Rapid Prototyping

Evolving capabilities of computed tomography imaging for transcatheter valvular heart interventions - new opportunities for precision medicine

The last decade has witnessed a substantial growth in percutaneous treatment options for heart valve disease. The development in these innovative therapies has been mirrored by advances in multi-detector computed tomography (MDCT). MDCT plays a central role in obtaining detailed pre-procedural anatomical information, helping to inform clinical decisions surrounding procedural planning, improve clinical outcomes and prevent potential complications. Improvements in MDCT image acquisition and processing techniques have led to increased application of advanced analytics in routine clinical care. Workflow implementation of patient-specific computational modeling, fluid dynamics, 3D printing, extended reality, extracellular volume mapping and artificial intelligence are shaping the landscape for delivering patient-specific care. This review will provide an insight of key innovations in the field of MDCT for planning transcatheter heart valve interventions.

Application of three-dimensional printing in plastic surgery: a bibliometric analysis

Recent years have seen the publication of numerous papers on the application of three-dimensional (3D) printing in plastic surgery. Despite this growing interest, a comprehensive bibliometric analysis of the field has yet to be conducted. To address this gap, we undertook a bibliometric study to map out the knowledge structure and identify research hotspots related to 3D printing in plastic surgery. We analyzed publications from 1995 to 2024, found in the Web of Science Core Collection (WoSCC), utilizing tools such as VOSviewer, CiteSpace, and the R package "bibliometrix". Our analysis included 1,057 documents contributed by 5,545 authors from 1,620 organizations across 71 regions, and these were published in 400 journals. We observed a steady growth in annual publications, with Europe, Asia, North America, and Oceania leading in research output. Notably, Shanghai Jiao Tong University emerged as a primary research institution in this domain. The Journal of Craniofacial Surgery and Journal of Oral and Maxillofacial Surgery have made significant contributions to the field, with Thieringer, Florian M being the most prolific and frequently cited author. Key areas of focus include medical education and surgical procedures, with "3D printing", "virtual surgical planning" and "reconstructive/orthognathic surgery" highlighted as future research hotspots. Our study provides a detailed bibliometric analysis, revealing the evolution and progress of 3D printing technologies in plastic surgery. As these technologies continue to advance, their impact on clinical practice and patient lives is expected to be profound.

Application of three-dimensional printing in cardiovascular diseases: a bibliometric analysis

AIM

This paper aimed to explore the application of three-dimensional (3D) printing in cardiovascular diseases, to reach an insight in this field and prospect the future trend.

METHODS

The articles were selected from the Web of Science Core Collection database. Excel 2019, VOSviewer 1.6.16, and CiteSpace 6.1.R6 were used to analyze the information.

RESULTS

A total of 467 papers of 3D printing in cardiovascular diseases were identified, and the first included literature appeared in 2000. A total of 692 institutions from 52 countries participated in the relevant research, while the United States of America contributed to 160 articles and were in a leading position. The most productive institution was Curtin University , and Zhonghua Sun who has posted the most articles ( n =8) was also from there. The Frontiers in Cardiovascular Medicine published most papers ( n =25). The Journal of Thoracic and Cardiovascular Surgery coveted the most citations ( n =520). Related topics of frontiers will still focus on congenital heart disease, valvular heart disease, and left atrial appendage closure.

CONCLUSIONS

The authors summarized the publication information of the application of 3D printing in cardiovascular diseases related literature from 2000 to 2023, including country and institution of origin, authors, and publication journal. This study can reflect the current hotspots and novel directions for the application of 3D printing in cardiovascular diseases.

Three-dimensional printing of mitral valve models using echocardiographic data improves the knowledge of cardiology fellow physicians in training

Background

High fidelity three-dimensional Mitral valve models (3D MVM) printed from echocardiography are currently being used in preparation for surgical repair.

Aim

We hypothesize that printed 3DMVM could have relevance to cardiologists in training by improving their understanding of normal anatomy and pathology.

Methods

Sixteen fellow physicians in pediatric and adult cardiology training were recruited. 3D echocardiography (3DE) video clips of six mitral valves (one normal and five pathological) were displayed and the fellows were asked to name the prolapsing segments in each. Following that, three still images of 3D MVMs in different projections: enface, profile and tilted corresponding to the same MVs seen in the clip were presented on a screen. Participating physicians were presented with a comprehensive questionnaire aimed at assessing whether the 3D MVM has improved their understanding of valvular anatomy. Finally, a printed 3D MVM of each of the valves was handed out, and the same questionnaire was re-administered to identify any further improvement in the participants' perception of the anatomy.

Results

The correct diagnosis using the echocardiography video clip of the Mitral valve was attained by 45% of the study participants. Both pediatric and adult trainees, regardless of the year of training demonstrated improved understanding of the anatomy of MV after observing the corresponding model image. Significant improvement in their understanding was noted after participants had seen and physically examined the printed model.

Conclusion

Printed 3D MVM has a beneficial impact on the cardiology trainees' understanding of MV anatomy and pathology compared to 3DE images.

Tertiary prevention and treatment of rheumatic heart disease: a National Heart, Lung, and Blood Institute working group summary

Although entirely preventable, rheumatic heart disease (RHD), a disease of poverty and social disadvantage resulting in high morbidity and mortality, remains an ever-present burden in low-income and middle-income countries (LMICs) and rural, remote, marginalised and disenfranchised populations within high-income countries. In late 2021, the National Heart, Lung, and Blood Institute convened a workshop to explore the current state of science, to identify basic science and clinical research priorities to support RHD eradication efforts worldwide. This was done through the inclusion of multidisciplinary global experts, including cardiovascular and non-cardiovascular specialists as well as health policy and health economics experts, many of whom also represented or closely worked with patient-family organisations and local governments. This report summarises findings from one of the four working groups, the Tertiary Prevention Working Group, that was charged with assessing the management of late complications of RHD, including surgical interventions for patients with RHD. Due to the high prevalence of RHD in LMICs, particular emphasis was made on gaining a better understanding of needs in the field from the perspectives of the patient, community, provider, health system and policy-maker. We outline priorities to support the development, and implementation of accessible, affordable and sustainable interventions in low-resource settings to manage RHD and related complications. These priorities and other interventions need to be adapted to and driven by local contexts and integrated into health systems to best meet the needs of local communities.

Three-dimensional printing and 3D slicer powerful tools in understanding and treating neurosurgical diseases

With the development of the 3D printing industry, clinicians can research 3D printing in preoperative planning, individualized implantable materials manufacturing, and biomedical tissue modeling. Although the increased applications of 3D printing in many surgical disciplines, numerous doctors do not have the specialized range of abilities to utilize this exciting and valuable innovation. Additionally, as the applications of 3D printing technology have increased within the medical field, so have the number of printable materials and 3D printers. Therefore, clinicians need to stay up-to-date on this emerging technology for benefit. However, 3D printing technology relies heavily on 3D design. 3D Slicer can transform medical images into digital models to prepare for 3D printing. Due to most doctors lacking the technical skills to use 3D design and modeling software, we introduced the 3D Slicer to solve this problem. Our goal is to review the history of 3D printing and medical applications in this review. In addition, we summarized 3D Slicer technologies in neurosurgery. We hope this article will enable many clinicians to leverage the power of 3D printing and 3D Slicer.

Imaging-Based, Patient-Specific Three-Dimensional Printing to Plan, Train, and Guide Cardiovascular Interventions: A Systematic Review and Meta-Analysis

BACKGROUND

To tailor cardiovascular interventions, the use of three-dimensional (3D), patient-specific phantoms (3DPSP) encompasses patient education, training, simulation, procedure planning, and outcome-prediction.

AIM

This systematic review and meta-analysis aims to investigate the current and future perspective of 3D printing for cardiovascular interventions.

METHODS

We systematically screened articles on Medline and EMBASE reporting the prospective use of 3DPSP in cardiovascular interventions by using combined search terms. Studies that compared intervention time depending on 3DPSP utilisation were included into a meta-analysis.

RESULTS

We identified 107 studies that prospectively investigated a total of 814 3DPSP in cardiovascular interventions. Most common settings were congenital heart disease (CHD) (38 articles, 6 comparative studies), left atrial appendage (LAA) occlusion (11 articles, 5 comparative, 1 randomised controlled trial [RCT]), and aortic disease (10 articles). All authors described 3DPSP as helpful in assessing complex anatomic conditions, whereas poor tissue mimicry and the non-consideration of physiological properties were cited as limitations. Compared to controls, meta-analysis of six studies showed a significant reduction of intervention time in LAA occlusion (n=3 studies), and surgery due to CHD (n=3) if 3DPSPs were used (Cohen's d=0.54; 95% confidence interval, 0.13 to 0.95; p=0.001), however heterogeneity across studies should be taken into account.

CONCLUSIONS

3DPSP are helpful to plan, train, and guide interventions in patients with complex cardiovascular anatomy. Benefits for patients include reduced intervention time with the potential for lower radiation exposure and shorter mechanical ventilation times. More evidence and RCTs including clinical endpoints are needed to warrant adoption of 3DPSP into routine clinical practice.

Combining patient-specific, digital 3D models with tele-education for adolescents with CHD

INTRODUCTION

Adolescents with CHD require transition to specialised adult-centred care. Previous studies have shown that adolescents' knowledge of their medical condition is correlated with transition readiness. Three-dimensional printed models of CHD have been used to educate medical trainees and patients, although no studies have focused on adolescents with CHD. This study investigates the feasibility of combining patient-specific, digital 3D heart models with tele-education interventions to improve the medical knowledge of adolescents with CHD.

METHODS

Adolescent patients with CHD, aged between 13 and 18 years old, were enrolled and scheduled for a tele-education session. Patient-specific digital 3D heart models were created using images from clinically indicated cardiac magnetic resonance studies. The tele-education session was performed using commercially available, web-conferencing software (Zoom, Zoom Video Communications Inc.) and a customised software (Cardiac Review 3D, Indicated Inc.) incorporating an interactive display of the digital 3D heart model. Medical knowledge was assessed using pre- and post-session questionnaires that were scored by independent reviewers.

RESULTS

Twenty-two adolescents completed the study. The average age of patients was 16 years old (standard deviation 1.5 years) and 56% of patients identified as female. Patients had a variety of cardiac defects, including tetralogy of Fallot, transposition of great arteries, and coarctation of aorta. Post-intervention, adolescents' medical knowledge of their cardiac defects and cardiac surgeries improved compared to pre-intervention (p < 0.01).

CONCLUSIONS

Combining patient-specific, digital 3D heart models with tele-education sessions can improve adolescents' medical knowledge and may assist with transition to adult-centred care.

Comparison of blood pool and myocardial 3D printing in the diagnosis of types of congenital heart disease

The study aimed to evaluate the effectiveness of blood pool and myocardial models made by stereolithography in the diagnosis of different types of congenital heart disease (CHD). Two modeling methods were applied in the diagnosis of 8 cases, and two control groups consisting of experts and students diagnosed the cases using echocardiography with computed tomography, blood pool models, and myocardial models. The importance, suitability, and simulation degree of different models were analyzed. The average diagnostic rate before and after 3D printing was used was 88.75% and 95.9% (P = 0.001) in the expert group and 60% and 91.6% (P = 0.000) in the student group, respectively. 3D printing was considered to be more important for the diagnosis of complex CHDs (very important; average, 87.8%) than simple CHDs (very important; average, 30.8%) (P = 0.000). Myocardial models were considered most realistic regarding the structure of the heart (average, 92.5%). In cases of congenital corrected transposition of great arteries, Williams syndrome, coronary artery fistula, tetralogy of Fallot, patent ductus arteriosus, and coarctation of the aorta, blood pool models were considered more effective (average, 92.1%), while in cases of double outlet right ventricle and ventricular septal defect, myocardial models were considered optimal (average, 80%).

Application of Patient-Specific Instrumentation in a Dog Model with Antebrachial Growth Deformity Using a 3-D Phantom Bone Model

One of the most frequent bone deformities in dogs is antebrachial growth deformity (AGD), which results from malunion of the distal growth plates. The objective of the present study was to re-align the limbs, which can correct the length mismatch and reset the coherence of the joint with the aid of a 3-D phantom model for surgical preplanning. A 14-month-old, intact female Golden Retriever with an angular deformity of the left radius and ulna was selected for the study. The diagnosis was confirmed by orthogonal radiographs. Moreover, computed tomography (CT) scans revealed a multiplane deformity with valgus, procurator, and external rotation of the left radius. The pre-surgical planning started with the quantification of the angular deformity, followed by a simulated virtual osteotomy, and concluded with an in vitro rehearsal surgery on 3-D printed phantom bone models. In the operating room, prefabricated patient-specific instrumentation (PSI) was attached at the planned site of the radial bone surface for a precise closing wedge osteotomy. Then two locking plates were fixed routinely. Post-operative radiographs showed accurate correction of the deformity as we had planned. At 12 weeks post-operatively, the follow-up surveys revealed improved gait, weight-bearing, and progression of bone healing. Our PSI design, based on novel surgical planning, was steady yet straightforward during the osteotomy. The osteotomy was performed without difficulty since the PSI that pre-determined the sites and angles let the surgeon perform the antebrachial malformation surgery. This method of operation reduces stress on the operator and helps to improve accuracy, repeatability, and surgery time.

Efficacy of the spiral flow generating extended tube during paediatric CCTA

INTRODUCTION

To compare the computed tomography (CT) number for paediatric cardiac computed tomography angiography (CCTA) and visualisation score of the three-dimensional (3D) images using the conventional T-shaped extended tube (T-tube) and spiral flow-generating extended tube (spiral-tube) connected between the contrast injector and cannula.

METHODS

In total, 108 patients suspected to have congenital heart disease (CHD) were considered for inclusion. We utilised the T-tube for intravenous contrast and spiral-tube in 54 patients each. Observers individually inspected randomized volume rendering images of the internal thoracic artery, each acquired from the with or without spiral-tube groups, using a four-point scale. We compared the mean CT number of the ascending aorta (AAO) and pulmonary artery (PA), contrast noise ratio (CNR), CT number for the AAO and PA enhancement ratio, and the visualisation scores between the groups.

RESULTS

There were no significant differences in patient characteristics between the with or without spiral-tube groups (p > 0.05). The mean CT number ±standard deviation for the AAO and PA, and the CNR without or with spiral-tube groups were 441.2 ± 89.2 and 489.8 ± 86.1 HU for the AAO, 436.3 ± 100.6 and 475.3 ± 85.2 HU for the PA, and 9.5 ± 2.2 and 10.8 ± 2.4 for the CNR, respectively (p < 0.05). In the spiral-tube group, the CT number, CNR, and visualisations score of the 3D images were significantly higher for the AAO and PA than those in the T-tube group (p < 0.05).

CONCLUSION

The spiral-tube proved to be beneficial in improving the CT number for the AAO and PA, CNR, and visualisation score compared with the conventional T-tube during paediatric CCTA.

IMPLICATIONS FOR PRACTICE

The spiral-tube may allow the visualisation of smaller blood vessels than those visualised by the conventional T-tube for paediatric patients in CCTA.

3D Printing-A Cutting Edge Technology for Treating Post-Infarction Patients

The increasing complexity of cardiovascular interventions requires advanced peri-procedural imaging and tailored treatment. Three-dimensional printing technology represents one of the most significant advances in the field of cardiac imaging, interventional cardiology or cardiovascular surgery. Patient-specific models may provide substantial information on intervention planning in complex cardiovascular diseases, and volumetric medical imaging from CT or MRI can be translated into patient-specific 3D models using advanced post-processing applications. 3D printing and additive manufacturing have a great variety of clinical applications targeting anatomy, implants and devices, assisting optimal interventional treatment and post-interventional evaluation. Although the 3D printing technology still lacks scientific evidence, its benefits have been shown in structural heart diseases as well as for treatment of complex arrhythmias and corrective surgery interventions. Recent development has enabled transformation of conventional 3D printing into complex 3D functional living tissues contributing to regenerative medicine through engineered bionic materials such hydrogels, cell suspensions or matrix components. This review aims to present the most recent clinical applications of 3D printing in cardiovascular medicine, highlighting also the potential for future development of this revolutionary technology in the medical field.

Transcatheter Closure of Left Ventricle to Coronary Sinus Fistula Post-MVR and Septal Myectomy

This paper describes the case of a patient who developed refractory heart failure due to a fistula from the left ventricle to the coronary sinus that was unintentionally created after a surgical myectomy and mitral valve replacement. Advanced image guidance with a pre-procedure 3-dimensional physical model and intraprocedure echocardiography fusion facilitated transcatheter plugging of the shunt with symptom resolution. (Level of Difficulty: Advanced.)

Update in Paravalvular Leak Closure

PURPOSE OF REVIEW

Given the low occurrence of clinically important paravalvular leak (PVL), there are no large registries or trials in this space to investigate management strategies. This review integrates newer evidence, particularly in imaging guidance for these complex procedures, novel techniques and approaches that our group has taken, as well as approaches to more complex PVL plugging reported in case reports.

RECENT FINDINGS

Perhaps the largest area of growth in the management of PVL is the use of advanced imaging in both pre-procedure evaluation and intra-procedural guidance with gated cardiac CT, 3D TEE, and fluoroscopy fusion technologies. Outside the USA, a new device, the Occlutech PLD, has become available with early data indicating high success rates. There remains little randomized data to support the efficacy of percutaneous PVL closure. Gated cardiac CT has become key to the pre-procedure evaluation for transcatheter closure as it allows for increased procedural efficiency and more accurate pre-procedure planning, particularly when combined with 3D printing. Intra-procedural TEE-fluoro fusion allows for more rapid crossing of defects by providing a visual target for interventionalists. The advent of purpose-built devices for PVL closure may further increase the efficacy and efficiency of percutaneous closure, but significant barriers remain for approval of these devices in the USA.

Application of 3D printing technology combined with PBL teaching model in teaching clinical nursing in congenital heart surgery: A case-control study

We aimed to explore the application of three-dimensional (3D) printing technology with problem-based learning (PBL) teaching model in clinical nursing education of congenital heart surgery, and to further improve the teaching quality of clinical nursing in congenital heart surgery. In this study, a total of 132 trainees of clinical nursing in congenital heart surgery from a grade-A tertiary hospital in 2019 were selected and randomly divided into 3D printing group or traditional group. The 3D printing group was taught with 3D printed heart models combined with PBL teaching technique, while the traditional group used conventional teaching aids combined with PBL technique for teaching. After the teaching process, the 2 groups of nursing students were assessed and surveyed separately to evaluate the results. Compared to the traditional group, the theoretical scores, clinical nursing thinking ability, self-evaluation for comprehensive ability, and teaching satisfaction from the questionnaires filled by the 3D printing group were all higher than the traditional group. The difference was found to be statistically significant (P < .05). Our study has shown the 3D printing technology combined with the PBL teaching technique in the clinical nursing teaching of congenital heart surgery achieved good results.

The role of CT in planning percutaneous structural heart interventions: Where to measure and why

As research continues to demonstrate successes in the use of percutaneous trans-vascular techniques in structural heart intervention, both the subspecialty trained and non-subspecialty trained cardiac imager find themselves performing and reporting larger amounts of information regarding cardiovascular findings. It is therefore imperative that the imager gains understanding and appreciation for how these various measurements are obtained, as well as their implication in a patient's care. Cardiac gated computed tomography (CT) has solidified its role and ability at providing high resolution images that can be used to obtain the key measurements used in structural heart intervention planning. This manuscript aims to provide an overview of what measurements are necessary to report when interpreting CT examinations purposed for structural heart intervention. This includes a review on indications and brief discussion on complications related to these procedures.

Biomaterials and 3D printing techniques used in the medical field

An implants' effectiveness depends upon the form of biomaterial used in its manufacture. A suitable material for implants should be biocompatible, sterile, mechanically stable and simple to shape. 3D printing technologies have been breaking new ground in the medical and medical industries in order to build patient-specific devices embedded in bioactive drugs, cells and proteins. Widespread use in medical 3D printing is a broad range of biomaterials including metals, ceramics, polymers and composites. Continuous work and developments in biomaterials used in 3D printing have contributed to significant growth of 3D printing applications in the production of personalised joints, prostheses, medication delivery system and 3D tissue engineering and regenerative medicine scaffolds. The present analysis focuses on the biomaterials used for therapeutic applications in different 3D printing technologies. Many specific forms of medical 3D printing technology are explored in depth, including fused deposition modelling, extrusion-based bioprinting, inkjet and poly-jet printing processes, their therapeutic uses, various types of biomaterial used today and the major shortcoming , are being studied in depth.

Application of 3D Printing in Preoperative Planning

Preoperative planning is critical for success in the surgical suite. Current techniques for surgical planning are limited; clinicians often rely on prior experience and medical imaging to guide the decision-making process. Furthermore, two-dimensional (2D) presentations of anatomical structures may not accurately portray their three-dimensional (3D) complexity, often leaving physicians ill-equipped for the procedure. Although 3D postprocessed images are an improvement on traditional 2D image sets, they are often inadequate for surgical simulation. Medical 3D printing is a rapidly expanding field and could provide an innovative solution to current constraints of preoperative planning. As 3D printing becomes more prevalent in medical settings, it is important that clinicians develop an understanding of the technologies, as well as its uses. Here, we review the fundamentals of 3D printing and key aspects of its workflow. The many applications of 3D printing for preoperative planning are discussed, along with their challenges.

CT-Based 3D Printing of the Glenoid Prior to Shoulder Arthroplasty: Bony Morphology and Model Evaluation

To demonstrate the 3D printed appearance of glenoid morphologies relevant to shoulder replacement surgery and to evaluate the benefits of printed models of the glenoid with regard to surgical planning. A retrospective review of patients referred for shoulder CT was performed, leading to a cohort of nine patients without arthroplasty hardware and exhibiting glenoid changes relevant to shoulder arthroplasty planning. Thin slice CT images were used to create both humerus-subtracted volume renderings of the glenoid, as well as 3D surface models of the glenoid, and 11 printed models were created. Volume renderings, surface models, and printed models were reviewed by a musculoskeletal radiologist for accuracy. Four fellowship-trained orthopaedic surgeons specializing in shoulder surgery reviewed each case individually as follows: First, the source CT images were reviewed, and a score for the clarity of the bony morphologies relevant to shoulder arthroplasty surgery was given. The volume rendering was reviewed, and the clarity was again scored. Finally, the printed model was reviewed, and the clarity again scored. Each printed model was also scored for morphologic complexity, expected usefulness of the printed model, and physical properties of the model. Mann-Whitney-Wilcoxon signed rank tests of the clarity scores were calculated, and the Spearman's ρ correlation coefficient between complexity and usefulness scores was computed. Printed models demonstrated a range of glenoid bony changes including osteophytes, glenoid bone loss, retroversion, and biconcavity. Surgeons rated the glenoid morphology as more clear after review of humerus-subtracted volume rendering, compared with review of the source CT images (p = 0.00903). Clarity was also better with 3D printed models compared to CT (p = 0.00903) and better with 3D printed models compared to humerus-subtracted volume rendering (p = 0. 00879). The expected usefulness of printed models demonstrated a positive correlation with morphologic complexity, with Spearman's ρ 0.73 (p = 0.0108). 3D printing of the glenoid based on pre-operative CT provides a physical representation of patient anatomy. Printed models enabled shoulder surgeons to appreciate glenoid bony morphology more clearly compared to review of CT images or humerus-subtracted volume renderings. These models were more useful as glenoid complexity increased.

Three-dimensional printing for cardiovascular diseases: from anatomical modeling to dynamic functionality

Three-dimensional (3D) printing is widely used in medicine. Most research remains focused on forming rigid anatomical models, but moving from static models to dynamic functionality could greatly aid preoperative surgical planning. This work reviews literature on dynamic 3D heart models made of flexible materials for use with a mock circulatory system. Such models allow simulation of surgical procedures under mock physiological conditions, and are; therefore, potentially very useful to clinical practice. For example, anatomical models of mitral regurgitation could provide a better display of lesion area, while dynamic 3D models could further simulate in vitro hemodynamics. Dynamic 3D models could also be used in setting standards for certain parameters for function evaluation, such as flow reserve fraction in coronary heart disease. As a bridge between medical image and clinical aid, 3D printing is now gradually changing the traditional pattern of diagnosis and treatment.

Virtual and augmented reality: potential applications in radiology

The modern-day radiologist must be adept at image interpretation, and the one who most successfully leverages new technologies may provide the highest value to patients, clinicians, and trainees. Applications of virtual reality (VR) and augmented reality (AR) have the potential to revolutionize how imaging information is applied in clinical practice and how radiologists practice. This review provides an overview of VR and AR, highlights current applications, future developments, and limitations hindering adoption.

3D printing tissue-mimicking materials for realistic transseptal puncture models

Applications of additive manufacturing (commonly referred to as 3D printing) in direct fabrication of models for pre-surgical planning, functional testing, and medical training are on the rise. However, one current limitation to the accuracy of models for cardiovascular procedural training is a lack of printable materials that accurately mimic human tissue. Most of the available elastomeric materials lack mechanical properties representative of human tissues. To address the gap, the authors explore the multi-material capability of material jetting additive manufacturing to combine non-curing and photo-curing inks to achieve material properties that more closely replicate human tissues. The authors explore the impact of relative material concentration on tissue-relevant properties from puncture and tensile testing under submerged conditions. Further, the authors demonstrate the ability to mimic the mechanical properties of the fossa ovalis, which proves beneficial for accurately simulating transseptal punctures. A fossa ovalis mimic was printed and assembled within a full patient-specific heart model for validation, where it exhibited accuracy in both mechanical properties and geometry. The explored material combination provides the opportunity to fabricate future medical models that are more realistic and better suited for pre-surgical planning and medical student training. This will ultimately guide safer, more efficient practices.

Moving beyond two-dimensional screens to interactive three-dimensional visualization in congenital heart disease

Beginning with the discovery of X-rays to the development of three-dimensional (3D) imaging, improvements in acquisition, post-processing, and visualization have provided clinicians with detailed information for increasingly accurate medical diagnosis and clinical management. This paper highlights advances in imaging technologies for congenital heart disease (CHD), medical adoption, and future developments required to improve pre-procedural and intra-procedural guidance.

Personalized Three-Dimensional Printing and Echoguided Procedure Facilitate Single Device Closure for Multiple Atrial Septal Defects

Background

To evaluate the feasibility of using a single device to close multiple atrial septal defects (ASDs) under the guidance of transthoracic echocardiography (TTE) and with the aid of three-dimensional (3D) printing models.

Methods

Sixty-two patients with multiple ASDs were retrospectively analyzed. Thirty of these patients underwent TTE-guided closure (3D printing and TTE group) after a simulation of occlusion in 3D printing models. The remaining 32 patients underwent ASD closure under fluoroscopic guidance (conventional group). Closure status was assessed immediately and at 6 months after device closure.

Results

Successful transcatheter closure with a single device was achieved in 26 patients in the 3D printing and TTE group and 27 patients in the conventional group. Gender, age [18.8 ± 15.9 (3–51) years in the 3D printing and TTE group; 14.0 ± 11.6 (3–50) years in the conventional group], mean maximum distance between defects, prevalence of 3 atrial defects and large defect distance (defined as distance ≥7 mm), and occluder size used were similarly distributed between groups. However, the 3D printing and TTE group had lower frequency of occluder replacement (3.8% vs 59.3%, p < 0.0001), prevalence of mild residual shunts (defined as <5 mm) immediately (19.2% vs 44.4%, p < 0.05) and at 6 months (7.7% vs 29.6%, p < 0.05) after the procedure, and cost (32960.8 ± 2018.7 CNY vs 41019.9 ± 13758.2 CNY, p < 0.01).

Conclusion

The combination of the 3D printing technology and ultrasound-guided interventional procedure provides a reliable new therapeutic approach for multiple ASDs, especially for challenging cases with large defect distance.

Accuracy and precision of measurements performed on three-dimensional printed pelvises when compared to computed tomography measurements

The preoperative contouring of plates decreases the duration of surgery and improves the quality of the reduction of pelvic fractures. Patient-tailored three-dimensionally printed pelvises might be an interesting tool for achieving that purpose. Currently, no study has evaluated the accuracy of measurements performed on three-dimensional printed models in comparison with computed tomography data for complex bones, such as the pelvis. This study examined whether the measurements obtained on pelvises printed using dual-material fused deposition modeling technology are not significantly different from those obtained on computed tomography images. The computed tomography images of the pelvic region from 10 dogs were used to produce three-dimensionally printed models with a dual-material fused deposition-modeling process. Four segments were measured on both three-dimensionally printed models and computed tomography images. The measurements were performed by three observers and repeated twice. Concordance correlation coefficients were used to assess the precision and accuracy of the measurements as well as evaluate the agreement between the methods. The accuracy of measurements between the methods was > 0.99 for all measurements. The precision was almost perfect for AE (0.996), substantial for BD and BC (0.963 and 0.958, respectively), and moderate for CD (0.912). These results indicate that, despite some minor variations, the measurements performed on printed models reproduced the computed tomography data reliably.

Three-dimensional printing in structural heart disease and intervention

Three-dimensional (3D) printing refers to the process by which physical objects are built by depositing materials in layers based on a specific digital design. It was initially used in manufacture industry. Inspired by the technology, clinicians have recently attempted to integrate 3D printing into medical applications. One of the medical specialties that has recently made such attempt is cardiology, especially in the field of structural heart disease (SHD). SHD refers to a group of non-coronary cardiovascular disorders and related interventions. Obvious examples are aortic stenosis, mitral regurgitation, atrial septal defect, and known or potential left atrial appendage (LAA) clots. In the last decade, cardiologists have witnessed a dramatic increase in the types and complexity of catheter-based interventions for SHD. Current imaging modalities have important limitations in accurate delineation of cardiac anatomies necessary for SHD interventions. Application of 3D printing in SHD interventional planning enables tangible appreciation of cardiac anatomy and allows in vitro interventional device testing. 3D printing is used in diagnostic workup, guidance of treatment strategies, and procedural simulation, facilitating hemodynamic research, enhancing interventional training, and promoting patient-clinician communication. In this review, we attempt to define the concept, technique, and work flow of 3D printing in SHD and its interventions, highlighting the reported clinical benefits and unsolved issues, as well as exploring future developments in this field.

Three-Dimensional Printing Applications in Percutaneous Structural Heart Interventions

Cardiovascular 3-dimensional printing refers to the fabrication of patients’ specific cardiac anatomic replicas based on volumetric imaging data sets obtained by echocardiography, computed tomography, or magnetic resonance imaging. It enables advanced visualization and enhanced anatomic and sometimes hemodynamic understanding and also improves procedural planning and allows interventional simulation. Also, it is helpful in communication with patients and trainees. These key advantages have led to its broad use in the field of cardiology ranging from congenital to vascular and valvular disease, particularly in structural heart interventions, where many emerging technologies are being developed and tested. This review summarizes the process of 3-dimensional printing and the workflow from imaging acquisition to model generation and discusses the cardiac applications of 3-dimensional printing focusing on its use in percutaneous structural interventions, where procedural planning now commonly relies on 3-dimensional printed models.

3D Bioprinting of cardiac tissue and cardiac stem cell therapy

Cardiovascular tissue engineering endeavors to repair or regenerate damaged or ineffective blood vessels, heart valves, and cardiac muscle. Current strategies that aim to accomplish such a feat include the differentiation of multipotent or pluripotent stem cells on appropriately designed biomaterial scaffolds that promote the development of mature and functional cardiac tissue. The advent of additive manufacturing 3D bioprinting technology further advances the field by allowing heterogenous cell types, biomaterials, and signaling factors to be deposited in precisely organized geometries similar to those found in their native counterparts. Bioprinting techniques to fabricate cardiac tissue in vitro include extrusion, inkjet, laser-assisted, and stereolithography with bioinks that are either synthetic or naturally-derived. The article further discusses the current practices for postfabrication conditioning of 3D engineered constructs for effective tissue development and stability, then concludes with prospective points of interest for engineering cardiac tissues in vitro. Cardiovascular three-dimensional bioprinting has the potential to be translated into the clinical setting and can further serve to model and understand biological principles that are at the root of cardiovascular disease in the laboratory.

Using a 3D printer in cardiac valve surgery: a systematic review

BACKGROUND

The use of the 3D printer in complex cardiac surgery planning.

OBJECTIVES

To analyze the use and benefits of 3D printing in heart valve surgery through a systematic review of the literature.

METHODS

This systematic review was reported following the Preferred Reporting Items for Systematic Review and registered in the Prospero (International Prospective Register of Systematic Reviews) database under the number CRD42017059034. We used the following databases: PubMed, EMBASE, Scopus, Web of Science and Lilacs. We included articles about the keywords "Heart Valves", "Heart Valve Prosthesis Implantation", "Heart Valve Prosthesis", "Printing, Three-Dimensional", and related entry terms. Two reviewers independently conducted data extraction and a third reviewer solved disagreements. All tables used for data extraction are available at a separate website. We used the Cochrane Collaboration tool to assess the risk of bias of the studies included.

RESULTS

We identified 301 articles and 13 case reports and case series that met the inclusion criteria. Our studies included 34 patients aged from 3 months to 94 years.

CONCLUSIONS

Up to the present time, there are no studies including a considerable number of patients. A 3D-printed model produced based on the patient enables the surgeon to plan the surgical procedure and choose the best material, size, format, and thickness to be used. This planning leads to reduced surgery time, exposure, and consequently, lower risk of infection.

Living the heart in three dimensions: applications of 3D printing in CHD

Advances in biomedical engineering have led to three-dimensional (3D)-printed models being used for a broad range of different applications. Teaching medical personnel, communicating with patients and relatives, planning complex heart surgery, or designing new techniques for repair of CHD via cardiac catheterisation are now options available using patient-specific 3D-printed models. The management of CHD can be challenging owing to the wide spectrum of morphological conditions and the differences between patients. Direct visualisation and manipulation of the patients' individual anatomy has opened new horizons in personalised treatment, providing the possibility of performing the whole procedure in vitro beforehand, thus anticipating complications and possible outcomes. In this review, we discuss the workflow to implement 3D printing in clinical practice, the imaging modalities used for anatomical segmentation, the applications of this emerging technique in patients with structural heart disease, and its limitations and future directions.

MR Imaging-Histology Correlation by Tailored 3D-Printed Slicer in Oncological Assessment

3D printing and reverse engineering are innovative technologies that are revolutionizing scientific research in the health sciences and related clinical practice. Such technologies are able to improve the development of various custom-made medical devices while also lowering design and production costs. Recent advances allow the printing of particularly complex prototypes whose geometry is drawn from precise computer models designed on in vivo imaging data. This review summarizes a new method for histological sample processing (applicable to e.g., the brain, prostate, liver, and renal mass) which employs a personalized mold developed from diagnostic images through computer-aided design software and 3D printing. Through positioning the custom mold in a coherent manner with respect to the organ of interest (as delineated by in vivo imaging data), the cutting instrument can be precisely guided in order to obtain blocks of tissue which correspond with high accuracy to the slices imaged. This approach appeared crucial for validation of new quantitative imaging tools, for an accurate imaging-histopathological correlation and for the assessment of radiogenomic features extracted from oncological lesions. The aim of this review is to define and describe 3D printing technologies which are applicable to oncological assessment and slicer design, highlighting the radiological and pathological perspective as well as recent applications of this approach for the histological validation of and correlation with MR images.

3D modeling: a future of cardiovascular medicine

Cardiovascular disease resulting from atypical cardiac structures continues to be a leading health concern despite advancements in diagnostic imaging and surgical techniques. However, the ability to visualize spatial relationships using current technologies remains a challenge. Therefore, 3D modeling has gained significant interest to understand complex and atypical cardiovascular disorders. Moreover, 3D modeling can be personalized and patient-specific. 3D models have been demonstrated to aid surgical planning and simulation, enhance communication among surgeons and patients, optimize medical device design, and can be used as a potential teaching tool in medical schools. In this review, we discuss the key components needed to generate cardiac 3D models. We highlight prevalent structural conditions that have utilized 3D modeling in pre-operative planning. Furthermore, we discuss the current limitations of routine use of 3D models in the clinic as well as future directions for utilization of this technology in the cardiovascular field.

The accuracy of computed tomography scans for rapid prototyping of canine skulls

This study’s objective was to determine the accuracy of using current computed tomography (CT) scan and software techniques for rapid prototyping by quantifying the margin of error between CT models and laser scans of canine skull specimens. Twenty canine skulls of varying morphology were selected from an anatomy collection at a veterinary school. CT scans (bone and standard algorithms) were performed for each skull, and data segmented (testing two lower threshold settings of 226HU and -650HU) into 3-D CT models. Laser scans were then performed on each skull. The CT models were compared to the corresponding laser scan to determine the error generated from the different types of CT model parameters. This error was then compared between the different types of CT models to determine the most accurate parameters. The mean errors for the 226HU CT models, both bone and standard algorithms, were not significant from zero error (p = 0.1076 and p = 0.0580, respectively). The mean errors for both -650HU CT models were significant from zero error (p < 0.001). Significant differences were detected between CT models for 3 CT model comparisons: Bone (p < 0.0001); Standard (p < 0.0001); and -650HU (p < 0.0001). For 226HU CT models, a significant difference was not detected between CT models (p = 0.2268). Independent of the parameters tested, the 3-D models derived from CT imaging accurately represent the real skull dimensions, with CT models differing less than 0.42 mm from the real skull dimensions. The 226HU threshold was more accurate than the -650HU threshold. For the 226HU CT models, accuracy was not dependent on the CT algorithm. For the -650 CT models, bone was more accurate than standard algorithms. Knowing the inherent error of this procedure is important for use in 3-D printing for surgical planning and medical education.

Additive manufacturing applications in cardiology: A review

BACKGROUND

Additive manufacturing (AM) has emerged as a serious planning, strategy, and education tool in cardiovascular medicine. This review describes and illustrates the application, development and associated limitation of additive manufacturing in the field of cardiology by studying research papers on AM in medicine/cardiology.

METHODS

Relevant research papers till August 2018 were identified through Scopus and examined for strength, benefits, limitation, contribution and future potential of AM. With the help of the existing literature & bibliometric analysis, different applications of AM in cardiology are investigated.

RESULTS

AM creates an accurate three-dimensional anatomical model to explain, understand and prepare for complex medical procedures. A prior study of patient's 3D heart model can help doctors understand the anatomy of the individual patient, which may also be used create training modules for institutions and surgeons for medical training.

CONCLUSION

AM has the potential to be of immense help to the cardiologists and cardiac surgeons for intervention and surgical planning, monitoring and analysis. Additive manufacturing creates a 3D model of the heart of a specific patient in lesser time and cost. This technology is used to create and analyse 3D model before starting actual surgery on the patient. It can improve the treatment outcomes for patients, besides saving their lives. Paper summarised additive manufacturing applications particularly in the area of cardiology, especially manufacturing of a patient-specific artificial heart or its component. Model printed by this technology reduces risk, improves the quality of diagnosis and preoperative planning and also enhanced team communication. In cardiology, patient data of heart varies from patient to patient, so AM technologies efficiently produce 3D models, through converting the predesigned virtual model into a tangible object. Companies explore additive manufacturing for commercial medical applications.

Radiation Dose Reduction with a Low-Tube Voltage Technique for Pediatric Chest Computed Tomographic Angiography Based on the Contrast-to-Noise Ratio Index

Introduction

The aim of this study was to evaluate the radiation dose and image quality at low tube-voltage pediatric chest computed tomographic angiography (CTA) that applies the same contrast-to-noise ratio (CNR) index as the standard tube voltage technique.

Materials and Methods

Contrast-enhanced chest CTA scans of 100 infants were acquired on a 64-row multidetector computed tomography (MDCT) scanner. In the retrospective study, we evaluated 50 images acquired at 120 kVp; the image noise level was set at 25 Hounsfield units. In the prospective study, we used an 80-kVp protocol; the image noise level was 40 Hounsfield units because the iodine contrast was 1.6 times higher than on 120-kVp scans; the CNR was as in the 120-kVp protocol. We compared the CT number, image noise, CT dose index volume (CTDIvol), and the dose-length product on scans acquired with the 2 protocols. A diagnostic radiologist and a pediatric cardiologist visually evaluated all CTA images.

Results

The mean CTDIvol and the mean dose-length product were 0.5 mGy and 7.8 mGy-cm for 80- and 1.2 mGy and 20.8 mGy-cm for 120-kVp scans, respectively ( P < .001). The mean CTDIvol was 42% lower at 80 kVp than at 120 kVp, and there was no significant difference in the visual scores assigned to the CTA images ( P = .28).

Conclusions

With the CNR index being the same at 80-kVp and 120-kVp imaging, the radiation dose delivered to infants subjected to chest CTA can be reduced without degradation of the image quality.

Novel, 3D Display of Heart Models in the Postoperative Care Setting Improves CICU Caregiver Confidence

BACKGROUND

Postoperative care delivered in the pediatric cardiac intensive care unit (CICU) relies on providers' understanding of patients' congenital heart defects (CHDs) and procedure performed. Novel, bedside use of virtual, three-dimensional (3D) heart models creates access to patients' CHD to improve understanding. This study evaluates the impact of patient-specific virtual 3D heart models on CICU provider attitudes and care delivery.

METHODS

Virtual 3D heart models were created from standard preoperative cardiac imaging of ten patients with CHD undergoing repair and displayed on a bedside tablet in the CICU. Providers completed a Likert questionnaire evaluating the models' value in understanding anatomy and improving care delivery. Responses were compared using two-tailed t test and Mann-Whitney U test and were also compared to previously collected CICU provider responses regarding use of printed 3D heart models.

RESULTS

Fifty-three clinicians (19 physicians, 34 nurses/trainees) participated; 49 (92%) of 53 and 44 (83%) of 53 reported at least moderate to high satisfaction with the virtual 3D heart's ability to enhance understanding of anatomy and surgical repair, respectively. Seventy-one percent of participants felt strongly that virtual 3D models improved their ability to manage postoperative problems. The majority of both groups (63% physicians, 53% nurses) felt that virtual 3D heart models improved CICU handoffs. Virtual 3D heart models were as effective as printed models in improving understanding and care delivery, with a noted provider preference for printed 3D heart models.

CONCLUSIONS

Virtual 3D heart models depicting patient-specific CHDs are perceived to improve understanding and postoperative care delivery in the CICU.

3D printing for preoperative planning and surgical training: a review

Surgeons typically rely on their past training and experiences as well as visual aids from medical imaging techniques such as magnetic resonance imaging (MRI) or computed tomography (CT) for the planning of surgical processes. Often, due to the anatomical complexity of the surgery site, two dimensional or virtual images are not sufficient to successfully convey the structural details. For such scenarios, a 3D printed model of the patient's anatomy enables personalized preoperative planning. This paper reviews critical aspects of 3D printing for preoperative planning and surgical training, starting with an overview of the process-flow and 3D printing techniques, followed by their applications spanning across multiple organ systems in the human body. State of the art in these technologies are described along with a discussion of current limitations and future opportunities.

Printed MDCT 3D models for prediction of left atrial appendage (LAA) occluder device size: a feasibility study

AIMS

Transoesophageal echocardiography (TEE) and multidetector computed tomography (MDCT) currently serve as imaging modalities for left atrial appendage (LAA) occlusion preprocedural planning. We assessed the feasibility of MDCT-based models to predict the correct size of device for LAA occlusion procedures.

METHODS AND RESULTS

Patients planned for LAA occlusion underwent MDCT before implantation, which was used for creating and printing 3D LAA models. Three cardiologists evaluated the 3D models and predicted the correct size of the device by manual manipulation. These predictions were compared with the actual device implanted during the procedure. Twenty-nine patients were included in this study. AMPLATZER and WATCHMAN devices were deployed in 12 and 17 patients, respectively. Two procedures were aborted due to failure of occlusion; all three physicians predicted it. There was good correlation between the 3D models and the inserted device for AMPLATZER devices with a concordance correlation coefficient of 0.778 (p=0.001) and poor agreement for WATCHMAN devices - concordance correlation coefficient of 0.315 (p=0.203). Agreement among the three physicians for AMPLATZER and WATCHMAN devices was excellent, with a calculated average intra-class correlation of 0.915 and 0.816, respectively.

CONCLUSIONS

We found LAA printed 3D models to be accurate for prediction of LAA occluder device size for the AMPLATZER device but not for the WATCHMAN device.

3D printing of normal and pathologic tricuspid valves from transthoracic 3D echocardiography data sets

Aims

To explore the feasibility of using transthoracic 3D echocardiography (3DTTE) data to generate 3D patient-specific models of tricuspid valve (TV).

Methods and Results

Multi-beat 3D data sets of the TV (32 vol/s) were acquired in five subjects with various TV morphologies from the apical approach and analysed offline with custom-made software. Coordinates representing the annulus and the leaflets were imported into MeshLab (Visual Computing Lab ISTICNR) to develop solid models to be converted to stereolithographic file format and 3D print. Measurements of the TV annulus antero-posterior (AP) and medio-lateral (ML) diameters, perimeter (P), and TV tenting height (H) and volume (V) obtained from the 3D echo data set were compared with those performed on the 3D models using a caliper, a syringe and a millimeter tape. Antero-posterior (4.2 ± 0.2 cm vs. 4.2 ± 0 cm), ML (3.7 ± 0.2 cm vs. 3.6 ± 0.1 cm), P (12.6 ± 0.2 cm vs. 12.7 ± 0.1 cm), H (11.2 ± 2.1 mm vs. 10.8 ± 2.1 mm) and V (3.0 ± 0.6 ml vs. 2.8 ± 1.4 ml) were similar (P = NS for all) when measured on the 3D data set and the printed model. The two sets of measurements were highly correlated (r = 0.991). The mean absolute error (2D - 3D) for AP, ML, P and tenting H was 0.7 ± 0.3 mm, indicating accuracy of the 3D model of <1 mm.

Conclusion

Three-dimensional printing of the TV from 3DTTE data is feasible with highly conserved fidelity. This technique has the potential for rapid integration into clinical practice to assist with decision-making, surgical planning, and teaching.

Applying 3D prints to reconstructing postmortem craniofacial features damaged by devastating head injuries

Postmortem facial identification is one of the most common techniques for establishing a deceased person's identity. In victims suffering from devastating cranial injuries, the feasibility of facial identification tasks can be compromised by damage to or disfigurement of the identifying cranial features. Although there are several reconstructive approaches, which help experts to restore the essence of person's physical appearance, thus enhancing the chances of recognition, only a few of them involve restoring the fractured cranial bones as the foundation for the reconstructed soft tissues. Here, we propose a technique based on replacement of heavily damaged hard tissues with generic prosthetics manufactured by 3D printing. Our approach does not require medical imaging technologies or other costly lab equipment. It is simple, affordable and relatively labor-efficient. The deceased's reconstructed craniofacial features can be subsequently assessed, photographed, drawn or otherwise reproduced in order to help determine his or her identity. In addition, the imagery can be displayed, published or broadcasted in media without concerns of being overly graphic.

The Various Applications of 3D Printing in Cardiovascular Diseases

PURPOSE OF REVIEW

To highlight the various applications of 3D printing in cardiovascular disease and discuss its limitations and future direction.

RECENT FINDINGS

Use of handheld 3D printed models of cardiovascular structures has emerged as a facile modality in procedural and surgical planning as well as education and communication. Three-dimensional (3D) printing is a novel imaging modality which involves creating patient-specific models of cardiovascular structures. As percutaneous and surgical therapies evolve, spatial recognition of complex cardiovascular anatomic relationships by cardiologists and cardiovascular surgeons is imperative. Handheld 3D printed models of cardiovascular structures provide a facile and intuitive road map for procedural and surgical planning, complementing conventional imaging modalities. Moreover, 3D printed models are efficacious educational and communication tools. This review highlights the various applications of 3D printing in cardiovascular diseases and discusses its limitations and future directions.

Clinical 3D printing: A protected health information (PHI) and compliance perspective

Advanced manufacturing techniques such as 3-dimensional (3D) printing, while mature in other industries, are starting to become more commonplace in clinical care. Clinicians are producing physical objects based on patient clinical data for use in planning care and educating patients, all of which should be managed like any other healthcare system data, except it exists in the "real" world. There are currently no provisions in the Health Insurance Portability and Accountability Act (HIPAA) either in its original 1996 form or in more recent updates that address the nature of physical representations of clinical data. We submit that if we define the source data as protected health information (PHI), then the objects 3D printed from that data need to be treated as both (PHI), and if used clinically, part of the clinical record, and propose some basic guidelines for quality and privacy like all documentation until regulatory frameworks can catch up to this technology. Many of the mechanisms designed in the paper and film chart era will work well with 3D printed patient data.

Recent advances in cardiac catheterization for congenital heart disease

The field of pediatric and adult congenital cardiac catheterization has evolved rapidly in recent years. This review will focus on some of the newer endovascular technological and management strategies now being applied in the pediatric interventional laboratory. Emerging imaging techniques such as three-dimensional (3D) rotational angiography, multi-modal image fusion, 3D printing, and holographic imaging have the potential to enhance our understanding of complex congenital heart lesions for diagnostic or interventional purposes. While fluoroscopy and standard angiography remain procedural cornerstones, improved equipment design has allowed for effective radiation exposure reduction strategies. Innovations in device design and implantation techniques have enabled the application of percutaneous therapies in a wider range of patients, especially those with prohibitive surgical risk. For example, there is growing experience in transcatheter duct occlusion in symptomatic low-weight or premature infants and stent implantation into the right ventricular outflow tract or arterial duct in cyanotic neonates with duct-dependent pulmonary circulations. The application of percutaneous pulmonary valve implantation has been extended to a broader patient population with dysfunctional ‘native’ right ventricular outflow tracts and has spurred the development of novel techniques and devices to solve associated anatomic challenges. Finally, hybrid strategies, combining cardiosurgical and interventional approaches, have enhanced our capabilities to provide care for those with the most complex of lesions while optimizing efficacy and safety.

An open source, 3D printed preclinical MRI phantom for repeated measures of contrast agents and reference standards

In medical imaging, clinicians, researchers and technicians have begun to use 3D printing to create specialized phantoms to replace commercial ones due to their customizable and iterative nature. Presented here is the design of a 3D printed open source, reusable magnetic resonance imaging (MRI) phantom, capable of flood-filling, with removable samples for measurements of contrast agent solutions and reference standards, and for use in evaluating acquisition techniques and image reconstruction performance. The phantom was designed using SolidWorks, a computer-aided design software package. The phantom consists of custom and off-the-shelf parts and incorporates an air hole and Luer Lock system to aid in flood filling, a marker for orientation of samples in the filled mode and bolt and tube holes for assembly. The cost of construction for all materials is under $90. All design files are open-source and available for download. To demonstrate utility, B₀ field mapping was performed using a series of gadolinium concentrations in both the unfilled and flood-filled mode. An excellent linear agreement (R²>0.998) was observed between measured relaxation rates (R₁/R₂) and gadolinium concentration. The phantom provides a reliable setup to test data acquisition and reconstruction methods and verify physical alignment in alternative nuclei MRI techniques (e.g. carbon-13 and fluorine-19 MRI). A cost-effective, open-source MRI phantom design for repeated quantitative measurement of contrast agents and reference standards in preclinical research is presented. Specifically, the work is an example of how the emerging technology of 3D printing improves flexibility and access for custom phantom design.