Application of generative adversarial network in magnetic resonance image reconstruction / 生物医学工程学杂志

Magnetic resonance imaging (MRI) is an important medical imaging method, whose major limitation is its long scan time due to the imaging mechanism, increasing patients' cost and waiting time for the examination. Currently, parallel imaging (PI) and compress sensing (CS) together with other reconstruction technologies have been proposed to accelerate image acquisition. However, the image quality of PI and CS depends on the image reconstruction algorithms, which is far from satisfying in respect to both the image quality and the reconstruction speed. In recent years, image reconstruction based on generative adversarial network (GAN) has become a research hotspot in the field of magnetic resonance imaging because of its excellent performance. In this review, we summarized the recent development of application of GAN in MRI reconstruction in both single- and multi-modality acceleration, hoping to provide a useful reference for interested researchers. In addition, we analyzed the characteristics and limitations of existing technologies and forecasted some development trends in this field.

Design and Research of Wearable Fall Protection Device for the Elderly / 中国医疗器械杂志

A protective device was designed that can be worn on the elderly, which consists of protective airbag, control box and protective mechanism. The combined acceleration, combined angular velocity and human posture angle are selected as the parameters to determine the fall, and the threshold algorithm and SVM algorithm are used to detect the fall. The protective mechanism is an inflatable device based on CO2 compressed air cylinder, and the equal-width cam structure is applied to its transmission part to improve the puncture efficiency of the compressed gas cylinder. A fall experiment was designed to obtain the combined acceleration and angular velocity eigenvalues of fall actions (forward fall, backward fall and lateral fall) and daily activities (sitting-standing, walking, jogging and walking up and down stairs), showing that the specificity and sensitivity of the protection module reached 92.1% and 84.4% respectively, which verified the feasibility of the fall protection device.

Comparison of drop jump force-time profiles of team sport athletes and active controls

Abstract Aim: Lower-body non-contact injuries in team sport athletes (TSAs) are associated when absorbing force, during cutting and landing movements due to a lack of eccentric strength and decreased neuromuscular control leading to excessively higher joint forces. Thus, this project aimed to identify if TSAs had different acceleration and deceleration force profiles compared to a control group (non-TSA) when performing drop jumps (DJs). Methods: University TSAs (n = 15) and non-TSAs (n = 10) performed a series of DJs from a 39 cm box onto a force-plate. All data were normalized to the individual's body mass. Between-group differences in ground reaction force (GRF), rate of force development (RFD), and propulsive and breaking impulses were compared via t-tests and standardized differences. Results: TSAs had significantly, and meaningfully greater RFD than the non-TSAs (p < 0.01, Hedges' g (ES) = 1.24, 53%). While not statistically significant, the non-TSA group produced practically larger mean GRFs than TSAs (p = .09, ES = 0.72, 12.1%). No significant or meaningful between-group differences were detected for propulsive impulse (p = 0.08, ES = 0.41, 9.1%), braking impulse (p = 0.85, ES = 0.25, 4.6%), or impulse ratio (p = 0.35, ES = 0.21, 6.7%). Conclusions: This study shows the presence of significant RFD differences during the DJ in TSAs compared to non-TSAs. Furthermore, this investigation also showed there was no difference between TSA and students in GRF and impulse metrics. Implications from these findings suggest that TSAs can produce force rapidly, but deceleration metrics were not different from untrained students.

Association between anthropometric and physical data of university soccer players from different positions / Associação entre dados antropométricos e físicos de jogadores universitários de futebol de diferentes posições

ABSTRACT The present study aimed to check if there is an association between fitness performance variables and to analyze the variation of fitness levels between playing positions university soccer players. Twenty university soccer players were selected (20.95 ± 1.84 years; 71.60 ± 11.65 kg; 176.85 ± 7.28 m) divided into defenders, midfielders and attackers. Body composition was assessed in a cross-sectional analysis that correlated fat mass, lean mass and fat-free mass by DXA with the physical capacity tests. The main results of the present study revealed that both 10-m and 20-m accelerations had moderate-to-large correlations with agility tests across the playing positions, however these accelerations were largely inversely correlated with YoYo intermittent recovery test in defenders and largely positively in midfielders. The agility test was moderately correlated with YoYo intermittent recovery test across the different playing positions. In conclusion, there the acceleration and the agility had a positive association with the different positions of the soccer players.

RESUMO O objetivo do presente estudo foi verificar se existe associção entre as variáveis de desempenho físico e analisar a variação dos níveis de aptidão física entre as posições de jogador de futebol universitário. Foram selecionados 20 jogadores de futebol universitário (20,95 ± 1,84 anos; 71,60 ± 11,65 kg; 176,85 ± 7,28 m) divididos em zagueiros, meio-campistas e atacantes. Mensurou-se a composição corporal em uma análise transversal e correlacionou-se a massa gorda, massa magra e massa livre de gordura por meio do DXA com os testes de capacidade física. As principais evidências do presente estudo revelaram que as acelerações de 10 e 20 m tiveram correlações de moderada a grande com o teste de agilidade nas posições de jogo, porém essas acelerações foram inversamente correlacionadas com o teste de recuperação intermitente nos defensores e amplamente positiva nos meio-campistas. O teste de agilidade foi moderadamente correlacionado com o teste de recuperação intermitente YoYo nas diferentes posições de jogo. Em conclusão, a aceleração e a agilidade tiveram uma associação positiva com as diferentes posições dos jogadores de futebol.

A Wearable System for Cervical Spondylosis Prevention Based on Artificial Intelligence / 中国医疗器械杂志

Accompanied by changes in modern work and lifestyle, the incidence of cervical spondylosis has increased year by year. In view of the fact long-term fixed posture of the head and neck is one of the main causes of cervical spondylosis, a set of wearable cervical spondylosis prevention system is developed. The system comprises a head and neck movement collection module based on the acceleration sensor and a head and neck motion recognition module based on artificial intelligence. Experimental results showed that the system can accurately identify long-term posture of the head and neck, and guide users to complete effective exercise therapy under the supervision of motion recognition module. Using this system can be beneficial for the prevention of cervical spondylosis.

Feasibility of Simultaneous Multislice Acceleration Technique in Diffusion-Weighted Magnetic Resonance Imaging of the Rectum

Peripheral blood immune cell-based biomarkers in anti-PD-1/PD-L1 therapy

Immune checkpoint blockade targeting PD-1 and PD-L1 has resulted in unprecedented clinical benefit for cancer patients. Anti-PD-1/PD-L1 therapy has become the standard treatment for diverse cancer types as monotherapy or in combination with other anti-cancer therapies, and its indications are expanding. However, many patients do not benefit from anti-PD-1/PD-L1 therapy due to primary and/or acquired resistance, which is a major obstacle to broadening the clinical applicability of anti-PD-1/PD-L1 therapy. In addition, hyperprogressive disease, an acceleration of tumor growth following anti-PD-1/PD-L1 therapy, has been proposed as a new response pattern associated with deleterious prognosis. Anti-PD-1/PD-L1 therapy can also cause a unique pattern of adverse events termed immune-related adverse events, sometimes leading to treatment discontinuation and fatal outcomes. Investigations have been carried out to predict and monitor treatment outcomes using peripheral blood as an alternative to tissue biopsy. This review summarizes recent studies utilizing peripheral blood immune cells to predict various outcomes in cancer patients treated with anti-PD-1/PD-L1 therapy.

Comfort optimization of a new type of foot mechanism for lower extremity exoskeleton / 生物医学工程学杂志

In order to reduce the impact caused by the contact between the foot and the ground when wearing the lower extremity exoskeleton under the condition of high load, this paper proposed an exoskeleton foot mechanism for improving the foot comfort, and optimized the key index of its influence on the comfort. Firstly, the physical model of foot mechanism was established based on the characteristics of foot stress in gait period, and then the mathematical model of vibration was abstracted. The correctness of the model was verified by the finite element analysis software ANSYS. Then, this paper analyzed the influence of vibration parameters on absolute transmissibility based on vibration mathematical model, and optimized vibration parameters with MATLAB genetic algorithm toolbox. Finally, this paper took white noise to simulate the road elevation as the vibration input, and used the visual simulation tool Simulink in MATLAB and the vibration equation to construct the acceleration simulation model, and then calculated the vibration weighted root mean square acceleration value of the foot. The results of this study show that this foot comfort mechanism can meet the comfort indexes of vibration absorption and plantar pressure, and this paper provides a relatively complete method for the design of exoskeleton foot mechanism, which has reference significance for the design of other exoskeleton foot and ankle joint rehabilitation mechanism.

Valoración de ecuaciones derivadas del flujo pulmonar y regurgitación tricuspídea: utilidad en el test de vasoreactividad pulmonar / Valuation of equations derived from Pulmonary Flow and Tricuspid Regurgitation: usefulness in Pulmonary Vasoreactivity Testing

RESUMEN: Antecedentes: La presión media arterial pulmonar (PMAP) es una variable hemodinámica indispensable para el diagnóstico, clasificación y pronóstico de la Hipertensión Pulmonar (HP). Su cuantificación se realiza en forma invasiva por cateterismo cardíaco derecho (CCD) y no invasivamente por ecocardiografía Doppler. Masuyama propuso su medición mediante el gradiente transvalvular pulmonar diastólico derivado de la velocidad máxima inicial de la regurgitación pulmonar (∆RPi2) correspondiendo cercanamente a la medición invasiva. Objetivos: Revalidar 3 métodos ecocardiográficos que estiman la PMAP y valorar la utilidad del método de Chemla en el Test de Reactividad Vascular Pulmonar (TRVP). Métodos: Estudio prospectivo, observacional, doble ciego divido en dos etapas. A) o I) 30 pacientes se realizó ecocardiografía Doppler diagnóstica en nuestro centro. Se midieron regurgitación tricuspídea (RT) y tiempo de aceleración pulmonar (TAP) para derivar las siguientes ecuaciones: 1) 0.61xPSAP+1.95 (Chemla) 2) Gradiente presión media RT (∆PmRT) +PAD (presión-aurícula derecha) (Aduen) y 3) 79-0.45xTAP o 90-0.60xTAP, según sea el valor del TAP. B) o II) 10 pacientes enrolados para realizar el TRVP comparando la medición ecocardiográfica (Chemla) con CCD. Resultados: En la primera parte del estudio se encontró alta correlación entre las 3 ecuaciones: ChemlaAduen, R2=0.91; Chemla-Kitabatake, R2=0.87; Aduen-Kitabatake, R2=0,91. En la segunda parte comparando la PMAP-Chemla y Cateterismo derecho (CD) obtuvimos alta correlación: en tiempo 0, 30 min y recuperación:(R2=0.87, 0.99, 0.98, respectivamente). Ambas partes del estudio mostraron límites de concordancia satisfactoria con valor medio de la diferencia entre los métodos cercano a 1 en el t30 y tR del TRVP. Conclusión: los métodos dependientes de la medición de la RT son efectivos y confiables para estimar la PMAP. El método de Chemla es útil en el TRVP.

ABSTRACTS: Background: Mean Pulmonary arterial pressure (PMAP)is an indispensable hemodynamic variable for the diagnosis, classification and prognosis of Pulmonary Hypertension (PH). Its quantification is performed invasively by cardiac catheterization and non-invasively by Doppler echocardiography. Masuyama proposed its measurement by the transvalvular diastolic pulmonary gradient derived from the initial maximum velocity of pulmonary regurgitation(ΔPRi2) corresponding closely to the invasive measurement. Objectives: to compare 3 known echocardiographic methods to estimate MPAP and demonstrate the usefulness of the Chemla method in the Pulmonary Vascular Reactivity Test (PVRT). Methods: prospective, observational, double-blind study divided into two stages. A) 30 patients underwent diagnostic Doppler echocardiography. Tricuspid regurgitation (TR) and pulmonary acceleration time (PAT) were measured to derive the equations: 1) 0.61xSPAP + 1.95 (Chemla) 2) Gradient mean pressure TR (ΔPmTR) + RAP (right atrium pressure) (Aduen).3) 79-0.45xPAT o 90-0.60xPAT depending on the value of PAT. B) 10 patients enrolled to PVRT comparing the echocardiographic measurement (Chemla) with right catheterization. Results: in the first part of the study a high correlation between the 3 equations was found : ChemlaAduen, R2 = 0.91; Chemla-Kitabatake, R2=0.87; Aduen-Kitabatake, R2=0.91. In the second part comparing the MPAP-Chemla and RHC we obtained a high correlation in time 0, 30 min and recovery: (R2=0.87,0,99,0.98, respectively). Both parts of the study showed satisfactory limits concordance with mean value of the difference between the methods close to 1 in the t30 and tR of the TRVP. Conclusion: the methods dependent on the measurement of the TR are effective and reliable for estimating MPAP. The Chemla method is useful in the PVRT.

Habilidades motoras fundamentais e nível de atividade física de crianças: um estudo com escolares do ensino fundamental / Fundamental motor skills and level of physical activity in children: a study with elementary school students

Habilidades Motoras Fundamentais (HMFS) são movimentos básicos como correr e arremessar, cujo desenvolvimento ocorre na infância e deve ser mantida por toda vida. A proficiência nessas habilidades é desejável para a execução adequada das atividades diárias, recreativas e competitivas. A literatura relata uma associação entre as HMFS com um aumento do nível de atividade física (NAF), indicando que as pessoas mais habilidosas são mais confiantes para executar suas atividades e consequentemente, são mais ativas fisicamente. No entanto, não se conhece bem a relação e impacto das HMFS sobre o NAF. Quando se considera os benefícios conhecidos da atividade física (AF) e a natureza do desenvolvimento motor, é racional reconhecer que o professor de Educação Física (EF) é o principal responsável pelo desenvolvimento das HMFS com importante impacto no futuro estilo de vida dos seus alunos. Assim, o objetivo deste estudo foi descrever e investigar os níveis de HMFS e sua associação com NAF em escolares do ensino fundamental. Método: Participaram deste estudo 148 crianças saudáveis (70 meninos; 78 meninas) com idades entre seis e 10 anos. O teste TGMD-2 foi usado para classificar os níveis das HMFS (em sete escalas) nos subtestes (locomoção e controle de objetos) e no quociente do desenvolvimento motor grosso (QDMG). O NAF foi determinado por acelerometria (Actigraph wGT3X-BT) por meio de "counts", considerando o Vetor Magnitude (VM) Semanal de AF Moderada/Vigorosa (Total Semanal MV), para classificar o NAF Total Semanal MV como sedentário ou ativo, de acordo com as classificações de Chandler et al. (2015). A associação entre os escores padrões das HMFS com o QDMG e com o NAF foi verificada (Pearson). A influência das HMFS sobre o NAF Total Semanal MV foi estabelecida por regressão linear simples explicativa, considerando o NAF como variável dependente e os escores padronizados dos subtestes e o QDMG como variáveis independentes. Para todas as análises realizadas (SPSS 20.0) considerou-se ?=0,05. Resultados: Para o NAF Total Semanal MV foram identificadas baixas correlações estatisticamente significantes com QDMG (r=0,33: p<0,001), escore padrão da locomoção (r = 0,24; p=0,004) e escore padrão controle de objetos (r=0,32: p<0,001). A regressão linear (?) mostrou que o QDMG explica 33.3% da variância do NAF Total Semanal MV [FANOVA = 18,216, p=0.001; r2ajustado=0.105]. De modo semelhante, a variância do NAF Total Semanal MV é explicada em diferentes magnitudes pelo escore padrão da locomoção (?=23.8%; [FANOVA = 8.738, p=0.004; r2=0.050]) e pelo controle de objetos (?=32,3%; [FANOVA = 16,991, p=0.001; r2=0.098]). As HMFS apresentaram um impacto de 33% no NAF Total Semanal MV. Crianças com níveis mais altos de HMFS foram as mais ativas fisicamente. Conclusão: Assim, pode-se considerar que os níveis de proficiência das HMFS têm importante influência no NAF Total Semanal MV das crianças. Diante disso, as crianças das séries iniciais necessitam de planos de ensino enfatizando o desenvolvimento das HMFS, pois são prioritariamente desenvolvidas nessa fase da infância

Fundamental Motor Skills (FMS) are basic movements, such as running and throwing, whose development occurs in childhood and must be maintained throughout life. Proficiency in these skills is desirable for proper performance of daily, recreational and competitive activities. The literature reports an association between FMS with an increase in the level of physical activity (LPA), indicating that people who are more skilled are more confident to perform activities and consequently, are more physically active. However, it is not well understood the relationship and impact of FMS on LPA. When considering the known benefits of physical activity (PA) and the nature of motor development, it is rational to recognize that the Physical Education (PE) teacher is the most responsible for the development of FMS with important impact on the future lifestyle of his/her students. Thus, the objective of this study was to describe and investigate levels of FMS and their association with LPA in elementary school students. Method: A total of 148 healthy children (70 boys, 78 girls) with ages between six and 10 years participated in this study. The TGMD-2 test was used to classify FMS levels (on seven scales) in the subtests (locomotor and object control) and in the Gross Motor Quotient (GMQ). The LPA was determined by accelerometry (Actigraph wGT3X-BT) by means of "counts", considering the Magnitude Vector (MV) Weekly of Moderate/Vigorous PA (Total Weekly MV), to classify the LPA Total Weekly VM as sedentary or active, according to the classifications of Chandler et al. (2015). The association between FMS standard scores with GMQ and LPA was verified (Pearson). The influence of the FMS on the LPA Total Weekly MV was established by simple linear regression, considering the LPA as the dependent variable and the standardized scores of the subtests and the GMQ as independent variables. All analyzes were performed considering ? = 0.05. Results: For the LPA Total Weekly MV, low statistically significant correlations were identified with GMQ (r = 0.33: p <0.001), standard locomotor score (r = 0.24, p = 0.004) p <0.001) and standard object control score (r = 0.32: p <0.001). The linear regression (?) showed that the GMQ explains 33.3% of the variance of the LPA Total Weekly MV [FANOVA = 18,216, p = 0.001; r2 set = 0.105]. Similarly, the variance of the LPA Total Weekly MV is explained in different magnitudes by the standard locomotor score (? = 23.8%, [FANOVA = 8.738, p = 0.004, r2 = 0.050]) and object control (?=32, 3%; [FANOVA = 16,991, p=0.001; r2=0.098]). FMS had a 33% impact on LPA Total Weekly MV. Children with higher levels of FMS were the most physically active. Conclusion: Thus, it can be considered that FMS proficiency levels have an important influence on children's LPA Total Weekly MV. Faced with this, children in early grade need teaching plans emphasizing the development FMS, as they are primarily developed at this stage of childhood

Response Patterns of Nursing Unit Managers regarding Workplace Bullying: A Q Methodology Approach

PURPOSE: The purpose of this study was to identify the response patterns of nursing unit managers regarding workplace bullying. METHODS: Q methodology was used to identify the response patterns. Thirty-six Q samples were selected from the Q population of 210 that included literature reviews and in-depth interviews with clinical nurses and nursing managers. Participants were 30 nursing unit managers who had experience managing workplace bullying and they classified the Q samples into a normal distribution frame measured on a nine-point scale. The data were analyzed using the PC-QUANL program. RESULTS: Five types of response patterns were identified: (1) sympathetic-understanding acceleration, (2) harmonious-team approach, (3) preventive-organizational management, (4) passive observation, and (5) leading-active intervention. The preventive-organizational management type was most frequently used by the nursing unit managers. CONCLUSION: The results of this study indicated that nursing unit managers attempted to prevent and solve workplace bullying in various ways. Therefore, it is necessary to develop and conduct leadership training and intervention programs that appropriately address the response patterns of nursing unit managers, such as those identified in this study.

Implication of Porphyromonas gingivalis in colitis and homeostasis of intestinal epithelium / 한국실험동물학회지

Emerging evidences have reported that periodontitis can be a risk factor for the pathogenesis of various systemic diseases. Porphyromonas gingivalis (Pg), one of the crucial pathogens in chronic periodontitis, has been spotlighted as a potential cause for the promotion and acceleration of periodontitis-associated systemic disorders. To investigate the association between Pg and intestinal disease or homeostasis, we treated Pg-derived lipopolysaccharide (LPS) in murine colitis model or intestinal organoid, respectively. Pg-derived LPS (Pg LPS) was administrated into chemically induced murine colitis model and disease symptoms were monitored compared with the infusion of LPS derived from E. coli (Ec LPS). Organoids isolated and cultured from mouse small intestine were treated with Pg or Ec LPS and further analyzed for the generation and composition of organoids. In vivo observations demonstrated that both Pg and Ec LPS exerted slight protective effects against murine colitis. Pg LPS did not affect the generation and growth of intestinal epithelial organoids. Among subtypes of epithelial cells, markers for stem cells, goblet cells or Paneth cells were changed in response to Pg LPS. Taken together, these results indicate that Pg LPS leads to partial improvement in colitis and that its treatment does not significantly affect the self-organization of intestinal organoids but may regulate the epithelial composition.

Muscle activity during low-speed rear impact / 中华创伤杂志(英文版)

PURPOSE@#Whiplash associated disorders remain a major health problem in terms of impact on health care and on societal costs. Aetiology remains controversial including the old supposition that the cervical muscles do not play a significant role. This study examined the muscle activity from relevant muscles during rear-end impacts in an effort to gauge their influence on the aetiology of whiplash associated disorders.@*METHODS@#Volunteers were subjected to a sub-injury level of rear impact. Surface electromyography (EMG) was used to record cervical muscle activity before, during and after impact. Muscle response time and EMG signal amplitude were analysed. Head, pelvis, and T1 acceleration data were recorded.@*RESULTS@#The activities of the cervical muscles were found to be significant. The sternocleidomastoideus, trapezius and erector spinae were activated on average 59 ms, 73 ms and 84 ms after the impact stimulus, respectively, prior to peak head acceleration (113 ms).@*CONCLUSION@#The cervical muscles reacted prior to peak head acceleration, thus in time to influence whiplash biomechanics and possibly injury mechanisms. It is recommended therefore, that muscular influences be incorporated into the development of the new rear-impact crash test dummy in order to make the dummy as biofidelic as possible.

Development of a Novel Intraoperative Neuromonitoring System Using an Accelerometer Sensor in Thyroid Surgery: A Porcine Model Study

OBJECTIVES: The sensitivity and positive predictive value of widely used intraoperative neuromonitoring (IONM) using electromyography (EMG) of the vocalis muscle in thyroid surgery are controversial. Thus, we developed a novel IONM system with an accelerometer sensor that uses the piezoelectric effect instead of EMG to detect laryngeal twitching. The objective of this study was to evaluate the feasibility and safety of this novel IONM system during thyroid surgery in a porcine model. METHODS: We developed an accelerometer sensor that uses the piezoelectric effect to measure laryngeal twitching in three dimensions. This novel accelerometer sensor was placed in the anterior neck skin (transcutaneous) or postcricoid area. Stimulus thresholds, amplitude, and latency of laryngeal twitching measured using the accelerometer sensor were compared to those measured through EMG of the vocalis muscle. RESULTS: The amplitudes of the accelerometer sensor at the anterior neck and postcricoid area were significantly lower than those of EMG because of differences in the measurement method used to evaluate laryngeal movement. However, no significant differences in stimulus thresholds between the EMG endotracheal tube and transcutaneous or postcricoid accelerometer sensors were observed. CONCLUSION: Accelerometer sensors located at the anterior neck or postcricoid area were able to identify laryngeal twitching. The stimulus intensity measured with these sensors was equivalent to that from conventional vocalis EMG. Our novel IONM system with an accelerometer sensor that checks changes in surface acceleration can be an alternative to EMG of the vocalis muscle for IONM in the future.

Methylphenidate and Central Precocious Puberty: A Probable Side Effect among Seven Children with the Attention Deficit Hyperactivity Disorder

Methylphenidate (MPH) is the most preferred drug for treatment of the attention deficit hyperactivity disorder (ADHD). Here, we aimed to discuss the possible effects and mechanisms of MPH on precocious puberty (PP) via a case series with seven children who had normal body mass index. In this case series we evaluated seven children with ADHD, who had received MPH for at least 6 months (0.5 mg/kg/dose three times a day, maximum 60 mg) and admitted to Department of Pediatric Endocrinology with PP symptoms. The mean age was 8.16 years. Basal hormonal levels (luteinizing hormone [LH], follicle stimulating hormone, and estrogen/testosterone) were within normal range. Results of LH-releasing hormone stimulation tests demonstrated central pubertal responses. Glutamine, dopamine and noradrenaline are most important excitatory neurotransmitters that have a role at the beginning of puberty. The effect of MPH, cumulating dopamine and noradrenaline in the synaptic gap could be associated with the acceleration of puberty with the excitatory effect of dopamine’s gonadotropin-releasing hormone (GnRH) release, excitatory effect of noradrenaline’s GnRH release and the disappearance of GnRH receptor expression suppressor effect on prolactin disinhibitory effect.

Real-Time Computed Tomography Volume Visualization with Ambient Occlusion of Hand-Drawn Transfer Function Using Local Vicinity Statistic / 대한의료정보학회지

OBJECTIVES: In this paper, we present an efficient method to visualize computed tomography (CT) datasets using ambient occlusion, which is a global illumination technique that adds depth cues to the output image. We can change the transfer function (TF) for volume rendering and generate output images in real time. METHODS: In preprocessing, the mean and standard deviation of each local vicinity are calculated. During rendering, the ambient light intensity is calculated. The calculation is accelerated on the assumption that the CT value of the local vicinity of each point follows the normal distribution. We approximate complex TF forms with a smaller number of connected line segments to achieve additional acceleration. Ambient occlusion is combined with the existing local illumination technique to produce images with depth in real time. RESULTS: We tested the proposed method on various CT datasets using hand-drawn TFs. The proposed method enabled real-time rendering that was approximately 40 times faster than the previous method. As a result of comparing the output image quality with that of the conventional method, the average signal-to-noise ratio was approximately 40 dB, and the image quality did not significantly deteriorate. CONCLUSIONS: When rendering CT images with various TFs, the proposed method generated depth-sensing images in real time.

Unconstrained detection of ballistocardiogram and heart rate based on vibration acceleration / 生物医学工程学杂志

The requirement for unconstrained monitoring of heartbeat during sleep is increasing, but the current detection devices can not meet the requirements of convenience and accuracy. This study designed an unconstrained ballistocardiogram (BCG) detection system using acceleration sensor and developed a heart rate extraction algorithm. BCG is a directional signal which is stronger and less affected by respiratory movements along spine direction than in other directions. In order to measure the BCG signal along spine direction during sleep, a 3-axis acceleration sensor was fixed on the bed to collect the vibration signals caused by heartbeat. An approximate frequency range was firstly assumed by frequency analysis to the BCG signals and segmental filtering was conducted to the original vibration signals within the frequency range. Secondly, to identify the true BCG waveform, the accurate frequency band was obtained by comparison with the theoretical waveform. The J waves were detected by BCG energy waveform and an adaptive threshold method was proposed to extract heart rates by using the information of both amplitude and period. The accuracy and robustness of the BCG detection system proposed and the algorithm developed in this study were confirmed by comparison with electrocardiogram (ECG). The test results of 30 subjects showed a high average accuracy of 99.21% to demonstrate the feasibility of the unconstrained BCG detection method based on vibration acceleration.

Prognostic value of right pulmonary artery distensibility in dogs with pulmonary hypertension

The right pulmonary artery distensibility (RPAD) index has been used in dogs with pulmonary hypertension (PH) caused by heartworm infection, myxomatous mitral valve disease, or patent ductus arteriosus. We hypothesized that this index correlates with the tricuspid regurgitation pressure gradient (TRPG) assessed by echocardiography and could predict survival in dogs with PH secondary to various causes. To assess this hypothesis, the medical records of 200 client-owned dogs at a referral institution were retrospectively reviewed. The RPAD index and the ratios of acceleration time to peak pulmonary artery flow (AT) and to the ejection time of pulmonary artery flow (ET) were recorded for each dog. The owners were contacted for follow-up assessments. The findings indicated that the RPAD index was correlated with the TRPG (R2 = 0. 362, p < 0.001). The survival time was significantly shorter in dogs with an RPAD index ≤ 21% that were followed up for 3 months and in dogs with an RPAD index ≤ 24% that were followed up for 1 year. Thus, the RPAD index was correlated with the TRPG and could predict the clinical outcome in dogs with PH caused by various diseases. This index could be used to evaluate the severity of PH in dogs without tricuspid regurgitation.

Growth Hormone and Aging: Updated Review

Role of growth hormone (GH) in mammalian aging is actively explored in clinical, epidemiological, and experimental studies. The age-related decline in GH levels is variously interpreted as a symptom of neuroendocrine aging, as one of causes of altered body composition and other unwelcome symptoms of aging, or as a mechanism of natural protection from cancer and other chronic diseases. Absence of GH signals due to mutations affecting anterior pituitary development, GH secretion, or GH receptors produces an impressive extension of longevity in laboratory mice. Extension of healthspan in these animals and analysis of survival curves suggest that in the absence of GH, aging is slowed down or delayed. The corresponding endocrine syndromes in the human have no consistent impact on longevity, but are associated with remarkable protection from age-related disease. Moreover, survival to extremely old age has been associated with reduced somatotropic (GH and insulin-like growth factor-1) signaling in women and men. In both humans and mice, elevation of GH levels into the supranormal (pathological) range is associated with increased disease risks and reduced life expectancy likely representing acceleration of aging. The widely advertised potential of GH as an anti-aging agent attracted much interest. However, results obtained thus far have been disappointing with few documented benefits and many troublesome side effects. Possible utility of GH in the treatment of sarcopenia and frailty remains to be explored.

Accelerated Time-of-Flight Magnetic Resonance Angiography with Sparse Undersampling and Iterative Reconstruction for the Evaluation of Intracranial Arteries

OBJECTIVE: To compare the image quality of three-dimensional time-of-flight (TOF) magnetic resonance angiography (MRA) with sparse undersampling and iterative reconstruction (sparse TOF) with that of conventional TOF MRA. MATERIALS AND METHODS: This study included 56 patients who had undergone sparse TOF MRA for intracranial artery evaluation on a 3T MR scanner. Conventional TOF MRA scans were also acquired from 29 patients with matched acquisition times and another 27 patients with matched scanning parameters. The image quality was scored using a five-point scale based on the delineation of arterial vessel segments, artifacts, overall vessel visualization, and overall image quality by two radiologists independently, and the data were analyzed using the non-parametric Wilcoxon signed-rank test. Contrast ratios (CRs) of vessels were compared using the paired t test. Interobserver agreement was calculated using the kappa test. RESULTS: Compared with conventional TOF at the same spatial resolution, sparse TOF with an acceleration factor of 3.5 could reduce acquisition time by 40% and showed comparable image quality. In addition, when compared with conventional TOF with the same acquisition time, sparse TOF with an acceleration factor of 5 could also achieve higher spatial resolution, better delineation of vessel segments, fewer artifacts, higher image quality, and a higher CR (p < 0.05). Good-to-excellent interobserver agreement (κ: 0.65–1.00) was obtained between the two radiologists. CONCLUSION: Compared with conventional TOF, sparse TOF can achieve equivalent image quality in a reduced duration. Furthermore, using the same acquisition time, sparse TOF could improve the delineation of vessels and decrease image artifacts.