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Background: Limited supply of resources during the COVID-19 emergency encouraged the local development of the Masi mechanical ventilator (MV). Despite the efforts to promote Masi, adopting this innovation faced multiple obstacles, regardless of its performance. We explored the perceptions among healthcare personnel towards incorporating Masi to provide ventilatory support to COVID-19 patients during the second wave in Peru (January to June 2021). Methods: We conducted twelve in-depth virtual interviews. Topics included experience when handling Masi, the impact of the training received, confidence in the device, barriers perceived, and enablers identified. All participants provided verbal informed consent. Results: Most of the participants were male physicians. Participants belonged to seven hospitals that exhibited a wide range of healthcare capacities. Globally, the adoption of Masi MV was driven by the scarcity of ventilatory devices in the wards and reinforced by appropriate training and prompt technical support. Participants reported that Masi's structural and operational features played both advantages and disadvantages. Hospital infrastructure readiness, availability of commercial MVs, mistrust in its simple appearance, and resistance to change among healthcare personnel were perceived as barriers, while low-cost, prompt technical support and user-friendliness were valuable enablers. The first two enablers were observed in participants regardless of their attitude towards Masi. Despite the small number of participants for this qualitative study, it is important to note that the sample size was sufficient to reach saturation, as the topics discussed with participants became redundant and did not yield new information. Conclusions: The perceptions among healthcare personnel to incorporate Masi as a mechanical ventilator for COVID-19 patients showed that communication, training and experience, and peer encouragement were essential to secure its use and sustainability of the technology. A priori judgments and perceptions unrelated to the performance of the novel device were observed, and its proper management may define its further implementation. Altogether our study suggests that along with strengthening local technological development, strategies to improve their adoption process must be considered as early as possible in medical innovations.
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Cutaneous leishmaniasis (CL) is a neglected disease caused by an intracellular parasite of the Leishmania genus. CL lacks tools that allow its understanding and treatment follow-up. This article presents the use of metrical and optical tools for the analysis of the temporal evolution of treated skin ulcers caused by CL in an animal model. Leishmania braziliensis and L. panamensis were experimentally inoculated in golden hamsters, which were treated with experimental and commercial drugs. The temporal evolution was monitored by means of ulcers' surface areas, as well as absorption and scattering optical parameters. Ulcers' surface areas were obtained via photogrammetry, which is a procedure that allowed for 3D modeling of the ulcer using specialized software. Optical parameters were obtained from a spectroscopy study, representing the cutaneous tissue's biological components. A one-way ANOVA analysis was conducted to identify relationships between both the ulcers' areas and optical parameters. As a result, ulcers' surface areas were found to be related to the following optical parameters: epidermis thickness, collagen, keratinocytes, volume-fraction of blood, and oxygen saturation. This study is a proof of concept that shows that optical parameters could be associated with metrical ones, giving a more reliable concept during the assessment of a skin ulcer's healing.
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Leishmaniose Cutânea , Úlcera Cutânea , Cricetinae , Animais , Úlcera , Leishmaniose Cutânea/tratamento farmacológico , Pele , Úlcera Cutânea/tratamento farmacológico , Úlcera Cutânea/parasitologia , Mesocricetus , Modelos Animais de DoençasRESUMO
Background: Pulmonary disease is a common cause of morbidity and mortality, but the majority of the people in the world lack access to diagnostic imaging for its assessment. We conducted an implementation assessment of a potentially sustainable and cost-effective model for delivery of volume sweep imaging (VSI) lung teleultrasound in Peru. This model allows image acquisition by individuals without prior ultrasound experience after only a few hours of training. Methods: Lung teleultrasound was implemented at 5 sites in rural Peru after a few hours of installation and staff training. Patients were offered free lung VSI teleultrasound examination for concerns of respiratory illness or research purposes. After ultrasound examination, patients were surveyed regarding their experience. Health staff and members of the implementation team also participated in separate interviews detailing their views of the teleultrasound system which were systematically analyzed for key themes. Results: Patients and staff rated their experience with lung teleultrasound as overwhelmingly positive. The lung teleultrasound system was viewed as a potential way to improve access to imaging and the health of rural communities. Detailed interviews with the implementation team revealed obstacles to implementation important for consideration such as gaps in lung ultrasound understanding. Conclusions: Lung VSI teleultrasound was successfully deployed to 5 health centers in rural Peru. Implementation assessment revealed enthusiasm for the system among members of the community along with important areas of consideration for future teleultrasound deployment. This system offers a potential means to increase access to imaging for pulmonary illness and improve the health of the global community.
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Objective. The mechanical behaviour of soft tissue is influenced by its elastic and viscous characteristics. Therefore, the aim of this study was to develop a validated method to characterise the viscoelastic properties of soft tissues based on ultrasound elastography data.Approach. Plantar soft tissue was chosen as the tissue of interest, and gelatine-phantoms replicating its mechanical properties were manufactured for validation of the protocol. Both plantar soft tissue and the phantom were scanned using Reverberant shear wave ultrasound (US) elastography at 400-600 Hz. Shear wave speed was estimated using the US particle velocity data. The viscoelastic parameters were extracted by fitting the Young's modulus as a function of frequency derived from the constitutive equations of the eight rheological models (four classic and their fractional-derivative versions) to the shear wave dispersion data. Furthermore, stress-time functions derived from the eight rheological models were fitted to the phantom stress-relaxation data.Main results. The viscoelastic parameters estimated using elastography data based on the fractional-derivative (FD) models, compared to the classic models, were closer to those quantified using the mechanical test. In addition, the FD-Maxwell and FD-Kelvin-Voigt models showed to more effectively replicate the viscoelastic behaviour of the plantar soft tissue with minimum number of model parameters (R2= 0.72 for both models) . Hence the FD-KV and FD-Maxwell models can more effectively quantify the viscoelastic characteristics of the soft tissue compared to other models.Significance. In this study, a method for mechanical characterisation of the viscoelastic properties of soft tissue in ultrasound elastography was developed and fully validated. An investigation into the most valid rheological model and its applications in plantar soft tissue assessment were also presented. This proposed approach for the characterisation of viscous and elastic mechanical properties of soft tissue has implications in assessing the soft tissue function where those can be used as markers for diagnosis or prognosis of tissue status.
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Técnicas de Imagem por Elasticidade , Técnicas de Imagem por Elasticidade/métodos , Módulo de Elasticidade , Ultrassonografia , Viscosidade , Reologia , Imagens de FantasmasRESUMO
We introduce an autonomous oxygen concentrator that was designed in Peru to fight the oxygen shortage produced worldwide as a consequence of the COVID-19 pandemic. Oxygen concentrators represent a suitable and favorable option for administering this gas at the patient's bedside in developing countries, especially when cylinders and tubed systems are unavailable or when access to them is restricted by lack of accessories, inadequate power supply, or shortage of qualified personnel. Our system uses a pressure swing adsorption technique to provide oxygen to patients at a flow rate of up to 15 l/min ± 1,5 l/min and a concentration of 93 % ± 3 %, offering robustness, safety and functionality. The quality measurements obtained from the validation process demonstrate repeatability and accuracy. The complete design files are provided in the source file repository to facilitate oxygen concentrator production in low and middle income countries, where access to oxygen is still a major problem even after the pandemic. Oxygen is part of the World Health Organization Model List of Essential Medicines and is perhaps the only medicine that has no substitute. This device can provide a reliable supply of oxygen for critically ill patients and improve their chances of survival.
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OBJECTIVES: Pulmonary disease is a significant cause of morbidity and mortality in adults and children, but most of the world lacks diagnostic imaging for its assessment. Lung ultrasound is a portable, low-cost, and highly accurate imaging modality for assessment of pulmonary pathology including pneumonia, but its deployment is limited secondary to a lack of trained sonographers. In this study, we piloted a low-cost lung teleultrasound system in rural Peru during the COVID-19 pandemic using lung ultrasound volume sweep imaging (VSI) that can be operated by an individual without prior ultrasound training circumventing many obstacles to ultrasound deployment. DESIGN: Pilot study. SETTING: Study activities took place in five health centres in rural Peru. PARTICIPANTS: There were 213 participants presenting to rural health clinics. INTERVENTIONS: Individuals without prior ultrasound experience in rural Peru underwent brief training on how to use the teleultrasound system and perform lung ultrasound VSI. Subsequently, patients attending clinic were scanned by these previously ultrasound-naïve operators with the teleultrasound system. PRIMARY AND SECONDARY OUTCOME MEASURES: Radiologists examined the ultrasound imaging to assess its diagnostic value and identify any pathology. A random subset of 20% of the scans were analysed for inter-reader reliability. RESULTS: Lung VSI teleultrasound examinations underwent detailed analysis by two cardiothoracic attending radiologists. Of the examinations, 202 were rated of diagnostic image quality (94.8%, 95% CI 90.9% to 97.4%). There was 91% agreement between radiologists on lung ultrasound interpretation among a 20% sample of all examinations (κ=0.76, 95% CI 0.53 to 0.98). Radiologists were able to identify sequelae of COVID-19 with the predominant finding being B-lines. CONCLUSION: Lung VSI teleultrasound performed by individuals without prior training allowed diagnostic imaging of the lungs and identification of sequelae of COVID-19 infection. Deployment of lung VSI teleultrasound holds potential as a low-cost means to improve access to imaging around the world.
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COVID-19 , Adulto , COVID-19/diagnóstico por imagem , Criança , Humanos , Pulmão/diagnóstico por imagem , Pandemias , Peru/epidemiologia , Projetos Piloto , Reprodutibilidade dos Testes , Ultrassonografia/métodosRESUMO
The Covid-19 outbreak challenged health systems around the world to design and implement cost-effective devices produced locally to meet the increased demand of mechanical ventilators worldwide. This study evaluates the physiological responses of healthy swine maintained under volume- or pressure-controlled mechanical ventilation by a mechanical ventilator implemented to bring life-support by automating a resuscitation bag and closely controlling ventilatory parameters. Physiological parameters were monitored in eight sedated animals (t0) prior to inducing deep anaesthesia, and during the next six hours of mechanical ventilation (t1-7). Hemodynamic conditions were monitored periodically using a portable gas analyser machine (i.e. BEecf, carbonate, SaO2, lactate, pH, PaO2, PaCO2) and a capnometer (i.e. ETCO2). Electrocardiogram, echocardiography and lung ultrasonography were performed to detect in vivo alterations in these vital organs and pathological findings from necropsy were reported. The mechanical ventilator properly controlled physiological levels of blood biochemistry such as oxygenation parameters (PaO2, PaCO2, SaO2, ETCO2), acid-base equilibrium (pH, carbonate, BEecf), and perfusion of tissues (lactate levels). In addition, histopathological analysis showed no evidence of acute tissue damage in lung, heart, liver, kidney, or brain. All animals were able to breathe spontaneously after undergoing mechanical ventilation. These preclinical data, supports the biological safety of the medical device to move forward to further evaluation in clinical studies.
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Reanimação Cardiopulmonar/instrumentação , Respiração Artificial/instrumentação , Ventiladores Mecânicos , Animais , Automação , Gasometria , COVID-19/complicações , COVID-19/patologia , COVID-19/fisiopatologia , Feminino , Hemodinâmica , Masculino , Respiração , SARS-CoV-2/fisiologia , SuínosRESUMO
Ultrasound imaging is a vital component of high-quality Obstetric care. In rural and under-resourced communities, the scarcity of ultrasound imaging results in a considerable gap in the healthcare of pregnant mothers. To increase access to ultrasound in these communities, we developed a new automated diagnostic framework operated without an experienced sonographer or interpreting provider for assessment of fetal biometric measurements, fetal presentation, and placental position. This approach involves the use of a standardized volume sweep imaging (VSI) protocol based solely on external body landmarks to obtain imaging without an experienced sonographer and application of a deep learning algorithm (U-Net) for diagnostic assessment without a radiologist. Obstetric VSI ultrasound examinations were performed in Peru by an ultrasound operator with no previous ultrasound experience who underwent 8 hours of training on a standard protocol. The U-Net was trained to automatically segment the fetal head and placental location from the VSI ultrasound acquisitions to subsequently evaluate fetal biometry, fetal presentation, and placental position. In comparison to diagnostic interpretation of VSI acquisitions by a specialist, the U-Net model showed 100% agreement for fetal presentation (Cohen's κ 1 (p<0.0001)) and 76.7% agreement for placental location (Cohen's κ 0.59 (p<0.0001)). This corresponded to 100% sensitivity and specificity for fetal presentation and 87.5% sensitivity and 85.7% specificity for anterior placental location. The method also achieved a low relative error of 5.6% for biparietal diameter and 7.9% for head circumference. Biometry measurements corresponded to estimated gestational age within 2 weeks of those assigned by standard of care examination with up to 89% accuracy. This system could be deployed in rural and underserved areas to provide vital information about a pregnancy without a trained sonographer or interpreting provider. The resulting increased access to ultrasound imaging and diagnosis could improve disparities in healthcare delivery in under-resourced areas.
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Placenta , Feminino , Humanos , GravidezRESUMO
Three hundred and ten rapid-manufactured mechanical ventilators, named Masi, were produced and validated in Peru, according to applicable standards. From these, a sample of 30 was taken and two ventilation parameters, tidal volume and peak inspiratory pressure, were statically analyzed using control charts and histograms. Results show that several points were outside estimated limits for Shewhart means and ranges charts, which could possibly be due to the quantity of equipment used for data recollection and the fact that the Masi team had over 20 engineers. Nevertheless, Masi ventilators met the tolerance required by their user´s manual and MHRA standard and Peruvian DIGEMID for every parameter.Clinical Relevance-This article shows the performance in the validation stage of the peruvian mechanical ventilator MASI built as an emergency response for the COVID-19 crisis.
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COVID-19 , Humanos , Peru , SARS-CoV-2 , Volume de Ventilação Pulmonar , Ventiladores MecânicosRESUMO
In response to Covid-19 crisis, 310 Masi ventilators were produced and validated in Lima, Peru, according to applicable standards. Four of them, were transported to Puno, in order to strengthen ICU Services there, but this set a major challenge to Masi team as effects of altitude on ventilators were unknown. Once there, ventilators were acclimated and calibrated. Volume tidal, I:E ratio, respiratory frequency and PEEP were tested, all of them presenting errors under 15%, except for tidal volume, for which a 25% negative correction was applied. After the installation of a new version of Masi software, parameters were tested again, all of them presenting results with errors below 15%, which allowed the Masi team to take them to ICU services for use.Clinical Relevance- Masi Peruvian Ventilators are able to perform according to their specifications at extremely high altitude, after the adequate calibration. These devices are an alternative to treat COVID-19 patients in the middle of the crisis.
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Altitude , COVID-19 , Humanos , Peru , SARS-CoV-2 , Ventiladores MecânicosRESUMO
BACKGROUND: Hepatic and biliary diseases are prevalent worldwide, but the majority of people lack access to diagnostic medical imaging for their assessment. The liver and gallbladder are readily amenable to sonographic examination, and ultrasound is a portable, cost-effective imaging modality suitable for use in rural and underserved areas. However, the deployment of ultrasound in these settings is limited by the lack of experienced sonographers to perform the exam. In this study, we tested an asynchronous telediagnostic system for right upper quadrant abdominal ultrasound examination operated by individuals without prior ultrasound experience to facilitate deployment of ultrasound to rural and underserved areas. METHODS: The teleultrasound system utilized in this study employs volume sweep imaging and a telemedicine app installed on a tablet which connects to an ultrasound machine. Volume sweep imaging is an ultrasound technique in which an individual scans the target region utilizing preset ultrasound sweeps demarcated by easily recognized external body landmarks. The sweeps are saved as video clips for later interpretation by an experienced radiologist. Teleultrasound scans from a Peruvian clinic obtained by individuals without prior ultrasound experience were sent to the United States for remote interpretation and quality assessment. Standard of care comparison was made to a same-day ultrasound examination performed by a radiologist. RESULTS: Individuals without prior ultrasound experience scanned 144 subjects. Image quality was rated "poor" on 36.8% of exams, "acceptable" on 38.9% of exams, and "excellent" on 24.3% of exams. Among telemedicine exams of "acceptable" or "excellent" image quality (n = 91), greater than 80% of the liver and gallbladder were visualized in the majority of cases. In this group, there was 95% agreement between standard of care and teleultrasound on whether an exam was normal or abnormal, with a Cohen's kappa of 0.84 (95% CI 0.7-0.98, p <0.0001). Finally, among these teleultrasound exams of "acceptable" or "excellent" image quality, the sensitivity for cholelithiasis was 93% (95% CI 68.1%-99.8%), and the specificity was 97% (95% CI 89.5%-99.6%). CONCLUSION: This asynchronous telediagnostic system allows individuals without prior ultrasound experience to effectively scan the liver, gallbladder, and right kidney with a high degree of agreement with standard of care ultrasound. This system can be deployed to improve access to diagnostic imaging in low-resource areas.
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Abdome/diagnóstico por imagem , Processamento de Imagem Assistida por Computador/métodos , Telemedicina , Ultrassonografia , Colelitíase/diagnóstico , Fígado Gorduroso/diagnóstico , Humanos , Área Carente de Assistência Médica , Peru , População Rural , Sensibilidade e EspecificidadeRESUMO
BACKGROUND: Ninety-four percent of all maternal deaths occur in low- and middle-income countries, and the majority are preventable. Access to quality Obstetric ultrasound can identify some complications leading to maternal and neonatal/perinatal mortality or morbidity and may allow timely referral to higher-resource centers. However, there are significant global inequalities in access to imaging and many challenges to deploying ultrasound to rural areas. In this study, we tested a novel, innovative Obstetric telediagnostic ultrasound system in which the imaging acquisitions are obtained by an operator without prior ultrasound experience using simple scan protocols based only on external body landmarks and uploaded using low-bandwidth internet for asynchronous remote interpretation by an off-site specialist. METHODS: This is a single-center pilot study. A nurse and care technician underwent 8 h of training on the telediagnostic system. Subsequently, 126 patients (68 second trimester and 58 third trimester) were recruited at a health center in Lima, Peru and scanned by these ultrasound-naïve operators. The imaging acquisitions were uploaded by the telemedicine platform and interpreted remotely in the United States. Comparison of telediagnostic imaging was made to a concurrently performed standard of care ultrasound obtained and interpreted by an experienced attending radiologist. Cohen's Kappa was used to test agreement between categorical variables. Intraclass correlation and Bland-Altman plots were used to test agreement between continuous variables. RESULTS: Obstetric ultrasound telediagnosis showed excellent agreement with standard of care ultrasound allowing the identification of number of fetuses (100% agreement), fetal presentation (95.8% agreement, κ =0.78 (p < 0.0001)), placental location (85.6% agreement, κ =0.74 (p < 0.0001)), and assessment of normal/abnormal amniotic fluid volume (99.2% agreement) with sensitivity and specificity > 95% for all variables. Intraclass correlation was good or excellent for all fetal biometric measurements (0.81-0.95). The majority (88.5%) of second trimester ultrasound exam biometry measurements produced dating within 14 days of standard of care ultrasound. CONCLUSION: This Obstetric ultrasound telediagnostic system is a promising means to increase access to diagnostic Obstetric ultrasound in low-resource settings. The telediagnostic system demonstrated excellent agreement with standard of care ultrasound. Fetal biometric measurements were acceptable for use in the detection of gross discrepancies in fetal size requiring further follow up.
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Assistência Perinatal , Consulta Remota/métodos , Desenvolvimento de Pessoal , Telemedicina/métodos , Ultrassonografia Pré-Natal , Diagnóstico Precoce , Intervenção Médica Precoce/normas , Feminino , Humanos , Obstetrícia/educação , Assistência Perinatal/métodos , Assistência Perinatal/normas , Peru/epidemiologia , Testes Imediatos/organização & administração , Gravidez , Trimestres da Gravidez , Melhoria de Qualidade/organização & administração , Serviços de Saúde Rural/normas , Serviços de Saúde Rural/tendências , Enfermagem Rural/métodos , Desenvolvimento de Pessoal/métodos , Desenvolvimento de Pessoal/organização & administração , Ultrassonografia Pré-Natal/métodos , Ultrassonografia Pré-Natal/normasRESUMO
In this article, we introduce a portable and low-cost ventilator that could be rapidly manufactured, to meet the increasing demand of ventilators worldwide produced by COVID-19 pandemic. These ventilators should be rapidly deployable and with functional capabilities to manage COVID-19 patients with severe acute respiratory distress syndrome (ARDS). Our implementation offers robustness, safety and functionality absent in existing solutions to the ventilator shortage (i.e., telemonitoring, easy-to-disinfect, modularity) by maintaining simplicity. The design makes use of a manual resuscitator as the core respiration component activated by a compression mechanism which consist of two electronically controlled paddles. The quality measurements obtained after testing on a calibrated artificial lung demonstrate repeatability and accuracy exceeding human capabilities of manual ventilation. The complete design files are provided in the supplementary materials to facilitate ventilator production even in resource-limited settings. The implementation of this mechanical ventilator could eliminate device rationing or splitting to serve multiple patients on ICUs.
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Billions of people around the world lack access to diagnostic imaging. To address this issue, we piloted a comprehensive ultrasound telediagnostic system, which uses ultrasound volume sweep imaging (VSI) acquisitions capable of being performed by operators without prior traditional ultrasound training and new telemedicine software capable of sending imaging acquisitions asynchronously over low Internet bandwidth for remote interpretation. The telediagnostic system was tested with obstetric, right upper quadrant abdominal, and thyroid volume sweep imaging protocols in Peru. Scans obtained by operators without prior ultrasound experience were sent for remote interpretation by specialists using the telemedicine platform. Scans obtained allowed visualization of the target region in 96% of cases with diagnostic imaging quality. This telediagnostic system shows promise in improving health care disparities in the developing world.
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Telemedicina , Feminino , Humanos , Peru , Gravidez , Software , UltrassonografiaRESUMO
Anemia is a disease present worldwide. High prevalence of anemia (43%) is found in the child population and its main long-term effect (slow cognitive development) can remain even if the disease has disappeared. One of the main reasons for the high prevalence of anemia in Peru is the poor screening coverage during the growth of the child due to the parents' fear of infringing pain on their children. We take advantage that anemia produces pallor in the hands, fingers and ungueal bed to develop a semaphore for this disease. This screening tool uses photographic images of the patient's ungueal bed to determine if they have a high, medium or low possibility of having anemia. Sixty people participated in the study and 6 photographic images for each participant's right hand were captured. The images were processed to extract regions of interest from each of the fingernails. Datasets were generated and a neural network was used to predict the risk of anemia. Initial results show that the proposed semaphore of anemia reaches a sensitivity of 0.79 and specificity of 0.91. These results indicate that the semaphore of anemia may be used as a screening method to reduce the number of blood tests and the time of evaluation from 15 minutes (rapid test with portable hemoglobinometer) to 1 minute.
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Anemia , Programas de Rastreamento , Anemia/diagnóstico , Criança , Humanos , Peru , Pesquisa , Sensibilidade e EspecificidadeRESUMO
OBJECTIVE: Pneumonia is the leading cause of pediatric mortality worldwide among children 0-5 years old. Lung ultrasound can be used to diagnose pneumonia in rural areas as it is a portable and relatively economic imaging modality with ~95% sensitivity and specificity for pneumonia in children. Lack of trained sonographers is the current limiting factor to its deployment in rural areas. In this study, we piloted training of a volume sweep imaging (VSI) ultrasound protocol for pneumonia detection in Peru with rural health workers. VSI may be taught to individuals with limited medical/ultrasound experience as it requires minimal anatomical knowledge and technical skill. In VSI, the target organ is imaged with a series of sweeps and arcs of the ultrasound probe in relation to external body landmarks. METHODS: Rural health workers in Peru were trained on a VSI ultrasound protocol for pneumonia detection. Subjects were given a brief didactic session followed by hands-on practice with the protocol. Each attempt was timed and mistakes were recorded. Participants performed the protocol until they demonstrated two mistake-free attempts. RESULTS: It took participants a median number of three attempts (range 1-6) to perform the VSI protocol correctly. Time to mastery took 51.4 ± 17.7 min. There were no significant differences among doctors, nurses, and technicians in total training time (P = 0.43) or number of attempts to success (P = 0.72). Trainee age was not found to be significantly correlated with training time (P = 0.50) or number of attempts to success (P = 0.40). CONCLUSION: Rural health workers learned a VSI protocol for pneumonia detection with relative ease in a short amount of time. Future studies should investigate the clinical efficacy of this VSI protocol for pneumonia detection. KEY MESSAGE: A volume sweep imaging (VSI) protocol for pneumonia detection can be taught with minimal difficulty to rural health workers without prior ultrasound experience. No difference was found in training performance related to education level or age. VSI involves no significant knowledge of anatomy or technical skill.
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Sonoelastography is an ultrasonic technique that uses Kasai's autocorrelation algorithms to generate qualitative images of tissue elasticity using external mechanical vibrations. In the absence of synchronization between the mechanical vibration device and the ultrasound system, the random initial phase and finite ensemble length of the data packets result in temporal artifacts in the sonoelastography frames and, consequently, in degraded image quality. In this work, the analytic derivation of an optimal selection of acquisition parameters (i.e., pulse repetition frequency, vibration frequency, and ensemble length) is developed in order to minimize these artifacts, thereby eliminating the need for complex device synchronization. The proposed rule was verified through experiments with heterogeneous phantoms, where the use of optimally selected parameters increased the average contrast-to-noise ratio (CNR) by more than 200% and reduced the CNR standard deviation by 400% when compared to the use of arbitrarily selected imaging parameters. Therefore, the results suggest that the rule for specific selection of acquisition parameters becomes an important tool for producing high quality sonoelastography images.
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A novel method for estimating the shear wave speed from crawling waves based on the amplitude modulation-frequency modulation model is proposed. Our method consists of a two-step approach for estimating the stiffness parameter at the central region of the material of interest. First, narrowband signals are isolated in the time dimension to recover the locally strongest component and to reject distortions from the ultrasound data. Then, the shear wave speed is computed by the dominant component analysis approach and its spatial instantaneous frequency is estimated by the discrete quasi-eigenfunction approximations method. Experimental results on phantoms with different compositions and operating frequencies show coherent speed estimations and accurate inclusion locations.
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Técnicas de Imagem por Elasticidade/métodos , Aumento da Imagem/métodos , Interpretação de Imagem Assistida por Computador/métodos , Algoritmos , Simulação por Computador , Módulo de Elasticidade , Modelos Biológicos , Imagens de FantasmasRESUMO
The study was designed to investigate the association between sleep disturbances and common mental disorders (CMDs) among Peruvian college students. A total of 2538 undergraduate students completed a self-administered questionnaire to gather information about sleep characteristics, sociodemographic, and lifestyle data. Evening chronotype, sleep quality, and daytime sleepiness were assessed using the Horne and Ostberg morningness-eveningness questionnaire, Pittsburgh Sleep Quality Index, and Epworth Sleepiness Scale, respectivelty. Presence of CMDs was evaluated using the General Health Questionnaire. Logistic regression procedures were used to examine the associations of sleep disturbances with CMDs while accounting for possible confounding factors. Overall, 32.9% of the participants had prevalent CMDs (39.3% among females and 24.4% among males). In multivariable-adjusted logistic models, those with evening chronotype (odds ratios (OR) = 1.43; 95% CI 1.00-2.05), poor sleep quality (OR = 4.50; 95% CI 3.69-5.49), and excessive daytime sleepiness (OR = 1.68; 95% CI 1.41-2.01) were at a relative increased odds of CMDs compared with those without sleep disturbances. In conclusion, we found strong associations between sleep disturbances and CMDs among Peruvian college students. Early education and preventative interventions designed to improve sleep habits may effectively alter the possibility of developing CMDs among young adults.
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Ritmo Circadiano/fisiologia , Transtornos Mentais/epidemiologia , Transtornos do Sono-Vigília/epidemiologia , Sono/fisiologia , Estudantes/estatística & dados numéricos , Adolescente , Adulto , Feminino , Humanos , Masculino , Peru/epidemiologia , Universidades , Adulto JovemRESUMO
El Lupinus mutabilis Sweet es una planta con alto contenido calórico y marcados efectos farmacológicos, por lo que pertenece al grupo de plantas nutracéuticas. Objetivo: Comparar la acción analgésica del Lupinus mutabilis S, con el de la Morfina, utilizando la técnica estandarizada de CYTED, del Plantar-test. Materiales y métodos: Utilizamos 50 ratones albinos, machos, de la cepa Holtzman, de aproximadamente 25 gramos de peso, obtenidos del bioterio del MINSA-Chorrillos, a los que previamente se les acondicionó en el bioterio de la Facultad de Medicina Humana de la Universidad San Martín de Porres y suministró alimento y agua. Se les distribuyó en cinco grupos, G1: Control negativo; G2: Lupinus mutabilis, 300 mg/kg; G3: Lupinus mutabilis, 300 mg/kg + Naloxona, 5 mg/kg; G4: Morfina, 10 mg/kg; y, G5: Morfina, 10 mg/kg + Naloxona, 5 mg/kg. Se determinó el umbral doloroso basal de cada uno de los animales en los diferentes grupos utilizando el test del Hot Plate, el mismo que se repitió a los 30, 60 y 90 ,imutos posteriores a la administración, vía intraperitoneal, de las sustancias correspondientes a cada grupo. Los resultados obtenidos fueron analizados estadisticamente con el programa Graph Pad Prism y Excel XP. Resultados: Apreciamos un efecto analgésico del Lupinus similar al de la Morfina, el mismo que fue bloqueado por Naloxona tanto en el grupo tratado con Morfina como en el tratado con Lupinus mutabilis, a la 1/2 hora. Conclusiones: El Lupinus mutabilis S, mostró un buen efecto analgésico, que al igual que la Morfina fue bloqueado por Naloxona.
Lupinus mutabilis Sweet is a plant with high calorie content and many pharmacological effects; therefore, we consider it as a nutraceutic plant. Objective: The present investigation was made with the purpose of comparing the analgesic properties of Lupinus mutabilis S with Morphine, using the standardized technique of CYTED from Plantar Test. Materials and Method: We used fifty albino mice; male of Holtzman bred weighing 25 grams approximately and got from biotherius at MINSA, Chorrillos, to whom previous conditioning in the biotherius from Facultad de Medicina Humana at Universidad de San Martin de Porres and supply of food and water, distributed in the following five groups, G1: Negative control groups, G2: Lupinus mutabilis 300 mg/kg; G3: Lupinus mutabilis, 300 mg/kg+Naloxoma, 5 mg/kg; G4: Morphine, 10 mg/kg and G5: Morphine. 10 mg/kg+Naloxona, 5 mg/kg. It was determined the basal painful threshold to each one of the animals in different groups, using the test of the Hot Plate, the same thing was repeated at 30, 60 and 90 minutus after administration by intraperitoneal via of substances according to each group. The results were analyzed statistically with the program GraphPad Prism and Excel XP. Results: We appreciate an analgesic effect of Lupinus mutabilis Sweet similar to morphine, the same that was blocked by Naloxone in both group treated with Morphine and Lupinus mutabilis at the first 30 minutes. Conclusions: Lupinus mutabilis Sweet showed a good pharmacological action, which like to Morphine that was blockaded by Naloxone.