scholarly journals Patient-specific three-dimensional printed pulmonary artery model: A preliminary study

2017 ◽  
Vol 3 (4) ◽  
pp. 170 ◽  
Author(s):  
Zhonghua Sun ◽  
Sultan Aldosari ◽  
Andrew Squelch
Keyword(s):  
Pulmonary Artery ◽  
Three Dimensional ◽  
Patient Specific ◽  
Preliminary Study

scholarly journals Computational Fluid Dynamics Characterization of Two Patient-Specific Systemic-to-Pulmonary Shunts before and after Operation

2019 ◽  
Vol 2019 ◽  
pp. 1-10 ◽  
Author(s):  
Neichuan Zhang ◽  
Haiyun Yuan ◽  
Xiangyu Chen ◽  
Jiawei Liu ◽  
Qifei Jian ◽  
...  
Keyword(s):  
Shear Stress ◽  
Wall Shear Stress ◽  
Pulmonary Artery ◽  
Energy Loss ◽  
Three Dimensional ◽  
Left Pulmonary Artery ◽  
Postoperative Recovery ◽  
Patient Specific ◽  
Wall Shear ◽  
Ct Data

Studying the haemodynamics of the central shunt (CS) and modified Blalock–Taussig shunt (MBTS) benefits the improvement of postoperative recovery for patients with an aorta-pulmonary shunt. Shunt configurations, including CS and MBTS, are virtually reconstructed for infants A and B based on preoperative CT data, and three-dimensional models of A, 11 months after CS, and B, 8 months after MBTS, are reconstructed based on postoperative CT data. A series of parameters including energy loss, wall shear stress, and shunt ratio are computed from simulation to analyse the haemodynamics of CS and MBTS. Our results showed that the shunt ratio of the CS is approximately 30% higher than the MBTS and velocity distribution in the left pulmonary artery (LPA) and right pulmonary artery (RPA) was closer to a natural development in the CS than the MBTS. However, energy loss of the MBTS is lower, and the MBTS can provide more symmetric pulmonary artery (PA) flow than the CS. With the growth of infants A and B, the shunt ratio of infants was decreased, but maximum wall shear stress and the distribution region of high wall shear stress (WSS) were increased, which raises the probability of thrombosis. For infant A, the preoperative abnormal PA structure directly resulted in asymmetric growth of PA after operation, and the LPA/RPA ratio decreased from 0.49 to 0.25. Insufficient reserved length of the MBTS led to traction phenomena with the growth of infant B; on the one hand, it increased the eddy current, and on the other hand, it increased the flow resistance of anastomosis, promoting asymmetric PA flow.

scholarly journals Application of A Microstructural Constitutive Model of the Pulmonary Artery to Patient-Specific Studies: Validation and Effect of Orthotropy

2006 ◽  
Vol 129 (2) ◽  
pp. 193-201 ◽  
Author(s):  
Yanhang Zhang ◽  
Martin L. Dunn ◽  
Kendall S. Hunter ◽  
Craig Lanning ◽  
D. Dunbar Ivy ◽  
...  
Keyword(s):  
Pulmonary Artery ◽  
Animal Studies ◽  
Three Dimensional ◽  
Vascular Anatomy ◽  
Initial Study ◽  
Patient Specific ◽  
Pulmonary Vasculature ◽  
Cross Linking ◽  
Microstructural Model ◽  
Pulmonary Arterial

We applied a statistical mechanics based microstructural model of pulmonary artery mechanics, developed from our previous studies of rats with pulmonary arterial hypertension (PAH), to patient-specific clinical studies of children with PAH. Our previous animal studies provoked the hypothesis that increased cross-linking density of the molecular chains may be one biological remodeling mechanism by which the PA stiffens in PAH. This study appears to further confirm this hypothesis since varying molecular cross-linking density in the model allows us to simulate the changes in the P‐D loops between normotensive and hypertensive conditions reasonably well. The model was combined with patient-specific three-dimensional vascular anatomy to obtain detailed information on the topography of stresses and strains within the proximal branches of the pulmonary vasculature. The effect of orthotropy on stress∕strain within the main and branch PAs obtained from a patient was explored. This initial study also puts forward important questions that need to be considered before combining the microstructural model with complex patient-specific vascular geometries.

Patient-Specific Three-Dimensional Computational Heart Modeling and Printing to Enhance Clinical Understandings and Treatment Planning: Congenital Recurrent Pulmonary Artery Stenosis and Transcatheter Pulmonary Valve Replacement

2020 ◽  
Author(s):  
Amanda C. Tenhoff ◽  
Varun Aggarwal ◽  
Rebecca Ameduri ◽  
Alex Deakyne ◽  
Tinen L. Iles ◽  
...  
Keyword(s):  
Congenital Heart Disease ◽  
Heart Disease ◽  
Pulmonary Artery ◽  
Congenital Heart ◽  
Pulmonary Valve ◽  
Three Dimensional ◽  
Patient Specific ◽  
Pulmonary Artery Stenosis ◽  
Three Dimensional Modeling ◽  
Dimensional Modeling

Abstract Advances in the surgical and interventional management of children with congenital heart disease has improved survival and outcomes. Each such patient is born with specific anatomical variations which call for detailed evaluations so to plan for appropriate patient-specific management. Significant progress has been made in commercially available two-dimensional imaging – i.e. echocardiogram, CT, and MRI – yet using such, three-dimensional anatomical details can be difficult to accurately represent. In addressing this concern, it has been shown that patient-specific three-dimensional modeling can be useful for interventional procedural or surgical planning [1]. Here we present two cases for which patient-specific anatomical three-dimensional modeling and printing were utilized for (1) the pre-sizing and placement of stents within a complex bifurcation pulmonary artery stenosis; and (2) evaluating the candidacy of the patient’s anatomy for a transcatheter pulmonary valve placement. Detailed within this technical brief are de-identified case information, workflows for model generations, and results regarding clinical usage. In conclusion, we found these patient-specific models to be an advantageous resource for treatment planning in these two pediatric congenital heart disease cases.

Three-Dimensional Simulations in Glenn Patients: Clinically Based Boundary Conditions, Hemodynamic Results and Sensitivity to Input Data

2011 ◽  
Vol 133 (11) ◽  
Author(s):  
G. Troianowski ◽  
C. A. Taylor ◽  
J. A. Feinstein ◽  
I. E. Vignon-Clementel
Keyword(s):  
Pulmonary Artery ◽  
Boundary Conditions ◽  
Clinical Data ◽  
Power Loss ◽  
Input Data ◽  
Three Dimensional ◽  
Patient Specific ◽  
Mean Flow ◽  
Fontan Surgery ◽  
The Impact

While many congenital heart defects can be treated without significant long term sequelae, some achieve successful palliation as their definitive endpoints. The single-ventricle defect is one such defect and leaves the child with only one operational ventricle, requiring the systemic and the pulmonary circulations to be placed in series through several operations performed during early childhood. Numerical simulations may be used to investigate these hemodynamic conditions and their relation to post-operative sequelae; however, they rely heavily on boundary condition prescription. In this study, we investigate the impact of hemodynamic input data uncertainties on simulation results. Imaged-based patient-specific models of the multi-branched pulmonary arteries and superior vena cava were built for five cavopulmonary connection (i.e. Glenn) patients. Magnetic resonance imaging and catheterization data were acquired for each patient prior to their Fontan surgery. Inflow and outflow boundary conditions were constructed to match available clinical data and resulted in the development of a framework to incorporate these types of clinical data into patient-specific simulations. Three-dimensional computational fluid dynamics simulations were run and hemodynamic indicators were computed. Power loss was low (and efficiency very high) and a linear correlation was found between power loss and cardiac index among the five patients. Other indicators such as low wall shear stress were considered to better characterize these patients. Flow was complex and oscillatory near the anastomosis, and laminar in the smaller branches. While common trends were seen among patients, results showed differences among patients, especially in the 3D maps, strengthening the importance of patient-specific simulations. A sensitivity analysis was performed to investigate the impact of input data (clinical and modeling) to construct boundary conditions on several indicators. Overall, the sensitivity of the output indicators to the input data was small but non-negligible. The sensitivity of commonly used hemodynamic indicators to compare patients is discussed in this context. Power efficiency was much more sensitive to pressure variation than power loss. To increase the precision of such indicators, mean flow split between right and left lungs needs to be measured with more accuracy with higher priority than refining the model of how the flow is distributed on average among the smaller branches. Although ±10% flow split imprecision seemed reasonable in terms of patient comparison, this study suggests that the common practice of imposing a right pulmonary artery/left pulmonary artery flow split of 55%/45% when performing patient specific simulations should be avoided. This study constitutes a first step towards understanding the hemodynamic differences between pre- and post Fontan surgery, predicting these differences, and evaluating surgical outcomes based on preoperative data.

scholarly journals Numerical computation of blood flow for a patient-specific hemodialysis shunt model

2021 ◽  
Author(s):  
Surabhi Rathore ◽  
Tomoki Uda ◽  
Viet Q. H. Huynh ◽  
Hiroshi Suito ◽  
Toshitaka Watanabe ◽  
...  
Keyword(s):  
Stokes Equations ◽  
Three Dimensional ◽  
Arteriovenous Shunt ◽  
Navier Stokes ◽  
Patient Specific ◽  
Stabilized Finite Element ◽  
Computed Tomography Scanning ◽  
Outflow Boundary ◽  
Stage Renal Disease ◽  
End Stage

AbstractHemodialysis procedure is usually advisable for end-stage renal disease patients. This study is aimed at computational investigation of hemodynamical characteristics in three-dimensional arteriovenous shunt for hemodialysis, for which computed tomography scanning and phase-contrast magnetic resonance imaging are used. Several hemodynamical characteristics are presented and discussed depending on the patient-specific morphology and flow conditions including regurgitating flow from the distal artery caused by the construction of the arteriovenous shunt. A simple backflow prevention technique at an outflow boundary is presented, with stabilized finite element approaches for incompressible Navier–Stokes equations.

scholarly journals Application of subject-specific adaptive mechanical loading for bone healing in a mouse tail vertebral defect

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Angad Malhotra ◽  
Matthias Walle ◽  
Graeme R. Paul ◽  
Gisela A. Kuhn ◽  
Ralph Müller
Keyword(s):  
Mechanical Loading ◽  
Bone Defect ◽  
Bone Healing ◽  
Three Dimensional ◽  
Patient Specific ◽  
Dependent Manner ◽  
Micro Computed Tomography ◽  
Computed Tomography Images ◽  
Bone Defect Healing ◽  
Subject Specific

AbstractMethods to repair bone defects arising from trauma, resection, or disease, continue to be sought after. Cyclic mechanical loading is well established to influence bone (re)modelling activity, in which bone formation and resorption are correlated to micro-scale strain. Based on this, the application of mechanical stimulation across a bone defect could improve healing. However, if ignoring the mechanical integrity of defected bone, loading regimes have a high potential to either cause damage or be ineffective. This study explores real-time finite element (rtFE) methods that use three-dimensional structural analyses from micro-computed tomography images to estimate effective peak cyclic loads in a subject-specific and time-dependent manner. It demonstrates the concept in a cyclically loaded mouse caudal vertebral bone defect model. Using rtFE analysis combined with adaptive mechanical loading, mouse bone healing was significantly improved over non-loaded controls, with no incidence of vertebral fractures. Such rtFE-driven adaptive loading regimes demonstrated here could be relevant to clinical bone defect healing scenarios, where mechanical loading can become patient-specific and more efficacious. This is achieved by accounting for initial bone defect conditions and spatio-temporal healing, both being factors that are always unique to the patient.

scholarly journals Effects of intracorneal ring segments implementation technique and design on corneal biomechanics and keratometry in a personalized computational analysis

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Niksa Mohammadi Bagheri ◽  
Mahmoud Kadkhodaei ◽  
Shiva Pirhadi ◽  
Peiman Mosaddegh
Keyword(s):  
Clinical Data ◽  
Three Dimensional ◽  
Element Model ◽  
Von Mises Stress ◽  
Patient Specific ◽  
Average Error ◽  
Constant Thickness ◽  
Arc Length ◽  
Implementation Techniques ◽  
Von Mises

AbstractThe implementation of intracorneal ring segments (ICRS) is one of the successfully applied refractive operations for the treatment of keratoconus (kc) progression. The different selection of ICRS types along with the surgical implementation techniques can significantly affect surgical outcomes. Thus, this study aimed to investigate the influence of ICRS implementation techniques and design on the postoperative biomechanical state and keratometry results. The clinical data of three patients with different stages and patterns of keratoconus were assessed to develop a three-dimensional (3D) patient-specific finite-element model (FEM) of the keratoconic cornea. For each patient, the exact surgery procedure definitions were interpreted in the step-by-step FEM. Then, seven surgical scenarios, including different ICRS designs (complete and incomplete segment), with two surgical implementation methods (tunnel incision and lamellar pocket cut), were simulated. The pre- and postoperative predicted results of FEM were validated with the corresponding clinical data. For the pre- and postoperative results, the average error of 0.4% and 3.7% for the mean keratometry value ($$\text {K}_{\text{mean}}$$ K mean ) were predicted. Furthermore, the difference in induced flattening effects was negligible for three ICRS types (KeraRing segment with arc-length of 355, 320, and two separate 160) of equal thickness. In contrast, the single and double progressive thickness of KeraRing 160 caused a significantly lower flattening effect compared to the same type with constant thickness. The observations indicated that the greater the segment thickness and arc-length, the lower the induced mean keratometry values. While the application of the tunnel incision method resulted in a lower $$\text {K}_{\text{mean}}$$ K mean value for moderate and advanced KC, the induced maximum Von Mises stress on the postoperative cornea exceeded the induced maximum stress on the cornea more than two to five times compared to the pocket incision and the preoperative state of the cornea. In particular, an asymmetric regional Von Mises stress on the corneal surface was generated with a progressive ICRS thickness. These findings could be an early biomechanical sign for a later corneal instability and ICRS migration. The developed methodology provided a platform to personalize ICRS refractive surgery with regard to the patient’s keratoconus stage in order to facilitate the efficiency and biomechanical stability of the surgery.

scholarly journals Imaging the Human Thyroid Using Three-Dimensional Diffuse Optical Tomography: A Preliminary Study

2021 ◽  
Vol 11 (4) ◽  
pp. 1670
Author(s):  
Tetsuya Mimura ◽  
Shinpei Okawa ◽  
Hiroshi Kawaguchi ◽  
Yukari Tanikawa ◽  
Yoko Hoshi
Keyword(s):  
Optical Tomography ◽  
Tumor Hypoxia ◽  
Three Dimensional ◽  
Diffuse Optical Tomography ◽  
Element Model ◽  
Needle Aspiration ◽  
Human Thyroid ◽  
Tissue Oxygen Saturation ◽  
Preliminary Study ◽  
First Time

Thyroid cancer is usually diagnosed by ultrasound imaging and fine-needle aspiration biopsy. However, diagnosis of follicular thyroid carcinomas (FTC) is difficult because FTC lacks nuclear atypia and a consensus on histological interpretation. Diffuse optical tomography (DOT) offers the potential to diagnose FTC because it can measure tumor hypoxia, while image reconstruction of the thyroid is still challenging mainly due to the complex anatomical features of the neck. In this study, we attempted to solve this issue by creating a finite element model of the human neck excluding the trachea (a void region). By reconstruction of the absorption coefficients at three wavelengths, 3D tissue oxygen saturation maps of the human thyroid are obtained for the first time by DOT.

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