Multimodality 3-dimensional image integration for congenital cardiac catheterization

Pulmonary Artery Stent Implantation

Pulmonary artery stent implantation has become integral in the treatment of pulmonary artery stenosis and is probably the most efficacious therapy for these lesions. Advancements in technology involving stent design and the equipment used for stent delivery have made this procedure much safer and more effective. Strategies to mitigate and successfully treat adverse events related to pulmonary artery stent implantation are reasonably well-established. Pulmonary artery stent implantation remains one of the most complex and technically challenging of congenital cardiac interventions.

Multimodality 3D image fusion with live fluoroscopy reduces radiation dose during catheterization of congenital heart defects

Introduction

Imaging fusion technology is promising as it is radiation and contrast sparing. Herein, we compare conventional biplane angiography to multimodality image fusion with live fluoroscopy using two-dimensional (2D)-three-dimensional (3D) registration (MMIF2D-3D) and assess MMIF2D-3D impact on radiation exposure and contrast volume during cardiac catheterization of patients with congenital heart disease (CHD).

Methods

We matched institutional MMIF2D-3D procedures and controls according to patient characteristics (body mass index, age, and gender) and the seven procedure-type subgroups. Then, we matched the number of tests and controls per subgroup using chronological ordering or propensity score matching. Subsequently, we combined the matched subgroups into larger subgroups of similar procedure type, keeping subgroups with at least 10 test and 10 control cases. Air kerma (AK) and dose area product (DAP) were normalized by body weight (BW), product of body weight and fluoroscopy time (BW × FT), or product of body weight and number of frames (BW × FR), and stratified by acquisition plane and irradiation event type (fluoroscopy or acquisition). Three senior interventionists evaluated the relevance of MMIF2D-3D (5-point Likert scale).

Results

The Overall group consisted of 54 MMIF2D-3D cases. The combined and matched subgroups were pulmonary artery stenting (StentPUL), aorta angioplasty (PlastyAO), pulmonary artery angioplasty (PlastyPUL), or a combination of the latter two (Plasty). The FT of the lateral plane reduced significantly by 69.6% for the Overall MMIF2D-3D population. AKBW and DAPBW decreased, respectively, by 43.9% and 39.3% (Overall group), 49.3% and 54.9% (PlastyAO), and 36.7% and 44.4% for the Plasty subgroup. All the aforementioned reductions were statistically significant except for DAPBW in the Overall and Plasty (sub)groups. The decrease of AKBW and DAPBW in the StentPUL and PlastyPUL subgroups was not statistically significant. The decrease in the median values of the weight-normalized contrast volume (CMCBW) in all five subgroups was not significant. Cardiologists considered MMIF2D-3D very useful with a median score of 4.

Conclusion

In our institution, MMIF2D-3D overall enabled significant AKBW reduction during the catheterization of CHD patients and was mainly driven by reduced FT in the lateral plane. We observed significant AKBW reduction in the Plasty and PlastyAO subgroups and DAPBW reduction in the PlastyAO subgroup. However, the decrease in CMCBW was not significant.

Novel Approaches to the Failing Congenital Heart

PURPOSE OF REVIEW

Heart failure is the leading cause of morbidity and mortality in adults with congenital heart disease and is characterized by a variety of underlying mechanisms. Here, we aim to elaborate on the medical and technological advancements in the management of heart failure in adult patients with congenital heart disease and highlight the use of imaging modalities to guide therapy.

RECENT FINDINGS

There have been several advances over the past decade with angiotensin receptor neprilysin and sodium-glucose cotransporter-2 inhibitors, atrioventricular valve clips, transcatheter pulmonary valves, catheter ablation, and cardiac resynchronization therapy, as well as the introduction of lymphatic interventions. Expanded use of echocardiography, cardiac magnetic resonance imaging, and cardiac computed tomography has guided many of these therapies. Significant innovations in the management of heart failure in adults with congenital heart disease have evolved with advancements in imaging modalities playing a critical role in guiding treatment therapies.

Augmented Reality Visualization of 3D Rotational Angiography in Congenital Heart Disease: A Comparative Study to Standard Computer Visualization

Augmented reality (AR) visualization of 3D rotational angiography (3DRA) provides 3D representations of cardiac structures with full visualization of the procedural environment. The purpose of this study was to evaluate the feasibility of converting 3DRAs of congenital heart disease patients to AR models, highlight the workflow for 3DRA optimization for AR visualization, and assess physicians' perceptions of their use. This single-center study prospectively evaluated 30 retrospectively-acquired 3DRAs that were converted to AR, compared to Computer Models (CM). Median patient age 6.5 years (0.24-38.8) and weight 20.6 kg (3.4-107.0). AR and CM quality were graded highly. RV pacing was associated with higher quality of both model types (p = 0.02). Visualization and identification of structures were graded as "very easy" in 81.1% (n = 73) and 67.8% (n = 61) of AR and CM, respectively. Fifty-nine (66%) grades 'Agreed' or 'Strongly Agreed' that AR models provided superior appreciation of 3D relationships; AR was found to be least beneficial in visualization of aortic arch obstruction. AR models were thought to be helpful in identifying pathology and assisting in interventional planning in 85 assessments (94.4%). There was significant potential seen in the opportunity for patient/family counseling and trainee/staff education with AR models. It is feasible to convert 3D models of 3DRAs into AR models, which are of similar image quality as compared to CM. AR models provided additional benefits to visualization of 3D relationships in most anatomies. Future directions include integration of interventional simulation, peri-procedural counseling of patients and families, and education of trainees and staff with AR models.

Use of a mixed reality system for navigational mapping during cardiac electrophysiological testing does not prolong case duration: A subanalysis from the Cardiac Augmented REality study

Background

CommandEP™ is a mixed reality (MXR) system for cardiac electrophysiological (EP) procedures that provides a real-time 3-dimensional digital image of cardiac geometry and catheter locations. In a previous study, physicians using the system demonstrated improved navigational accuracy. This study investigated the impact of the CommandEP system on EP procedural times compared to the standard-of-care electroanatomic mapping system (EAMS) display.

Objective

The purpose of this retrospective case-controlled analysis was to evaluate the impact of a novel MXR interface on EP procedural times compared to a case-matched cohort.

Methods

Cases from the Cardiac Augmented REality (CARE) study were matched for diagnosis and weight using a contemporary cohort. Procedural time was compared from the roll-in and full implementation cohort. During routine EP procedures, operators performed tasks during the postablation waiting phase, including creation of cardiac geometry and 5-point navigation under 2 conditions: (1) EAMS first; and (2) CommandEP.

Results

From a total of 16 CARE study patients, the 10 full implementation patients were matched to a cohort of 20 control patients (2 controls:1 CARE, matched according to pathology and age/weight). No statistical difference in total case times between CARE study patients vs control group (118 ± 29 minutes vs 97 ± 20 minutes; P = .07) or fluoroscopy times (6 ± 4 minutes vs 7 ± 6 minutes; P = .9). No significant difference in case duration for CARE study patients comparing roll-in vs full-implementation cohort (121 ± 26 minutes vs 118 ± 29 minutes; P = .96). CommandEP wear time during cases was significantly longer in full implementation cases (53 ± 24 minutes vs 24 ± 5 minutes; P = .0009). During creation of a single cardiac geometry, no significant time difference was noted between CommandEP vs EAMS (284 ± 45 seconds vs 268 ± 43 seconds; P = .1) or fluoroscopy use (9 ± 19 seconds vs 6 ± 18 seconds; P = .25). During point navigation tasks, there was no difference in total time (CommandEP 31 ± 14 seconds vs EAMS 28 ± 15 seconds; P = .16) or fluoroscopy time (CommandEP 0 second vs EAMS 0 second).

Conclusion

MXR did not prolong overall procedural time compared to a matched cohort. There was no prolongation in study task completion time. Future studies with experienced CommandEP users directly assessing procedural time and task completion time in a randomized study population would be of interest.

Cinematic versus volume rendered imaging for the depiction of complex congenital heart disease

INTRODUCTION

Planning for surgical intervention for patients with complex congenital heart disease requires a comprehensive understanding of the individual's anatomy. Cinematic rendering (CR) is a novel technique that purportedly builds on traditional volume rendering (VR) by converting CT image data into clearly defined 3D reconstructions through the stimulation and propagation of light rays. The purpose of this study was to compare CR to VR for the understanding of critical anatomy in unoperated complex congenital heart disease.

METHODS

In this retrospective study, CT data sets from 20 sequential scanned cases of unoperated paediatric patients with complex congenital heart disease were included. 3D images were produced at standardised and selected orientations, matched for both VR and CR. The images were then independently reviewed by two cardiologists, two radiologists and two surgeons for overall image quality, depth perception and the visualisation of surgically relevant anatomy, the coronary arteries and the pulmonary veins.

RESULTS

Cinematic rendering demonstrated significantly superior image quality, depth perception and visualisation of surgically relevant anatomy than VR.

CONCLUSION

Cinematic rendering is a novel 3D CT-rendering technique that may surpass the traditionally used volumetric rendering technique in the provision of actionable pre-operative anatomical detail for complex congenital heart disease.

Optimizing 3D Rotational Angiography for Congenital Cardiac Catheterization

The aim of the study was to determine the variables associated with high-quality (HQ) versus low-quality (LQ) three-dimensional rotational angiography (3DRA) and create guides for optimization of approach to 3DRA in congenital cardiac catheterization (CCC). CCC has adopted 3DRA as a mainstay, but there has not been systematic analysis of approach to and factors associated with HQ 3DRA. This was a single-center, retrospective study of 3DRAs using Canon Infinix-I platform. Reconstructions were graded by 3 interventionalists. Quality was dichotomized into HQ and LQ. Univariable analyses and multivariable logistic regression models were performed. From 8/2016 to 12/2018, 208 3DRAs were performed in 195 CCCs; median age 7 years (2, 16), weight 23 kg (12, 57). The majority of 3DRAs were performed in patients with biventricular physiology (N = 137, 66%) and in pulsatile sites (N = 144, 69%). HQ 3DRA (N = 182, 88%) was associated with greater total injection volume [2.20 mL/kg (1.44, 3.29) vs. 1.62 mL/kg (1.10, 1.98), p = 0.005] and more dilute contrast solution [60% (50, 100) vs. 100% (60, 100), p = 0.007], but not with contrast volume administered (p = 0.2) on univariable analysis. On multivariable logistic regression, HQ 3DRA was significantly associated with patient weight [OR 0.97 (95% CI (0.94, 0.99), p = 0.018], total injection volume [OR 1.04 (95% CI 1.01, 1.07) p = 0.011], and percent contrast solution [OR 0.97 (95% CI 0.95, 1.00), p = 0.022]. These data resulted in creation of scatter plots and a novel 3DRA Nomogram for estimating the probability of HQ 3DRA. This is the first study to create evidence-based contrast dose guides and nomogram for 3DRA in CCC. HQ 3DRA was associated with lower weight, higher total injection volumes, and more dilute contrast solution.

The Expanding Uses of Medical Extended Reality in the Cardiac Catheterization Laboratory: Pre-procedural Planning, Intraprocedural Guidance, and Intraprocedural Navigation

The use of innovative imaging practices in the field of interventional cardiology and electrophysiology has led to significant progress in both diagnostic and therapeutic capabilities. 3D reconstructions of 2D images allows a proceduralist to develop a superior understanding of patient anatomy. Medical extended reality (MXR) technologies employ 3D interactive images for the user to improve depth perception and spatial awareness. Although MXR procedural navigation is a relatively new concept, the potential for use within interventional cardiology and EP is significant with the eventual goal of improving patient outcomes and reducing patient harm. This review article will discuss the current landscape of MXR use in the catheterization lab including pre-procedural planning, intraprocedural planning and intraprocedural guidance in diagnostic cardiac catheterization, valvar and coronary interventions, electrophysiology studies, and device implants.

Early preclinical experience of a mixed reality ultrasound system with active GUIDance for NEedle-based interventions: The GUIDE study

Background

Use of ultrasound (US) to facilitate vascular access has increased compared to landmark-based procedures despite ergonomic challenges and need for extrapolation of 2-dimensional images to understand needle position. The MantUS™ system (Sentiar, Inc.,) uses a mixed reality (MxR) interface to display US images and integrate real-time needle tracking.

Objective

The purpose of this prospective preclinical study was to evaluate the feasibility and usability of MantUS in a simulated environment.

Methods

Participants were recruited from pediatric cardiology and critical care. Access was obtained in 2 vascular access training models: a femoral access model and a head and neck model for a total of 4 vascular access sites under 2 conditions—conventional US and MantUS. Participants were randomized for order of completion. Videos were obtained, and quality of access including time required, repositions, number of attempts, and angle of approach were quantified.

Results

Use of MantUS resulted in an overall reduction in number of needle repositions (P = .03) and improvement in quality of access as measured by distance (P <.0001) and angle of elevation (P = .006). These findings were even more evident in the right femoral vein (RFV) access site, which was a simulated anatomic variant with a deeper more oblique vascular course. Use of MantUS resulted in faster time to access (P = .04), fewer number of both access attempts (P = .02), and number of needle repositions (P <.0001) compared to conventional US. Postparticipant survey showed high levels of usability (87%) and a belief that MantUS may decrease adverse outcomes (73%) and failed access attempts (83%).

Conclusion

Use of MantUS improved vascular access among all comers, including the quality of access. This improvement was even more notable in the vascular variant (RFV). MantUS readily benefited users by providing improved spatial understanding. Further development of MantUS will focus on improving user interface and experience, with larger clinical usage and in-human studies.

Transcatheter Device Therapy and the Integration of Advanced Imaging in Congenital Heart Disease

Transcatheter device intervention is now offered as first line therapy for many congenital heart defects (CHD) which were traditionally treated with cardiac surgery. While off-label use of devices is common and appropriate, a growing number of devices are now specifically designed and approved for use in CHD. Advanced imaging is now an integral part of interventional procedures including pre-procedure planning, intra-procedural guidance, and post-procedure monitoring. There is robust societal and industrial support for research and development of CHD-specific devices, and the regulatory framework at the national and international level is patient friendly. It is against this backdrop that we review transcatheter implantable devices for CHD, the role and integration of advanced imaging, and explore the current regulatory framework for device approval.

Interventional cardiac magnetic resonance imaging: current applications, technology readiness level, and future perspectives

BACKGROUND

Cardiac magnetic resonance (CMR) provides excellent temporal and spatial resolution, tissue characterization, and flow measurements. This enables major advantages when guiding cardiac invasive procedures compared with X-ray fluoroscopy or ultrasound guidance. However, clinical implementation is limited due to limited availability of technological advancements in magnetic resonance imaging (MRI) compatible equipment. A systematic review of the available literature on past and present applications of interventional MR and its technology readiness level (TRL) was performed, also suggesting future applications.

METHODS

A structured literature search was performed using PubMed. Search terms were focused on interventional CMR, cardiac catheterization, and other cardiac invasive procedures. All search results were screened for relevance by language, title, and abstract. TRL was adjusted for use in this article, level 1 being in a hypothetical stage and level 9 being widespread clinical translation. The papers were categorized by the type of procedure and the TRL was estimated.

RESULTS

Of 466 papers, 117 papers met the inclusion criteria. TRL was most frequently estimated at level 5 meaning only applicable to in vivo animal studies. Diagnostic right heart catheterization and cavotricuspid isthmus ablation had the highest TRL of 8, meaning proven feasibility and efficacy in a series of humans.

CONCLUSION

This article shows that interventional CMR has a potential widespread application although clinical translation is at a modest level with TRL usually at 5. Future development should be directed toward availability of MR-compatible equipment and further improvement of the CMR techniques. This could lead to increased TRL of interventional CMR providing better treatment.

Renaissance of Cardiac Imaging to Assist Percutaneous Interventions in Congenital Heart Diseases:The Role of Three-Dimensional Echocardiography and Multimodality Imaging

Percutaneous interventions have completely refashioned the management of children with congenital heart diseases (CHD) and the use of non-invasive imaging has become the gold standard to plan and guide these procedures in the modern era. We are now facing a dual challenge to improve the standard of care in low-risk patients, and to shift our strategies from the classic open chest surgery to imaging-guided percutaneous interventions in high-risk patients. Such rapid evolution of ultrasound technologies over the last 20 years have permitted the integration of transthoracic, transesophageal and intracardiac echocardiography into the interventional workflow to improve image guidance and reduce radiation burden from fluoroscopy and angiography. Specifically, miniaturization of transesophageal probe and advances in three-dimensional (3D) imaging techniques have enabled real-time 3D image guidance during complex interventional procedure, In addition, multimodality and fusion imaging techniques harness the strengths of different modalities to enhance understanding of anatomical and spatial relationship between different structures, improving communication and coordination between interventionalists and imaging specialists. In this review, we aim to provide an overview of 3D imaging modalities and multimodal fusion in procedural planning and live guidance of percutaneous interventions. At the present times, 3D imaging can no longer be considered a luxury but a routine clinical tool to improve procedural success and patient outcomes.

Three-Dimensional Virtual and Printed Prototypes in Complex Congenital and Pediatric Cardiac Surgery-A Multidisciplinary Team-Learning Experience

Three-dimensional (3D) virtual modeling and printing advances individualized medicine and surgery. In congenital cardiac surgery, 3D virtual models and printed prototypes offer advantages of better understanding of complex anatomy, hands-on preoperative surgical planning and emulation, and improved communication within the multidisciplinary team and to patients. We report our single center team-learning experience about the realization and validation of possible clinical benefits of 3D-printed models in surgical planning of complex congenital cardiac surgery. CT-angiography raw data were segmented into 3D-virtual models of the heart-great vessels. Prototypes were 3D-printed as rigid “blood-volume” and flexible “hollow”. The accuracy of the models was evaluated intraoperatively. Production steps were realized in the framework of a clinical/research partnership. We produced 3D prototypes of the heart-great vessels for 15 case scenarios (nine males, median age: 11 months) undergoing complex intracardiac repairs. Parity between 3D models and intraoperative structures was within 1 mm range. Models refined diagnostics in 13/15, provided new anatomic information in 9/15. As a team-learning experience, all complex staged redo-operations (13/15; Aristotle-score mean: 10.64 ± 1.95) were rehearsed on the 3D models preoperatively. 3D-printed prototypes significantly contributed to an improved/alternative operative plan on the surgical approach, modification of intracardiac repair in 13/15. No operative morbidity/mortality occurred. Our clinical/research partnership provided coverage for the extra time/labor and material/machinery not financed by insurance. 3D-printed models provided a team-learning experience and contributed to the safety of complex congenital cardiac surgeries. A clinical/research partnership may open avenues for bioprinting of patient-specific implants.

A Thrombin-Responsive Nanoprobe for In Vivo Visualization of Thrombus Formation through Three-Dimensional Optical/Computed Tomography Hybrid Imaging

Early spontaneous detection of thrombin activation benefits precise theranostics for thrombotic vascular disease. Herein, a thrombin-responsive nanoprobe conjugated by a FITC dye, PEGylated Fe₃O₄ nanoparticles, and a thrombin-sensitive peptide (LASG) was constructed to visualize thrombin activation and subsequent thrombosis in vivo. The FITC dye was linked to the LASG coated on the Fe₃O₄ nanoparticles for sensing the thrombin activity via the Förster resonance energy transfer effect. In vitro fluorescence imaging showed that the fluorescence signal intensity increased significantly after incubation with thrombin in contrast to that of the control group (p < 0.05), and the signal intensity was enhanced with the increase in thrombin concentration. Further in vivo fluorescence imaging also revealed that the signal elevated markedly in the left common carotid artery (LCCA) lesion of the mice thrombosis model after nanoprobe injection, in contrast to that of the control + nanoprobe group (p < 0.05). Moreover, the thrombin inhibitor bivalirudin could decrease the filling defect of the LCCA. Three-dimensional fusion images of micro-CT and fluorescence confirmed that filling defects in the LCCA were nicely colocalized with fluorescence signal caused by nanoprobes. The nanoplatform based on a thrombin-activatable visualization system could provide smart responsive and dynamic imaging of thrombosis in vivo.

CT-Guided Endovascular Exclusion of Pseudoaneurysmal Subclavian Bypass After Early-Age Surgical Correction of Complex Aortic Coarctation

We describe a 64-year-old woman with subclavian pseudoaneurysm after aortic coarctation repair, treated using a hybrid approach involving true three-dimensional analysis and image fusion-guided placement of thoracic endovascular aortic repair stents. This case illustrates the potential complications of coarctation repair and need for lifelong surveillance in these patients. (Level of Difficulty: Advanced.)

Sedation and anaesthesia for cardiac catheterisation

Since the introduction of cardiac catheterisation for Paediatric Cardiology in 1947, the subspecialty has seen dramatic changes. The advancement of non-invasive imaging techniques such as echocardiography, CT and cardiac MRI has shifted the focus for paediatric cardiac catheterisations from a primarily diagnostic tool (to define anatomy, assess haemodynamics and calculate shunts) to an important treatment option for various congenital heart defects.

Radiation dose reduction for 3D angiography images in pediatric and congenital cardiology

OBJECTIVES

The purpose of this study was to investigate the influence of simulated reduced-dose three-dimensional angiography (3DA) on the accuracy and precision of linear measurements derived from 3DA datasets.

BACKGROUND

Three-dimensional angiography is performed during X-ray guided interventional procedures to aid diagnosis and inform treatment strategies for children and adults with congenital heart disease. However, 3DA contributes substantially to patient radiation dose and may lead to an increased radiation-induced cancer risk.

METHODS

Reduced-dose patient 3DA images were simulated by adding quantum noise to the 2D projection angiograms, then reconstructing the projection angiograms into the 3DA dataset. Dose reduction in the range 33-72% was simulated. Five observers performed 46 vessel diameter measurements along prespecified axes within 23 vessel segments from 11 patient 3DA datasets. Statistical tests were performed to assess the influence of radiation dose reduction on the accuracy and precision of vessel diameter measurements.

RESULTS

Vessel diameter measurements were in the range 5.9- 22.7 mm. Considering all vessel segments and observers, the influence of dose level on the accuracy of diameter measurements was in the range 0.02 - 0.15 mm (p .05-.8). Interobserver variability increased modestly with vessel diameter, but was not influence by dose level (p = .52). The statistical test for observer recall bias was negative (p = .51).

CONCLUSIONS

Simulated dose reduction up to 72% did not affect the accuracy or precision of the diameter measurements acquired from 3DA images. These findings may embolden 3DA radiation dose reduction for pediatric and congenital heart disease patients.

Innovations in Congenital Interventional Cardiology

This article aims to summarize some of the key advances in congenital interventional cardiology over the past few years, from novel imaging technologies, such as virtual reality, fusion imaging, and 3-dimensional printed models, to newly available devices and techniques to facilitate complex procedures including percutaneous pulmonary valve replacement and hybrid procedures. It is an exciting time for the field, with rapid development of techniques, devices, and imaging tools that allow a minimally invasive approach for many congenital cardiac defects with progressively less radiation and contrast doses.

Emerging 3D technologies and applications within congenital heart disease: teach, predict, plan and guide

3D visualization technologies have evolved to become a mainstay in the management of congenital heart disease (CHD) with a growing presence within multiple facets. Printed and virtual 3D models allow for a more comprehensive approach to educating trainees and care team members. Computational fluid dynamics can take 3D modeling to the next level, by predicting post-procedural outcomes and helping to determine surgical approach. 3D printing and extended reality are developing resources for pre-procedural planning and intra-procedural guidance with the potential to revolutionize decision-making and procedural success. Challenges still remain within existing technologies and their applications to the CHD field. Addressing these gaps, both by those within and outside of CHD, will transform education and patient care within our field.

Applications of three-dimensional transesophageal echocardiography in congenital heart disease

Three-dimensional echocardiography allows for presurgical planning for congenital heart disease, reduces radiation using fusion imaging in catheter interventions, and provides guidance during catheter interventions and lead placements or extractions. The purpose of this review is to detail applications of three-dimensional transesophageal echocardiography in presurgical planning of congenital heart disease, guidance of catheter interventions such as fusion imaging, and guidance in electrophysiology lead extractions or placements.

Three-Dimensional Rotational Angiography during Catheterization of Congenital Heart Disease - A ten Years' experience at a single center

This paper aims to assess the usability and advantages of three-dimensional rotational angiography (3DRA) in patients with congenital heart disease (CHD) and its application in the cath lab. Up to now, its use in CHD is not widespread or standardized. We analyzed all patients with CHD who underwent a 3DRA at our facility between January 2010 and May 2019. The 3DRAs were evaluated for radiation exposure, contrast dye consumption, diagnostic utility and image quality. We performed 872 3DRAs. 3DRA was used in 67.1% of the cases for interventional procedures and in 32.9% for diagnostic purposes. Two different acquisition programs were applied. The median dose-area product (DAP) for all 872 rotations was 54.1 µGym² (21.7–147.5 µGym²) and 1.6 ml/kg (0.9–2.07 ml/kg) of contrast dye was used. Diagnostic utility of the generated 3D-model was rated superior to the native 3D angiography in 94% (819/872). 3DRA is an excellent and save diagnostic and interventional tool. However, 3DRA has not become a standard imaging procedure in pediatric cardiology up to now. Effort and advantage seems to be unbalanced, but new less invasive techniques may upgrade this method in future.

Initial experience with cinematic rendering for the visualization of extracardiac anatomy in complex congenital heart defects†

OBJECTIVES

Detailed anatomical information is essential for planning of surgical therapy in patients with congenital heart disease. We wanted to determine whether cinematic rendering, the novel 3-dimensional visualization technique, could help paediatric cardiac surgeons achieve better preoperative visualization of the extracardiac anatomy in patients with complex congenital heart defects. Therefore, cinematic rendering was compared to the traditional volume rendering technique by means of a questionnaire with predefined criteria.

METHODS

Picture sets from 20 infant patients (mean age = 17 days) were generated from computed tomography data with both the cinematic rendering and the volume rendering techniques. These were presented side by side in a digital high-resolution portfolio without labelling them. Three experienced paediatric cardiac surgeons were provided with these portfolios and a questionnaire. They were asked to evaluate the images individually in predefined categories on a 4-point Likert scale from 1 = 'fully acceptable' to 4 = 'unacceptable'.

RESULTS

Cinematic rendering scored significantly better values on the Likert scale in 7 of 9 categories, namely 'spatial impression in general', 'depth perception', 'delineation of the atrial appendages/pulmonary veins/peripheral pulmonary arteries', 'assessability of the anterior interventricular sulcus' and 'assessability of the aortic arch branches'.

CONCLUSIONS

Cinematic rendering is a valuable software tool, and our data suggest that it provides significantly better visualization than volume rendering. The surgeons appraised improved depth perception and delineation of structures adjacent to the heart as the most significant advantages.

Giving up knowledge is almost never a good idea: an interview with Dr Evan Zahn

The history of congenital interventional cardiology has seen numerous groundbreaking innovations typically related to the introduction of a new device or a novel treatment technique. Similarly, imaging of cardiac defects has changed dramatically over the past decades, although some of the advancements have seemed to omit the catheterisation laboratories. Rotational angiography, one of the imaging techniques for guidance of cardiac catheterisation currently referred to as "advanced", in fact was described already in 1960s.1 More recently its improved version, including three-dimensional reconstruction (3DRA), became a valuable intra-procedural imaging tool in interventional cardiology and neuroradiology.2 Dr Evan Zahn was one of the pioneers of 3DRA in the field of congenital cardiology, setting an example for many to follow. With his innovative publication and subsequent lecture at 2011 Pediatric and Adult Interventional Cardiac Symposium (PICS-AICS) on "The Emerging Use of 3-Dimensional Rotational Angiography in Congenital Heart Disease" he motivated many to explore benefits of this modality to strive for improved procedural outcomes and reduced patients' burden of cardiac catheterisation3. I was one of those to take Dr Zahn's thoughts and implement them into routine workflow.4-6 However, almost a decade after Dr Zahn shared his important work, despite tremendous efforts by teams from Utrecht, (Netherlands) and Columbus (Ohio, United States of America) to popularise 3D imaging in catheterisation laboratory during dedicated meetings, two-dimensional (2D) angiography does not seem to be threatened in many, otherwise-progressive, laboratories. During the recent 30th Japanese Pediatric Interventional Cardiology (JPIC) meeting I had the opportunity to ask Dr Zahn why giving up knowledge is almost never a good idea, what is technology's natural order of things, and why the technology has to be more than just exciting, pretty, and new.

Pros, cons and future perspectives - three questions on three dimensional guidance for cardiac catheterization in congenital heart disease

Step changes in angiographic imaging are not commonplace. Since the move from analogue to digital and flat detector plates, two-dimensional imaging technology has certainly evolved but not jumped forward. Of all the routine imaging techniques used in cardiology, angiography has been the last modality to embrace the third dimension. Although the development of rotational angiography was initially for the benefit of neuroimaging and fusion of cross sectional datasets was aimed at the treatment of descending aortic pathology, interventional physicians in congenital and structural cardiology have immersed themselves in this technology over the last 10 years. Like many disruptive technologies, its introduction has divided opinion. We aimed to explore the mindset of those in the field of interventional cardiology who are driving imaging forward. These structured interviews recorded during the 21^st Pediatric and Adult Interventional Cardiac Symposium illustrate the challenges and sticking points as well as giving an insight into the direction of travel for three-dimensional imaging and fusion techniques. Covering a wide range of career development, seniority and experience, the interviewees in this article are probably responsible for the majority of the published literature on invasive three-dimensional imaging in congenital heart disease.

Three-dimensional rotational angiography in congenital heart disease: Present status and evolving future

Three-dimensional rotational angiography (3D-RA) enables volumetric imaging through rotation of the C-arm of an angiographic system and real-time 3D reconstruction during cardiac catheterization procedures. In the field of congenital heart disease (CHD), 3D-RA has gained considerable traction, owing to its capability for enhanced visualization of spatial relationships in complex cardiac morphologies and real time image guidance in an intricate interventional environment. This review provides an overview of the current applications, strengths, and limitations of 3D-RA acquisition in the management of CHD and potential future directions. In addition, issues of dosimetry, radiation exposure, and optimization strategies will be reviewed. Further implementation of 3D-RA will be driven by patient benefits relative to existing 3D imaging capabilities and fusion techniques balanced against radiation exposure.

X-ray fused with MRI guidance of pre-selected transcatheter congenital heart disease interventions

OBJECTIVES

To determine whether X-ray fused with MRI (XFM) is beneficial for select transcatheter congenital heart disease interventions.

BACKGROUND

Complex transcatheter interventions often require three-dimensional (3D) soft tissue imaging guidance. Fusion imaging with live X-ray fluoroscopy can potentially improve and simplify procedures.

METHODS

Patients referred for select congenital heart disease interventions were prospectively enrolled. Cardiac MRI data was overlaid on live fluoroscopy for procedural guidance. Likert scale operator assessments of value were recorded. Fluoroscopy time, radiation exposure, contrast dose, and procedure time were compared to matched cases from our institutional experience.

RESULTS

Forty-six patients were enrolled. Pre-catheterization, same day cardiac MRI findings indicated intervention should be deferred in nine patients. XFM-guided cardiac catheterization was performed in 37 (median age 8.7 years [0.5-63 years]; median weight 28 kg [5.6-110 kg]) with the following prespecified indications: pulmonary artery (PA) stenosis (n = 13), aortic coarctation (n = 12), conduit stenosis/insufficiency (n = 9), and ventricular septal defect (n = 3). Diagnostic catheterization showed intervention was not indicated in 12 additional cases. XFM-guided intervention was performed in the remaining 25. Fluoroscopy time was shorter for XFM-guided intervention cases compared to matched controls. There was no significant difference in radiation dose area product, contrast volume, or procedure time. Operator Likert scores indicated XFM provided useful soft tissue guidance in all cases and was never misleading.

CONCLUSIONS

XFM provides operators with meaningful three-dimensional soft tissue data and reduces fluoroscopy time in select congenital heart disease interventions.

Complicated coarctation repair: The importance of three-dimensional cross-sectional imaging in late postoperative assessment

Coarctation of the aorta (CoA) represents 5%–8% of congenital heart disease patients and is one of the most common causes of neonatal surgical intervention. These patients require close lifelong follow-up due to frequent long-term complications. Although transthoracic echocardiography is the first-line technique for its diagnosis and follow-up, cross-sectional imaging with cardiovascular magnetic resonance (CMR) gives excellent anatomical and functional information, especially in complex CoA. We present the case of a 17-year-old patient who underwent complicated neonatal CoA repair and demonstrate how CMR and thorough operative records helped to define the exact anatomy of repair many years after surgery. Furthermore, we conclude that keeping surgical drawings in the patient records can be of great importance, especially in complicated cases.

Virtual museum of congenital heart defects: digitization and establishment of a database for cardiac specimens

Education and training of morphology for medical students, and professionals specializing in pediatric cardiology and surgery has traditionally been based on hands-on encounter with congenitally malformed cardiac specimens. Large international archives are no longer widely available due to stricter data protection rules, a reduced number of autopsies, attrition rate of existing specimens, and most importantly due to a higher survival rate of patients. Our Cardiac Archive houses about 400 cardiac specimens with congenital heart disease. The collection spans almost 60 years and thus goes back to pre-surgical era. Unfortunately, attrition rate due to desiccation has led to an increased natural decay in recent years. The present multi-institutional project focuses on saving the collection by digitization. Specimens are scanned by high-resolution micro-CT/MRI. Virtual 3D-models are segmented and a comprehensive database is built. We now report an initial feasibility study with six test specimens that provided promising results, however, adequate presentation of the intracardiac anatomy, including septa and cardiac valves requires further refinements. Computer assisted design methods are necessary to overcome consequences of pathological examination, shrinkage and/or distortion of the specimens. For a next step, we anticipate an expandable web-based virtual museum with interactive reference and training tools. Web access for professional third parties will be provided by registration/subscription. In a future phase, segmental wall motion data could be added to virtual models. 3D-printed models may replace actual specimens and serve as hands-on surgical training to elucidate complex morphologies, promote surgical emulation, and extract more accurate procedural knowledge based on such a collection.

Magnetic resonance and computed tomography imaging fusion for live guidance of percutaneous pulmonary valve implantation

Introduction

Until recently, two-dimensional (2D) angiography was the mainstay of guidance for percutaneous pulmonary valve implantation (PPVI). Recent advances in fusion software have enabled direct fusion of pre-intervention imaging, magnetic resonance imaging (MRI) or computed tomography (CT) scans, to create a reliable three-dimensional (3D) roadmap for procedural guidance.

Aim

To report initial two-center experience with direct 2D–3D image fusion for live guidance of PPVI with MRI- and CT-derived 3D roadmaps.

Material and methods

We performed a prospective study on PPVIs guided with the new fusion imaging platform introduced in the last quarter of 2015.

Results

3D guidance with an MRI- (n = 14) or CT- (n = 8) derived roadmap was utilized during 22 catheterizations for right ventricular outflow tract balloon sizing (n = 7) or PPVI (n = 15). Successful 2D–3D registration was performed in all but 1 patient. Six (27%) patients required intra-procedural readjustment of the 3D roadmap due to distortion of the anatomy after introduction of a stiff wire. Twenty-one (95%) interventions were successful in the application of 3D imaging. Patients in the CT group received less contrast volume and had a shorter procedural time, though the differences were not statistically significant. Those in the MRI group had significantly lower weight adjusted radiation exposure.

Conclusions

With intuitive segmentation and direct 2D–3D fusion of MRI or CT datasets, VesselNavigator facilitates PPVI. Our initial data show that utilization of CT-derived roadmaps may lead to less contrast exposure and shorter procedural time, whereas application of MRI datasets may lead to lower radiation exposure.

A new approach of three-dimensional guidance in paediatric cath lab: segmented and tessellated heart models for cardiovascular interventions in CHD

BACKGROUND

Optimal imaging is essential for catheter-based interventions in CHD. The three-dimensional models in volume-rendering technique currently in use are not standardised. This paper investigates the feasibility and impact of novel three-dimensional guidance with segmented and tessellated three-dimensional heart models in catheterisation of CHD. In addition, a nearly radiation-free two- to three-dimensional registration and a biplane overlay were used.Methods and resultsWe analysed 60 consecutive cases in which segmented tessellated three-dimensional heart models were merged with live fluoroscopy images and aligned using the tracheal bifurcation as a fiducial mark. The models were generated from previous MRI or CT by dedicated medical software. We chose the stereo-lithography format, as this promises advantage over volume-rendering-technique models regarding visualisation. Prospects, potential benefits, and accuracy of the two- to three-dimensional registration were rated separately by two paediatric interventionalists on a five-point Likert scale. Fluoroscopy time, radiation dose, and contrast dye consumption were evaluated. Over a 10-month study period, two- to three-dimensional image fusion was applied to 60 out of 354 cases. Of the 60 catheterisations, 73.3% were performed in the context of interventions. The accuracy of two- to three-dimensional registration was sufficient in all cases. Three-dimensional guidance was rated superior to conventional biplane imaging in all 60 cases. We registered significantly smaller amounts of used contrast dye (p<0.01), lower levels of radiation dose (p<0.02), and less fluoroscopy time (p<0.01) during interventions concerning the aortic arch compared with a control group.

CONCLUSIONS

Two- to three-dimensional image fusion can be applied successfully in most catheter-based interventions of CHD. Meshes in stereo-lithography format are accurate and base for standardised and reproducible three-dimensional models.

Innovative interventional catheterization techniques for congenital heart disease

Since 1929, when the first cardiac catheterization was safely performed in a human by Dr. Werner Forssmann (on himself), there has been a rapid progression of cardiac catheterization techniques and technologies. Today, these advances allow us to treat a wide variety of patients with congenital heart disease using minimally invasive techniques; from fetus to infants to adults, and from simple to complex congenital cardiac lesions. In this article, we will explore some of the exciting advances in cardiac catheterization for the treatment of congenital heart disease, including transcatheter valve implantation, hybrid procedures, biodegradable technologies, and magnetic resonance imaging (MRI)-guided catheterization. Additionally, we will discuss innovations in imaging in the catheterization laboratory, including 3D rotational angiography (3DRA), fusion imaging, and 3D printing, which help to make innovative interventional approaches possible.

Three-dimensional modelling and three-dimensional printing in pediatric and congenital cardiac surgery

Three-dimensional (3D) modelling and printing methods greatly support advances in individualized medicine and surgery. In pediatric and congenital cardiac surgery, personalized imaging and 3D modelling presents with a range of advantages, e.g., better understanding of complex anatomy, interactivity and hands-on approach, possibility for preoperative surgical planning and virtual surgery, ability to assess expected results, and improved communication within the multidisciplinary team and with patients. 3D virtual and printed models often add important new anatomical findings and prompt alternative operative scenarios. For the lack of critical mass of evidence, controlled randomized trials, however, most of these general benefits remain anecdotal. For an individual surgical case-scenario, prior knowledge, preparedness and possibility of emulation are indispensable in raising patient-safety. It is advocated that added value of 3D printing in healthcare could be raised by establishment of a multidisciplinary centre of excellence (COE). Policymakers, research scientists, clinicians, as well as health care financers and local entrepreneurs should cooperate and communicate along a legal framework and established scientific guidelines for the clinical benefit of patients, and towards financial sustainability. It is expected that besides the proven utility of 3D printed patient-specific anatomical models, 3D printing will have a major role in pediatric and congenital cardiac surgery by providing individually customized implants and prostheses, especially in combination with evolving techniques of bioprinting.

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.

Innovation in 3D Echocardiographic Imaging

PURPOSE OF REVIEW

The purpose of this review is to detail three-dimensional echocardiographic (3DE) innovations in pre-surgical planning of congenital heart disease, guidance of catheter interventions such as fusion imaging, and functional assessment of patients with congenital heart disease.

RECENT FINDINGS

Innovations in 3DE have helped us delineate the details of atrioventricular valve function and understand the mechanism of atrioventricular valve failure in patients with atrioventricular septal defect and single ventricle post repair. Advancement in holographic display of 3D datasets allows for better manipulation of 3D images in three dimensions and better understanding of anatomic relationships. 3DE with fusion imaging reduces radiation in catheter interventions and provides presentations of 3DE images in the similar fashion as the fluoroscopic images to improve communication between cardiologists. Lastly, 3DE allows for quantitative ventricular volumetric and functional assessment. Recent innovations in 3DE allow for pre-surgical planning for congenital heart disease, reduce radiation using fusion imaging in catheter interventions, and enable accurate assessment of ventricular volume and function without geometric assumptions.

Accuracy and Specific Value of Cardiovascular 3D-Models in Pediatric CT-Angiography

Computed tomography (CT)-angiography is routinely performed prior to catheter-based and surgical treatment in congenital heart disease. To date, little is known about the accuracy and advantage of different 3D-reconstructions in CT-data. Exact anatomical information is crucial. We analyzed 35 consecutive CT-angiographies of infants with congenital heart disease. All datasets are reconstructed three-dimensionally using volume rendering technique (VRT) and threshold-based segmentation (stereolithographic model, STL). Additionally, the two-dimensional maximum intensity projection (MIP) reconstructs two-dimensional data. In each dataset and resulting image, measurements of vascular diameters for four different vessels were estimated and compared to the reference standard, measured via multiplanar reformation (MPR). The resulting measurements obtained via the STL-images, MIP-images, and the VRT-images were compared with the reference standard. There was a significant difference (p < 0.05) between measurements. The mean difference was 0.0 for STL-images, -0.1 for MIP-images, and -0.3 for VRT-images. The range of the differences was -0.7 to 1.0 mm for STL-images, -0.6 to 0.5 mm for MIP-images and -1.1 to 0.7 mm for VRT-images. There was an excellent correlation between the STL-, MIP-, VRT-measurements, and the reference standard. Inter-reader reliability was excellent (p < 0.01). STL-models of cardiovascular structures are more accurate than the traditional VRT-models. Additionally, they can be standardized and are reproducible.

Fusion Imaging for Procedural Guidance

The field of percutaneous structural heart interventions has grown tremendously in recent years. This growth has fueled the development of new imaging protocols and technologies in parallel to help facilitate these minimally-invasive procedures. Fusion imaging is an exciting new technology that combines the strength of 2 imaging modalities and has the potential to improve procedural planning and the safety of many commonly performed transcatheter procedures. In this review we discuss the basic concepts of fusion imaging along with the relative strengths and weaknesses of static vs dynamic fusion imaging modalities. This review will focus primarily on echocardiographic-fluoroscopic fusion imaging and its application in commonly performed transcatheter structural heart procedures.

Novel Three-Dimensional Image Fusion Software to Facilitate Guidance of Complex Cardiac Catheterization : 3D image fusion for interventions in CHD

We report initial experience with novel three-dimensional (3D) image fusion software for guidance of transcatheter interventions in congenital heart disease. Developments in fusion imaging have facilitated the integration of 3D roadmaps from computed tomography or magnetic resonance imaging datasets. The latest software allows live fusion of two-dimensional (2D) fluoroscopy with pre-registered 3D roadmaps. We reviewed all cardiac catheterizations guided with this software (Philips VesselNavigator). Pre-catheterization imaging and catheterization data were collected focusing on fusion of 3D roadmap, intervention guidance, contrast and radiation exposure. From 09/2015 until 06/2016, VesselNavigator was applied in 34 patients for guidance (n = 28) or planning (n = 6) of cardiac catheterization. In all 28 patients successful 2D-3D registration was performed. Bony structures combined with the cardiovascular silhouette were used for fusion in 26 patients (93%), calcifications in 9 (32%), previously implanted devices in 8 (29%) and low-volume contrast injection in 7 patients (25%). Accurate initial 3D roadmap alignment was achieved in 25 patients (89%). Six patients (22%) required realignment during the procedure due to distortion of the anatomy after introduction of stiff equipment. Overall, VesselNavigator was applied successfully in 27 patients (96%) without any complications related to 3D image overlay. VesselNavigator was useful in guidance of nearly all of cardiac catheterizations. The combination of anatomical markers and low-volume contrast injections allowed reliable 2D-3D registration in the vast majority of patients.