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1.
Cureus ; 16(1): e52300, 2024 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-38357039

RESUMO

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.

2.
Cureus ; 16(1): e52583, 2024 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-38371073

RESUMO

Introduction Ultrasound-guided peripheral venous catheter placement (UG-PVCP) is a key skill for establishing intravenous access, especially in patients with anatomical challenges. Ultrasound is highly operator-dependent, and it is essential to ensure a sufficient level of competence when educating healthcare professionals. Competence can be acquired through simulation-based training (SBT) using phantoms or simulators. We developed a phantom for SBT, and in this study, we explore the phantom's usability and technical fidelity. Methods Novices with no experience in UG-PVCP and experts who routinely performed the procedure were asked to perform three ultrasound-guided catheter placement attempts on the phantom. Afterward, they were asked to complete a usability questionnaire consisting of 14 questions exploring the usability and fidelity of the phantom. Results Fifty-seven participants were included in the study: 29 novices and 28 experts. When assessing positive questions about the frequency of use, ease of use, integration of functionality, quickness to learn, and confidence level, the study showed a median score of 4 to 5 out of 5 in the two groups. The median was 1 to 2 out of 5 for negative questions assessing cumbersomeness, unnecessary complexity, and model inconsistency. In an additional comment textbox, one participant mentioned that the cannulation did not feel realistic but that it was good for cannulation practice. Conclusions We believe the phantom is suitable for an educational curriculum since it shows a high level of usability, scoring high on positive questions while scoring low on negative questions, and having high functional fidelity.

3.
Phys Eng Sci Med ; 47(1): 261-272, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-38150058

RESUMO

Diagnostic ultrasound (US) scanners are generally evaluated using proprietary quality assurance (QA) phantoms, but their prohibitively high cost may prevent organizations to perform the necessary tests. This study aimed to develop a low-cost gel wax phantom with targets to determine the lateral and axial resolution and diameter of a hyperechoic target in an US scanner. The acoustic property (AP) of gel wax, which includes the speed of sound (cus), acoustic impedance (Z), and attenuation coefficient (µ), were determined for multiple transducers operating at 2.25, 5, 10, 15, and 30 MHz. These results were compared to the AP of soft tissue. Two polytetrafluoroethylene (PTFE) rectangular frames with holes separated by 5, 10, and 20 mm were constructed. Nylon filaments and stainless-steel disc (SS disc) (diameter = 16.8 mm) were threaded through the frames and suitably placed in gel wax to obtain orthogonal targets in the phantom. The target dimensions obtained from computerized tomography (CT) and US images of the phantom were compared for phantom validation. The average cus=1431.4 m/s, mass density ρ = 0.87 g/cm3, Z = 1.24 MRayls, and µ ranged from 0.7 to 0.98 dB/cm/MHz for gel wax at 22 °C. The US image measurement exhibited a maximum error in determining the diameter of the SS disc, resulting in a value of 18 mm instead of its actual value of 16.8 mm. The phantom volume decreased by 1.8% in 62 weeks. The present phantom is affordable, stable, customizable, and can be used to evaluate diagnostic US scanners across multiple centers.


Assuntos
Tomografia Computadorizada por Raios X , Ultrassom , Ultrassonografia/métodos , Imagens de Fantasmas , Acústica
4.
J Ultrason ; 23(93): e73-e79, 2023 06.
Artigo em Inglês | MEDLINE | ID: mdl-37520745

RESUMO

Aim: We sought to create and describe a self-made simulator designed and created for teaching purposes: a high-fidelity ultrasound phantom for demonstrating antral follicle count, ultrasound supervision of controlled of ovarian stimulation, and ultrasound-guided oocyte retrieval. Materials and methods: The uterus and ovaries of the ultrasound phantom were made from beef tongue, a male condom, latex gloves, cotton suture threads, bi-distilled water, and ultrasound gel. The components were placed in a pelvis created using three-dimensional (3D) printing. The phantom was presented to and evaluated by a group of 14 physicians pursuing a postgraduate course in reproductive medicine. Two training stations were structured: one to simulate antral follicle count and controlled ovarian stimulation and the other to simulate ultrasound-guided oocyte retrieval. Future specialists were requested to complete a feedback questionnaire evaluating the self-made simulator and the two practice stations. Results: The transvaginal ultrasound phantom was successfully created, making it possible to simulate antral follicle count, ultrasound control of ovarian hyperstimulation, and oocyte retrieval, and to capture ultrasound images. A review of the answers provided in the feedback questionnaire showed that the phantom had a good appearance and design, was realistic, helped to improve motor coordination, and could be a useful tool in the training of specialists in assisted reproduction. Conclusion: This phantom was designed to enable instruction and practice in the evaluation of ovarian follicles and ultrasound-guided oocyte retrieval in a supervised training environment. This self-made simulator is proposed as a training tool that could be included in the curricular structure of residency and postgraduate programs in reproductive medicine.

5.
Cureus ; 15(4): e37295, 2023 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-37168147

RESUMO

Ultrasound identification of soft tissue pathology is a useful skill for the emergency physician, but it requires practice and familiarity to be effective. Given its rising popularity in the Emergency Department, regional anesthesia is another essential skill that requires practice. Realistic models can help create procedural confidence and accuracy. Since entry-level professional-grade models can be cost-prohibitive, the development of simple and affordable models for teaching is valuable for emergency provider education, especially in resource-limited settings. Other inexpensive models have been produced and discussed in ultrasound; literature; however, no models have yet been designed for the replication of several different modalities in a single model. We developed and successfully tested a meat phantom model utilizing materials available at a local grocery store that can be quickly assembled in a short amount of time with minimal effort. This low-cost, easy-to-make phantom accurately replicates human tissue and pathology and is ideal for learners to practice several skill sets at once.

6.
Sensors (Basel) ; 23(4)2023 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-36850766

RESUMO

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.


Assuntos
Realidade Aumentada , Óculos Inteligentes , Humanos , Punções , Ultrassonografia
7.
J Vasc Access ; 24(2): 271-276, 2023 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-34250855

RESUMO

Clinicians commonly place ultrasound-guided intravenous catheters in peripheral veins for the diagnostic and therapeutic treatments of patients. This procedural skill requires practice and static phantom models are a commonly used education tool. Several commercial models that simulate blood vessels within tissue are available; however, they can be expensive. There are many examples of "Do-It-Yourself" models proposed; however, many of these require time to create the model. Mixing water and gelatin to make a gelatinous material, and the time necessary to set and store the phantom may deter people from pursuing these options. We propose Konnyaku jelly, or "yam cake," found in many Asian grocery stores, as the substrate to create a phantom model. When imaging with ultrasound, this model is similar to commercially available models, however the cost is less than $3.00 and preparation is about 5 min. We believe that Konnyaku jelly should be a more generally accepted homemade static model for phantom preparation.


Assuntos
Cateterismo , Gelatina , Humanos , Análise Custo-Benefício , Ultrassonografia/métodos , Imagens de Fantasmas , Ultrassonografia de Intervenção/métodos
8.
Ultrasound Med Biol ; 49(1): 18-30, 2023 01.
Artigo em Inglês | MEDLINE | ID: mdl-36210247

RESUMO

Ultrasound-guided needle interventions are common procedures in medicine, and tissue-mimicking phantoms are widely used for simulation training to bridge the gap between theory and clinical practice in a controlled environment. This review assesses tissue-mimicking materials from 24 studies as candidates for a high-fidelity ultrasound phantom, including methods for evaluating relevant acoustic and mechanical properties and to what extent the reported materials mimic the superficial layers of biological tissue. Speed of sound, acoustic attenuation, Young's modulus, hardness, needle interaction forces, training efficiency and material limitations were systematically evaluated. Although gelatin and agar have the closest acoustic values to tissue, mechanical properties are limited, and strict storage protocols must be employed to counteract dehydration and microbial growth. Polyvinyl chloride (PVC) has superior mechanical properties and is a suitable alternative if durability is desired and some ultrasound realism to human tissue may be sacrificed. Polyvinyl alcohol (PVA), while also requiring hydration, performs well across all categories. Furthermore, we propose a framework for the evaluation of future ultrasound-guided needle intervention tissue phantoms to increase the fidelity of training programs and thereby improve clinical performance.


Assuntos
Agulhas , Ultrassonografia de Intervenção , Humanos , Imagens de Fantasmas , Ultrassonografia , Módulo de Elasticidade , Ultrassonografia de Intervenção/métodos
9.
Brachytherapy ; 21(6): 799-805, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36050143

RESUMO

PURPOSE/OBJECTIVES: There is a clinical need to develop anatomic phantoms for simulation-based learning in gynecological brachytherapy. Here, we provide a step-by-step approach to build a life-sized gynecological training phantom based on magnetic resonance imaging (MRI) of an individual patient. Our hypothesis is that this phantom can generate convincing ultrasound (US) images that are similar to patient scans. METHODS: Organs-at-risk were manually segmented using patient scans (MRI). The gynecological phantom was constructed using positive molds from 3D printing and polyvinyl chloride (PVC) plastisol. Tissue texture/acoustic properties were simulated using different plastic softener/hardener ratios and microbead densities. Nine readers (residents) were asked to evaluate 10 cases (1 ultrasound image per case) and categorize each as a "patient" or "phantom" image. To evaluate whether the phantom and patient images were equivalent, we used a multireader, multicase equivalence study design with two composite null hypotheses with proportion (pr) at H01: pr ≤ 0.35 and H02: pr ≥ 0.65. Readers were also asked to review US videos and identify the insertion of an interstitial needle into the pelvic phantom. Computed Tomography (CT) and magnetic resonance (MR) images of the phantom were acquired for a feasibility study. RESULTS: Readers correctly classified "patient" and "phantom" scans at pr = 53.3% ± 6.2% (p values 0.013 for H01 and 0.054 for H02, df = 5.96). Readers reviewed US videos and identified the interstitial needle 100% of the time in transabdominal view, and 78% in transrectal view. The phantom was CT and MR safe. CONCLUSIONS: We have outlined a manufacturing process to create a life-sized, gynecological phantom that is compatible with multi-modality imaging and can be used to simulate clinical scenarios in image-guided brachytherapy procedures.


Assuntos
Braquiterapia , Humanos , Braquiterapia/métodos , Imagens de Fantasmas , Imageamento por Ressonância Magnética/métodos , Tomografia Computadorizada por Raios X/métodos , Espectroscopia de Ressonância Magnética
10.
J Med Ultrasound ; 30(2): 130-134, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35832372

RESUMO

A significant limitation of homemade phantoms is shelf life. Our goal was to compare the impact on shelf life of easily obtained additives. Fifteen additives were mixed into a gelatin-psyllium hydrophilic mucilloid fiber phantom; three of these additives were used as a layer on top of the phantom. The mixtures were stored in the refrigerator and at room temperature. The samples were evaluated daily for microbial growth and phantom degradation. A 4% of chlorhexidine gluconate layer on top of the phantom quickly made the phantom unusable. The addition of benzoic acid and bleach to the mixture negatively affected phantom appearance with ultrasound imaging. The addition of household bleach or 4% chlorhexidine gluconate to the mixture or a 10% povidone-iodine layer on top of the phantom was the best way to preserve samples stored at room temperature. The refrigerated sample outlasted the paired room temperature sample in every case, with most room temperature samples becoming unusable by day 10 and most refrigerated samples lasting past 50 days.

11.
Ultrasound J ; 14(1): 14, 2022 Mar 26.
Artigo em Inglês | MEDLINE | ID: mdl-35347463

RESUMO

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.

12.
Brachytherapy ; 21(1): 110-119, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-34876360

RESUMO

PURPOSE/OBJECTIVE(S): Standardized simulation training geared towards interstitial brachytherapy (IS BT) for gynecologic malignancies is lacking in radiation oncology resident education. We developed and implemented a curriculum for IS BT training with (1) lecture on equipment, workflow, and guidelines, (2) hands-on ultrasound-guided IS BT workshop, and (3) treatment planning workshop. METHODS AND MATERIAL: The cost in materials of each phantom was approximately $66. After a lecture, two alternating workshops were performed. The first session consisted of a hands-on ultrasound-guided IS BT workshop with one resident imaging the phantom with a transabdominal ultrasound probe and the other resident implanting the phantom with needles. A second session consisted of a hands-on treatment planning workshop using BrachyVision and an l-Q spreadsheet with the following objectives: coverage goal, meeting D2cc constraints, and minimizing V200. The primary outcome was improvement in knowledge assessed with Likert-style questions and objective knowledge-based questions (KBQs). RESULTS: Four of the seven medical residents that participated in this curriculum had prior IS BT experience. Residents reported significantly improved knowledge regarding gynecologic IS BT equipment and procedure, evaluating gynecologic anatomy using ultrasound, CT simulation, contouring, and plan review (overall median pre-session subjective score 2 (1) -(3) versus post-session score 4 (3) -(4, p < 0.01). Residents demonstrated improvement in answering KBQs correctly from 44% correct at baseline to 88% after completion of the curriculum (p < 0.01). All residents "Agree" and "Strongly Agree" the session was an effective learning experience. CONCLUSIONS: Residents participating in phantom training with an ultrasound curriculum and a treatment planning session is effective for improving knowledge and skills in IS BT for radiation oncology residents.


Assuntos
Braquiterapia , Internato e Residência , Treinamento por Simulação , Braquiterapia/métodos , Competência Clínica , Currículo , Feminino , Humanos
13.
J Ultrasound ; 25(2): 259-263, 2022 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-33797736

RESUMO

Specialized training in ocular ultrasound is not a focus for most emergency medicine residencies, despite the fact that it allows physicians to quickly and accurately identify ocular pathology and prioritize emergency ophthalmological consultations. Therefore, we tested the value of utilizing normal and pathologic ocular ultrasound phantoms as a training tool for residents. Twenty emergency medicine residents were given a pre-test including written and practical skills diagnosis of ocular phantom pathologies, a short video on common ocular pathologies, practice time with the phantoms and a post-test including written and scanning components. Residents were then asked to complete an overall evaluation of the learning activity. After didactic and hands-on training with phantoms, residents demonstrated a significant increase in knowledge, skills and preparedness for diagnosing real patients with ocular pathologies. Overall, the phantoms allowed residents an unrestricted opportunity to practice and refine their technique. This study provided a framework for teaching emergency medicine residents the basics of ocular US through a brief didactic and practical intervention using novel ocular pathology US phantoms. Our curriculum resulted in both objective and subjective improvement in residents' performance and understanding of ocular US.


Assuntos
Internato e Residência , Competência Clínica , Currículo , Humanos , Sistemas Automatizados de Assistência Junto ao Leito , Ultrassonografia/métodos
14.
Int J Hyperthermia ; 39(1): 22-33, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-34936844

RESUMO

PURPOSE: High-intensity focused ultrasound (HIFU) treatment requires prior evaluation of the HIFU transducer output. A method using micro-capsulated thermochromic liquid crystal (MTLC) to evaluate the temperature distribution in the media during HIFU exposure has been previously developed. However, the color-coded temperature range of commercial MTLC is approximately 10 °C, which is insufficient for temperature measurement for HIFU exposure. We created two layers of tissue-mimicking phantoms with different color-coded temperature ranges, and a new visualization method was developed by utilizing the axisymmetric pressure distribution of a HIFU focus. METHODS: A two-layer phantom with two sensitivity ranges was created. The HIFU transducer was set to align the focal point to the boundary between the two layers. Images of the upper and lower layers were flipped along the boundary between the two layers such that they overlapped with each other, assuming the pressure distribution of HIFU to be axisymmetric. RESULTS: The experimental and simulation results were compared to evaluate the accuracy of the phantom temperature measurement. The experimental time profile of the temperature and spatial distribution around the HIFU focus matched well with that of the simulation. However, there is room for improvement in the accuracy in the axial direction of HIFU focus. CONCLUSION: Users can apply our proposed method in clinical practice to promptly assess the output of the HIFU transducer before treatment.


Assuntos
Ablação por Ultrassom Focalizado de Alta Intensidade , Temperatura Corporal , Ablação por Ultrassom Focalizado de Alta Intensidade/métodos , Imagens de Fantasmas , Temperatura , Transdutores
15.
Ultrasonics ; 116: 106484, 2021 May 29.
Artigo em Inglês | MEDLINE | ID: mdl-34102524

RESUMO

The study investigated ultrasound (US) transducer push, tantamount to applied transducer pressure, during abdominal aortic aneurysm (AAA) US scanning in a simulated non-clinical setup. During an assessment of maximal AAA diameter on a three-dimensional print-based AAA phantom, US transducer push varied as much as 2000% (range: 0.52-12.45 kPa) amongst 16 experienced sonographers. The mean transducer push was 5.54 ± 3.91 kPa (CV = 0.71). Deformation of a standardized gel-pad allowed for transducer push calculation based on US images; Young's modulus of the gel-pad was estimated to 44,26 N/m2. The method is theoretically validated in a safe and non-clinical environment. Future investigations with the aim of clinical validation of the gel-pad principle on AAA patients are suggested, including the objectification of the magnitude of an eventual transducer push-related error during US AAA diameter measurement.

16.
Ultrasound ; 29(2): 73-82, 2021 May.
Artigo em Inglês | MEDLINE | ID: mdl-33995553

RESUMO

INTRODUCTION: The quantification of heating effects during exposure to ultrasound is usually based on laboratory experiments in water and is assessed using extrapolated parameters such as the thermal index. In our study, we have measured the temperature increase directly in a simulator of the maternal-fetal environment, the 'ISUOG Phantom', using clinically relevant ultrasound scanners, transducers and exposure conditions. METHODS: The study was carried out using an instrumented phantom designed to represent the pregnant maternal abdomen and which enabled temperature recordings at positions in tissue mimics which represented the skin surface, sub-surface, amniotic fluid and fetal bone interface. We tested four different transducers on a commercial diagnostic scanner. The effects of scan duration, presence of a circulating fluid, pre-set and power were recorded. RESULTS: The highest temperature increase was always at the transducer-skin interface, where temperature increases between 1.4°C and 9.5°C were observed; lower temperature rises, between 0.1°C and 1.0°C, were observed deeper in tissue and at the bone interface. Doppler modes generated the highest temperature increases. Most of the heating occurred in the first 3 minutes of exposure, with the presence of a circulating fluid having a limited effect. The power setting affected the maximum temperature increase proportionally, with peak temperature increasing from 4.3°C to 6.7°C when power was increased from 63% to 100%. CONCLUSIONS: Although this phantom provides a crude mimic of the in vivo conditions, the overall results showed good repeatability and agreement with previously published experiments. All studies showed that the temperature rises observed fell within the recommendations of international regulatory bodies. However, it is important that the operator should be aware of factors affecting the temperature increase.

17.
Ultrason Imaging ; 43(5): 253-261, 2021 09.
Artigo em Inglês | MEDLINE | ID: mdl-34036871

RESUMO

The ultrasound phantoms used to educate medical students should not only closely mimic the ultrasound characteristics of human soft tissues but also be inexpensive and easy to manufacture. I have been studying handmade ultrasound phantoms and proposed an ultrasound phantom comprising calcium alginate hydrogel that met these requirements but caused a speckle pattern similar to that observed in ultrasound images of liver. In this study, I show that adding ethanol to the precursors used to fabricate the phantom reduces the speckle pattern. The ultrasound propagation velocity and attenuation coefficient of the phantom were 1561 ± 8 m/s and 0.54 ± 0.18 dB/cm/MHz, respectively (mean ± standard deviation), which are within the ranges of those in human soft tissues (1530-1600 m/s and 0.3-1.0 dB/cm/MHz, respectively). This phantom is easy to fabricate without special equipment, is inexpensive, and is suitable for elementary training on ultrasound diagnosis, operation of ultrasound-guided needles, and blind catheter insertion.


Assuntos
Alginatos , Educação Médica , Humanos , Imagens de Fantasmas , Ultrassonografia
18.
Int Endod J ; 54(2): 231-240, 2021 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-32931061

RESUMO

AIM: To develop a laboratory-based tooth model of simulated blood flow in teeth and evaluate it using ultrasound Doppler flowmetry (UDF). METHODOLOGY: A laboratory-based tooth model for UDF was created based on a microfluidic experimental model proposed by Kim & Park (2016 a,b). Twenty-one maxillary or mandibular anterior human teeth within 1 month of extraction were used. Four holes were made in each tooth to fit 1.6-mm diameter polytetrafluoroethylene (PTFE) tubes: at the apical foramen, palatal surface in the centre of the crown, palatal surface apical to the cementoenamel junction (CEJ) and the root centre. Fluid mimicking pulsating blood was pumped (pressure range: 0-200 mbar, flow rate range: 0-80 µL min-1 ) into the apical foramen via the PTFE tubes, which exited the tooth through the palatal surface in the centre of the crown (control group), palatal surface below the CEJ (group 1) and the palatal surface at the mid-root level (group 2). An UDF transducer of 20 MHz was placed at a 60° angle to the labial surface of tooth and was used to measure the fluid flow velocity (Vs, Vas, Vm, Vam, Vd, Vad and Vakd). The flow velocity of the different groups was compared using the Wilcoxon signed-rank test, with a 95% confidence level. RESULTS: UDF facilitated the detection of the simulated pulpal blood flow in the control group and group 1, but not in group 2. The mean and standard deviations of Vas, Vam and Vakd were 0.921 ± 0.394, 0.479 ± 0.208 and 0.396 ± 0.220 cm s-1 , respectively, in the control group, and 0.865 ± 0.368, 0.424 ± 0.215 and 0.487 ± 0.279 cm s-1 , respectively, in group 1. The pulpal blood flow values of the control group and group 1 were not significantly different (p > 0.05). CONCLUSIONS: This laboratory study revealed that ultrasound Doppler flowmetry enabled the detection of simulated blood flow below the level of the CEJ but not at the mid-root level.


Assuntos
Polpa Dentária , Laboratórios , Polpa Dentária/diagnóstico por imagem , Humanos , Fluxometria por Laser-Doppler , Fluxo Sanguíneo Regional , Reologia , Ultrassonografia
19.
Ultrasound Med Biol ; 47(3): 820-832, 2021 03.
Artigo em Inglês | MEDLINE | ID: mdl-33328132

RESUMO

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.


Assuntos
Imagens de Fantasmas , Impressão Tridimensional , Ultrassonografia/métodos , Humanos
20.
Ann Anat ; 232: 151563, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-32585296

RESUMO

PURPOSE: Today, ultrasound-guided peripheral endovascular interventions have the potential to be an alternative to conventional interventions that are still X-ray and contrast agent based. For the further development of this approach, a research environment is needed that represents the individual patient-specific endovascular properties as realistically as possible. Aim of the project was the construction of a phantom that combines ultrasound capabilities and the possibility to simulate peripheral endovascular interventions. MATERIAL AND METHODS: We designed a modular ultrasound-capable phantom with exchangeable patient specific vascular anatomy. For the manufacturing of the vascular pathologies, we used 3D printing technology. Subsequently, we evaluated the constructed simulator with regards to its application for endovascular development projects. RESULTS: We developed an ultrasound-capable phantom with an exchangeable 3D-printed segment of the femoral artery. This modality allows the study of several patient-specific 3D-printed pathologies. Compared to the flow properties of a human artery (male; age 28) the phantom shows realistic flow properties in the duplex ultrasound image. We proved the feasibility of the simulator by performing an ultrasound-guided endovascular procedure. Overall, the simulator showed realistic intervention conditions. CONCLUSIONS: With the help of the constructed simulator, new endovascular procedures and navigation systems, such as ultrasound-guided peripheral vascular interventions, can be further developed. Additionally, in our opinion, the use of such simulators can also reduce the need for animal experiments.


Assuntos
Procedimentos Endovasculares/métodos , Artéria Femoral/anatomia & histologia , Imagens de Fantasmas/classificação , Impressão Tridimensional , Adulto , Alternativas ao Uso de Animais , Simulação por Computador , Estudos de Viabilidade , Humanos , Masculino , Ultrassonografia de Intervenção
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