Full waveform inversion(FWI)has showed great potential in the detection of musculoskeletal disease.However,FWI is an ill-posed inverse problem and has a high requirement on the initial model during the imaging process...Full waveform inversion(FWI)has showed great potential in the detection of musculoskeletal disease.However,FWI is an ill-posed inverse problem and has a high requirement on the initial model during the imaging process.An inaccurate initial model may lead to local minima in the inversion and unexpected imaging results caused by cycle-skipping phenomenon.Deep learning methods have been applied in musculoskeletal imaging,but need a large amount of data for training.Inspired by work related to generative adversarial networks with physical informed constrain,we proposed a method named as bone ultrasound imaging with physics informed generative adversarial network(BUIPIGAN)to achieve unsupervised multi-parameter imaging for musculoskeletal tissues,focusing on speed of sound(SOS)and density.In the in-silico experiments using a ring array transducer,conventional FWI methods and BUIPIGAN were employed for multiparameter imaging of two musculoskeletal tissue models.The results were evaluated based on visual appearance,structural similarity index measure(SSIM),signal-to-noise ratio(SNR),and relative error(RE).For SOS imaging of the tibia–fibula model,the proposed BUIPIGAN achieved accurate SOS imaging with best performance.The specific quantitative metrics for SOS imaging were SSIM 0.9573,SNR 28.70 dB,and RE 5.78%.For the multi-parameter imaging of the tibia–fibula and human forearm,the BUIPIGAN successfully reconstructed SOS and density distributions with SSIM above 94%,SNR above 21 dB,and RE below 10%.The BUIPIGAN also showed robustness across various noise levels(i.e.,30 dB,10 dB).The results demonstrated that the proposed BUIPIGAN can achieve high-accuracy SOS and density imaging,proving its potential for applications in musculoskeletal ultrasound imaging.展开更多
BACKGROUND:We aimed to evaluate the utility of point-of-care ultrasound(POCUS)in the assessment of hand infections that present to the emergency department(ED)and its impact on medical decision making and patient mana...BACKGROUND:We aimed to evaluate the utility of point-of-care ultrasound(POCUS)in the assessment of hand infections that present to the emergency department(ED)and its impact on medical decision making and patient management.METHODS:We conducted a retrospective review of patients who presented to two urban academic EDs with clinical presentations concerning for skin and soft tissue infections(SSTI)of the hand between December 2015 and December 2021.Two trained POCUS fellowship physicians reviewed an ED POCUS database for POCUS examinations of the hand.We then reviewed patients’electronic health records(EHR)for demographic characteristics,history,physical examination findings,ED course,additional imaging studies,consultations,impact of POCUS on patient care and final disposition.RESULTS:We included a total of 50 cases(28 male,22 female)in the final analysis.The most common presenting symptoms and exam findings were pain(100%),swelling(90%),and erythema(74%).The most common sonographic findings were edema(76%),soft tissue swelling(78%),and fluid surrounding the tendon(57%).POCUS was used in medical decision making 68%of the time(n=34),with the use of POCUS leading to changes in management 38%of the time(n=19).POCUS use led to early antibiotic use(11/19),early consultation(10/19),and led to the performance of a required procedure(8/19).The POCUS diagnosis was consistent with the discharge diagnosis of flexor tenosynovitis 8/12 times,abscess 12/16 times,and cellulitis 14/20 times.CONCLUSION:POCUS is beneficial for evaluating of hand infections that present to the ED and can be used as an important part of medical decision making to expedite patient care.展开更多
BACKGROUND:Ultrasound guidance is commonly used for accessing difficult peripheral veins.For successful access,a tourniquet is required for venodilation.Tourniquets decrease the compressibility and increase the diamet...BACKGROUND:Ultrasound guidance is commonly used for accessing difficult peripheral veins.For successful access,a tourniquet is required for venodilation.Tourniquets decrease the compressibility and increase the diameter of veins;they also obfuscate artery-vein differentiation on ultrasound.We aimed to establish the upper limit of sphygmomanometer cuff pressure that facilitates artery-vein differentiation during ultrasound-guided peripheral intravenous access.METHODS:We employed the sphygmomanometer cuff as a tourniquet for venodilation and tested it on seven participants at six different levels as follows:0 mmHg,DBP/2,DBP,(DBP+SBP)/2,SBP,and SBP+20 mmHg.We used an ultrasound probe attached to a pressure-measuring instrument to record cross-sectional images of the cubital artery and vein.During ultrasonography,compression was applied to the blood vessels through the skin.The following day,we measured the wrist pulse pressure and observed the oximeter pulse wave at six different tourniquet pressure levels.Repeated-measures analysis of variance(ANOVA)on ranks and Tukey’s post-hoc analysis were used for multiple comparisons.RESULTS:Arterial pulsation was maintained at tourniquet pressures between 0 mmHg and(DBP+SBP)/2.However,arterial pulsation decreased or disappeared when the tourniquet pressure reached or exceeded the SBP.Moreover,at this pressure level,the superior compressibility of veins compared to that of arteries was no longer observed.Compression of the artery to 75% and 50% of its original diameter increased arterial pulsation.CONCLUSION:Arterial pulsation and the superior compressibility are useful indicators for differentiating veins from arteries until the tourniquet pressure reaches(DBP+SBP)/2.However,these indicators are not reliable once the tourniquet pressure exceeds the SBP.展开更多
In order to suppress the low-frequency ultrasound vibration in the broadband range of 20 k Hz—100 k Hz,this paper proposes and discusses an acoustic metamaterial with low-frequency ultrasound vibration attenuation pr...In order to suppress the low-frequency ultrasound vibration in the broadband range of 20 k Hz—100 k Hz,this paper proposes and discusses an acoustic metamaterial with low-frequency ultrasound vibration attenuation properties,which is configured by hybrid arc and sharp-angle convergent star-shaped lattices.The effect of the dispersion relation and the bandgap characteristic for the scatterers in star-shaped are simulated and analyzed.The target bandgap width is extended by optimizing the geometry parameters of arc and sharp-angle convergent lattices.The proposed metamaterial configured by optimized hybrid lattices exhibits remarkable broad bandgap characteristics by bandgap complementarity,and the simulation results verify a 99%vibration attenuation amplitude can be obtained in the frequency of20 k Hz—100 k Hz.After the fabrication of the proposed hybrid configurational star-shaped metamaterial by 3D printing technique,the transmission loss experiments are performed,and the experimental results indicate that the fabricated metamaterial has the characteristics of broadband vibration attenuation and an amplitude greater than 85%attenuation for the target frequency.These results demonstrate that the hybrid configurational star-shaped metamaterials can effectively widen the bandgap and realize high efficiency attenuation,which has capability for the vibration attenuation in the application of highprecise equipment.展开更多
Handheld ultrasound devices are known for their portability and affordability,making them widely utilized in underdeveloped areas and community healthcare for rapid diagnosis and early screening.However,the image qual...Handheld ultrasound devices are known for their portability and affordability,making them widely utilized in underdeveloped areas and community healthcare for rapid diagnosis and early screening.However,the image quality of handheld ultrasound devices is not always satisfactory due to the limited equipment size,which hinders accurate diagnoses by doctors.At the same time,paired ultrasound images are difficult to obtain from the clinic because imaging process is complicated.Therefore,we propose a modified cycle generative adversarial network(cycleGAN) for ultrasound image enhancement from multiple organs via unpaired pre-training.We introduce an ultrasound image pre-training method that does not require paired images,alleviating the requirement for large-scale paired datasets.We also propose an enhanced block with different structures in the pre-training and fine-tuning phases,which can help achieve the goals of different training phases.To improve the robustness of the model,we add Gaussian noise to the training images as data augmentation.Our approach is effective in obtaining the best quantitative evaluation results using a small number of parameters and less training costs to improve the quality of handheld ultrasound devices.展开更多
BACKGROUND: Point-of-care ultrasound(US) is a proven diagnostic imaging tool in the emergency department(ED). Modern US devices are now more compact, affordable and portable, which has led to increased usage in auster...BACKGROUND: Point-of-care ultrasound(US) is a proven diagnostic imaging tool in the emergency department(ED). Modern US devices are now more compact, affordable and portable, which has led to increased usage in austere environments. However, studies supporting the use of US in the prehospital setting are limited. The primary outcome of this pilot study was to determine if paramedics could perform cardiac ultrasound in the fi eld and obtain images that were adequate for interpretation. A secondary outcome was whether paramedics could correctly identify cardiac activity or the lack thereof in cardiac arrest patients.METHODS: We performed a prospective educational study using a convenience sample of professional paramedics without ultrasound experience. Eligible paramedics participated in a 3-hour session on point-of-care US. The paramedics then used US during emergency calls and saved the scans for possible cardiac complaints including: chest pain, dyspnea, loss of consciousness, trauma, or cardiac arrest.RESULTS: Four paramedics from two distinct fire stations enrolled a total of 19 unique patients, of whom 17 were deemed adequate for clinical decision making(89%, 95%CI 67%–99%). Paramedics accurately recorded 17 cases of cardiac activity(100%, 95%CI 84%–100%) and 2 cases of cardiac standstill(100%, 95%CI 22%–100%).CONCLUSION: Our pilot study suggests that with minimal training, paramedics can use US to obtain cardiac images that are adequate for interpretation and diagnose cardiac standstill. Further large-scale clinical trials are needed to determine if prehospital US can be used to guide care for patients with cardiac complaints.展开更多
Photoacoustic imag ing(PAI)is a nonin vasive biomedical imag ing tech no logy capable of multiscale imag ing of biological samples from orga ns dow n to cells.Multiscale PAI requires differe nt ultraso und tra nsducer...Photoacoustic imag ing(PAI)is a nonin vasive biomedical imag ing tech no logy capable of multiscale imag ing of biological samples from orga ns dow n to cells.Multiscale PAI requires differe nt ultraso und tra nsducers that are flat or focused because the current widely-used piezoelectric transducers are rigid and lack the flexibility to tune their spatial ultrasound responses.Inspired by the rapidly-developing flexible photonics,we exploited the inherent flexibility and low-loss features of optical fibers to develop a flexible fiber-laser ultrasound sensor(FUS)for multiscale PAI.By simply bending the fiber laser from straight to curved geometry,the spatial ultraso und resp onse of the FUS can be tuned for both wide-view optical-resolution photoacoustic microscopy at optical diffraction-limited depth(~1 mm)and photoacoustic computed tomography at optical dissipation-limited depth of several centimeters.A radio-frequency demodulation was employed to get the readout of the beat frequency variation of two orthogonal polarization modes in the FUS output,which ensures low-noise and stable ultrasound detection.Compared to traditional piezoelectrical transducers with fixed ultrasound responses once manufactured,the flexible FUS provides the freedom to design multiscale PAI modalities including wearable microscope,intravascular endoscopy,and portable tomography system,which is attractive to fundamental biologic-al/medical studies and clinical applications.展开更多
Transdermal drug delivery （TDD） can effectively bypass the first-pass effect. In this paper, ultrasound-facilitated TDD on fresh porcine skin was studied under various acoustic parameters, including frequency, ampli...Transdermal drug delivery （TDD） can effectively bypass the first-pass effect. In this paper, ultrasound-facilitated TDD on fresh porcine skin was studied under various acoustic parameters, including frequency, amplitude, and exposure time. The delivery of yellow-green fluorescent nanoparticles and high molecular weight hyaluronic acid （HA） in the skin samples was observed by laser confocal microscopy and ultraviolet spectrometry, respectively. The results showed that, with the application of ultrasound exposures, the permeability of the skin to these markers （e.g., their penetration depth and concentration） could be raised above its passive diffusion permeability. Moreover, ultrasound-facilitated TDD was also tested with/without the presence of ultrasound contrast agents （UCAs）. When the ultrasound was applied without UCAs, low ultrasound frequency will give a better drug delivery effect than high frequency, but the penetration depth was less likely to exceed 200 p.m. However, with the help of the ultrasound-induced microbubble cavitation effect, both the penetration depth and concentration in the skin were significantly enhanced even more. The best ultrasound-facilitated TDD could be achieved with a drug penetration depth of over 600 p.m, and the penetration concentrations of fluorescent nanoparticles and HA increased up to about 4-5 folds. In order to get better understanding of ultrasound-facilitated TDD, scanning electron microscopy was used to examine the surface morphology of skin samples, which showed that the skin structure changed greatly under the treatment of ultrasound and UCA. The present work suggests that, for TDD applications （e.g., nanoparticle drug carriers, transdermal patches and cosmetics）, protocols and methods presented in this paper are potentially useful.展开更多
BACKGROUND: Diagnostic imaging is an integral aspect of care that is often insufficient, if not altogether absent, in rural and remote regions of low to middle income countries(LMICs) such as Tanzania. The introductio...BACKGROUND: Diagnostic imaging is an integral aspect of care that is often insufficient, if not altogether absent, in rural and remote regions of low to middle income countries(LMICs) such as Tanzania. The introduction of ultrasound can significantly impact treatment in these countries due to its portability, low cost, safety, and usefulness in various medical assessments. This study reviews the implementation of a four-week ultrasound course administered annually from 2013–2016 in a healthcare professional school in Mwanza, Tanzania by first-year allopathic US medical students.METHODS: Participants(n=582, over 4 years) were recruited from the Tandabui Institute of Health Sciences and Technology to take the ultrasound course. Subjects were predominantly clinical officer students, but other participants included other healthcare professional students, practicing healthcare professionals, and school employees. Data collected includes pre-course examination scores, post-course examination scores, course quiz scores, demographic surveys, and postcourse feedback surveys. Data was analyzed using two-tailed t-tests and the single factor analysis of variance(ANOVA).RESULTS: For all participants who completed both the pre-and post-course examinations(n=229, 39.1% of the total recruited), there was a significant mean improvement in their ultrasound knowledge of 42.5%, P<0.01.CONCLUSION: Our data suggests that trained first-year medical students can effectively teach a point of care ultrasound course to healthcare professional students within four weeks in Tanzania. Future investigation into the level of long-term knowledge retention, impact of ultrasound training on knowledge of human anatomy and diagnostic capabilities, and how expansion of an ultrasound curriculum has impacted access to care in rural Tanzania is warranted.展开更多
Objective Focused cardiac ultrasound(FCU)and lung ultrasound(LU)are increasingly being used in critically ill patients.This study aimed to investigate the effect of FCU in combination with LU on these patients and to ...Objective Focused cardiac ultrasound(FCU)and lung ultrasound(LU)are increasingly being used in critically ill patients.This study aimed to investigate the effect of FCU in combination with LU on these patients and to determine if the timing of ultrasound examination was associated with treatment change.Methods This is a multicenter cross-sectional observational study.Consecutive patients admitted to the intensive care unit(ICU)were screened for enrollment.FCU and LU were performed within the first 24 h,and treatment change was proposed by the performer based on the ultrasound results and other clinical conditions.Results Among the 992 patients included,502 were examined within 6 h of ICU admission(early phase group),and 490 were examined after 6 h of admission(later phase group).The early phase group and the later phase group had similar proportions of treatment change(48.8%vs.49.0%,χ^(2)=0.003,P=0.956).In the multivariable analysis,admission for respiratory failure was an independent variable associated with treatment change,with an odds ratio(OR)of 2.357[95%confidence interval(CI):1.284-4.326,P=0.006];the timing of examination was not associated with treatment change(OR=0.725,95%CI:0.407-1.291,P=0.275).Conclusions FCU in combination with LU,whether performed during the early phase or later phase,had a significant impact on the treatment of critically ill patients.Patients with respiratory failure were more likely to experience treatment change after the ultrasound examination.展开更多
Hyperthermia effects （39-44 ℃） induced by pulsed high-intensity focused ultrasound （HIFU） have been regarded as a promising therapeutic tool for boosting immune responses or enhancing drug delivery into a solid t...Hyperthermia effects （39-44 ℃） induced by pulsed high-intensity focused ultrasound （HIFU） have been regarded as a promising therapeutic tool for boosting immune responses or enhancing drug delivery into a solid tumor. However, previous studies also reported that the cell death occurs when cells are maintained at 43 ℃ for more than 20 minutes. The aim of this study is to investigate thermal responses inside in vivo rabbit auricular veins exposed to pulsed HIFU （1.17 MHz, 5300 W/cm2, with relatively low-duty ratios （0.2%-4.3%）. The results show that： （1） with constant pulse repetition frequency （PRF） （e.g., 1 Hz）, the thermal responses inside the vessel will increase with the increasing duty ratio; （2） a temperature elevation to 43 ℃ can be identified at the duty ratio of 4.3%; （3） with constant duty ratios, the change of PRF will not significantly affect the temperature measurement in the vessel; （4） as the duty ratios lower than 4.3%, the presence of microbubbles will not significantly enhance the thermal responses in the vessel, but will facilitate HIFU-induced inertial cavitation events.展开更多
BACKGROUND:The use of ultrasound(US)within healthcare has inspired the development of new US technology.There have been few studies comparing the use of handheld US to standard US for medical education.This research a...BACKGROUND:The use of ultrasound(US)within healthcare has inspired the development of new US technology.There have been few studies comparing the use of handheld US to standard US for medical education.This research aims to determine whether a handheld US device can provide a comparable primary learning experience to that of a standard US machine.METHODS:Over two days of instruction,participants were taught and evaluated on core US fundamentals.The standard group received instruction on standard US machines,while the handheld group received instruction on handheld US devices.Participants completed a qualitative survey regarding their experience.Six hundred and four images were obtained and graded by two emergency medicine physicians.RESULTS:A total of 119 Swiss medical students were enrolled in our study.There was no statistically significant difference in the US assessment measurements,except for faster endpoint septal separation(EPSS)vascular setup time in the handheld group(P=0.001).There was no statistically significant difference in participants’perceived difficulty of US learning(P=0.198),comfort level(P=0.188),or self-estimated capability to perform US in the future(P=0.442).There was no statistically significant difference in the percentage of correctly obtained images(P=0.211)or images that were clinically useful(P=0.256).The median quality score of images obtained by the standard group was eight compared to seven in handheld group(P<0.01).CONCLUSION:Our data suggest a handheld US machine can perform as well as a standard US machine as an educational tool despite sacrifices in image quality.展开更多
BACKGROUND: The current standard for con? rmation of correct supra-diaphragmatic central venous catheter(CVC) placement is with plain ? lm chest radiography(CXR). We hypothesized that a simple point-of-care ultrasound...BACKGROUND: The current standard for con? rmation of correct supra-diaphragmatic central venous catheter(CVC) placement is with plain ? lm chest radiography(CXR). We hypothesized that a simple point-of-care ultrasound(POCUS) protocol could effectively con? rm placement and reduce time to con? rmation.METHODS: We prospectively enrolled a convenience sample of patients in the emergency department and intensive care unit who required CVC placement. Correct positioning was considered if turbulent flow was visualized in the right atrium on sub-xiphoid, parasternal or apical cardiac ultrasound after injecting 5 cc of sterile, non-agitated, normal saline through the CVC.RESULTS: Seventy-eight patients were enrolled. POCUS had a sensitivity of 86.8%(95%CI 77.1%–93.5%) and speci? city of 100%(95%CI 15.8%–100.0%) for identifying correct central venous catheter placement. Median POCUS and CXR completion were 16 minutes(IQR 10–29) and 32 minutes(IQR 19–45), respectively.CONCLUSION: Ultrasound may be an effective tool to confirm central venous catheter placement in instances where there is a delay in obtaining a con? rmatory CXR.展开更多
BACKGROUND: The study aimed to compare the time to overall length of stay(LOS) for patients who underwent point-of-care ultrasound(POCUS) versus radiology department ultrasound(RDUS).METHODS: This was a prospective st...BACKGROUND: The study aimed to compare the time to overall length of stay(LOS) for patients who underwent point-of-care ultrasound(POCUS) versus radiology department ultrasound(RDUS).METHODS: This was a prospective study on a convenience sample of patients who required pelvic ultrasound imaging as part of their emergency department(ED) assessment.RESULTS: We enrolled a total of 194 patients who were on average 32 years-old. Ninety-eight(51%) patients were pregnant(<20 weeks). Time to completion of RDUS was 66 minutes longer than POCUS(95%CI 60–73, P<0.01). Patients randomized to the RDUS arm experienced a 120 minute longer ED length of stay(LOS)(95%CI 66–173, P<0.01)CONCLUSION: In patients who require pelvic ultrasound as part of their diagnostic evaluation, POCUS resulted in a signifi cant decrease in time to ultrasound and ED LOS.展开更多
Objective: To study on the preparation process of a new surfactant-based microbubble ultrasound contrast agent and to evaluate its contrast effects in vivo. Methods: Microbubble ultrasound contrast agent with three es...Objective: To study on the preparation process of a new surfactant-based microbubble ultrasound contrast agent and to evaluate its contrast effects in vivo. Methods: Microbubble ultrasound contrast agent with three ester surfactants and other additives as its shell materials was prepared by sonication. Sulfur hexafluoride was adopted as the inner gas of the microbubbles. New methods through the combination of optical microscope and some softwares were used to measure the size distribution and the concentration of the microbubbles. Some parameters such as the pH value of the phosphate buffer, quantity of the carboxylic methyl cellulose in the shell materials, selection of the ultrasound power and process time, were studied. Six hybirded dogs were used to verify the in vivo contrast imaging of the contrast agent using second harmonic power Doppler modality. Safety and persistent time of the agent inner animal body were also investigated. Results: Ultrasound contrast agent prepared in the experiment had an average microbubble diameter of 3.95 microns with concentration of 3.6×109 microbubbles per millilitre. Carboxylic methyl cellulose was found as an important shell material which had obviously effect on the microbubble stability and production even with a little quantity. The buffer pH value also had a key role on the microbubble formation and the final production. When the buffer pH value reached 7.4, there was no microbubble produced. Under the approximate microbubble production, process time could be shorten with the increasing ultrasound power. The obvious ultrasound contrast imaging effects were detected in the dog's heart chamber and liver as well as kidney using only one millilitre agent when diluted. The agent was found safe to the dogs. At the same time, persistent time of the agent was found over 20 min in the dog's body. Conclusion: The new ultrasound contrast agent prepared in the experiment has high microbubble production and concentration, narrow microbubble size distribution ranging in several microns, well stability, little dosage needed in the contrast, well safety to the dogs and long persistent time, obvious contrast imaging effect in the dog's heart chamber, kidney and liver. These experiment data indicate that the new ultrasound contrast agent with three ester surfactants and carboxylic methyl cellulose as its main shell materials can be further developed for clinical purposes.展开更多
BACKGROUND:Volume resuscitation has only been demonstrated to be effective in approximately fifty percent of patients.The remaining patients do not respond to volume resuscitation and may even develop adverse outcomes...BACKGROUND:Volume resuscitation has only been demonstrated to be effective in approximately fifty percent of patients.The remaining patients do not respond to volume resuscitation and may even develop adverse outcomes(such as acute pulmonary edema necessitating endotracheal intubation).We believe that point-of-care ultrasound is an excellent modality by which to adequately predict which patients may benefi t from volume resuscitation.DATA RESOURCES:We performed a search using PubMed,Scopus,and MEDLINE.The following search terms were used:fluid responsiveness,ultrasound,non-invasive,hemodynamic,fluid challenge,and passive leg raise.Preference was given to clinical trials and review articles that were most relevant to the topic of assessing a patient’s cardiovascular ability to respond to intravenous fl uid administration using ultrasound.RESULTS:Point-of-care ultrasound can be easily employed to measure the diameter and collapsibility of various large vessels including the inferior vena cava,common carotid artery,subclavian vein,internal jugular vein,and femoral vein.Such parameters are closely related to dynamic measures of fluid responsiveness and can be used by providers to help guide fluid resuscitation in critically ill patients.CONCLUSION:Ultrasound in combination with passive leg raise is a non-invasive,costand time-effective modality that can be employed to assess volume status and response to fluid resuscitation.Traditionally sonographic studies have focused on the evaluation of large veins such as the inferior vena cava,and internal jugular vein.A number of recently published studies also demonstrate the usefulness of evaluating large arteries to predict volume status.展开更多
BACKGROUND:Point-of-care ultrasound(POCUS)has become increasingly integrated into the practice of emergency medicine.A common application is the extended focused assessment with sonography in trauma(eFAST)exam.The Ame...BACKGROUND:Point-of-care ultrasound(POCUS)has become increasingly integrated into the practice of emergency medicine.A common application is the extended focused assessment with sonography in trauma(eFAST)exam.The American College of Emergency Physicians has guidelines regarding the scope of ultrasound in the emergency department and the appropriate documentation.The objective of this study was to conduct a review of performed,documented and billed eFAST ultrasounds on trauma activation patients.METHODS:This was a retrospective review of all trauma activation patients during a 10-month period at an academic level-one trauma center.A list comparing all trauma activations was crossreferenced with a list of all billed eFAST scans.Medical records were reviewed to determine whether an eFAST was indicated,performed,and appropriately documented.RESULTS:We found that 1,507 of 1,597 trauma patients had indications for eFAST,but 396(27%)of these patients did not have a billed eFAST.Of these 396 patients,87(22%)had documentation in the provider note that an eFAST was performed but there was no separate procedure note.The remaining 309(78%)did not have any documentation of the eFAST in the patient’s chart although an eFAST was recorded and reviewed during ultrasound quality assurance.CONCLUSION:A significant proportion of trauma patients had eFAST exams performed but were not documented or billed.Lack of documentation was multifactorial.Emergency ultrasound programs require appropriate reimbursement to support training,credentialing,equipment,quality assurance,and device maintenance.Our study demonstrates a significant absence of adequate documentation leading to potential revenue loss for an emergency ultrasound program.展开更多
The effect and mechanism of ultrasound and CaF_(2) on vanadium leaching from vanadium-bearing shale were investigated systematically.In consideration of the enhancement for vanadium recovery,the combination of ultraso...The effect and mechanism of ultrasound and CaF_(2) on vanadium leaching from vanadium-bearing shale were investigated systematically.In consideration of the enhancement for vanadium recovery,the combination of ultrasound and CaF_(2)(66.28%) exerts more evident effects than ultrasound(26.97%) and CaF_(2)(60.35%) alone,demonstrating the synergetic effect of ultrasound and CaF_(2).Kinetic analysis manifests that the product layer diffusion controls vanadium leaching in ultrasound system without CaF_(2),however product layer diffusion and interfacial reaction is the rate-controlling step for vanadium leaching in other three leaching systems.The combination of ultrasound and CaF_(2) notably decreases the activation energy(E_(a)) from 62.03 to 27.61 kJ/mol,nevertheless individual CaF_(2) only reduces the E_(a) to 50.70 kj/mol.X-ray diffraction and fourier transform infrared spectrometer analyses show that the decomposition degree of the vanadium-bearing mica structure is the most significant in ultrasound and CaF_(2) system,proving the highest release degree of vanadium.Specific surface area and pore distribution combined with scanning electron microscope analyses reveal that the action of ultrasound and CaF_(2) would provide higher specific surface area,more abundant pores structure and cracks for the particles,which further prompts the rapid diffusion of H^(+),F^(-)and HF,and achieves the conspicuous improvement of vanadium leaching recovery.展开更多
BACKGROUND:Current point-of-care ultrasound protocols in the evaluation of lower extremity deep vein thrombosis (DVT) can miss isolated femoral vein clots.Extended compression ultrasound (ECUS) includes evaluation of ...BACKGROUND:Current point-of-care ultrasound protocols in the evaluation of lower extremity deep vein thrombosis (DVT) can miss isolated femoral vein clots.Extended compression ultrasound (ECUS) includes evaluation of the femoral vein from the femoral vein/deep femoral vein bifurcation to the adductor canal.Our objective is to determine if emergency physicians (EPs) can learn ECUS for lower extremity DVT evaluation after a focused training session.METHODS:Prospective study at an urban academic center.Participants with varied ultrasound experience received instruction in ECUS prior to evaluation.Two live models with varied levels of difficult sonographic anatomy were intentionally chosen for the evaluation.Each participant scanned both models.Pre-and post-study surveys were completed.RESULTS:A total of 96 ultrasound examinations were performed by 48 participants (11 attendings and 37 residents).Participants' assessment scores averaged 95.8% (95% CI 93.3%-98.3%) on the easier anatomy live model and averaged 92.3% (95% CI 88.4%-96.2%) on the difficult anatomy model.There were no statistically significant differences between attendings and residents.On the model with easier anatomy,all but 1 participant identified and compressed the proximal femoral vein successfully,and all participants identified and compressed the mid and distal femoral vein.With the difficult anatomy,97.9% (95% CI93.8%-102%) identified and compressed the proximal femoral vein,whereas 93.8% (95% CI 86.9%-100.6%) identified and compressed the mid femoral vein,and 91.7% (95% CI83.9%-99.5%) identified and compressed the distal femoral vein.CONCLUSION:EPs at our institution were able to perform ECUS with good reproducibility after a focused training session.展开更多
A microfiber with large evanescent field encapsulated in PDMS is proposed and demonstrated for ultrasound sensing.The compact size and large evanescent field of microfiber provide an excellent platform for the interac...A microfiber with large evanescent field encapsulated in PDMS is proposed and demonstrated for ultrasound sensing.The compact size and large evanescent field of microfiber provide an excellent platform for the interaction between optical signal and ultrasound wave,exhibiting a high sensitivity of 3.5 mV/kPa,which is approximately 10 times higher than the single-mode fiber sensor.Meanwhile,a phase feedback stabilization module is introduced into the coherent demodulation system for long-term stable measurement.In addition,a photoacoustic tomography experiment with the microfiber ultrasound sensor is implemented to verify the excellent performance on imaging,with the depth of 12 mm,the highest lateral resolution of 65μm and axial resolution of 250μm,respectively.The highly sensitive microfiber ultrasound sensor provides a competitive alternative for various applications,such as industrial non-destructive testing,biomedical ultrasound and photoacoustic imaging.展开更多
基金Project supported by the National Natural Science Foundation of China(Grant Nos.12122403 and 12327807).
文摘Full waveform inversion(FWI)has showed great potential in the detection of musculoskeletal disease.However,FWI is an ill-posed inverse problem and has a high requirement on the initial model during the imaging process.An inaccurate initial model may lead to local minima in the inversion and unexpected imaging results caused by cycle-skipping phenomenon.Deep learning methods have been applied in musculoskeletal imaging,but need a large amount of data for training.Inspired by work related to generative adversarial networks with physical informed constrain,we proposed a method named as bone ultrasound imaging with physics informed generative adversarial network(BUIPIGAN)to achieve unsupervised multi-parameter imaging for musculoskeletal tissues,focusing on speed of sound(SOS)and density.In the in-silico experiments using a ring array transducer,conventional FWI methods and BUIPIGAN were employed for multiparameter imaging of two musculoskeletal tissue models.The results were evaluated based on visual appearance,structural similarity index measure(SSIM),signal-to-noise ratio(SNR),and relative error(RE).For SOS imaging of the tibia–fibula model,the proposed BUIPIGAN achieved accurate SOS imaging with best performance.The specific quantitative metrics for SOS imaging were SSIM 0.9573,SNR 28.70 dB,and RE 5.78%.For the multi-parameter imaging of the tibia–fibula and human forearm,the BUIPIGAN successfully reconstructed SOS and density distributions with SSIM above 94%,SNR above 21 dB,and RE below 10%.The BUIPIGAN also showed robustness across various noise levels(i.e.,30 dB,10 dB).The results demonstrated that the proposed BUIPIGAN can achieve high-accuracy SOS and density imaging,proving its potential for applications in musculoskeletal ultrasound imaging.
文摘BACKGROUND:We aimed to evaluate the utility of point-of-care ultrasound(POCUS)in the assessment of hand infections that present to the emergency department(ED)and its impact on medical decision making and patient management.METHODS:We conducted a retrospective review of patients who presented to two urban academic EDs with clinical presentations concerning for skin and soft tissue infections(SSTI)of the hand between December 2015 and December 2021.Two trained POCUS fellowship physicians reviewed an ED POCUS database for POCUS examinations of the hand.We then reviewed patients’electronic health records(EHR)for demographic characteristics,history,physical examination findings,ED course,additional imaging studies,consultations,impact of POCUS on patient care and final disposition.RESULTS:We included a total of 50 cases(28 male,22 female)in the final analysis.The most common presenting symptoms and exam findings were pain(100%),swelling(90%),and erythema(74%).The most common sonographic findings were edema(76%),soft tissue swelling(78%),and fluid surrounding the tendon(57%).POCUS was used in medical decision making 68%of the time(n=34),with the use of POCUS leading to changes in management 38%of the time(n=19).POCUS use led to early antibiotic use(11/19),early consultation(10/19),and led to the performance of a required procedure(8/19).The POCUS diagnosis was consistent with the discharge diagnosis of flexor tenosynovitis 8/12 times,abscess 12/16 times,and cellulitis 14/20 times.CONCLUSION:POCUS is beneficial for evaluating of hand infections that present to the ED and can be used as an important part of medical decision making to expedite patient care.
基金supported by the Department of Advanced Acute Medicine at Nagoya City University.
文摘BACKGROUND:Ultrasound guidance is commonly used for accessing difficult peripheral veins.For successful access,a tourniquet is required for venodilation.Tourniquets decrease the compressibility and increase the diameter of veins;they also obfuscate artery-vein differentiation on ultrasound.We aimed to establish the upper limit of sphygmomanometer cuff pressure that facilitates artery-vein differentiation during ultrasound-guided peripheral intravenous access.METHODS:We employed the sphygmomanometer cuff as a tourniquet for venodilation and tested it on seven participants at six different levels as follows:0 mmHg,DBP/2,DBP,(DBP+SBP)/2,SBP,and SBP+20 mmHg.We used an ultrasound probe attached to a pressure-measuring instrument to record cross-sectional images of the cubital artery and vein.During ultrasonography,compression was applied to the blood vessels through the skin.The following day,we measured the wrist pulse pressure and observed the oximeter pulse wave at six different tourniquet pressure levels.Repeated-measures analysis of variance(ANOVA)on ranks and Tukey’s post-hoc analysis were used for multiple comparisons.RESULTS:Arterial pulsation was maintained at tourniquet pressures between 0 mmHg and(DBP+SBP)/2.However,arterial pulsation decreased or disappeared when the tourniquet pressure reached or exceeded the SBP.Moreover,at this pressure level,the superior compressibility of veins compared to that of arteries was no longer observed.Compression of the artery to 75% and 50% of its original diameter increased arterial pulsation.CONCLUSION:Arterial pulsation and the superior compressibility are useful indicators for differentiating veins from arteries until the tourniquet pressure reaches(DBP+SBP)/2.However,these indicators are not reliable once the tourniquet pressure exceeds the SBP.
基金National Natural Science Foundation of China(Grant Nos.51821003,52175524,61704158)the Natural Science Foundation of Shanxi Province(Grant No.202103021224206)Shanxi"1331 Project"Key Subjects Construction to provide fund for conducting experiments。
文摘In order to suppress the low-frequency ultrasound vibration in the broadband range of 20 k Hz—100 k Hz,this paper proposes and discusses an acoustic metamaterial with low-frequency ultrasound vibration attenuation properties,which is configured by hybrid arc and sharp-angle convergent star-shaped lattices.The effect of the dispersion relation and the bandgap characteristic for the scatterers in star-shaped are simulated and analyzed.The target bandgap width is extended by optimizing the geometry parameters of arc and sharp-angle convergent lattices.The proposed metamaterial configured by optimized hybrid lattices exhibits remarkable broad bandgap characteristics by bandgap complementarity,and the simulation results verify a 99%vibration attenuation amplitude can be obtained in the frequency of20 k Hz—100 k Hz.After the fabrication of the proposed hybrid configurational star-shaped metamaterial by 3D printing technique,the transmission loss experiments are performed,and the experimental results indicate that the fabricated metamaterial has the characteristics of broadband vibration attenuation and an amplitude greater than 85%attenuation for the target frequency.These results demonstrate that the hybrid configurational star-shaped metamaterials can effectively widen the bandgap and realize high efficiency attenuation,which has capability for the vibration attenuation in the application of highprecise equipment.
文摘Handheld ultrasound devices are known for their portability and affordability,making them widely utilized in underdeveloped areas and community healthcare for rapid diagnosis and early screening.However,the image quality of handheld ultrasound devices is not always satisfactory due to the limited equipment size,which hinders accurate diagnoses by doctors.At the same time,paired ultrasound images are difficult to obtain from the clinic because imaging process is complicated.Therefore,we propose a modified cycle generative adversarial network(cycleGAN) for ultrasound image enhancement from multiple organs via unpaired pre-training.We introduce an ultrasound image pre-training method that does not require paired images,alleviating the requirement for large-scale paired datasets.We also propose an enhanced block with different structures in the pre-training and fine-tuning phases,which can help achieve the goals of different training phases.To improve the robustness of the model,we add Gaussian noise to the training images as data augmentation.Our approach is effective in obtaining the best quantitative evaluation results using a small number of parameters and less training costs to improve the quality of handheld ultrasound devices.
文摘BACKGROUND: Point-of-care ultrasound(US) is a proven diagnostic imaging tool in the emergency department(ED). Modern US devices are now more compact, affordable and portable, which has led to increased usage in austere environments. However, studies supporting the use of US in the prehospital setting are limited. The primary outcome of this pilot study was to determine if paramedics could perform cardiac ultrasound in the fi eld and obtain images that were adequate for interpretation. A secondary outcome was whether paramedics could correctly identify cardiac activity or the lack thereof in cardiac arrest patients.METHODS: We performed a prospective educational study using a convenience sample of professional paramedics without ultrasound experience. Eligible paramedics participated in a 3-hour session on point-of-care US. The paramedics then used US during emergency calls and saved the scans for possible cardiac complaints including: chest pain, dyspnea, loss of consciousness, trauma, or cardiac arrest.RESULTS: Four paramedics from two distinct fire stations enrolled a total of 19 unique patients, of whom 17 were deemed adequate for clinical decision making(89%, 95%CI 67%–99%). Paramedics accurately recorded 17 cases of cardiac activity(100%, 95%CI 84%–100%) and 2 cases of cardiac standstill(100%, 95%CI 22%–100%).CONCLUSION: Our pilot study suggests that with minimal training, paramedics can use US to obtain cardiac images that are adequate for interpretation and diagnose cardiac standstill. Further large-scale clinical trials are needed to determine if prehospital US can be used to guide care for patients with cardiac complaints.
基金This work was supported by the National Natural Science Foundation of China(61775083,61705082,61805102,and 61860206002)the Local Innovative and Research Teams Project of Guangdong Pearl River Talents Program(2019BT02X105)Guangzhou Science and Technology Plan(201904020032).
文摘Photoacoustic imag ing(PAI)is a nonin vasive biomedical imag ing tech no logy capable of multiscale imag ing of biological samples from orga ns dow n to cells.Multiscale PAI requires differe nt ultraso und tra nsducers that are flat or focused because the current widely-used piezoelectric transducers are rigid and lack the flexibility to tune their spatial ultrasound responses.Inspired by the rapidly-developing flexible photonics,we exploited the inherent flexibility and low-loss features of optical fibers to develop a flexible fiber-laser ultrasound sensor(FUS)for multiscale PAI.By simply bending the fiber laser from straight to curved geometry,the spatial ultraso und resp onse of the FUS can be tuned for both wide-view optical-resolution photoacoustic microscopy at optical diffraction-limited depth(~1 mm)and photoacoustic computed tomography at optical dissipation-limited depth of several centimeters.A radio-frequency demodulation was employed to get the readout of the beat frequency variation of two orthogonal polarization modes in the FUS output,which ensures low-noise and stable ultrasound detection.Compared to traditional piezoelectrical transducers with fixed ultrasound responses once manufactured,the flexible FUS provides the freedom to design multiscale PAI modalities including wearable microscope,intravascular endoscopy,and portable tomography system,which is attractive to fundamental biologic-al/medical studies and clinical applications.
基金Project partially supported by the National Natural Science Foundation of China(Grant Nos.81127901,81227004,81473692,81673995,11374155,11574156,11274170,11274176,11474001,11474161,11474166,and 11674173)the Natural Science Foundation of Jiangsu Province,China(Grant No.BK2011812)+1 种基金the Fundamental Research Funds for the Central Universitiesthe National High-Tech Research and Development Program of China(Grant No.2012AA022702)
文摘Transdermal drug delivery （TDD） can effectively bypass the first-pass effect. In this paper, ultrasound-facilitated TDD on fresh porcine skin was studied under various acoustic parameters, including frequency, amplitude, and exposure time. The delivery of yellow-green fluorescent nanoparticles and high molecular weight hyaluronic acid （HA） in the skin samples was observed by laser confocal microscopy and ultraviolet spectrometry, respectively. The results showed that, with the application of ultrasound exposures, the permeability of the skin to these markers （e.g., their penetration depth and concentration） could be raised above its passive diffusion permeability. Moreover, ultrasound-facilitated TDD was also tested with/without the presence of ultrasound contrast agents （UCAs）. When the ultrasound was applied without UCAs, low ultrasound frequency will give a better drug delivery effect than high frequency, but the penetration depth was less likely to exceed 200 p.m. However, with the help of the ultrasound-induced microbubble cavitation effect, both the penetration depth and concentration in the skin were significantly enhanced even more. The best ultrasound-facilitated TDD could be achieved with a drug penetration depth of over 600 p.m, and the penetration concentrations of fluorescent nanoparticles and HA increased up to about 4-5 folds. In order to get better understanding of ultrasound-facilitated TDD, scanning electron microscopy was used to examine the surface morphology of skin samples, which showed that the skin structure changed greatly under the treatment of ultrasound and UCA. The present work suggests that, for TDD applications （e.g., nanoparticle drug carriers, transdermal patches and cosmetics）, protocols and methods presented in this paper are potentially useful.
文摘BACKGROUND: Diagnostic imaging is an integral aspect of care that is often insufficient, if not altogether absent, in rural and remote regions of low to middle income countries(LMICs) such as Tanzania. The introduction of ultrasound can significantly impact treatment in these countries due to its portability, low cost, safety, and usefulness in various medical assessments. This study reviews the implementation of a four-week ultrasound course administered annually from 2013–2016 in a healthcare professional school in Mwanza, Tanzania by first-year allopathic US medical students.METHODS: Participants(n=582, over 4 years) were recruited from the Tandabui Institute of Health Sciences and Technology to take the ultrasound course. Subjects were predominantly clinical officer students, but other participants included other healthcare professional students, practicing healthcare professionals, and school employees. Data collected includes pre-course examination scores, post-course examination scores, course quiz scores, demographic surveys, and postcourse feedback surveys. Data was analyzed using two-tailed t-tests and the single factor analysis of variance(ANOVA).RESULTS: For all participants who completed both the pre-and post-course examinations(n=229, 39.1% of the total recruited), there was a significant mean improvement in their ultrasound knowledge of 42.5%, P<0.01.CONCLUSION: Our data suggests that trained first-year medical students can effectively teach a point of care ultrasound course to healthcare professional students within four weeks in Tanzania. Future investigation into the level of long-term knowledge retention, impact of ultrasound training on knowledge of human anatomy and diagnostic capabilities, and how expansion of an ultrasound curriculum has impacted access to care in rural Tanzania is warranted.
文摘Objective Focused cardiac ultrasound(FCU)and lung ultrasound(LU)are increasingly being used in critically ill patients.This study aimed to investigate the effect of FCU in combination with LU on these patients and to determine if the timing of ultrasound examination was associated with treatment change.Methods This is a multicenter cross-sectional observational study.Consecutive patients admitted to the intensive care unit(ICU)were screened for enrollment.FCU and LU were performed within the first 24 h,and treatment change was proposed by the performer based on the ultrasound results and other clinical conditions.Results Among the 992 patients included,502 were examined within 6 h of ICU admission(early phase group),and 490 were examined after 6 h of admission(later phase group).The early phase group and the later phase group had similar proportions of treatment change(48.8%vs.49.0%,χ^(2)=0.003,P=0.956).In the multivariable analysis,admission for respiratory failure was an independent variable associated with treatment change,with an odds ratio(OR)of 2.357[95%confidence interval(CI):1.284-4.326,P=0.006];the timing of examination was not associated with treatment change(OR=0.725,95%CI:0.407-1.291,P=0.275).Conclusions FCU in combination with LU,whether performed during the early phase or later phase,had a significant impact on the treatment of critically ill patients.Patients with respiratory failure were more likely to experience treatment change after the ultrasound examination.
基金Project supported by the National Basic Research Program of China (Grant No. 2011CB707900)the National Natural Science Foundation of China (Grant Nos. 11074123, 10974095, 10904068, and 10204014)+2 种基金the Fundamental Research Funds for the Central Universities of China (Grant Nos. 111602040 and 1095020409)the Natural Science Foundation of Jiangsu Province of China (Grant No. BK2011812)the Priority Academic Program Development of Jiangsu Higher Educaton Institutions of China
文摘Hyperthermia effects （39-44 ℃） induced by pulsed high-intensity focused ultrasound （HIFU） have been regarded as a promising therapeutic tool for boosting immune responses or enhancing drug delivery into a solid tumor. However, previous studies also reported that the cell death occurs when cells are maintained at 43 ℃ for more than 20 minutes. The aim of this study is to investigate thermal responses inside in vivo rabbit auricular veins exposed to pulsed HIFU （1.17 MHz, 5300 W/cm2, with relatively low-duty ratios （0.2%-4.3%）. The results show that： （1） with constant pulse repetition frequency （PRF） （e.g., 1 Hz）, the thermal responses inside the vessel will increase with the increasing duty ratio; （2） a temperature elevation to 43 ℃ can be identified at the duty ratio of 4.3%; （3） with constant duty ratios, the change of PRF will not significantly affect the temperature measurement in the vessel; （4） as the duty ratios lower than 4.3%, the presence of microbubbles will not significantly enhance the thermal responses in the vessel, but will facilitate HIFU-induced inertial cavitation events.
文摘BACKGROUND:The use of ultrasound(US)within healthcare has inspired the development of new US technology.There have been few studies comparing the use of handheld US to standard US for medical education.This research aims to determine whether a handheld US device can provide a comparable primary learning experience to that of a standard US machine.METHODS:Over two days of instruction,participants were taught and evaluated on core US fundamentals.The standard group received instruction on standard US machines,while the handheld group received instruction on handheld US devices.Participants completed a qualitative survey regarding their experience.Six hundred and four images were obtained and graded by two emergency medicine physicians.RESULTS:A total of 119 Swiss medical students were enrolled in our study.There was no statistically significant difference in the US assessment measurements,except for faster endpoint septal separation(EPSS)vascular setup time in the handheld group(P=0.001).There was no statistically significant difference in participants’perceived difficulty of US learning(P=0.198),comfort level(P=0.188),or self-estimated capability to perform US in the future(P=0.442).There was no statistically significant difference in the percentage of correctly obtained images(P=0.211)or images that were clinically useful(P=0.256).The median quality score of images obtained by the standard group was eight compared to seven in handheld group(P<0.01).CONCLUSION:Our data suggest a handheld US machine can perform as well as a standard US machine as an educational tool despite sacrifices in image quality.
文摘BACKGROUND: The current standard for con? rmation of correct supra-diaphragmatic central venous catheter(CVC) placement is with plain ? lm chest radiography(CXR). We hypothesized that a simple point-of-care ultrasound(POCUS) protocol could effectively con? rm placement and reduce time to con? rmation.METHODS: We prospectively enrolled a convenience sample of patients in the emergency department and intensive care unit who required CVC placement. Correct positioning was considered if turbulent flow was visualized in the right atrium on sub-xiphoid, parasternal or apical cardiac ultrasound after injecting 5 cc of sterile, non-agitated, normal saline through the CVC.RESULTS: Seventy-eight patients were enrolled. POCUS had a sensitivity of 86.8%(95%CI 77.1%–93.5%) and speci? city of 100%(95%CI 15.8%–100.0%) for identifying correct central venous catheter placement. Median POCUS and CXR completion were 16 minutes(IQR 10–29) and 32 minutes(IQR 19–45), respectively.CONCLUSION: Ultrasound may be an effective tool to confirm central venous catheter placement in instances where there is a delay in obtaining a con? rmatory CXR.
文摘BACKGROUND: The study aimed to compare the time to overall length of stay(LOS) for patients who underwent point-of-care ultrasound(POCUS) versus radiology department ultrasound(RDUS).METHODS: This was a prospective study on a convenience sample of patients who required pelvic ultrasound imaging as part of their emergency department(ED) assessment.RESULTS: We enrolled a total of 194 patients who were on average 32 years-old. Ninety-eight(51%) patients were pregnant(<20 weeks). Time to completion of RDUS was 66 minutes longer than POCUS(95%CI 60–73, P<0.01). Patients randomized to the RDUS arm experienced a 120 minute longer ED length of stay(LOS)(95%CI 66–173, P<0.01)CONCLUSION: In patients who require pelvic ultrasound as part of their diagnostic evaluation, POCUS resulted in a signifi cant decrease in time to ultrasound and ED LOS.
基金Supported by the High Technology Research Development Program of China(863 Program,No.2001AA218031)and the National Natural Science Foundation of China(No.30270404).
文摘Objective: To study on the preparation process of a new surfactant-based microbubble ultrasound contrast agent and to evaluate its contrast effects in vivo. Methods: Microbubble ultrasound contrast agent with three ester surfactants and other additives as its shell materials was prepared by sonication. Sulfur hexafluoride was adopted as the inner gas of the microbubbles. New methods through the combination of optical microscope and some softwares were used to measure the size distribution and the concentration of the microbubbles. Some parameters such as the pH value of the phosphate buffer, quantity of the carboxylic methyl cellulose in the shell materials, selection of the ultrasound power and process time, were studied. Six hybirded dogs were used to verify the in vivo contrast imaging of the contrast agent using second harmonic power Doppler modality. Safety and persistent time of the agent inner animal body were also investigated. Results: Ultrasound contrast agent prepared in the experiment had an average microbubble diameter of 3.95 microns with concentration of 3.6×109 microbubbles per millilitre. Carboxylic methyl cellulose was found as an important shell material which had obviously effect on the microbubble stability and production even with a little quantity. The buffer pH value also had a key role on the microbubble formation and the final production. When the buffer pH value reached 7.4, there was no microbubble produced. Under the approximate microbubble production, process time could be shorten with the increasing ultrasound power. The obvious ultrasound contrast imaging effects were detected in the dog's heart chamber and liver as well as kidney using only one millilitre agent when diluted. The agent was found safe to the dogs. At the same time, persistent time of the agent was found over 20 min in the dog's body. Conclusion: The new ultrasound contrast agent prepared in the experiment has high microbubble production and concentration, narrow microbubble size distribution ranging in several microns, well stability, little dosage needed in the contrast, well safety to the dogs and long persistent time, obvious contrast imaging effect in the dog's heart chamber, kidney and liver. These experiment data indicate that the new ultrasound contrast agent with three ester surfactants and carboxylic methyl cellulose as its main shell materials can be further developed for clinical purposes.
文摘BACKGROUND:Volume resuscitation has only been demonstrated to be effective in approximately fifty percent of patients.The remaining patients do not respond to volume resuscitation and may even develop adverse outcomes(such as acute pulmonary edema necessitating endotracheal intubation).We believe that point-of-care ultrasound is an excellent modality by which to adequately predict which patients may benefi t from volume resuscitation.DATA RESOURCES:We performed a search using PubMed,Scopus,and MEDLINE.The following search terms were used:fluid responsiveness,ultrasound,non-invasive,hemodynamic,fluid challenge,and passive leg raise.Preference was given to clinical trials and review articles that were most relevant to the topic of assessing a patient’s cardiovascular ability to respond to intravenous fl uid administration using ultrasound.RESULTS:Point-of-care ultrasound can be easily employed to measure the diameter and collapsibility of various large vessels including the inferior vena cava,common carotid artery,subclavian vein,internal jugular vein,and femoral vein.Such parameters are closely related to dynamic measures of fluid responsiveness and can be used by providers to help guide fluid resuscitation in critically ill patients.CONCLUSION:Ultrasound in combination with passive leg raise is a non-invasive,costand time-effective modality that can be employed to assess volume status and response to fluid resuscitation.Traditionally sonographic studies have focused on the evaluation of large veins such as the inferior vena cava,and internal jugular vein.A number of recently published studies also demonstrate the usefulness of evaluating large arteries to predict volume status.
文摘BACKGROUND:Point-of-care ultrasound(POCUS)has become increasingly integrated into the practice of emergency medicine.A common application is the extended focused assessment with sonography in trauma(eFAST)exam.The American College of Emergency Physicians has guidelines regarding the scope of ultrasound in the emergency department and the appropriate documentation.The objective of this study was to conduct a review of performed,documented and billed eFAST ultrasounds on trauma activation patients.METHODS:This was a retrospective review of all trauma activation patients during a 10-month period at an academic level-one trauma center.A list comparing all trauma activations was crossreferenced with a list of all billed eFAST scans.Medical records were reviewed to determine whether an eFAST was indicated,performed,and appropriately documented.RESULTS:We found that 1,507 of 1,597 trauma patients had indications for eFAST,but 396(27%)of these patients did not have a billed eFAST.Of these 396 patients,87(22%)had documentation in the provider note that an eFAST was performed but there was no separate procedure note.The remaining 309(78%)did not have any documentation of the eFAST in the patient’s chart although an eFAST was recorded and reviewed during ultrasound quality assurance.CONCLUSION:A significant proportion of trauma patients had eFAST exams performed but were not documented or billed.Lack of documentation was multifactorial.Emergency ultrasound programs require appropriate reimbursement to support training,credentialing,equipment,quality assurance,and device maintenance.Our study demonstrates a significant absence of adequate documentation leading to potential revenue loss for an emergency ultrasound program.
基金supported by the National Natural Science Foundation of China (51874222 and 52074204)the Fundamental Research Funds for the Central Universities (No. 2020-YB029)。
文摘The effect and mechanism of ultrasound and CaF_(2) on vanadium leaching from vanadium-bearing shale were investigated systematically.In consideration of the enhancement for vanadium recovery,the combination of ultrasound and CaF_(2)(66.28%) exerts more evident effects than ultrasound(26.97%) and CaF_(2)(60.35%) alone,demonstrating the synergetic effect of ultrasound and CaF_(2).Kinetic analysis manifests that the product layer diffusion controls vanadium leaching in ultrasound system without CaF_(2),however product layer diffusion and interfacial reaction is the rate-controlling step for vanadium leaching in other three leaching systems.The combination of ultrasound and CaF_(2) notably decreases the activation energy(E_(a)) from 62.03 to 27.61 kJ/mol,nevertheless individual CaF_(2) only reduces the E_(a) to 50.70 kj/mol.X-ray diffraction and fourier transform infrared spectrometer analyses show that the decomposition degree of the vanadium-bearing mica structure is the most significant in ultrasound and CaF_(2) system,proving the highest release degree of vanadium.Specific surface area and pore distribution combined with scanning electron microscope analyses reveal that the action of ultrasound and CaF_(2) would provide higher specific surface area,more abundant pores structure and cracks for the particles,which further prompts the rapid diffusion of H^(+),F^(-)and HF,and achieves the conspicuous improvement of vanadium leaching recovery.
文摘BACKGROUND:Current point-of-care ultrasound protocols in the evaluation of lower extremity deep vein thrombosis (DVT) can miss isolated femoral vein clots.Extended compression ultrasound (ECUS) includes evaluation of the femoral vein from the femoral vein/deep femoral vein bifurcation to the adductor canal.Our objective is to determine if emergency physicians (EPs) can learn ECUS for lower extremity DVT evaluation after a focused training session.METHODS:Prospective study at an urban academic center.Participants with varied ultrasound experience received instruction in ECUS prior to evaluation.Two live models with varied levels of difficult sonographic anatomy were intentionally chosen for the evaluation.Each participant scanned both models.Pre-and post-study surveys were completed.RESULTS:A total of 96 ultrasound examinations were performed by 48 participants (11 attendings and 37 residents).Participants' assessment scores averaged 95.8% (95% CI 93.3%-98.3%) on the easier anatomy live model and averaged 92.3% (95% CI 88.4%-96.2%) on the difficult anatomy model.There were no statistically significant differences between attendings and residents.On the model with easier anatomy,all but 1 participant identified and compressed the proximal femoral vein successfully,and all participants identified and compressed the mid and distal femoral vein.With the difficult anatomy,97.9% (95% CI93.8%-102%) identified and compressed the proximal femoral vein,whereas 93.8% (95% CI 86.9%-100.6%) identified and compressed the mid femoral vein,and 91.7% (95% CI83.9%-99.5%) identified and compressed the distal femoral vein.CONCLUSION:EPs at our institution were able to perform ECUS with good reproducibility after a focused training session.
基金financial supports from National Natural Science Foundation of China (NSFC)(No.61922033)Foundation for Innovative Research Groups of Hubei Province of China (2018CFA004)Innovation Fund of WNLO
文摘A microfiber with large evanescent field encapsulated in PDMS is proposed and demonstrated for ultrasound sensing.The compact size and large evanescent field of microfiber provide an excellent platform for the interaction between optical signal and ultrasound wave,exhibiting a high sensitivity of 3.5 mV/kPa,which is approximately 10 times higher than the single-mode fiber sensor.Meanwhile,a phase feedback stabilization module is introduced into the coherent demodulation system for long-term stable measurement.In addition,a photoacoustic tomography experiment with the microfiber ultrasound sensor is implemented to verify the excellent performance on imaging,with the depth of 12 mm,the highest lateral resolution of 65μm and axial resolution of 250μm,respectively.The highly sensitive microfiber ultrasound sensor provides a competitive alternative for various applications,such as industrial non-destructive testing,biomedical ultrasound and photoacoustic imaging.
