Three-dimensional printing of a complex CHD to plan surgical repair

Clinical situations for which 3D printing is considered an appropriate representation or extension of data contained in a medical imaging examination: pediatric congenital heart disease conditions

BACKGROUND

The use of medical 3D printing (focusing on anatomical modeling) has continued to grow since the Radiological Society of North America's (RSNA) 3D Printing Special Interest Group (3DPSIG) released its initial guideline and appropriateness rating document in 2018. The 3DPSIG formed a focused writing group to provide updated appropriateness ratings for 3D printing anatomical models across a variety of congenital heart disease. Evidence-based- (where available) and expert-consensus-driven appropriateness ratings are provided for twenty-eight congenital heart lesion categories.

METHODS

A structured literature search was conducted to identify all relevant articles using 3D printing technology associated with pediatric congenital heart disease indications. Each study was vetted by the authors and strength of evidence was assessed according to published appropriateness ratings.

RESULTS

Evidence-based recommendations for when 3D printing is appropriate are provided for pediatric congenital heart lesions. Recommendations are provided in accordance with strength of evidence of publications corresponding to each cardiac clinical scenario combined with expert opinion from members of the 3DPSIG.

CONCLUSIONS

This consensus appropriateness ratings document, created by the members of the RSNA 3DPSIG, provides a reference for clinical standards of 3D printing for pediatric congenital heart disease clinical scenarios.

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.

3D Printed Cardiac Models as an Adjunct to Traditional Teaching of Anatomy in Congenital Heart Disease-A Randomised Controlled Study

INTRODUCTION

Three-dimensional (3D) printed cardiac models are increasingly being used for medical education, simulation and training, communication, surgical planning and research. Given the complexities of congenital cardiac anatomy, 3D printing is well suited as an adjunct to traditional teaching methods. This study aims to explore the influence of 3D printed cardiac models as a teaching aid for nurses and paediatric trainees. We hypothesise that using 3D models as an adjunct to didactic teaching methods improves knowledge and confidence levels of participants, regardless of their cardiology experience.

METHOD

A prospective randomised study was performed recruiting paediatric nurses and doctors at a tertiary paediatric hospital. All participants undertook traditional congenital cardiac teaching describing normal cardiac anatomy and seven congenital lesions of increasing complexity (atrial septal defect, ventricular septal defect, vascular ring, partial anomalous pulmonary venous return, tetralogy of Fallot, transposition of the great arteries, and double outlet right ventricle). The intervention group received an additional recorded demonstration while handling 3D printed models of a normal heart and the same lesions. Pre- and post-intervention assessments were completed using a subjective Likert-scale questionnaire and objective multiple-choice examination.

RESULTS

A total of 73 health practitioners (30 cardiac nurses and 43 paediatric trainees) were included. Subjective knowledge and confidence levels substantially improved in the intervention group (both p<0.001), with no differences observed in the control group. Greater improvement in both subjective and objective post-test scores was observed in the intervention group. A pronounced difference between pre- and post-teaching objective examination scores was found in both groups (p=0.002), with larger improvements observed in the intervention group. The mean score in the intervention group after teaching increased by 4.27 (21.4% improvement), as opposed to 2.28 (11.4% improvement) in the control group. There was no difference in pre-test score or post-test improvement based on previous cardiology experience.

DISCUSSION

Three-dimensional (3D) printed cardiac models, when used as an adjunct to traditional teaching methods, substantially improve knowledge and confidence levels of health professionals on a range of congenital cardiac lesions. These models enhance the learners' educational experience and understanding of cardiac anatomy by overcoming the limitation of two-dimensional representations of 3D structures.

Optimized preoperative planning of double outlet right ventricle patients by 3D printing and virtual reality: a pilot study

OBJECTIVES

In complex double outlet right ventricle (DORV) patients, the optimal surgical approach may be difficult to assess based on conventional 2-dimensional (2D) ultrasound (US) and computed tomography (CT) imaging. The aim of this study is to assess the added value of 3-dimensional (3D) printed and 3D virtual reality (3D-VR) models of the heart used for surgical planning in DORV patients, supplementary to the gold standard 2D imaging modalities.

METHODS

Five patients with different DORV subtypes and high-quality CT scans were selected retrospectively. 3D prints and 3D-VR models were created. Twelve congenital cardiac surgeons and paediatric cardiologists, from 3 different hospitals, were shown 2D-CT first, after which they assessed the 3D print and 3D-VR models in random order. After each imaging method, a questionnaire was filled in on the visibility of essential structures and the surgical plan.

RESULTS

Spatial relationships were generally better visualized using 3D methods (3D printing/3D-VR) than in 2D. The feasibility of ventricular septum defect patch closure could be determined best using 3D-VR reconstructions (3D-VR 92%, 3D print 66% and US/CT 46%, P < 0.01). The percentage of proposed surgical plans corresponding to the performed surgical approach was 66% for plans based on US/CT, 78% for plans based on 3D printing and 80% for plans based on 3D-VR visualization.

CONCLUSIONS

This study shows that both 3D printing and 3D-VR have additional value for cardiac surgeons and cardiologists over 2D imaging, because of better visualization of spatial relationships. As a result, the proposed surgical plans based on the 3D visualizations matched the actual performed surgery to a greater extent.

Feasibility and accuracy of printed models of complex cardiac defects in small infants from cardiac computed tomography

BACKGROUND

Three-dimensional (3-D) printed models are increasingly used to enhance understanding of complex anatomy in congenital heart disease.

OBJECTIVE

To assess feasibility and accuracy of 3-D printed models obtained from cardiac CT scans in young children with complex congenital heart diseases.

MATERIALS AND METHODS

We included children with conotruncal heart anomalies who were younger than 2 years and had a cardiac CT scan in the course of their follow-up. We used cardiac CT scan datasets to generate 3-D models. To assess the models' accuracy, we compared four diameters for each child between the CT images and the printed models, including the largest diameters (D_max) of ventricular septal defects and aortic annulus and their minimal diameters (D_min).

RESULTS

We obtained images from 14 children with a mean age of 5.5 months (range 1-24 months) and a mean weight of 6.7 kg (range 3.4-14.5 kg). We generated 3-D models for all children. Mean measurement difference between CT images and 3-D models was 0.13 mm for D_min and 0.12 mm for D_max for ventricular septal defect diameters, and it was 0.16 mm for D_min and -0.13 mm for D_max for aortic annulus diameter, indicating a non-clinically significant difference.

CONCLUSION

Three-dimensional printed models could be feasibly generated from cardiac CT scans in a small pediatric population with complex congenital heart diseases. This technique is highly accurate and reliably reflects the same structural dimensions when compared to CT source images.

Three-dimensional printing in medicine: a systematic review of pediatric applications

BACKGROUND

Three-dimensional printing (3DP) addresses distinct clinical challenges in pediatric care including: congenital variants, compact anatomy, high procedural risk, and growth over time. We hypothesized that patient-specific applications of 3DP in pediatrics could be categorized into concise, discrete categories of use.

METHODS

Terms related to "three-dimensional printing" and "pediatrics" were searched on PubMed, Scopus, Ovid MEDLINE, Cochrane CENTRAL, and Web of Science. Initial search yielded 2122 unique articles; 139 articles characterizing 508 patients met full inclusion criteria.

RESULTS

Four categories of patient-specific 3DP applications were identified: Teaching of families and medical staff (9.3%); Developing intervention strategies (33.9%); Procedural applications, including subtypes: contour models, guides, splints, and implants (43.0%); and Material manufacturing of shaping devices or prosthetics (14.0%). Procedural comparative studies found 3DP devices to be equivalent or better than conventional methods, with less operating time and fewer complications.

CONCLUSION

Patient-specific applications of Three-Dimensional Printing in Medicine can be elegantly classified into four major categories: Teaching, Developing, Procedures, and Materials, sharing the same TDPM acronym. Understanding this schema is important because it promotes further innovation and increased implementation of these devices to improve pediatric care.

IMPACT

This article classifies the pediatric applications of patient-specific three-dimensional printing. This is a first comprehensive review of patient-specific three-dimensional printing in both pediatric medical and surgical disciplines, incorporating previously described classification schema to create one unifying paradigm. Understanding these applications is important since three-dimensional printing addresses challenges that are uniquely pediatric including compact anatomy, unique congenital variants, greater procedural risk, and growth over time. We identified four classifications of patient-specific use: teaching, developing, procedural, and material uses. By classifying these applications, this review promotes understanding and incorporation of this expanding technology to improve the pediatric care.

Three-dimensional printing in radiation oncology: A systematic review of the literature

Purpose/objectives

Three‐dimensional (3D) printing is recognized as an effective clinical and educational tool in procedurally intensive specialties. However, it has a nascent role in radiation oncology. The goal of this investigation is to clarify the extent to which 3D printing applications are currently being used in radiation oncology through a systematic review of the literature.

Materials/methods

A search protocol was defined according to preferred reporting items for systematic reviews and meta‐analyses (PRISMA) guidelines. Included articles were evaluated using parameters of interest including: year and country of publication, experimental design, sample size for clinical studies, radiation oncology topic, reported outcomes, and implementation barriers or safety concerns.

Results

One hundred and three publications from 2012 to 2019 met inclusion criteria. The most commonly described 3D printing applications included quality assurance phantoms (26%), brachytherapy applicators (20%), bolus (17%), preclinical animal irradiation (10%), compensators (7%), and immobilization devices (5%). Most studies were preclinical feasibility studies (63%), with few clinical investigations such as case reports or series (13%) or cohort studies (11%). The most common applications evaluated within clinical settings included brachytherapy applicators (44%) and bolus (28%). Sample sizes for clinical investigations were small (median 10, range 1–42). A minority of articles described basic or translational research (11%) and workflow or cost evaluation studies (3%). The number of articles increased over time (P < 0.0001). While outcomes were heterogeneous, most studies reported successful implementation of accurate and cost‐effective 3D printing methods.

Conclusions

Three‐dimensional printing is rapidly growing in radiation oncology and has been implemented effectively in a diverse array of applications. Although the number of 3D printing publications has steadily risen, the majority of current reports are preclinical in nature and the few clinical studies that do exist report on small sample sizes. Further dissemination of ongoing investigations describing the clinical application of developed 3D printing technologies in larger cohorts is warranted.

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.

Quantitative and qualitative comparison of low- and high-cost 3D-printed heart models

Current visualization techniques of complex congenital heart disease (CHD) are unable to provide comprehensive visualization of the anomalous cardiac anatomy as the medical datasets can essentially only be viewed from a flat, two-dimensional (2D) screen. Three-dimensional (3D) printing has therefore been used to replicate patient-specific hearts in 3D views based on medical imaging datasets. This technique has been shown to have a positive impact on the preoperative planning of corrective surgery, patient-doctor communication, and the learning experience of medical students. However, 3D printing is often costly, and this impedes the routine application of this technology in clinical practice. This technical note aims to investigate whether reducing 3D printing costs can have any impact on the clinical value of the 3D-printed heart models. Low-cost and a high-cost 3D-printed models based on a selected case of CHD were generated with materials of differing cost. Quantitative assessment of dimensional accuracy of the cardiac anatomy and pathology was compared between the 3D-printed models and the original cardiac computed tomography (CT) images with excellent correlation (r=0.99). Qualitative evaluation of model usefulness showed no difference between the two models in medical applications.

Radiological Society of North America (RSNA) 3D printing Special Interest Group (SIG): guidelines for medical 3D printing and appropriateness for clinical scenarios

Medical three-dimensional (3D) printing has expanded dramatically over the past three decades with growth in both facility adoption and the variety of medical applications. Consideration for each step required to create accurate 3D printed models from medical imaging data impacts patient care and management. In this paper, a writing group representing the Radiological Society of North America Special Interest Group on 3D Printing (SIG) provides recommendations that have been vetted and voted on by the SIG active membership. This body of work includes appropriate clinical use of anatomic models 3D printed for diagnostic use in the care of patients with specific medical conditions. The recommendations provide guidance for approaches and tools in medical 3D printing, from image acquisition, segmentation of the desired anatomy intended for 3D printing, creation of a 3D-printable model, and post-processing of 3D printed anatomic models for patient care.

Three-dimensional printing in congenital heart disease: A systematic review

Three-dimensional (3D) printing has shown great promise in medicine with increasing reports in congenital heart disease (CHD). This systematic review aims to analyse the main clinical applications and accuracy of 3D printing in CHD, as well as to provide an overview of the software tools, time and costs associated with the generation of 3D printed heart models. A search of different databases was conducted to identify studies investigating the application of 3D printing in CHD. Studies based on patient's medical imaging datasets were included for analysis, while reports on in vitro phantom or review articles were excluded from the analysis. A total of 28 studies met selection criteria for inclusion in the review. More than half of the studies were based on isolated case reports with inclusion of 1-12 cases (61%), while 10 studies (36%) focused on the survey of opinion on the usefulness of 3D printing by healthcare professionals, patients, parents of patients and medical students, and the remaining one involved a multicentre study about the clinical value of 3D printed models in surgical planning of CHD. The analysis shows that patient-specific 3D printed models accurately replicate complex cardiac anatomy, improve understanding and knowledge about congenital heart diseases and demonstrate value in preoperative planning and simulation of cardiac or interventional procedures, assist surgical decision-making and intra-operative orientation, and improve patient-doctor communication and medical education. The cost of 3D printing ranges from USD 55 to USD 810. This systematic review shows the usefulness of 3D printed models in congenital heart disease with applications ranging from accurate replication of complex cardiac anatomy and pathology to medical education, preoperative planning and simulation. The additional cost and time required to manufacture the 3D printed models represent the limitations which need to be addressed in future studies.

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.

3D Printing is a Transformative Technology in Congenital Heart Disease

Survival in congenital heart disease has steadily improved since 1938, when Dr. Robert Gross successfully ligated for the first time a patent ductus arteriosus in a 7-year-old child. To continue the gains made over the past 80 years, transformative changes with broad impact are needed in management of congenital heart disease. Three-dimensional printing is an emerging technology that is fundamentally affecting patient care, research, trainee education, and interactions among medical teams, patients, and caregivers. This paper first reviews key clinical cases where the technology has affected patient care. It then discusses 3-dimensional printing in trainee education. Thereafter, the role of this technology in communication with multidisciplinary teams, patients, and caregivers is described. Finally, the paper reviews translational technologies on the horizon that promise to take this nascent field even further.

Clinical value of patient-specific three-dimensional printing of congenital heart disease: Quantitative and qualitative assessments

Objective

Current diagnostic assessment tools remain suboptimal in demonstrating complex morphology of congenital heart disease (CHD). This limitation has posed several challenges in preoperative planning, communication in medical practice, and medical education. This study aims to investigate the dimensional accuracy and the clinical value of 3D printed model of CHD in the above three areas.

Methods

Using cardiac computed tomography angiography (CCTA) data, a patient-specific 3D model of a 20-month-old boy with double outlet right ventricle was printed in Tango Plus material. Pearson correlation coefficient was used to evaluate correlation of the quantitative measurements taken at analogous anatomical locations between the CCTA images pre- and post-3D printing. Qualitative analysis was conducted by distributing surveys to six health professionals (two radiologists, two cardiologists and two cardiac surgeons) and three medical academics to assess the clinical value of the 3D printed model in these three areas.

Results

Excellent correlation (r = 0.99) was noted in the measurements between CCTA and 3D printed model, with a mean difference of 0.23 mm. Four out of six health professionals found the model to be useful in facilitating preoperative planning, while all of them thought that the model would be invaluable in enhancing patient-doctor communication. All three medical academics found the model to be helpful in teaching, and thought that the students will be able to learn the pathology quicker with better understanding.

Conclusion

The complex cardiac anatomy can be accurately replicated in flexible material using 3D printing technology. 3D printed heart models could serve as an excellent tool in facilitating preoperative planning, communication in medical practice, and medical education, although further studies with inclusion of more clinical cases are needed.