Creation and Validation of a Simulator for Neonatal Brain Ultrasonography: A Pilot Study

Overcoming roadblocks in clinical innovation via high fidelity simulation: use of a phantom simulator to achieve FDA and IRB approval of a clinical trial of fetal embolization of vein of Galen malformations

BACKGROUND

Vein of Galen malformation (VOGM) is a rare, life-threatening vascular malformation in neonates and is treated with embolization. However, even at the most experienced centers, patients face high mortality and morbidity. In utero treatment options have been limited by lack of animal models or simulations.

OBJECTIVE

To create a novel ultrasound phantom simulator for a preclinical feasibility study of in utero fetal intervention for VOGM.

METHODS

Novel phantoms were designed and built in two configurations of spherical and windsock shape from cryogel material to mimic the salient vasculature of the fetal VOGM, based on real-patient fetal MR imaging dimensions. Critical anatomy was realistically mimicked within this model and transtorcular ultrasound-guided coil deployment was simulated. Each phantom model was assessed before and after treatment to evaluate coil mass deposition within the target.

RESULTS

The two phantoms underwent pretreatment T2-weighted MR imaging assessment, ultrasound-guided embolization, post-treatment MR and fluoroscopic imaging, and visual inspection of the sliced phantoms for target embolization verification. Postoperative MR scans confirmed realistic compact deposition of the coil masses within the central cavity. Phantom embolization results were submitted as part of the institutional review board and US Food and Drug Administration investigative device exemption approval for a first-in-humans clinical trial of fetal intervention for VOGM.

CONCLUSIONS

A phantom simulator for fetal intervention of VOGM produces lifelike results during trial interventions, removing obstacles to feasibility and safety evaluations, typically precluded by non-availability of appropriate animal models. The study provides a proof of concept for potentially wider applications of medical simulation to enable novel procedural advancements in neurointerventions.

3D Modeling and Advanced Visualization of the Pediatric Brain, Neck, and Spine

The ready availability of advanced visualization tools on picture archiving and communication systems workstations or even standard laptops through server-based or cloud-based solutions has enabled greater adoption of these techniques. We describe how radiologists can tailor imaging techniques for optimal 3D reconstructions provide a brief overview of the standard and newer "on-screen" techniques. We describe the process of creating 3D printed models for surgical simulation and education, with examples from the authors' institution and the existing literature. Finally, the review highlights current uses and potential future use cases for virtual reality and augmented reality applications in a pediatric neuroimaging setting.

Impact of Simulation Training on Radiology Resident Performance in Neonatal Head Ultrasound

RATIONALE AND OBJECTIVES

The aim of this study was to determine whether resident performance in head ultrasound on neonates improves following brain phantom simulation training.

MATERIALS AND METHODS

Ten junior radiology residents with at least one year of radiology training were divided into two equal groups. Both groups received a detailed head ultrasound protocol sheet and observed a technologist perform a head ultrasound on a neonatal patient at the beginning of their first pediatric radiology rotation. Both groups of residents also received teaching with a brain phantom model. Group A residents independently performed one head ultrasound exam, subsequently received phantom simulation training, and then performed a post-training head ultrasound exam. Group B residents received phantom simulation training prior to their first head ultrasound exam. Three pediatric radiologists independently and blindly reviewed the ultrasound images of each head ultrasound exam for proficiency of image acquisition using a validated scoring system. Scores of Group A residents prior to phantom training were compared to their scores after phantom training as well as to scores of Group B residents using simple linear regression.

RESULTS

There was a statistically significant improvement in the performance of head ultrasound on neonates when comparing the same residents pre- and postphantom training (p = 0.003). Residents who initially trained with the phantom performed significantly better on their first head ultrasound examination on a neonate than those residents who did not (p = 0.005).

CONCLUSION

Our novel head ultrasound phantom training model significantly improves radiology resident performance of head ultrasound on neonates and may, therefore, be beneficial for residency education.

Use of three-dimensional printing for simulation in ultrasound education: a scoping review

Background

There is a significant learning curve when teaching ultrasonography to medical trainees; task trainers can help learners to bridge this gap and develop their skills. Three-dimensional printing technology has the potential to be a great tool in the development of such simulators.

Objective

This scoping review aimed to identify what 3D-printed models have been used in ultrasound education to date, how they were created and the pros and limitations involved.

Design

Researchers searched three online databases to identify 3D-printed ultrasound models used in medical education.

Results

Twelve suitable publications were identified for inclusion in this review. The models from included articles simulated largely low frequency and/or high stakes events, with many models simulating needle guidance procedures. Most models were created by using patient imaging data and a computer-aided design software to print structures directly or print casting molds. The benefits of 3D-printed educational trainers are their low cost, reproducibility, patient specificity and accuracy. The current limitations of this technology are upfront investments and a lack of optimisation of materials.

Conclusions

The use of 3D-printed ultrasound task trainers is in its infancy, and more research is needed to determine whether or not this technology will benefit medical learners in the future.

Neonatal brain ultrasound training for beginners: Could a head phantom be useful?

Background

The traditional method of teaching the technique of neonatal brain ultrasonography is based upon the interaction between the practitioner and the neonate under the supervision of a tutor. This approach has disadvantages in that it may result in a longer imaging examination and the patient may become agitated. As demand for ultrasound services escalates and departments get busier, this often means that the trainee and supervisor are under pressure to work rapidly. Such environments are common but not conducive to the development of adequate skills and competencies. A neonatal head phantom used as part of a dedicated study day could help the beginner to learn basic elements of the ultrasound examination within a safe stress-free environment. It offers the opportunity to repeat the examination as often as the trainee wishes without time pressures and the distraction of a moving and potentially very sick baby.

Aim

The aim of this study is to evaluate the efficacy of a commercial phantom as a means for the practitioner to acquire the fundamental principles of neonatal brain ultrasound.

Method

A total of 17 participants attending a one day neonatal ultrasound course aimed at beginners were invited to complete a short two-part questionnaire that assessed their perceived improvement in scanning ability before and after using a commercially available head phantom.

Results

Of the 14 returned questionnaires, the overall perceived understanding, ability and confidence improved and anxiety levels about the procedure fell. The median pre-training score was 9.0 compared with the median post-training score of 12.0 (P = 0.005, Wilcoxon signed-rank test). At least 79% (up to 86%) of participants valued their experience with the phantom and would recommend the course to colleagues. Furthermore, about two-thirds reported that they would like to have additional practise with the phantom. Preliminary data from this study suggest that beginners found the head phantom useful for mastering some of the early skills required for neonatal brain ultrasound examinations, which in turn improved their confidence and reduced anxiety.

Patient-Specific Polyvinyl Alcohol Phantom Fabrication with Ultrasound and X-Ray Contrast for Brain Tumor Surgery Planning

Phantoms are essential tools for clinical training, surgical planning and the development of novel medical devices. However, it is challenging to create anatomically accurate head phantoms with realistic brain imaging properties because standard fabrication methods are not optimized to replicate any patient-specific anatomical detail and 3D printing materials are not optimized for imaging properties. In order to test and validate a novel navigation system for use during brain tumor surgery, an anatomically accurate phantom with realistic imaging and mechanical properties was required. Therefore, a phantom was developed using real patient data as input and 3D printing of molds to fabricate a patient-specific head phantom comprising the skull, brain and tumor with both ultrasound and X-ray contrast. The phantom also had mechanical properties that allowed the phantom tissue to be manipulated in a similar manner to how human brain tissue is handled during surgery. The phantom was successfully tested during a surgical simulation in a virtual operating room.

The phantom fabrication method uses commercially available materials and is easy to reproduce. The 3D printing files can be readily shared, and the technique can be adapted to encompass many different types of tumor.

Simulation-Based Structured Education Supports Focused Neonatal Cranial Ultrasound Training

OBJECTIVES

Brain injury in preterm neonates may cause clinical deterioration and requires timeous bedside diagnosis. Teaching cranial ultrasound (US) skills using fragile preterm neonates is challenging. The purpose of this study was to test the effectiveness and feasibility of using task-trainer computer-based simulators and US-suitable cranial phantoms in combination with teaching sessions in teaching novices to perform focused cranial US evaluations for identifying substantial intraventricular hemorrhage.

METHODS

This was a prospective interventional educational study targeting participants with no prior skills in neonatal cranial US. Participants attended a 2-day training workshop, with didactic and hands-on interactive sessions using computer-based and 3-dimensional printed phantom simulators. Participants then performed a cranial US scan on a healthy neonate to assess the diagnostic quality of the images acquired. Individual precourse and postcourse knowledge tests were compared. To test recall, participants also submitted US images acquired on neonates within 3 and 6 months of attending the course.

RESULTS

Forty-five participants completed the training modules. Mean knowledge scores increased significantly (in brain anatomy, brain physiology, intracranial disorders, and US physics domains). Thirty-eight cranial US scans were acquired during the course, 22 within 3 months after completion, and 34 within 6 months after completion. Thirty-two (84%) of the initial 38 case images, 17 (77%) of 22 images submitted within 3 months, and 32 (94%) of 34 images submitted within 6 months after course completion were of diagnostic quality.

CONCLUSIONS

A structured training module with didactic and hand-on training sessions using simulators and phantoms is feasible and supports training of clinicians to perform focused cranial US examinations.

Development and Characterization of Medical Phantoms for Ultrasound Imaging Based on Customizable and Mouldable Polyvinyl Alcohol Cryogel-Based Materials and 3-D Printing: Application to High-Frequency Cranial Ultrasonography in Infants

This work presents an affordable and easily customizable methodology for phantom manufacturing, which can be used to mimic different anatomic organs and structures. This methodology is based on the use of polyvinyl alcohol-based cryogels as a physical substitute for biologic soft tissues and of 3-D printed polymers for hard tissues, moulding and supporting elements. Thin and durable soft-tissue mimicking layers and multilayer arrangements can be obtained using these materials. Special attention was paid to the acoustic properties (sound speed, attenuation coefficient and mechanical impedance) of the materials developed to simulate soft tissues. These properties were characterized as a function of the additives concentration (propylene-glycol and alumina particles). The polyvinyl alcohol formulation proposed in this work is stable over several freeze-thaw cycles, allowing the manufacturing of multilayer materials with controlled properties. The manufacturing methodology presented was applied to the development of a phantom for high-frequency cranial ultrasonography in infants. This phantom was able to reproduce the main characteristics of the ultrasound images obtained in neonates through the anterior fontanel, down to 8-mm depth.

Accessible Personal Ultrasound Training Simulator

OBJECTIVES

Ultrasound simulators are increasingly used for teaching and training purposes, but development has been limited by the need for dedicated and often expensive hardware. The objective of this study was to develop and deploy an accessible and very low-cost personal ultrasound training simulator and obtain trainee feedback.

METHODS

An ultrasound simulator software program that uses a smartphone as a "mock-probe" and a laptop computer as a "mock ultrasound machine" was created. Spatial positional data is acquired from the smartphone's inbuilt accelerometer and gyroscope and transmitted to the laptop computer for processing and display of simulated ultrasound images in real time by the software program. After obtaining institutional review board approval and informed consent, all first-year radiology residents at our institution were provided access to the simulator program during the "bootcamp" introductory conference series, and a written survey was conducted to obtain feedback.

RESULTS

A personal ultrasound training simulator software program (Persimus) that reliably performs motion sensing along 2 axes and displays simulated ultrasound images was developed. Nine of 12 (75%) first-year residents at our institution participated in the written survey. Residents' scored values were 8.44 ± 1.33 and 8.44 ± 1.33 (mean + standard deviation) for perceived utility and overall impression and satisfaction, respectively, of the simulator on the Likert scale (1-10, with 10 being the highest score).

CONCLUSION

Personal ultrasound simulators are technically feasible. These are well received by first-year radiology residents and perceived as useful to their education.

A New Paradigm in Cleft Lip Procedural Excellence: Creation and Preliminary Digital Validation of a Lifelike Simulator

Simulation is becoming an increasingly important tool for hands-on surgical education in a no-risk environment. Cleft lip repair is a common procedure where precise technique is needed to achieve optimal outcome, making it an ideal candidate for simulation. A digital simulated patient with a typical unilateral complete cleft lip and alveolus was constructed using existing three-dimensional imaging studies. Key surface and internal anatomical elements were characterized in detail. A prototype high-fidelity simulator was constructed with silicone and synthetic polymers over a supportive scaffold, piloted by three surgeons using multiple techniques, and digitally compared to real patients. All surgeons completed key steps of a cleft lip repair on the simulator and found it approximated the haptics and anatomy of a cleft lip. Surface change and anthropometric movements accomplished on the simulator were similar for all three surgeons. In digital comparison to analogous real patient data, the simulator anthropometric movements and topographic change were similar to real nasolabial movement. A high-fidelity cleft lip simulator provides "on-demand" opportunity to realistically practice all steps of a cleft lip repair, with implications for overcoming volume-outcome relationship challenges of diminishing operative experience for resident surgeons.

Sonography Simulators: Use and Opportunities in CAAHEP-Accredited Programs

Concern for patient safety and increased demands on health professionals have resulted in challenges for the clinical training of sonography students. The purpose of this study was to examine simulation use in Commission on Accreditation of Allied Health Education Programs (CAAHEP)–accredited sonography programs. A prospective cross-sectional study was conducted. Program directors were sent a survey that addressed the use of simulation and the perception of simulation’s educational value. Of the 230 sonography programs identified, 137 responded, for a response rate of 60%. Of the respondents, 75% indicated they used simulation and 89% reported that it was a good teaching tool. The programs indicated that 81% recorded a positive student experience using simulation. Simulation was rated most useful for improved anatomic identification (55%) and transducer manipulation (64%). Simulation is commonly used for educational training in CAAHEP-accredited sonography programs and is perceived as a positive tool to enhance education of students. More research is needed to establish best use and educational practice.

Patient-specific neurosurgical phantom: assessment of visual quality, accuracy, and scaling effects

BACKGROUND

Training in medical education depends on the availability of standardized materials that can reliably mimic the human anatomy and physiology. One alternative to using cadavers or animal bodies is to employ phantoms or mimicking devices. Styrene-ethylene/butylene-styrene (SEBS) gels are biologically inert and present tunable properties, including mechanical properties that resemble the soft tissue. Therefore, SEBS is an alternative to develop a patient-specific phantom, that provides real visual and morphological experience during simulation-based neurosurgical training.

RESULTS

A 3D model was reconstructed and printed based on patient-specific magnetic resonance images. The fused deposition of polyactic acid (PLA) filament and selective laser sintering of polyamid were used for 3D printing. Silicone and SEBS materials were employed to mimic soft tissues. A neuronavigation protocol was performed on the 3D-printed models scaled to three different sizes, 100%, 50%, and 25% of the original dimensions. A neurosurgery team (17 individuals) evaluated the phantom realism as "very good" and "perfect" in 49% and 31% of the cases, respectively, and rated phantom utility as "very good" and "perfect" in 61% and 32% of the cases, respectively. Models in original size (100%) and scaled to 50% provided a quantitative and realistic visual analysis of the patient's cortical anatomy without distortion. However, reduction to one quarter of the original size (25%) hindered visualization of surface details and identification of anatomical landmarks.

CONCLUSIONS

A patient-specific phantom was developed with anatomically and spatially accurate shapes, that can be used as an alternative for surgical planning. Printed models scaled to sizes that avoided quality loss might save time and reduce medical training costs.