PATIENT-SPECIFIC BIOFIDELIC HUMAN CORONARY ARTERY SURROGATES

2018 ◽  
Vol 18 (05) ◽  
pp. 1850049 ◽  
Author(s):  
ARNAB CHANDA ◽  
KAITLYN CURRY
Keyword(s):  
Coronary Artery ◽  
Experimental Studies ◽  
The United States ◽  
Surrogate Models ◽  
Thin Layers ◽  
Patient Specific ◽  
Material System ◽  
Biomechanical Behavior ◽  
Arterial Lumen ◽  
3D Printed

Coronary artery disease (CAD) is the number one killer for both men and women in the United States. To date, unavailability of human coronary arteries due to ethical and biosafety issues has not allowed for many experimental studies on understanding the pathophysiology of CAD. Also, patient-specific arterial blockage conditions are very difficult to estimate using 2D imaging, which prevents the development of effective surgical mitigation steps. Additionally, to date, a majority of stent surgery failures (over 50%), mainly attributed to poor stent design (such as an oversized stent causing local damage of arterial wall and subsequent growth of scar tissue through the stent leading to re-blocking the artery, or in-stent restenosis), are impossible to evaluate. In the current work, a methodology to fabricate patient-specific three-layer biofidelic coronary artery surrogates was developed. This novel method involves the generation of a true-scale MRI-based patient-specific 3D arterial lumen model, which is 3D printed. A four-part silicone material system is developed, which precisely mimics the nonlinear biomechanical behavior of arterial layers, namely the intima (innermost), media (middle) and adventitia (outer). Using the 3D printed arterial lumen model as a positive mold, thin layers ([Formula: see text][Formula: see text]mm) of the layer-specific silicone-based materials are deposited, and subsequently pulled out once cured. The final product is a three-layer coronary artery model which is exactly of the same size and dimensions, and similar mechanical property as that of the actual coronary artery of a patient. Such surrogate models would be extremely helpful for cardiologists and heart surgeons to understand patient-specific atherosclerotic conditions (based on the location and size of blockages), simulate CAD-based surgeries and also evaluate stent implantation procedures. Additionally, these coronary artery surrogate models will allow stent manufacturers to design better and more reliable stents in the future to avoid stent oversizing-based arterial damage conditions and improve stent deployment techniques.

Abstract 17031: Noninvasive CT-Based Hemodynamic Assessment Using 3D Printing and Virtual Functional Assessment Index

Circulation ◽  
2020 ◽  
Vol 142 (Suppl_3) ◽  
Author(s):  
Kranthi K Kolli ◽  
Abdul Zahid ◽  
Alexandre Caprio ◽  
Patricia Xu ◽  
Robert Shepherd ◽  
...  
Keyword(s):  
Coronary Artery ◽  
Pressure Drop ◽  
3D Printing ◽  
Functional Assessment ◽  
Patient Specific ◽  
Fractional Flow ◽  
Flow Rates ◽  
Assessment Index ◽  
3D Printed

Background: Virtual functional assessment index (vFAI), an alternative approach for assessing hemodynamic significance of stenosis has been shown to enhance the diagnostic performance of coronary computed tomography angiography (CCTA) based on evaluating the area under pressure drop-flow curve for a stenosis. Previously, this was assessed via computational fluid dynamics. We investigated the evaluation of vFAI from CCTA images using 3D printing and an in vitro flow loop and its efficacy as compared to the invasively measured fractional flow reserve (FFR). Methods and Results: Eighteen patients with varying degrees of coronary artery disease who underwent non-invasive CCTA scans and invasive FFR of their left anterior descending coronary artery (LAD) were included. The LAD artery was segmented and reconstructed using Mimics (Materialise inc.,). The segmented models were then 3D printed using Carbon 3D printer (Carbon Inc.,) with rigid resins. An in vitro flow circulation system representative of invasive measurements in a cardiac catheterization laboratory was developed to experimentally evaluate the hemodynamic parameters of pressure and flow (Fig A). For each model, a range of physiological flow rates was applied by a peristaltic steady flow pump and titrated by a flow sensor. The pressure drop and the pressure ratio (Pd/Pa) were assessed for patient-specific aortic pressure and differing flow rates. vFAI was evaluated as the normalized area under the P d /P a vs Q curve from 0 to 240 mL/min. There was a strong correlation between vFAI and FFR, (R = 0.83, p < 0.001; Fig B) and a very good agreement between the two parameters by Bland-Altman analysis. The mean difference of measurements from the two methods was 0.06 (SD = 0.08, p=0.0063; Fig C), indicating a small systematic overestimation of the FFR by vFAI. Conclusions: vFAI can be effectively derived from 3D CTCA datasets using 3D-printed in vitro models, based on evaluation over a range of hemodynamic conditions.

scholarly journals 3D printed patient-specific bone models for anatomy education from medical imaging

2021 ◽  
Author(s):  
Arivazhagan Pugalendhi ◽  
◽  
SenthilMurugan Arumugam ◽  
Rajesh Ranganathan ◽  
Sivakumar Ganesan ◽  
...  
Keyword(s):  
3D Printing ◽  
Surgical Planning ◽  
Thin Layers ◽  
Physical Models ◽  
Patient Specific ◽  
Anatomy Education ◽  
Healthcare Applications ◽  
Surgical Guides ◽  
Solid Objects ◽  
3D Printed

Evolution of 3D printing from medical image datasets are escalating and has widespread in healthcare applications such as anatomical models, surgical guides, and customized implants. In 3D printing, solid objects are fabricated by the frequently added the thin layers of material as per the digital model. This paper demonstrates the fabrication of 3D printed patient-specific bone models of leg and ankle foot from Digital Imaging and Communications in Medicine (DICOM) files. Processing of DICOM file is prepared by D2P (DICOM to PRINT) software and physical models are produced by Stratasys uPrint 3D printer. This 3D printed anatomical model eliminates the requirement of actual human bones, significance of preservation and mistakes in assembly of bones. The results of the study not only encourage education, surgical planning and validating medical devices but stimulate exciting innovations.

scholarly journals 3D Printed Personalized External Aortic Root Model in Marfan Syndrome with Isolated Sinus of Valsalva Aneurysm Caused by a Novel Pathogenic FBN1 p.Gly1127Cys Variant

Diagnostics ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 1057
Author(s):  
Jung Sun Cho ◽  
Joonhong Park ◽  
Jong Bum Kwon ◽  
Dae-Won Kim ◽  
Mahn-Won Park
Keyword(s):  
Coronary Artery ◽  
Marfan Syndrome ◽  
Aortic Root ◽  
Amino Acid Position ◽  
Cardiovascular Complications ◽  
Patient Specific ◽  
Sinus Of Valsalva ◽  
Sinus Of Valsalva Aneurysm ◽  
Root Model ◽  
3D Printed

The major cause of death in Marfan syndrome (MFS) is cardiovascular complications, particularly progressive dilatation of the proximal aorta, rendering these patients at risk of aortic dissection or fatal rupture. We report a 3D printed personalized external aortic root model for MFS with an isolated sinus of Valsalva aneurysm caused by a novel pathogenic FBN1 variant. A 67-year-old female with a history of lens dislocation and retinal detachment in the left eye was admitted for the evaluation of resting dyspnea several months prior. Transesophageal and transthoracic echocardiography revealed severe aortic valve regurgitation and a large left coronary sinus of Valsalva aneurysm in the proband. Sanger sequencing identified a heterozygous p.Gly1127Cys variant in the FBN1 gene; previously, a mutation at this amino acid position was described as pathogenic (p.Gly1127Ser; rs137854468). A 3D printed personalized external aortic root model based on a multidetector computed tomography scan was constructed to illustrate the location of the ostium of the left main coronary artery on the aneurysm of the left coronary artery cusp. Aortic root replacement with the Bentall procedure matched the exact shape of the 3D printed model. Creation of a 3D printed patient-specific model could be useful in facilitating the development of next-generation medical devices and resolving the risks of postoperative complications and aortic root disease.

scholarly journals The 3D Printing of Freestanding PLLA Thin Layers and Improving First Layer Consistency through the Introduction of Sacrificial PVA

2021 ◽  
Vol 11 (14) ◽  
pp. 6320
Author(s):  
David M. Roper ◽  
Kyung-Ah Kwon ◽  
Serena M. Best ◽  
Ruth E. Cameron
Keyword(s):  
Thin Layers ◽  
Patient Specific ◽  
Thickness Variation ◽  
Layer By Layer ◽  
Fused Filament Fabrication ◽  
Thin Structures ◽  
Complex Patient ◽  
Layer Deposition ◽  
Layer Structures ◽  
3D Printed

Fused filament fabrication (FFF) is an inexpensive way of producing objects through a programmed layer-by-layer deposition. For multi-layer, macro-scaled prints, acceptable printing is achieved provided, amongst other factors, first layer adhesion is sufficient to fix a part to the surface during printing. However, in the deposition of structures with a single or few layers, first layer consistency is significantly more important and is an issue that has been previously overlooked. As layer-to-bed adhesion is prioritised in first layer printing, thin layer structures are difficult to remove without damage. The deposition of controllable thin structures has potential in tissue engineering through the use of bioactive filaments and incorporation of microfeatures into complex, patient-specific scaffolds. This paper presents techniques to progress the deposition of thin, reproducible structures. The linear thickness variation of 3D-printed single PVA and PLLA layers is presented as a function of extrusion factor and the programmed vertical distance moved by the nozzle between layers (the layer separation). A sacrificial PVA layer is shown to significantly improve first layer consistency, reducing the onus on fine printer calibration in the deposition of single layers. In this way, the linear variation in printed single PLLA layers with bed deviation is drastically reduced. Further, this technique is used to demonstrate the printing of freestanding thin layers of ~25 µm in thickness.

Family Influences on Youth Offending

2018 ◽  
pp. 377-403
Author(s):  
Abigail A. Fagan ◽  
Kristen M. Benedini
Keyword(s):  
Life Course ◽  
Family Environment ◽  
Parenting Practices ◽  
Experimental Studies ◽  
The United States ◽  
Parental Violence ◽  
Youth Delinquency ◽  
The Impact ◽  
Children’S Exposure

This chapter reviews the degree to which empirical evidence demonstrates that families influence youth delinquency. Because they are most likely to be emphasized in life-course theories, this chapter focuses on parenting practices such as parental warmth and involvement, supervision and discipline of children, and child maltreatment. It also summarizes literature examining the role of children's exposure to parental violence, family criminality, and young (teenage) parents in affecting delinquency. Because life-course theories are ideally tested using longitudinal data, which allow examination of, in this case, the impact of parenting practices on children's subsequent behaviors, this chapter focuses on evidence generated from prospective studies conducted in the United States and other countries. It also discusses findings from experimental studies designed to reduce youth substance use and delinquency by improving the family environment.

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 Appropriate utilization of cardiac computed tomography for the assessment of stable coronary artery disease

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Michael Hammer ◽  
Muhtashim Mian ◽  
Levi Elhadad ◽  
Mary Li ◽  
Idan Roifman
Keyword(s):  
Computed Tomography ◽  
Coronary Artery Disease ◽  
Coronary Artery ◽  
Cardiac Imaging ◽  
Cardiac Computed Tomography ◽  
The United States ◽  
Appropriate Use ◽  
Potential Cost ◽  
Cardiac Computed Tomography Angiography ◽  
Artery Disease

Abstract Background Appropriate use criteria (AUC) have been developed in response to growth in cardiac imaging utilization and concern regarding associated costs. Cardiac computed tomography angiography (CCTA) has emerged as an important modality in the evaluation of coronary artery disease, however its appropriate utilization in actual practice is uncertain. Our objective was to determine the appropriate utilization of CCTA in a large quaternary care institution and to compare appropriate utilization pre and post publication of the 2013 AUC guidelines. We hypothesized that the proportion of appropriate CCTA utilization will be similar to those of other comparable cardiac imaging modalities and that there would be a significant increase in appropriate use post AUC publication. Methods We employed a retrospective cohort study design of 2577 consecutive patients undergoing CCTA between January 1, 2012 and December 30, 2016. An appropriateness category was assigned for each CCTA. Appropriateness classifications were compared pre- and post- AUC publication via the chi-square test. Results Overall, 83.5% of CCTAs were deemed to be appropriate based on the AUC. Before the AUC publication, 75.0% of CCTAs were classified as appropriate whereas after the AUC publication, 88.0% were classified as appropriate (p < 0.001). The increase in appropriate utilization, when extrapolated to the Medicare population of the United States, was associated with potential cost savings of approximately $57 million per year. Conclusions We report a high rate of appropriate use of CCTA and a significant increase in the proportion of CCTAs classified as appropriate after the AUC publication.

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