Using simulation for interventional radiology training

Mixed reality in interventional radiology: a focus on first clinical use of XR90 augmented reality-based visualization and navigation platform

INTRODUCTION

Augmented reality (AR) and virtual reality (VR) are emerging tools in interventional radiology (IR), enhancing IR education, preprocedural planning, and intraprocedural guidance.

AREAS COVERED

This review identifies current applications of AR/VR in IR, with a focus on studies that assess the clinical impact of AR/VR. We outline the relevant technology and assess current limitations and future directions in this space. We found that the use of AR in IR lags other surgical fields, and the majority of the data exists in case series or small-scale studies. Educational use of AR/VR improves learning anatomy, procedure steps, and procedural learning curves. Preprocedural use of AR/VR decreases procedure times, especially in complex procedures. Intraprocedural AR for live tracking is accurate within 5 mm live patients and has up to 0.75 mm in phantoms, offering decreased procedure time and radiation exposure. Challenges include cost, ergonomics, rapid segmentation, and organ motion.

EXPERT OPINION

The use of AR/VR in interventional radiology may lead to safer and more efficient procedures. However, more data from larger studies is needed to better understand where AR/VR is confers the most benefit in interventional radiology clinical practice.

Avoiding adverse events in interventional radiology - a systematic review on the instruments

BACKGROUND

Avoiding AEs is a pivotal fundament for high patient safety in an efficient interventional radiology (IR) department. Although IR procedures are considered to have a lower risk than their surgical alternatives, they account for one third of all radiological adverse events (AEs) and in general, the number of AEs is increasing. Thus, measures to prevent AEs in IR are of interest.

METHODS

A systematic literature search was conducted via handsearch and Ovid. A structured data extraction was performed with all included studies and their quality of evidence was evaluated. Finally, data were aggregated for further statistical analysis.

RESULTS

After screening 1,899 records, 25 full-text publications were screened for eligibility. Nine studies were included in the review. Of those, four studies investigated in simulator training, one in team training, three in checklists, and one in team time-out. Eight were monocenter studies, and five were conducted in a non-clinical context. Study quality was low. Aggregation and analysis of data was only possible for the studies about checklists with an overall reduction of the median error per procedure from 0.35 to 0.06, observed in a total of 20,399 and 58,963 procedures, respectively.

CONCLUSION

The evidence on the instruments to avoid AEs in IR is low. Further research should be conducted to elaborate the most powerful safety tools to improve patient outcomes in IR by avoiding AEs.

Advancing IR in Underserved Regions: Interventional Radiology Simulation Near and Far

Simulation facilitates learning by imitating real-world systems or processes utilizing educational tools and models. Various fields, including business, aviation, and education use simulation for training. In healthcare, simulation provides trainees opportunities to develop procedural skills in a safe environment, building their understanding through hands-on interactions and experiences rather than passive didactics. Simulation is classified into low, medium, and high fidelity, based on how closely it mimics real-life experience. Its use in education is a valuable adjunct to instructional support and training with multiple potential benefits. Interventional radiology (IR) trainees can build technical and clinical proficiency prior to working directly on a patient. Simulation promotes experiential learning, constructivist learning, and student centeredness, thus giving students control over their learning and knowledge acquisition. More recently, the creative use of remote simulation has augmented traditional virtual didactic lectures, thereby further engaging international learners and enhancing remote collaboration. Despite the challenges to implementation, the addition of simulation in IR education is proving invaluable to supporting trainees and physicians in underserved regions.

Implementation and Evaluation of a Comprehensive Simulation Curriculum for the IR/DR Integrated Residency

RATIONALE AND OBJECTIVES

Endovascular simulation is a validated training method, allowing residents to improve technical skills with interventional equipment in a risk-free environment. The purpose of this study was to assess the utility and efficacy of supplementing the IR/DR Integrated Residency training program with a dedicated 2-year endovascular simulation curriculum.

MATERIALS AND METHODS

Trainees participated in a 2-year curriculum that included the completion of 8 modules using a high-fidelity endovascular simulator (Mentice AB, Gothenberg, Sweden). Procedural modules included IVC filter placement, transarterial chemoembolization, trauma embolization, uterine artery embolization, prostate artery embolization, and peripheral arterial disease interventions. Each quarter, two trainees were filmed while completing an assigned module. Sessions led by IR faculty were held with film footage review and didactics on the assigned topic. Pre- and postcase surveys were collected to evaluate trainee comfort and confidence and assess the validity of the simulation. At the conclusion of the 2-year period, a postcurriculum survey was sent to all trainees to determine how residents viewed the utility of the simulation sessions.

RESULTS

Eight residents participated in the pre- and postcase surveys. The simulation curriculum significantly increased trainee confidence for these 8 residents. A separate postcurriculum survey was completed by all 16 IR/DR residents. All 16 residents felt that simulation was a helpful addition to their education. A total of 87.5% of all residents felt that the sessions improved their confidence in the IR procedure room. A total of 75% of all residents believe that the simulation curriculum should be incorporated into the IR residency program.

CONCLUSION

Adoption of a 2-year simulation curriculum can be considered for existing IR/DR training programs with access to high-fidelity endovascular simulators using the described approach.

Artificial Intelligence, Augmented Reality, and Virtual Reality Advances and Applications in Interventional Radiology

Artificial intelligence (AI) uses computer algorithms to process and interpret data as well as perform tasks, while continuously redefining itself. Machine learning, a subset of AI, is based on reverse training in which evaluation and extraction of data occur from exposure to labeled examples. AI is capable of using neural networks to extract more complex, high-level data, even from unlabeled data sets, and better emulate, or even exceed, the human brain. Advances in AI have and will continue to revolutionize medicine, especially the field of radiology. Compared to the field of interventional radiology, AI innovations in the field of diagnostic radiology are more widely understood and used, although still with significant potential and growth on the horizon. Additionally, AI is closely related and often incorporated into the technology and programming of augmented reality, virtual reality, and radiogenomic innovations which have the potential to enhance the efficiency and accuracy of radiological diagnoses and treatment planning. There are many barriers that limit the applications of artificial intelligence applications into the clinical practice and dynamic procedures of interventional radiology. Despite these barriers to implementation, artificial intelligence in IR continues to advance and the continued development of machine learning and deep learning places interventional radiology in a unique position for exponential growth. This review describes the current and possible future applications of artificial intelligence, radiogenomics, and augmented and virtual reality in interventional radiology while also describing the challenges and limitations that must be addressed before these applications can be fully implemented into common clinical practice.

A model for training ultrasound-guided fine-needle punctures

OBJECTIVE

To evaluate the efficacy of a training program in ultrasound-guided fine needle puncture using a cost-effective model.

METHODS

We evaluated the training of 20 resident radiology physicians, based on a theoretical course and a practical simulation part with models that focused on the puncture technique of thyroid nodules. The total time to perform the procedure, the number of punctures on the model surface, and the application of a questionnaire were used to assess the performance and confidence of the resident physicians in performing the procedure.

RESULTS

The training model used was easy to reproduce, inexpensive, versatile, and capable of simulating the echotexture of thyroid tissue. There was a significant reduction in the total time needed to perform the procedure with a mean of 173.7 s±91.28 s from R1 and 112.8 s±17.66 s from R2 before the course vs. 19.2 s±112.8 s and 14.3 s±9.36 s, respectively, after the course (p<0.0001); as well as the number of superficial punctures, with a mean of 2.2 punctures±0.92 from R1 and 1.5 punctures±0.32 from R2 before the course vs 1.1 punctures±0.71 and 1.0 puncture±0.0, respectively, after the course (p<0.0001). There was also a subjective improvement in the performance and confidence in performing this procedure.

CONCLUSIONS

An inexpensive and easy-to-reproduce gelatin-based model enabled adequate training of resident physicians and proved capable of improving their skills and confidence in simulating the procedure, even with a short period of training.

Virtual reality in interventional radiology education: a systematic review

The aim of this study was to compare virtual reality simulation with other methods of teaching interventional radiology. We searched multiple databases-Cochrane Library; Medline (PubMed); Embase; Trip Medical; Education Resources Information Center; Cumulative Index to Nursing and Allied Health Literature; Scientific Electronic Library Online; and Latin-American and Caribbean Health Sciences Literature-for studies comparing virtual reality simulation and other methods of teaching interventional radiology. This systematic review was performed in accordance with the criteria established by the Preferred Reporting Items for Systematic Reviews and Meta-Analyses and the Best Evidence Medical Education (BEME) Collaboration. Eligible studies were evaluated by using the quality indicators provided in the BEME Guide No. 11 and the Kirkpatrick model of training evaluation. After the eligibility and quality criteria had been applied, five randomized clinical trials were included in the review. The Kirkpatrick level of impact varied among the studies evaluated, three studies being classified as level 2B and two being classified as level 4B. Among the studies evaluated, there was a consensus that virtual reality aggregates concepts and is beneficial for the teaching of interventional radiology. Although the use of virtual reality has been shown to be effective for skill acquisition and learning in interventional radiology, there is still a lack of studies evaluating and standardizing the employment of this technology in relation to the numerous procedures that exist within the field of expertise.

Endovascular simulation as a supplemental training tool during the COVID-19 national emergency

The ongoing COVID pandemic raises many concerns as our healthcare system is pushed to its limits and as a consequence, Interventional Radiology training may be compromised. Endovascular simulators allow trainees many benefits to build and maintain endovascular skills in a safe environment. Our experience demonstrates a methodology to maintain IR training with use of didactic and simulation supplementation during the COVID-19 pandemic, which may be helpful for incorporation at other institutions facing similar challenges.

Developing and Evaluating a Simulator for Complex IVC Filter Retrieval

RATIONALE AND OBJECTIVES

Simulation models allow trainees to acquire and develop procedural skills without compromising patient safety. Complex inferior vena cava (IVC) filter retrieval requires the operator to be proficient at using devices, such as endobronchial forceps, and advanced techniques to carefully dissect free embedded filter tips encased in fibrous tissue adherent to the IVC. Therefore, it is important to develop an effective, inexpensive model to simulate tip-embedded IVC filter retrieval.

MATERIALS AND METHODS

Silicone tubes (Flexi-Seal SIGNAL, ConvaTec Inc., Skilman, NJ), IVC filters (Cook Günther Tulip Vena Cava Filter, Cook Medical, Bloomington, IN), and endobronchial forceps (Lymol Medical, Woburn, MA) were obtained to assemble the model. A total of 12 combinations of adhesive binding methods were used to adhere IVC filter fragments to the silicone tubes, and these were blind tested. A single operator with over 10 years of experience using forceps scored the adhesives subjectively on a three-point scale for adherence, elasticity, and tactile feel. The adhesive most similar to IVC fibrous tissue was selected to assemble the final tip-embedded IVC filter model. 20 trainees were then assigned to practice on the model. A 3-point scale scoring metric objectively measured confidence before and after training on the model.

RESULTS

Sil-poxy Silicone Adhesive (Smooth-On, Macungie, PA) was found to be the most similar to human IVC fibrous tissue with an average score of 3 of 3 on all metrics. Comparing scores from before and after use of the model, trainee confidence improved significantly (p < 0.1) in all three categories from 1.20 to 2.10 (handling forceps), 1.05 to 2.15 (understanding tactile feel of fibrous tissue), and 1.05 to 1.70 (overall confidence).

CONCLUSION

The development of a low-cost simulator for embedded IVC filters is feasible and can be used to improve trainee confidence and skill for complex IVC filter retrieval.

Special Ultrasound Phantom for Interventional Training: Construction, Advantages, and Application

Interventional radiology procedures are becoming more challenging over time; thus, there is a need for excellent and reliable training methods. Training on live patients is neither safe nor an ethical solution. Alternatives are many and varied, but the most popular is ultrasound guided simulators. This report shows how a simple, homemade, low-cost phantom material, and construction modules can provide several advantages over ordinary gelatin phantoms. A new layering technique and target synthesis are described for the biopsy phantom, including tips on decreasing the needle pass artifact as well as controlling the mixture echogenicity.

High-Fidelity Endovascular Simulation

With the ongoing changes in graduate medical education, emphasis has been placed on simulation models to increase clinical exposure and optimize learning. In specific, high-fidelity simulation presents as a potential option for procedural-skill development in interventional radiology. With improved haptic, visual, and tactile dynamics, high-fidelity endovascular simulators have gained increasing support from trainees and certified interventionalists alike. The 2 most common high-fidelity endovascular simulators utilized today are the Procedicus VIST and ANGIO Mentor, which contain notable differences in technical features, case availability, and cost. From the perspective of a trainee, high-fidelity simulation allows for the ability to perform a greater volume of cases. Additionally, without the risk of potential harm to the patient, trainees can focus on repetition and improved performance in a stress-free environment. When errors are made, high-fidelity simulator metrics will generate instantaneous feedback and error notification, erasing ambiguity and thus facilitating learning. Furthermore, in an environment devoid of time and cost stressors, the supervising physician is afforded the opportunity to properly mentor and instruct the trainee throughout the case. For the experienced interventionalists, high-fidelity simulation allows for a decreased learning curve for new procedures or techniques, as well as the opportunity for procedure rehearsal for unusual or high-risk cases. Despite the limitations created by cost, high-fidelity endovascular simulation should continue to be increasingly utilized in the development of the interventional radiology curriculum.

Lightly Embalmed Cadavers as a Training Tool for Ultrasound-Guided Procedures Commonly Used in Interventional Radiology

RATIONALE AND OBJECTIVES

Competency in ultrasound (US) imaging and US-guided procedures is often difficult for medical students and residents to master. The use of simulation training has been strongly encouraged but the quality of phantom models available for US-guided procedures is limited. As a feasible alternative, we describe the innovative use of a lightly embalmed cadaver for realistic practice of common interventional radiology (IR) procedures prior to direct patient care.

MATERIALS AND METHODS

Lightly embalmed cadavers were positioned as patients would be in the IR suite: supine, prone, and erect seated position. Lidocaine was injected and visualized under standard percutaneous techniques and sonographic guidance was used to simulate common US-guided procedures performed in IR including liver biopsy, kidney biopsy, thoracentesis, and vascular access.

RESULTS

The ability to position cadavers was a key factor that allowed entire procedures to be simulated. Medical students with very limited exposure to US imaging and diagnostic radiology residents with minimal exposure to US imaging successfully completed common US-guided procedures. Arterial and venous vascular access was obtained. Wires were passed and catheters easily placed via both access sites. The texture of the tissue layers provided realistic feedback for the trainees as they advanced the needle or dilated the tissues. Images from each simulated procedure resembled images expected in a living patient.

CONCLUSION

Lightly embalmed cadavers are an innovative and feasible tool to simulate common IR US-guided procedures in a realistic fashion for deliberate practice in advance of first-attempt encounters with patients.

VCSim3: a VR simulator for cardiovascular interventions

PURPOSE

Effective and safe performance of cardiovascular interventions requires excellent catheter/guidewire manipulation skills. These skills are currently mainly gained through an apprenticeship on real patients, which may not be safe or cost-effective. Computer simulation offers an alternative for core skills training. However, replicating the physical behaviour of real instruments navigated through blood vessels is a challenging task.

METHODS

We have developed VCSim3-a virtual reality simulator for cardiovascular interventions. The simulator leverages an inextensible Cosserat rod to model virtual catheters and guidewires. Their mechanical properties were optimized with respect to their real counterparts scanned in a silicone phantom using X-ray CT imaging. The instruments are manipulated via a VSP haptic device. Supporting solutions such as fluoroscopic visualization, contrast flow propagation, cardiac motion, balloon inflation, and stent deployment, enable performing a complete angioplasty procedure.

RESULTS

We present detailed results of simulation accuracy of the virtual instruments, along with their computational performance. In addition, the results of a preliminary face and content validation study conveyed on a group of 17 interventional radiologists are given.

CONCLUSIONS

VR simulation of cardiovascular procedure can contribute to surgical training and improve the educational experience without putting patients at risk, raising ethical issues or requiring expensive animal or cadaver facilities. VCSim3 is still a prototype, yet the initial results indicate that it provides promising foundations for further development.

Should there be greater exposure to interventional radiology in the undergraduate curriculum?

Medical imaging has been one of the most revolutionary innovations in medicine. Today, as health care professionals shift their focus toward more sophisticated technology and minimally invasive procedures, interventional radiology (IR) has become a rapidly expanding specialty. Despite these advances, there is a lack of doctors specializing in this field. A growing body of evidence suggests that the low number of applicants for posts may be due to poor exposure to the specialty at medical school. In this article, we outline the importance of IR in today's health care system. Next, we evaluate the evidence that there is a lack of knowledge of IR not only among medical students in the UK but globally. We further discuss how a more effective incorporation of IR in the undergraduate curriculum can enhance medical students' interest in the field and subsequently increase the number of doctors specializing in IR. Finally, we suggest alternative strategies to gauge medical students' interest in IR, including teaching via e-learning and virtual reality.

Face and content validity of the virtual reality simulator 'ScanTrainer®'

Background

Ultrasonography is a first-line imaging in the investigation of women’s irregular bleeding and other gynaecological pathologies, e.g. ovarian cysts and early pregnancy problems. However, teaching ultrasound, especially transvaginal scanning, remains a challenge for health professionals. New technology such as simulation may potentially facilitate and expedite the process of learning ultrasound. Simulation may prove to be realistic, very close to real patient scanning experience for the sonographer and objectively able to assist the development of basic skills such as image manipulation, hand-eye coordination and examination technique.

Objective

The aim of this study was to determine the face and content validity of a virtual reality simulator (ScanTrainer®, MedaPhor plc, Cardiff, Wales, UK) as reflective of real transvaginal ultrasound (TVUS) scanning.

Method

A questionnaire with 14 simulator-related statements was distributed to a number of participants with differing levels of sonography experience in order to determine the level of agreement between the use of the simulator in training and real practice.

Results

There were 36 participants: novices (n = 25) and experts (n = 11) who rated the simulator. Median scores of face validity statements between experts and non-experts using a 10-point visual analogue scale (VAS) ratings ranged between 7.5 and 9.0 (p > 0.05) indicated a high level of agreement. Experts’ median scores of content validity statements ranged from 8.4 to 9.0.

Conclusions

The findings confirm that the simulator has the feel and look of real-time scanning with high face validity. Similarly, its tutorial structures and learning steps confirm the content validity.

Electronic supplementary material

The online version of this article (10.1186/s10397-017-1020-6) contains supplementary material, which is available to authorized users.

Learning curve of radiology residents during training in fluoroscopy-guided facet joint injections

OBJECTIVE

To develop a simulator for training in fluoroscopy-guided facet joint injections and to evaluate the learning curve for this procedure among radiology residents.

MATERIALS AND METHODS

Using a human lumbar spine as a model, we manufactured five lumbar vertebrae made of methacrylate and plaster. These vertebrae were assembled in order to create an anatomical model of the lumbar spine. We used a silicon casing to simulate the paravertebral muscles. The model was placed into the trunk of a plastic mannequin. From a group of radiology residents, we recruited 12 volunteers. During simulation-based training sessions, each student carried out 16 lumbar facet injections. We used three parameters to assess the learning curves: procedure time; fluoroscopy time; and quality of the procedure, as defined by the positioning of the needle.

RESULTS

During the training, the learning curves of all the students showed improvement in terms of the procedure and fluoroscopy times. The quality of the procedure parameter also showed improvement, as evidenced by a decrease in the number of inappropriate injections.

CONCLUSION

We present a simple, inexpensive simulation model for training in facet joint injections. The learning curves of our trainees using the simulator showed improvement in all of the parameters assessed.

Human Thiel-Embalmed Cadaveric Aortic Model with Perfusion for Endovascular Intervention Training and Medical Device Evaluation

Purpose

The purpose of this investigation was to evaluate human Thiel-embalmed cadavers with the addition of extracorporeal driven ante-grade pulsatile flow in the aorta as a model for simulation training in interventional techniques and endovascular device testing.

Materials and Methods

Three human cadavers embalmed according to the method of Thiel were selected. Extracorporeal pulsatile ante-grade flow of 2.5 L per min was delivered directly into the aorta of the cadavers via a surgically placed connection. During perfusion, aortic pressure and temperature were recorded and optimized for physiologically similar parameters. Pre- and post-procedure CT imaging was conducted to plan and follow up thoracic and abdominal endovascular aortic repair as it would be in a clinical scenario. Thoracic endovascular aortic repair (TEVAR) and endovascular abdominal repair (EVAR) procedures were conducted in simulation of a clinical case, under fluoroscopic guidance with a multidisciplinary team present.

Results

The Thiel cadaveric aortic perfusion model provided pulsatile ante-grade flow, with pressure and temperature, sufficient to conduct a realistic simulation of TEVAR and EVAR procedures. Fluoroscopic imaging provided guidance during the intervention. Pre- and post-procedure CT imaging facilitated planning and follow-up evaluation of the procedure.

Conclusion

The human Thiel-embalmed cadavers with the addition of extracorporeal flow within the aorta offer an anatomically appropriate, physiologically similar robust model to simulate aortic endovascular procedures, with potential applications in interventional radiology training and medical device testing as a pre-clinical model.

Electronic supplementary material

The online version of this article (doi:10.1007/s00270-017-1643-z) contains supplementary material, which is available to authorized users.

High fidelity, low cost moulage as a valid simulation tool to improve burns education

Simulation allows the opportunity for repeated practice in controlled, safe conditions. Moulage uses materials such as makeup to simulate clinical presentations. Moulage fidelity can be assessed by face validity (realism) and content validity (appropriateness). The aim of this project is to compare the fidelity of professional moulage to non-professional moulage in the context of a burns management course. Four actors were randomly assigned to a professional make-up artist or a course faculty member for moulage preparation such that two actors were in each group. Participants completed the actor-based burn management scenarios and answered a ten-question Likert-scale questionnaire on face and content validity. Mean scores and a linear mixed effects model were used to compare professional and non-professional moulage. Cronbach's alpha assessed internal consistency. Twenty participants experienced three out of four scenarios and at the end of the course completed a total of 60 questionnaires. Professional moulage had higher average ratings for face (4.30 v 3.80; p=0.11) and content (4.30 v 4.00; p=0.06) validity. Internal consistency of face (α=0.91) and content (α=0.85) validity questions was very good. The fidelity of professionally prepared moulage, as assessed by content validity, was higher than non-professionally prepared moulage. We have shown that using professional techniques and low cost materials we can prepare quality high fidelity moulage simulations.

Simulation-based surgical education

The reduction in time for training at the workplace has created a challenge for the traditional apprenticeship model of training. Simulation offers the opportunity for repeated practice in a safe and controlled environment, focusing on trainees and tailored to their needs. Recent technological advances have led to the development of various simulators, which have already been introduced in surgical training. The complexity and fidelity of the available simulators vary, therefore depending on our recourses we should select the appropriate simulator for the task or skill we want to teach. Educational theory informs us about the importance of context in professional learning. Simulation should therefore recreate the clinical environment and its complexity. Contemporary approaches to simulation have introduced novel ideas for teaching teamwork, communication skills and professionalism. In order for simulation-based training to be successful, simulators have to be validated appropriately and integrated in a training curriculum. Within a surgical curriculum, trainees should have protected time for simulation-based training, under appropriate supervision. Simulation-based surgical education should allow the appropriate practice of technical skills without ignoring the clinical context and must strike an adequate balance between the simulation environment and simulators.

The use of computerised simulators for training of transthoracic and transoesophageal echocardiography. The future of echocardiographic training?

BACKGROUND

Echocardiography is the commonest form of non-invasive cardiac imaging but due to its methodology, it is operator dependent. Numerous advances in technology have resulted in the development of interactive programs and simulators to teach trainees the skills to perform particular procedures, including transthoracic and transoesophageal echocardiography.

METHODS

Forty trainee sonographers assessed a computerised mannequin echocardiographic simulator and were taught how to obtain an apical two-chamber (A2C) view and image the superior vena cava (SVC). Forty-two attendees at a TOE simulator workshop assessed its utility and commented on perceived future use, using defined criteria.

RESULTS

One hundred percent and 88% of sonographers found the simulator useful in obtaining the SVC or A2C view respectively. All users found it easy to use and the majority found it helped with image acquisition and interpretation. Attendees of the TOE training day assessed the simulator with 100% finding it easy to use, as well as the augmented reality graphics benefiting image acquisition. Ninety percent felt that it was realistic.

CONCLUSIONS

This study revealed that both trainee sonographers and TOE proceduralists found the simulation process was realistic, helped in image acquisition and improved assessment of spatial relationships. Echocardiographic simulators may play an important role in the future training of echocardiographic skills.

Real-time image-based B-mode ultrasound image simulation of needles using tensor-product interpolation

In this paper, we propose an interpolation-based method for simulating rigid needles in B-mode ultrasound images in real time. We parameterize the needle B-mode image as a function of needle position and orientation. We collect needle images under various spatial configurations in a water-tank using a needle guidance robot. Then we use multidimensional tensor-product interpolation to simulate images of needles with arbitrary poses and positions using collected images. After further processing, the interpolated needle and seed images are superimposed on top of phantom or tissue image backgrounds. The similarity between the simulated and the real images is measured using a correlation metric. A comparison is also performed with in vivo images obtained during prostate brachytherapy. Our results, carried out for both the convex (transverse plane) and linear (sagittal/para-sagittal plane) arrays of a trans-rectal transducer indicate that our interpolation method produces good results while requiring modest computing resources. The needle simulation method we present can be extended to the simulation of ultrasound images of other wire-like objects. In particular, we have shown that the proposed approach can be used to simulate brachytherapy seeds.

Advanced catheter technology: is this the answer to overcoming the long learning curve in complex endovascular procedures

INTRODUCTION

Advanced endovascular procedures require a high degree of skill with a long learning curve. We aimed to identify differential increases in endovascular skill acquisition in novices using conventional (CC), manually steerable (MSC) and robotic endovascular catheters (RC).

MATERIALS/METHODS

10 novices cannulated all vessels within a CT-reconstructed pulsatile-flow arch phantom in the Simulated Endovascular Suite. Subjects were randomly assigned to conventional/manually-steerable/robotic techniques as the first procedure undertaken. The operators repeated the task weekly for 5 weeks. Quantitative (cannulation times, wire/catheter-tip movements, vessel wall hits) and qualitative metrics (validated rating scale (IC3ST)) were compared.

RESULTS

Subjects exhibited statistically significant differences when comparing initial to final performance for total procedure times and catheter-tip movements with all catheter types. Sequential non-parametric comparisons identified learning curve plateau levels at weeks 2 or 3(RCs, MSCs), and at week 4(CCs) for the majority of metrics. There were significantly fewer catheter-tip movements using advanced catheter technology after training (Week 5: CC 74 IQR(59-89) versus MSC 62(44-81); p = 0.028, and RC 33 (28-44); p = 0.012). RCs virtually eliminated wall hits at the arch (CC 29(28-76) versus RC 8(6-9); p = 0.005) and produced significantly higher overall performance scores (p < 0.02).

CONCLUSION

Advanced endovascular catheters, although more intricate, do not seem to take longer to master and in some areas offer clear advantages with regards to positional control, at a faster rate. RCs seem to be the most intuitive and advanced skill acquisition occurs with minimal training. Robotic endovascular technology may have a significantly shorter path to proficiency allowing an increased number of trainees to attempt more complex endovascular procedures earlier and with a greater degree of safety.