Versatile, Reusable, and Inexpensive Ultrasound Phantom Procedural Trainers

Enhancing Access to Neuraxial Ultrasound Phantoms for Medical Education of Pediatric Anesthesia Trainees: Tutorial

Unlabelled

Opportunities to learn ultrasound-guided/assisted (USGA) neuraxial techniques for pediatric patients are limited, given the inherent high stakes and small margin of error in this population. Simulation is especially valuable in pediatrics because it enhances competency and efficiency, without added risk, when learning new skills, specifically those seen with ultrasound-guided regional anesthetic techniques. However, access to simulation opportunities involving the use of phantom models in medical education is limited due to excessive costs. We describe a process for producing ultrasound phantoms by using synthetic ballistic gelatin; these ultrasound phantoms can be used for simulation and are affordable, reproducible, and indefinitely shelf stable. The ultrasound images produced by these phantoms are comparable to those obtained from a real pediatric patient, including the sacral anatomy necessary for caudal epidural blocks, as validated by practicing pediatric anesthesiologists. Phantom models offer a more cost-effective alternative to commercially prepared phantoms, thereby expanding access to realistic simulations for neuraxial ultrasound in pediatric medical education, without the prohibitively high expense.

Design, manufacturing, and multi-modal imaging of stereolithography 3D printed flexible intracranial aneurysm phantoms

BACKGROUND

Physical vascular phantoms are instrumental in studying intracranial aneurysms and testing relevant imaging tools and training systems to provide improved clinical care. Current vascular phantom production methods have major limitations in capturing the biophysical and morphological characteristics of intracranial aneurysms with good fidelity and multi-modal imaging capacity. With stereolithography (SLA) 3D printing technology becoming more accessible, newer flexible and transparent printing materials with higher precision controls open the door for improving the efficiency and quality of producing anthropomorphic vascular phantoms but have rarely been explored for the application.

PURPOSE

This technical note intends to report the feasibility of using SLA 3D printing technology to manufacture flexible intracranial aneurysm phantoms with similar scales to the real anatomy, as well as their capacity for multi-modal flow imaging and analysis, including ultrasound flow imaging, high-speed filming, and particle image velocimetry analysis.

METHODS

We designed and 3D-printed two intracranial aneurysm phantoms with an SLA 3D printer using Formlabs Elastic 50A resin. By using a micropump to introduce cyclical flows in the phantoms, we first employed conventional Doppler and vector flow ultrasonography to observe and measure different fluidic properties. Then, a high-speed camera was used to record particles flowing within the phantom, and we further conducted a particle image velocimetry analysis, including the distribution of mean 2D velocity vectors, average velocity magnitudes, and the mean vorticity fields in the phantom for the high-speed imaging data.

RESULTS

We successfully 3D-printed flexible intracranial aneurysm phantoms with similar dimensions to the real anatomy. Additionally, we validated the phantoms' ability to allow visualization, measurement, and analysis of flow dynamics based on both real-time ultrasound and optical imaging.

CONCLUSIONS

Our proof-of-concept study illustrates that SLA 3D printing using commercial elastic resins can significantly contribute towards facilitating the fabrication of flexible intracranial aneurysms phantoms for training, research, and preoperative planning.

Discriminative Ability of Dye Injected Into a Meat Model to Determine Accuracy of Ultrasound-Guided Injection

INTRODUCTION

The utility of using meat models for ultrasound-guided regional anesthesia simulation training has been well established. Feedback is considered the most important element of successful simulation-based education, and simulation offers an opportunity for evaluation. The objective of this study was to establish the discriminative ability of dye injected into a meat model to determine whether injectate is properly placed in the perineural (PN) space, thus providing an additional tool for learner feedback and evaluation.

METHODS

Meat models containing a beef tendon (simulating a nerve) were injected with dye in one of 3 locations: PN, intraneural, and intramuscular. Blinded assessors then independently interpreted the dye staining on the models, marked the interpreted injection location, ease of interpretation, and whether staining was present on the beef tendon.

RESULTS

Thirty meat models were injected with dye and independently assessed. Determining the location of injection was deemed to be easy or very easy in 72% of the models. Assessors correctly identified PN, intraneural, and intramuscular injections 100%, 95%, and 85% of the time, respectively. Assessor agreement was 87%.

CONCLUSIONS

The location of dye injected into a meat model, simulating a peripheral nerve blockade, can be accurately and reliably scored to provide feedback to learners. This technique offers a novel means of providing feedback to trainees and assessing block success in ultrasound-guided regional anesthesia simulation.

A method for mimicking tumour tissue in brain ex-vivo ultrasound for research application and clinical training

BACKGROUND

Intraoperative ultrasound is becoming a common tool in neurosurgery. However, effective simulation methods are limited. Current, commercial, and homemade phantoms lack replication of anatomical correctness and texture complexity of brain and tumour tissue in ultrasound images.

METHODS

We utilise ex-vivo brain tissue, as opposed to synthetic materials, to achieve realistic echogenic complexity and anatomical correctness. Agar, at 10-20% concentrate, is injected into brain tissue to simulate the tumour mass. A commercially available phantom was purchased for benchmarking.

RESULTS

Qualitative analysis is performed by experienced professionals, measuring the impact of the addition of agar and comparing it to the commercial phantom. Overall, the use of ex vivo tissue was deemed more accurate and representative, compared to the synthetic materials-based phantom, as it provided good visualisation of real brain anatomy and good contrast within tissue. The agar tumour correctly produced a region of higher echogenicity with slight diffusion along the margin and expected interaction with the neighbouring anatomy.

CONCLUSION

The proposed method for creating tumour-mimicking tissue in brain tissue is inexpensive, accurate, and simple. Beneficial for both the trainee clinician and the researcher. A total of 576 annotated images are made publicly available upon request.

Feasibility of ultrasound-guided nerve blocks in simulated microgravity: a proof-of-concept study for regional anaesthesia during deep space missions

BACKGROUND

With crewed deep space exploration on the horizon, preparation for potential astronaut health crises in space missions has become vital. Administration of anaesthesia and analgesia presents many challenges owing to constraints specific to space (physiologic and ergonomic challenges associated with microgravity) and nonspecific factors (isolation and lack of supplies). Regional anaesthesia can be the safest option; however, we hypothesised that the ergonomics of microgravity would compromise ease and accuracy of nerve blocks.

METHODS

We evaluated the feasibility of regional anaesthesia in a simulated microgravity environment (free-floating underwater conditions) using a meat (bovine muscle) model. Forty meat models were randomised for injection under simulated microgravity or normal gravity conditions. Success rates were determined by blinded assessors after injection. Parameters assessed included time to block, ease of image acquisition, and ease of needle placement.

RESULTS

The median time to block in normal gravity was 27 (interquartile range 21-69) s vs 35 (interquartile range 22-48) s in simulated microgravity (P=0.751). Ease of image acquisition was similar in both conditions, as was ease of needle placement. There was no significant difference in the rate of accidental intraneural injections (5% vs 5%), with block success rates comparable in both scenarios (80% normal gravity vs 85% microgravity, P>0.999).

CONCLUSIONS

Regional anaesthesia appears feasible for experts in simulated microgravity despite the ergonomic challenges. Although our model has limitations and might not fully capture the complexities of actual space conditions, it provides a foundation for future research into anaesthesia and analgesia during deep space missions.

Fun with electricity: A novel ballistics gelatin model with LED tracking for ultrasound needle guidance

Background

Use of ultrasound (US) for procedural needle guidance can improve success rates, safety, and accuracy. Often, training is performed on task trainers, which can be prohibitively expensive. Determining undesired needle placement is difficult when the needle is poorly visualized with US. Currently available simulation phantoms cannot provide real-time feedback on the location of needle placement.

Objectives

The primary objective was to develop and determine feasibility of a low-cost simulation phantom with an internal circuit and LED light system to determine when a needle contacts internal structures. We also aimed to determine whether its use was associated with increased comfort level.

Methods

Emergency medicine (EM) residents (PGY-1 to PGY-3) performed in-plane and out-of-plane US needle guidance using homemade phantoms. Comfort levels were assessed by pre- and post intervention survey. Outcomes were measured on Likert scale (minimum = 1, maximum = 5). The primary outcome was change in confidence markers before and after the simulation task. Secondary outcomes were survey results of comparisons of these models to prior training experiences on simulators and humans.

Results

All EM residents (30) in our program were invited to participate. Twenty participants enrolled and completed the study. In the primary outcome, median comfort with out-of-plane and in-plane guidance increased after using the model but was more pronounced for out-of-plane guidance. On a posttest survey, residents rated the models overall very similar to prior experience on simulators (median 5/5 [IQR 4.0-5.0]) and moderately similar to humans (median 3/5 [IQR 3.0-4.0]).

Conclusions

We created a low-cost ballistic gelatin phantom with an internal electric needle guidance system. Use of the phantom for training was associated with increased learner comfort with the procedure. Learners rated the characteristics of the phantom as similar to higher-cost commercial equipment and humans.

The Iterative Design and Development of an Affordable Ultrasound Simulator

Simulation-based medical education (SBME) offers a secure and controlled environment for training in ultrasound-related clinical skills such as nerve blocking and intravenous cannulation. Sonographer training for point-of-care ultrasound often adopts the train-the-trainer (TTT) model, wherein a select group of sonographers receive on-site training to subsequently instruct others. This model traditionally relies on expensive commercial ultrasound simulators, which presents a barrier to the scale-up of the TTT model. This study aims to address the need for cost-effective ultrasound simulators suitable for both initial and cascaded TTT. The objective of this report is to present the design and development of an affordable ultrasound simulator, which mimics anatomical features under ultrasound. The simulator was created using additive manufacturing techniques, including 3D printing, ballistic gel, and silicone work. We report on three development-feedback iterations, with feedback provided by an experienced sonographer from FUJIFILM Sonosite Canada Inc. using the think-aloud approach. Overall the results indicate that de-gassed silicone may serve as a good medium; vessels are best produced as hollow canals within the de-gassed silicone; 3D-printed bones cast acoustic shadows, which are reduced by increasing rigidity of the structures, and 3D printing filament and silicone can be used for nerve bundles. Future developments will focus on achieving anatomical accuracy, exploring alternative materials and printing parameters for the bones, and analyzing embedded structures at varying depths within the silicone. The next steps involve integrating the simulator into ultrasound curricula for a formal assessment of its effectiveness as a training tool.

Development of a three-dimensional computer model of the equine heart using a polyurethane casting technique and in vivo contrast-enhanced computed tomography

INTRODUCTION/OBJECTIVES

Insight into the three-dimensional (3D) anatomy of the equine heart is essential in veterinary education and to develop minimally invasive intracardiac procedures. The aim was to create a 3D computer model simulating the in vivo anatomy of the adult equine heart.

ANIMALS

Ten horses and five ponies.

MATERIALS AND METHODS

Ten horses, euthanized for non-cardiovascular reasons, were used for in situ cardiac casting with polyurethane foam and subsequent computed tomography (CT) of the excised heart. In five anaesthetized ponies, a contrast-enhanced electrocardiogram-gated CT protocol was optimized to image the entire heart. Dedicated image processing software was used to create 3D models of all CT scans derived from both methods. Resulting models were compared regarding relative proportions, detail and ease of segmentation.

RESULTS

The casting protocol produced high detail, but compliant structures such as the pulmonary trunk were disproportionally expanded by the foam. Optimization of the contrast-enhanced CT protocol, especially adding a delayed phase for visualization of the cardiac veins, resulted in sufficiently detailed CT images to create an anatomically correct 3D model of the pony heart. Rescaling was needed to obtain a horse-sized model.

CONCLUSIONS

Three-dimensional computer models based on contrast-enhanced CT images appeared superior to those based on casted hearts to represent the in vivo situation and are preferred to obtain an anatomically correct heart model useful for education, client communication and research purposes. Scaling was, however, necessary to obtain an approximation of an adult horse heart as cardiac CT imaging is restricted by thoracic size.

Natural ballistic gelatine ultrasound phantoms are suitable to be used for student education and can be produced cheaply and effectively

Practical experience in ultrasonography at medical and veterinary schools is difficult to achieve using live models due to ethical considerations. A solution to this problem has been the creation of synthetic ultrasound phantoms that allow simulation of both ultrasound scans and ultrasound-guided procedures. Whilst commercially available phantoms are expensive in a resource-limited environment, it would be desirable to create affordable, reusable, homemade phantoms which could be used to aid student learning. Recent studies have indicated that ballistic gelatine is an excellent material for this. A prospective, experimental study was performed with three ultrasound phantoms for student use. Vascular, bladder, and liver parenchymal models were produced with a natural ballistic gel, along with instructions for their construction and maintenance. Model efficacy was evaluated by assessing students' performance in completing a set of tasks when performing ultrasound on a dog. Group one received training with the models, group two received prior training without the models and the group three received no training. Entry and exit questionnaires assessed students' confidence in ultrasound scanning having used the models. Student questionnaires showed that students enjoyed using the models and found them more useful than existing teaching aids. It was also found that the models produced better practical skills in students that trained with them, in comparison to existing teaching. The models were easy to make, produced good images, and are reusable.

Augmenting Image-Guided Procedures through In Situ Visualization of 3D Ultrasound via a Head-Mounted Display

Medical ultrasound (US) is a commonly used modality for image-guided procedures. Recent research systems providing an in situ visualization of 2D US images via an augmented reality (AR) head-mounted display (HMD) were shown to be advantageous over conventional imaging through reduced task completion times and improved accuracy. In this work, we continue in the direction of recent developments by describing the first AR HMD application visualizing real-time volumetric (3D) US in situ for guiding vascular punctures. We evaluated the application on a technical level as well as in a mixed-methods user study with a qualitative prestudy and a quantitative main study, simulating a vascular puncture. Participants completed the puncture task significantly faster when using 3D US AR mode compared to 2D US AR, with a decrease of 28.4% in time. However, no significant differences were observed regarding the success rate of vascular puncture (2D US AR-50% vs. 3D US AR-72%). On the technical side, the system offers a low latency of 49.90 ± 12.92 ms and a satisfactory frame rate of 60 Hz. Our work shows the feasibility of a system that visualizes real-time 3D US data via an AR HMD, and our experiments show, furthermore, that this may offer additional benefits in US-guided tasks (i.e., reduced task completion time) over 2D US images viewed in AR by offering a vividly volumetric visualization.

Simulation-based procedure training (SBPT) in rarely performed procedures: a blueprint for theory-informed design considerations

Simulation-based procedure training is now integrated within health professions education with literature demonstrating increased performance and translational patient-level outcomes. The focus of published work has been centered around description of such procedural training and the creation of realistic part-task models. There has been little attention with regards to design consideration, specifically around how simulation and educational theory should directly inform programme creation. Using a case-based approach in cardiology as an example, we present a blueprint for theory-informed simulation-based procedure training linking learning needs analysis and defining suitable objectives to matched fidelity. We press the importance of understanding how to implement and utilise task competence benchmarking in practice, and the role of feedback and debriefing in cycles of repeated practice. We conclude with evaluation and argue why this should be considered part of the initial design process rather than an after-thought following education delivery.

Cost-Effective Training Models in Point-of-Care Ultrasound for Medical Students in Emergency Medicine: An Evaluation of Current Resources

Background

Ultrasound is becoming more widely utilized in clinical practice; however, its effectiveness is limited by the operator’s skills. Simulation models are attractive options for developing skills because they allow inexperienced users to practice without the risk of endangering patients.

Objective

The purpose of this study was to identify commercially available and homemade ultrasound models to describe them in terms of materials, cost, and whether they are high- or low-fidelity for medical student education.

Methods

This is an investigational study on cost-effective ultrasound training methods for medical students. Our study was performed using search engines in Google, Google Scholar, and PubMed to search for models for the following five modalities: foreign body identification, intravenous (IV) injection training, abdominal ultrasound, ocular ultrasound, and ultrasound-guided lumbar puncture training.

Results

Most homemade models for foreign body identification, IV injection training, and ocular ultrasound could be created for less than $20. IV injection training models were the cheapest commercially available models. There are multiple commercially available options for abdominal ultrasound models, but no options were found for homemade construction. The construction cost for lumbar puncture models was larger due to the need to purchase an anatomically accurate set of lumbar vertebrae.

Conclusions

This study provides initial guidance and suggestions for ultrasound training models that are currently available. Ultrasound models that can be cheaply made or purchased increase accessibility for medical students to gain early exposure in a cost-effective and safe manner.

A 3-D-Printed Patient-Specific Ultrasound Phantom for FAST Scan

Ultrasound phantoms are commonly used to assess the performance of ultrasound systems and ensure their proper functionality, in addition to providing opportunities for medical training. However, Focused Assessment with Sonography for Trauma (FAST) phantoms, in particular, are prohibitively expensive and procedure specific. This work explores the use of additive manufacturing to fabricate a patient-specific, full-scale torso ultrasound phantom. Phantom geometry was derived from anonymized computed tomography scans and segments into discrete organs. The digital organs (torso, skeleton, liver, spleen) were 3-D printed and used as castable molds for producing their respective body features. These organs were integrated with artificial hemorrhages to produce a realistic training tool for FAST scans. The resulting phantom is low in cost, has a verified shelf-life of at least 1 y and was positively reviewed by a trauma and emergency radiologist for its ability to provide accurate geometric and ultrasound information.

Review of simulation model for education of point-of-care ultrasound using easy-to-make tools

Point-of-care ultrasound (POCUS) is a powerful diagnostic tool and provides treatment guidelines in acute critical settings. However, the limitation of using POCUS is operator dependent. Appropriate and validated training for acquiring and using skills in practice must be conducted before using POCUS in clinical settings in order to keep patients safe. Simulation education models have been introduced as a way to solve and overcome these concerns. However, the commercial simulator with sufficiently secured fidelity is expensive and not always available. This review focused on the inexpensive and easily made simulators for education on POCUS in critical specific situations related to the airway, breathing, circulation, and disability. We introduced the simulators that used non-infectious materials, with easily transportable features, and that had a sonographic appearance reproducibility similar to human tissue. We also introduced the recipe of each simulator in two parts: Materials surrounding disease simulators (surrounding materials) and specific disease simulators themselves (target simulators). This review article covered the following: endotracheal or oesophageal intubation, lung (A-lines, B-lines, lung sliding, and pleural effusions such as hemothorax), central vein access, pericardial fluid (cardiac tamponade), the structure related to the eyes, soft tissue abscess, nerve (regional nerve block), and skull fracture simulators.

A Unique Approach to Building a Learner-Guided Ultrasound Simulator for Central Venous Access Training

Commercial central line vascular access trainers are available but have significant limitations including cost, size, and limited durability when used for the complete procedure. A unique central venous access trainer was constructed using silicone loaf pan, ballistic gel, copper pipe and aluminum rods as vessels conduits, with varying inserts including latex and silicone to simulate different vascular structures, and the use of camouflage. This trainer is inexpensive, portable, reusable, allows the complete procedure to be simulated, and may be customized to the specific needs of the learner. The assembled simulator demonstrated excellent ultrasound visualization, including varying size and vessel character, allowed modification to specific learner needs, while at the same time being light-weight, portable, inexpensive, and reusable. A moderate-fidelity central venous access simulator can be constructed in a cost-effective manner, which can be optimized to the learner skill level and allows the entire procedure to be completed on the simulator.

Cardiac Tissue-Mimicking Ballistic Gel Phantom for Ultrasound Imaging in Clinical and Research Applications

Ballistic gel was investigated as a tissue-mimicking material in an anthropomorphic cardiac phantom for ultrasound imaging. The gel was tested for its acoustic properties and its compatibility with conventional plastics molding techniques. Speed of sound and attenuation were evaluated in the range 2-12 MHz. The speed of sound was 1537 ± 39 m/s, close to typical values for cardiac tissue (∼1576 m/s). The attenuation coefficient was 1.07 dB/cm·MHz, within the range of values previously reported for cardiac tissue (0.81-1.81 dB/cm·MHz). A cardiac model based on human anatomy was developed using established image segmentation processes and conventional plastic molding techniques. Key anatomic features were observed, captured and identified in the model using an intracardiac ultrasound imaging system. These favorable results along with the material's durability and processes that allow for repetitive production of detailed whole-heart models at low cost are promising. There are numerous applications for geometrically complex phantoms in research, training, device development and clinical use.

Customized Low-Cost Model for Hands-on Training in Intraoperative Ultrasound for Neurosurgeons: Our Experience and Review of Literature

BACKGROUND

Practical ultrasound (US) training is essential to overcome operator dependence and optimize image acquisition. For intraoperative neurosurgical application, in addition to hand-eye coordination, ultrasound training should incorporate training for visuomotor and visuospatial skills, as well as 3-dimensional depth orientation. Our agar-based, low-cost model has been developed keeping these skill sets in mind.

MATERIALS AND METHODS

We have described preparation of an agar-based, low-cost customizable model using commonly available echogenic objects as targets, which allows the clinician to perform various training tasks like depth insonation, target localization, and biopsy and resection cavity insonation. This low-cost model was implemented for internal training and validated at an international training course.

RESULTS

The cost of the model was 4 USD, and its preparation time was <1 hour. It can be used for performing multiple US training tasks and provides realistic images and good tactile feedback. However, the model is perishable and artifacts are occasionally visible. Feedback survey results showed that >80% of participants felt the model was useful for US training.

CONCLUSIONS

Our customizable low-cost US training model is an effective and efficient tool for US training with high acceptance by neurosurgeons. It faithfully mimics various intraoperative tasks and helps clinicians gain confidence to use intraoperative ultrasound as an adjunct during the procedures. This model can be used by individual surgeons/departments for ongoing training, as well as for larger training courses and workshops.

A simple, realistic walled phantom for intravascular and intracardiac applications

PURPOSE

This work aims to develop a simple, anatomically and haptically realistic vascular phantom, compatible with intravascular and intracardiac ultrasound. The low-cost, dual-layered phantom bridges the gap between traditional wall-only and wall-less phantoms by showing both the vessel wall and surrounding tissue in ultrasound imaging. This phantom can better assist clinical tool training, testing of intravascular devices, blood flow studies, and validation of algorithms for intravascular and intracardiac surgical systems.

METHODS

Polyvinyl alcohol cryogel (PVA-c) incorporating a scattering agent was used to obtain vessel and tissue-mimicking materials. Our specific design targeted the inferior vena cava and renal bifurcations which were modelled using CAD software. A custom mould and container were 3D-printed for shaping the desired vessel wall. Three phantoms were prepared by varying both the concentrations of scattering agent as well as the number of freeze-thaw cycles to which the phantom layers were subjected during the manufacturing process. Each phantom was evaluated using ultrasound imaging using the Foresight™ ICE probe. Geometrical validation was provided by comparing CAD design to a CT scan of the phantom.

RESULTS

The desired vascular phantom was constructed using 2.5% and 0.05% scattering agent concentration in the vessel and tissue-mimicking layers, respectively. Imaging of the three phantoms showed that increasing the number of freeze-thaw cycles did not significantly enhance the image contrast. Comparison of the US images with their CT equivalents resulted in an average error of 0.9[Formula: see text] for the lumen diameter.

CONCLUSION

The phantom is anatomically realistic when imaged with intracardiac ultrasound and provides a smooth lumen for the ultrasound probe and catheter to manoeuvre. The vascular phantom enables validation of intravascular and intracardiac image guidance systems. The simple construction technique also provides a workflow for designing complex, multi-layered arterial phantoms.

Ballistic research techniques: visualizing gunshot wounding patterns

There are difficulties associated with mapping gunshot wound (GSW) patterns within opaque models. Depending on the damage measurement parameters required, there are multiple techniques that can provide methods of "seeing" the GSW pattern within an opaque model. The aim of this paper was to test several of these techniques within a cadaveric animal limb model to determine the most effective. The techniques of interest were flash X-ray, ultrasound, physical dissection, and computed-tomography (CT). Fallow deer hind limbs were chosen for the model with four limbs used for each technique tested. Quarantined 7.62 × 39 mm ammunition was used for each shot, and each limb was only shot once, on an outdoor range with shots impacting at muzzle velocity. Flash X-ray provided evidence of yaw within the limb during the projectile's flight; ultrasound though able to visualise the GSW track, was too subjective and was abandoned; dissection proved too unreliable due to the tissue being cadaveric so also too subjective; and lastly, CT with contrast provided excellent imaging in multiple viewing planes and 3D image reconstruction; this allowed versatile measurement of the GSW pattern to collect dimensions of damage as required. Of the different techniques examined in this study, CT with contrast proved the most effective to allow precise GSW pattern analysis within a cadaveric animal limb model. These findings may be beneficial to others wishing to undertake further ballistic study both within clinical and forensic fields.

[Simulator model for ultrasound-guided pericardiocentesis : Construction manual and practical evaluation]

An important challenge in learning ultrasound-assisted interventions, such as pericardiocentesis, is the navigation of the needle in a three-dimensional space on the basis of a two-dimensional image. In order to learn this in vitro realistic simulators are required. We manufactured a model which allows simulation of pericardiocentesis on the basis of ballistic gelatin (12.6%, 250 Bloom). Furthermore, the pericardiocentesis model was subjectively evaluated by 37 anesthetists in a pre-post design. The models used proved to be technically simple to manufacture, hard wearing and realistic. They are therefore regularly used in our hospitals to learn ultrasound-assisted interventions.

A Versatile, Low-Cost, Three-Dimensional-Printed Ultrasound Procedural Training Phantom of the Human Knee

The use of musculoskeletal ultrasound is expanding in many medical disciplines, and simulation trainers have been successfully employed to help practitioners learn various ultrasound techniques. While there are fewer commercial trainers in musculoskeletal ultrasound than other ultrasound modalities, the ones that do exist can be prohibitively expensive. Several less expensive phantom trainers have been described in the literature, including those made of ballistic gelatine. The authors present a three-dimensional printed knee phantom that was overlaid with ballistic gelatine as a viable option for training.

An easy-to-handle speed of sound test object for skills labs using additive manufacturing (RAPTUS-SOS)

A new generation of speed of sound (SOS) test object is presented that is fully constructed using additive manufacturing processes with a 3D-printer. The object contains 2 compartments with thin filaments and tubes that can be filled with fluid substances. The filaments are located at equal distances to each other; the tubes have fixed diameters. Depending on the chosen fluids (e.g. water, glycerol-water, corn oil, salt water) and room temperature, the mismatch in distance or diameter depending on the SOS error has been measured using ultrasound imaging equipment. The velocity of the fluid could be calculated deductively with high accuracy (range of total error: 0.1-3.4%). The results show that 3D-printed objects or additive manufacturing techniques can be suitable to use as teaching test objects within skills labs.

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.

The effect of military clothing on gunshot wounding patterns in gelatine

With no two gunshot wounds (GSW) being the same, novel research into wound ballistics is challenging. It is evident that the majority of previous wound ballistic research has been conducted without the presence of clothing. Whilst the effect of clothing on wound contamination has been explored, there is a paucity of literature examining the effect of clothing on GSW patterns. The aim of this study was to test the effect of Multi-Terrain Pattern (MTP) UK military clothing on GSW patterns within calibrated blocks of 10% by mass gelatine, using two types of ammunition commonly used in recent conflicts—7.62 × 39 mm and 5.45 × 39 mm. In total, 36 blocks were shot, 18 by each projectile type, further divided into 6 with no clothing layers (C_nil), 6 with a single clothing layer (C_min) and 6 with maximum clothing layers (C_max) worn on active duty. Blocks were analysed with high-speed video and dissection to capture measurements of damage, and results compared using analysis of variance (ANOVA). Results showed significantly different damage measurements within blocks with C_max for both ammunition types compared to the other clothing states. This may result in GSWs that require more extensive surgical management, inviting further study.

Low-cost three-dimensional printed phantom for neuraxial anesthesia training: Development and comparison to a commercial model

METHODS

Anonymized CT DICOM data was segmented to create a 3D model of the lumbar spine. The 3D model was modified, placed inside a digitally designed housing unit and fabricated on a desktop 3D printer using polylactic acid (PLA) filament. The model was filled with an echogenic solution of gelatin with psyllium fiber. Twenty-two staff anesthesiologists performed a spinal and epidural on the 3D printed simulator and a commercially available Simulab phantom. Participants evaluated the tactile and ultrasound imaging fidelity of both phantoms via Likert-scale questionnaire.

RESULTS

The 3D printed neuraxial phantom cost $13 to print and required 25 hours of non-supervised printing and 2 hours of assembly time. The 3D printed phantom was found to be less realistic to surface palpation than the Simulab phantom due to fragility of the silicone but had significantly better fidelity for loss of resistance, dural puncture and ultrasound imaging than the Simulab phantom.

CONCLUSION

Low-cost neuraxial phantoms with fidelity comparable to commercial models can be produced using CT data and low-cost infrastructure consisting of FLOS software and desktop 3D printers.

Ultrasound-guided lumbar puncture with a needle-guidance system: A prospective and controlled study to evaluate the learnability and feasibility of a newly developed approach

OBJECTIVE

To evaluate the learnability and feasibility of a new technique comprising a needle-guidance-system (NGS) for ultrasound-assisted lumbar puncture.

METHOD

Using a randomized crossover study design, 24 medical students were asked to perform an ultrasound-assisted lumbar puncture on a gel phantom using two different techniques that each included a paramedian insertion site. Procedure 1 (P1) used a pre-procedural ultrasound scan to predetermine the ideal insertion point. Procedure 2 (P2) applied a new technique comprising an NGS for performing real-time ultrasound-guided lumbar puncture. Success rates and performance times for both procedures were compared. Participants were also asked to complete a post-study questionnaire, both to quantitatively assess the workload involved and state their personal preferences.

RESULTS

In comparison to the pre-procedural scan (P1), the NGS (P2) was associated with a significant increase in the number of successful punctures per participant (5 (P2) [interquartile range: 3.3-5.0] vs. 3 (P1) [interquartile range: 1.3-4.0], p = 0.005), and led to a significant reduction in performance time (118 seconds vs. 80.6 seconds, p < 0.001). In terms of workload perception, NGS use was associated with significantly better performances and lower frustration levels, as rated by students in the post-study questionnaire. Finally, 23/24 participants stated their preference for P2.

CONCLUSION

Our newly-developed technique for real-time ultrasound-guided lumbar puncture proved to be learnable and feasible for novices, and only required a small amount of training. The use of an NGS therefore has the potential to serve as a key feature of the ultrasound-assisted lumbar puncture.

A novel method for creating custom shaped ballistic gelatin trainers using plaster molds

Simulation based procedural training is an effective and frequently used method for teaching vascular access techniques which often require commercial trainers. These can be prohibitively expensive, which allows for homemade trainers made of gelatin to be a more cost-effective and attractive option. Previously described trainers are often rectangular with a flat surface that is dissimilar to human anatomy. We describe a novel method to create a more anatomically realistic trainer using ballistic gelatin, household items, and supplies commonly found in an emergency department such as the plaster wrap typically used to make splints.