use. In the future, the use of multi-scale designs and refinement networks should be further investigated. A larger number of cases with meningiomas below 3 ml might also be needed to improve the performance for the smallest tumors.

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