Ultrasound Phantoms to Protect Patients from Novices

EURO-MUSCULUS/USPRM phantom recipe for (musculoskeletal) interventional ultrasound training

Considering the growing role of ultrasound-guided procedures in musculoskeletal medicine, training as regards these interventions is pivotal. While hands-on training on cadavers can be considered optimal, it has several drawbacks, e.g., high cost, poor availability, and technical challenges regarding preservation. Apart from cadavers, different approaches to practicing needle guidance are taught in ultrasound workshops whereby phantoms from meat (e.g., chicken breast), cheese or gelatin are used. Likewise, this article aims to provide a detailed description as to how different gelatin-based phantoms can be prepared. In line with the EURO-MUSCULUS/USPRM (European Musculoskeletal Ultrasound Study Group/Ultrasound Study Group of the International Society of Physical and Rehabilitation Medicine) protocols/background, the authors describe particular basic and advanced phantoms to be used for practicing different technical/manual skills pertaining to common ultrasound-guided procedures. The present manuscript can be considered a practical and ready-to-use "recipe book" for readers who are interested in the wide spectrum of interventional ultrasound.

Agarose as a Tissue Mimic for the Porcine Heart, Kidney, and Liver: Measurements and a Springpot Model

Agarose gels are often used as a tissue mimic. The goal of this work was to determine the appropriate agarose concentrations that result in mechanical properties that match three different porcine organs. Strain tests were carried out with an amplitude varying from 0.01% to 10% at a frequency of 1 Hz on a range of agarose concentrations and porcine organs. Frequency sweep tests were performed from 0.1 Hz to a maximum of 9.5 Hz at a shear strain amplitude of 0.1% for agarose and porcine organs. In agarose samples, the effect of pre-compression of the samples up to 10% axial strain was considered during frequency sweep tests. The experimental measurements from agarose samples were fit to a fractional order viscoelastic (springpot) model. The model was then used to predict stress relaxation in response to a step strain of 0.1%. The prediction was compared to experimental relaxation data, and the results agreed within 12%. The agarose concentrations (by mass) that gave the best fit were 0.25% for the liver, 0.3% for the kidney, and 0.4% for the heart. At a frequency of 0.1 Hz and a shear strain of 0.1%, the agarose concentrations that best matched the shear storage modulus of the porcine organs were 0.4% agarose for the heart, 0.3% agarose for the kidney, and 0.25% agarose for the liver.

[State of the art: Simulation in US]

Technical simulation of diagnostic and therapeutic procedures is of growing relevance for student education and advanced medical training and has already been introduced in the field of ultrasound. This review gives a broad overview on different levels of simulation for ultrasound diagnostics and highlights the technical background of the methodology. A critical review of the literature reveals recommendations for implementing simulation techniques in medical studies and professional ultrasound training. An analysis of strengths and weaknesses shows the advantages of simulation especially in the context of individual learning situations and COVID-19-related restrictions for personal interaction. However, simulation techniques cannot replace the experiences of complex clinical examinations with direct interaction to real patients. Therefore, future applications may focus on repetition and assessment of achieved competencies by using standardized feedback mechanisms in order to preserve the limited resources for practical medical training.

Comparison of human cadaver and blue phantom for teaching ultrasound-guided regional anesthesia to novice postgraduate students of anesthesiology: A randomized controlled trial

Background and Aims

Simulation is increasingly used in medical teaching. Various studies have evaluated different simulation models for training of regional anesthesia (RA). We compared the use of human cadaver and blue phantom models for training of regional anesthesia to novice postgraduate students of anesthesiology.

Material and Methods

Fifty students were taught knobology of the ultrasonography (USG) machine. They were divided into two equal groups by computer-generated random number table, and the groups assigned were kept in sealed envelopes. In group BP, students were trained on a blue phantom model, and in group HC, students were trained on human cadaver. After training, a didactic video of sonoanatomy of the supraclavicular block was shown to all participants. The block performance was then judged on patients requiring supraclavicular block. The primary objective of the study was to compare the block performance time, and secondary objectives were the quality of image acquired, orientation of transducer to the target, identification of ultrasound artifacts, errors committed, complications, and success rate.

Results

The mean block performance time was shorter in group HC compared to group BP (451.96 ± 50.25 and 526.48 ± 43.486 s, respectively; P < 0.001). The image quality score, transducer orientation to the target, and identification of USG artifacts were better in group HC compared to group BP, with lesser number of needle passes.

Conclusion

Cadaver-based training produced better results compared to blue phantom simulator model for teaching of ultrasound-guided RA to novice postgraduate trainees of anesthesiology.

Do-It-Yourself Ultrasonography Phantom Model for Improving Hand Skills: A Technical Report

This technical report focuses on developing a do-it-yourself (DIY) model of a water phantom for training in ultrasound-guided needle insertion techniques. Ultrasound technology is becoming more widely used in perioperative and intensive care settings. However, accurate needle placement using ultrasound guidance necessitates strong spatial reasoning and hand-eye coordination. To address this, the authors experimented with a water phantom model that is cost-effective, easily accessible, and efficient for training. The DIY water phantom was made using materials such as an examination glove, a used vial rubber cap, water, adhesive tape, sealing glue, and a target object. This technical report discusses the process of assembling the water phantom and the potential benefits it offers for ultrasound training.

Implementing ultrasound-guided nerve blocks in the emergency department: A low-cost, low-fidelity training approach

Background

Managing acute pain is a common challenge in the emergency department (ED). Though widely used in perioperative settings, ED-based ultrasound-guided nerve blocks (UGNBs) have been slow to gain traction. Here, we develop a low-cost, low-fidelity, simulation-based training curriculum in UGNBs for emergency physicians to improve procedural competence and confidence.

Methods

In this pre-/postintervention study, ED physicians were enrolled to participate in a 2-h, in-person simulation training session composed of a didactic session followed by rotation through stations using handmade pork-based UGNB models. Learner confidence with performing and supervising UGNBs as well as knowledge and procedural-based competence were assessed pre- and posttraining via electronic survey quizzes. One-way repeated-measures ANOVAs and pairwise comparisons were conducted. The numbers of nerve blocks performed clinically in the department pre- and postintervention were compared.

Results

In total, 36 participants enrolled in training sessions, eight participants completed surveys at all three data collection time points. Of enrolled participants, 56% were trainees, 39% were faculty, 56% were female, and 53% self-identified as White. Knowledge and competency scores increased immediately postintervention (mean ± SD t0 score 66.9 ± 8.9 vs. t1 score 90.4 ± 11.7; p < 0.001), and decreased 3 months postintervention but remained elevated above baseline (t2 scores 77.2 ± 11.5, compared to t0; p = 0.03). Self-reported confidence in performing UGNBs increased posttraining (t0 5.0 ± 2.3 compared to t1 score 7.1 ± 1.5; p = 0.002) but decreased to baseline levels 3 months postintervention (t2 = 6.0 ± 1.9, compared to t0; p = 0.30).

Conclusions

A low-cost, low-fidelity simulation curriculum can improve ED provider procedural-based competence and confidence in performing UGNBs in the short term, with a trend toward sustained improvement in knowledge and confidence. Curriculum adjustments to achieve sustained improvement in confidence performing and supervising UGNBs long term are key to increased ED-based UGNB use.

The ultrasound use of simulators, current view, and perspectives: Requirements and technical aspects (WFUMB state of the art paper)

Simulation has been shown to improve clinical learning outcomes, speed up the learning process and improve learner confidence, whilst initially taking pressure off busy clinical lists. The World Federation for Ultrasound in Medicine and Biology (WFUMB) state of the art paper on the use of simulators in ultrasound education introduces ultrasound simulation, its advantages and challenges. It describes different simulator types, including low and high-fidelity simulators, the requirements and technical aspects of simulators, followed by the clinical applications of ultrasound simulation. The paper discusses the role of ultrasound simulation in ultrasound clinical training, referencing established literature. Requirements for successful ultrasound simulation acceptance into educational structures are explored. Despite being in its infancy, ultrasound simulation already offers a wide range of training opportunities and likely holds the key to a broader point of care ultrasound education for medical students, practicing doctors, and other health care professionals. Despite the drawbacks of simulation, there are also many advantages, which are expanding rapidly as the technology evolves.

Promoting simulation-based training in radiology: a homemade phantom for the practice of ultrasound-guided procedures

OBJECTIVE

Ultrasound-guided intervention is an essential skill for many radiologists and critical for accurate diagnosis and treatment in many radiology subspecialties. Simulation using phantoms have demonstrated statistically significant benefits for trainees within the literature. We propose a novel phantom model which the authors feel is ideal for training clinical radiology trainees in the performance of ultrasound-guided procedures.

METHODS

The recipe to prepare a homemade phantom is described. Results of a local survey from trainees preparing and using the phantom are also presented.

RESULTS

This realistic training simulation model can be adapted to suit a variety of biopsy devices and procedures including soft tissue biopsy and cyst aspiration. The phantom mimics the sonographic appearances of soft tissue and biopsy targets can be concealed within. The phantom was easily prepared by 22 trainees (Likert score 4.5) and it functioned well (Likert score of 4.7).

CONCLUSION

In summary, our phantom model is ideal for training clinical radiology trainees in the performance of ultrasound-guided core biopsy. The availability and low cost of the model, combined with the ease of preparation and reproducibility, make this an efficient and effective addition to the training process.

ADVANCES IN KNOWLEDGE

A low cost easily handmade phantom recipe is described that could be easily implemented in training schemes.

Evaluation of a Low-cost Renal Simulator for the Diagnostic Ultrasound Training of Veterinary Medicine Students

The acquisition of ultrasound diagnostic skills via training is important for undergraduate veterinary medical students. Unfortunately, commercial simulators are costly, which limits their use and makes it necessary to develop low-cost simulators for training purposes. The aim of this study was to evaluate the efficacy of an easily constructed, low-cost, high-fidelity renal simulator for use in diagnostic ultrasound training of veterinary medical students. To construct the simulators, donated cat kidneys were embedded in a prepared agar matrix. The echogenicity of ultrasound scans obtained on the kidney simulator was assessed by the subject lecturers and compared with images acquired during clinical routine diagnostic procedures. Five students with no prior experience of the technique, under the direct supervision of a lecturer, performed five B-mode ultrasound examinations of the renal structure of the simulator. The structure of the kidney was assessed, and its length, width and thickness were measured. Three lecturers performed the same procedure as the students, and their results were used for comparison. Appropriate anatomical and ultrasonographic realism was achieved for each of the three layers of the kidney (cortex, medulla and pelvis), and similar pixel values were obtained with the simulator model and actual clinical diagnostic ultrasounds. In addition, the kidney dimensions acquired by the students were consistent with those acquired by the lecturers. Thus, the proposed kidney simulator can be used for the training of veterinary medicine students in ultrasonographic diagnostic techniques.

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.

The use of joints of meat as phantoms for ultrasound-guided needling skills: a prospective blinded study

BACKGROUND

Needle visualisation during ultrasound-guided procedures is a skill that can be difficult to practise, with commercially available phantoms being expensive and often unrealistic. Our aim was to find an inexpensive, reproducible model that could be used to assist in developing this skill.

METHODS

Pork shoulder, beef brisket, and lamb shoulder joints were compared to a standard blue ultrasound phantom. Five 'chunky' yarn pieces were twisted together and threaded through each joint to simulate hyperechoic nerves. Participants were instructed to ultrasound each specimen and insert a needle close to a nerve like structure. Using a visual analogue scale, specimens were scored based on realism of appearances of ultrasound images and 'feel' of needling.

RESULTS

38 people participated. All specimens of meat scored significantly higher than the blue phantom (p = 0.01). There was no significant difference between the different types of meat.

CONCLUSIONS

Pork, beef and lamb joints are an effective model to use for simulation training for needling skills. They have limited lifespan, but due to its relatively low cost, it is feasible to discard the meat after each training workshop. We hope the use of inexpensive meat products will make ultrasound simulation training simpler to organise and more effective.

Fabrication of low-cost realistic three-dimensional static kidney phantom for ultrasound-guided biopsy applications

Background:

The rapid growth of using ultrasound-guided interventional procedures, including biopsy and drainage, which considered painful procedures, leads to improving the practice cycle of ultrasound-guided procedures. Fabrication of low-cost tissue-mimicking phantoms that serve as a training tool medium for kidney needle biopsy procedures has dramatically overcome the drawbacks associated with these practices, such as reducing the number of miss lesions, medical errors, and recurrence rate as well as these phantoms are widely available and considered a good substitute for cadavers which were not always available and relativity expensive. However, several drawbacks are associated with current kidney phantom models, mainly the short shelf life and the high fabrication cost.

Methods:

This study aims to fabricate a realistic three-dimensional static mature human kidney phantom from low cost and available material for training on ultrasound-guided interventional procedures mainly biopsy test; the material used to fabricate our model is the gelatin-agar mixture.

Results:

This model proved that it is a tissue-mimicking material by measuring their acoustic properties which nearly the same as real human kidney tissue.

Conclusion:

The results of practicing interventional procedures on our phantom model showed good and easy uses for interventional procedures training as well as make it a preferable and economically affordable model.

Making a convenient, low-cost phantom with a previously unreported material for practicing ultrasound-guided procedures

Ultrasound-guided procedures require excellent hand-eye coordination and practice. Trainees should gain this important skill with a phantom prior to performing procedures on patients. Currently available phantoms each have their own unique limitations. We propose an easily made, inexpensive, tissue-like phantom using a previously unreported material. The sonographic appearance of the phantom, with and without a 14-gauge needle, is compared with breast tissue, gelatin phantoms, and commercial phantoms. Target lesions can be produced using readily available materials. The proposed phantom is cheaper than commercial phantoms; performs better than gelatin phantoms, and is ultimately a superior practice tool for residents.

Current status of pain medicine training in anesthesiology and pain medicine residency programs in university hospitals of Korea: a survey of residents’ opinions

Background

In Korea, anesthesiologists are expected to be mainstream pain medicine (PM) practitioners. However, anesthesiology and pain medicine (APM) residency programs mostly emphasize anesthesia learning, leading to insufficient PM learning. Therefore, this study evaluated the current status of PM training in APM residency programs in 10 Korean university hospitals.

Methods

Overall, 156 residents undergoing APM training participated anonymously in our survey, focusing on PM training. We assessed the aim, satisfaction status, duration, opinion on duration, desired duration, weaknesses of the training programs and plans of residents after graduating. We divided the residents into junior (first and second year) and senior (third and fourth year). Survey data were compared between groups.

Results

Senior showed significantly different level of satisfaction grade than did junior (p=0.026). Fifty-seven (81.4%) residents in junior and forty (46.5%) residents in senior underwent PM training for ≤2 months. Most (108; 69.2%) residents felt that the training period was too short for PM learning and 95 (60.9%) residents desired a training period of ≥6 months. The most commonly expressed weakness of the training was low interventional opportunity (29.7%), followed by short duration (26.6%). After residency, 80 (49.1%) residents planned to pursue a fellowship.

Conclusions

Dissatisfaction with PM training was probably due to a structural tendency of the current program towards anesthesia training and insufficient clinical experience, which needs to be rectified, with a change in PM curriculum.

Impact of simulation-based anesthesiology training using an anesthetized porcine model for ultrasound-guided transversus abdominis plane block

Objective

This study was performed to assess the impact of simulation-based training for ultrasound-guided transversus abdominis plane (TAP) block using anesthetized pigs.

Methods

In this prospective study, 23 participating residents (10 in their second year, 13 in their third year) underwent simulation-based training for ultrasound-guided TAP block. The residents completed standard questionnaires comprising 10 multiple-choice questions regarding essential general knowledge of abdominal ultrasound and TAP block before and after the training session. On a 5-point Likert scale, they reported their levels of comfort with the use of ultrasound and block equipment, subject/operator positioning, proper block technique, image documentation, needle handling, anxiety, and their overall confidence with the procedure.

Results

Compared with those before training, the comfort levels of the residents significantly improved for all measures except needle handling. The participants also indicated significantly reduced anxiety regarding performance of the TAP block technique.

Conclusion

The use of anesthetized pigs in simulation-based training for ultrasound-guided TAP block improves procedural knowledge and confidence while reducing the associated anxiety in anesthesiology trainees.

Investigation of a Cost-effective and Durable Material for Containing Ballistic Gel in the Construction of Ultrasound Phantoms

There is significant variability in the realism, cost, and structural integrity of sonographic simulators available for use currently. A common material that is used for the production of sonographic simulators is synthetic ballistic gelatin, which requires a high melting temperature for molding. In this experiment, we investigated the structural integrity of high-density polyethylene (HDPE) when exposed to melted ballistics gel for the assimilation of a sonographic lumbar puncture simulator.

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 efficacy of cervical spine phantoms for improving resident proficiency in performing ultrasound-guided cervical medial branch block: A prospective, randomized, comparative study

BACKGROUND

Few studies have been conducted on the utility of cervical spine phantoms for practicing cervical procedures. Here, we describe a simple method for creating a cervical spine phantom and investigate whether the use of a gelatin-based phantom is associated with improved proficiency in performing ultrasound-guided cervical medial branch block.

METHODS

A cervical spine phantom was prepared using a cervical spine model immersed in a mixture of gelatin and psyllium husk. In total, 27 participants, inexperienced in spinal ultrasonography, were enrolled and allocated to 1 of 2 groups (training group, n = 18; control group, n = 9). All participants were tested (test-1) following an introductory course of basic ultrasonography. Participants in the control group were tested again after 1 week (test-2). Those in the training group received a further individual 3-hour training session, and were tested again after 1 week (test-2).

RESULTS

The mean performance score in test-1 was 62.5 ± 10.1 points in the training group and 62.3 ± 4.1 points in the control group [95% confidence interval (95% CI) -5.5 to 5.8; P = .954]. In test-2, the mean score was 86.8 ± 6.5 points and 59.9 ± 4.4 points in the training and control groups, respectively (95% CI 21.9-31.8; P < .001). The mean time required to complete test-1 was 84.6 ± 26.6 seconds in training group and 90.7 ± 43.9 seconds in the control group (95% CI -34.0 to 21.7; P = .653); in test-2, the time required was 56.6 ± 27.9 and 91.2 ± 43.8 seconds (95% CI -63.0 to -6.2; P = .019), respectively. Interobserver reliability showed excellent agreement based on the intraclass correlation coefficient, and moderate to almost perfect agreement by kappa statistics.

CONCLUSION

Training using a gelatin-based cervical spine phantom helps novices acquire the skills necessary to perform ultrasound-guided cervical medial branch blocks.

Silicone-based composite materials simulate breast tissue to be used as ultrasonography training phantoms

A silicone-based composite breast phantom is fabricated to be used as an education model in ultrasonography training. A matrix of silicone formulations is tracked to mimic the ultrasonography and tactile response of human breast tissue. The performance of two different additives: (i) silicone oil and (ii) vinyl-terminated poly (dimethylsiloxane) (PDMS) are monitored by a home-made acoustic setup. Through the use of 75 wt% vinyl-terminated PDMS in two-component silicone elastomer mixture, a sound velocity of 1.29 ± 0.09 × 10³ m/s and an attenuation coefficient of 12.99 ± 0.08 dB/cm-values those match closely to the human breast tissue-are measured with 5 MHz probe. This model can also be used for needle biopsy as well as for self-exam trainings. Herein, we highlight the fabrication of a realistic, durable, accessible, and cost-effective training platform that contains skin layer, inner breast tissue, and tumor masses.

A pictorial review of signature patterns living in musculoskeletal ultrasonography

The musculoskeletal system is mainly composed of the bones, muscles, tendons, and ligaments, in addition to nerves and blood vessels. The greatest difficulty in an ultrasonographic freeze-frame created by the examiner is recognition of the targeted structures without indicators, since an elephant's trunk may not be easily distinguished from its leg. It is not difficult to find descriptive ultrasonographic terms used for educational purposes, which help in distinguishing features of these structures either in a normal or abnormal anatomic condition. However, the terms sometimes create confusion when describing common objects, for example, in Western countries, pears have a triangular shape, but in Asia they are round. Skilled experts in musculoskeletal ultrasound have tried to express certain distinguishing features of anatomic landmarks using terms taken from everyday objects which may be reminiscent of that particular feature. This pictorial review introduces known signature patterns of distinguishing features in musculoskeletal ultrasound in a normal or abnormal condition, and may stir the beginners' interest to play a treasure-hunt game among unfamiliar images within a boundless ocean.