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1.
Med Image Anal ; 77: 102362, 2022 04.
Artigo em Inglês | MEDLINE | ID: mdl-35091277

RESUMO

Multi-sequence cardiac magnetic resonance (CMR) provides essential pathology information (scar and edema) to diagnose myocardial infarction. However, automatic pathology segmentation can be challenging due to the difficulty of effectively exploring the underlying information from the multi-sequence CMR data. This paper aims to tackle the scar and edema segmentation from multi-sequence CMR with a novel auto-weighted supervision framework, where the interactions among different supervised layers are explored under a task-specific objective using reinforcement learning. Furthermore, we design a coarse-to-fine framework to boost the small myocardial pathology region segmentation with shape prior knowledge. The coarse segmentation model identifies the left ventricle myocardial structure as a shape prior, while the fine segmentation model integrates a pixel-wise attention strategy with an auto-weighted supervision model to learn and extract salient pathological structures from the multi-sequence CMR data. Extensive experimental results on a publicly available dataset from Myocardial pathology segmentation combining multi-sequence CMR (MyoPS 2020) demonstrate our method can achieve promising performance compared with other state-of-the-art methods. Our method is promising in advancing the myocardial pathology assessment on multi-sequence CMR data. To motivate the community, we have made our code publicly available via https://github.com/soleilssss/AWSnet/tree/master.


Assuntos
Cicatriz , Imageamento por Ressonância Magnética , Edema , Coração , Ventrículos do Coração , Humanos , Imageamento por Ressonância Magnética/métodos
2.
Ultrasonics ; 119: 106594, 2022 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-34628298

RESUMO

Pixel-based beamforming generates focused data by assuming that the waveforms received on a linear transducer array are composed of spherical pulses. It does not take into account the spatiotemporal spread in the data from the length of the excitation pulse or from the transfer functions of the transducer elements. As a result, these beamformers primarily have impacts on lateral, rather than axial, resolution. This paper proposes an efficient method to improve the axial resolution for pixel-based beamforming. We extend our field pattern analysis and show that the received waveforms should be passed through a Wiener filter before being used in the coherent pixel-based beamformer. This filter is designed based on signals echoed from a single scatterer at the transmit focus. The beamformer output is then combined with a coherence factor, that is adaptive to the signal-to-noise ratio, to improve the image contrast and suppress artifacts that have arisen during the filtering process. We validate the proposed method and compare it with other beamforming strategies using a series of experiments, including simulation, phantom and in vivo studies. It is shown to offer significant improvements in axial resolution and contrast over coherent pixel-based beamforming, as well as other spatial filters derived from synthetic aperture imaging. The method also demonstrates robustness to modeling errors in the experimental data. Overall, the imaging results show that the proposed approach has the potential to be of value in clinical applications.


Assuntos
Aumento da Imagem/instrumentação , Ultrassonografia/instrumentação , Algoritmos , Artefatos , Simulação por Computador , Imagens de Fantasmas , Razão Sinal-Ruído
3.
J Oncol ; 2021: 6060762, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34956364

RESUMO

One of the most frequent malignancies in the head and neck is nasopharyngeal carcinoma (NPC). MicroRNAs, a kind of tiny noncoding RNA molecule, have been used as negative regulators in different types of cancer therapy in recent decades by downregulating their targets. Recent research suggests that microRNAs play an important role in cancer's epithelial-to-mesenchymal transition (EMT), supporting or inhibiting EMT development. The epithelial-to-mesenchymal transition (EMT) is linked to a variety of cancer-related activities, including growth, metastasis, and invasion. Previous research has linked EMT to cancer stem-like characteristics as well as treatment resistance. Moreover, since microRNAs (miRNAs) are important regulators of the EMT phenotype, certain miRNAs have an effect on cancer stemness and treatment resistance. As a result, both fundamental research and clinical therapy benefit from knowing the connection between EMT-associated miRNAs and cancer stemness/drug resistance. As a result, we looked at the different functions that EMT-associated miRNAs (miR-137) play in the stem-like characteristics of malignant cells in this article. Then we looked at how EMT-associated miRNAs interact with nasopharyngeal cancer's drug-resistant complex signaling pathways. Using qRT-PCR, we evaluated the performance of several micro RNAs with the proposed miR-137 for inhibiting invasion, metastasis, and the EMT process. In conclusion, our findings showed that miR-137 acted as a tumor suppressor gene in controlling NPC EMT and metastasis and that it may be a new therapeutic strategy and prognosis marker for the disease.

4.
Artigo em Inglês | MEDLINE | ID: mdl-34928809

RESUMO

Hard sample selection can effectively improve model convergence by extracting the most representative samples from a training set. However, due to the large capacity of medical images, existing sampling strategies suffer from insufficient exploitation for hard samples or high time cost for sample selection when adopted by 3D patch-based models in the field of multi-organ segmentation. In this paper, we present a novel and effective online hard patch mining (OHPM) algorithm. In our method, an average shape model that can be mapped with all training images is constructed to guide the exploration of hard patches and aggregate feedback from predicted patches. The process of hard mining is formalized as a multi-armed bandit problem and solved with bandit algorithms. With the shape model, OHPM requires negligible time consumption and can intuitively locate difficult anatomical areas during training. The employment of bandit algorithms ensures online and sufficient hard mining. We integrate OHPM with advanced segmentation networks and evaluate them on two datasets containing different anatomical structures. Comparative experiments with other sampling strategies demonstrate the superiority of OHPM in boosting segmentation performance and improving model convergence. The results in each dataset with each network suggest that OHPM significantly outperforms other sampling strategies by nearly 2% average Dice score.

5.
IEEE J Biomed Health Inform ; 25(10): 3854-3864, 2021 10.
Artigo em Inglês | MEDLINE | ID: mdl-33999826

RESUMO

Automatic and accurate detection of anatomical landmarks is an essential operation in medical image analysis with a multitude of applications. Recent deep learning methods have improved results by directly encoding the appearance of the captured anatomy with the likelihood maps (i.e., heatmaps). However, most current solutions overlook another essence of heatmap regression, the objective metric for regressing target heatmaps and rely on hand-crafted heuristics to set the target precision, thus being usually cumbersome and task-specific. In this paper, we propose a novel learning-to-learn framework for landmark detection to optimize the neural network and the target precision simultaneously. The pivot of this work is to leverage the reinforcement learning (RL) framework to search objective metrics for regressing multiple heatmaps dynamically during the training process, thus avoiding setting problem-specific target precision. We also introduce an early-stop strategy for active termination of the RL agent's interaction that adapts the optimal precision for separate targets considering exploration-exploitation tradeoffs. This approach shows better stability in training and improved localization accuracy in inference. Extensive experimental results on two different applications of landmark localization: 1) our in-house prenatal ultrasound (US) dataset and 2) the publicly available dataset of cephalometric X-Ray landmark detection, demonstrate the effectiveness of our proposed method. Our proposed framework is general and shows the potential to improve the efficiency of anatomical landmark detection.


Assuntos
Mãos , Redes Neurais de Computação , Feminino , Humanos , Gravidez , Radiografia
6.
Artigo em Inglês | MEDLINE | ID: mdl-32167889

RESUMO

Tracking the myotendinous junction (MTJ) in consecutive ultrasound images is crucial for understanding the mechanics and pathological conditions of the muscle-tendon unit. However, the lack of reliable and efficient identification of MTJ due to poor image quality and boundary ambiguity restricts its application in motion analysis. In recent years, with the rapid development of deep learning, the region-based convolution neural network (RCNN) has shown great potential in the field of simultaneous objection detection and instance segmentation in medical images. This article proposes a region-adaptive network (RAN) to localize MTJ region and to segment it in a single shot. Our model learns about the salient information of MTJ with the help of a composite architecture. Herein, a region-based multitask learning network explores the region containing MTJ, while a parallel end-to-end U-shaped path extracts the MTJ structure from the adaptively selected region for combating data imbalance and boundary ambiguity. By demonstrating the ultrasound images of the gastrocnemius, we showed that the RAN achieves superior segmentation performance when compared with the state-of-the-art Mask RCNN method with an average Dice score of 80.1%. Our proposed method is robust and reliable for advanced muscle and tendon function examinations obtained by ultrasound imaging.


Assuntos
Aprendizado Profundo , Interpretação de Imagem Assistida por Computador/métodos , Músculo Esquelético/diagnóstico por imagem , Tendões/diagnóstico por imagem , Ultrassonografia/métodos , Adulto , Articulação do Tornozelo/diagnóstico por imagem , Feminino , Humanos , Masculino , Adulto Jovem
7.
Ultrasound Med Biol ; 46(3): 828-841, 2020 03.
Artigo em Inglês | MEDLINE | ID: mdl-31901383

RESUMO

Ultrasound volume projection imaging (VPI) has been recently suggested. This novel imaging method allows a non-radiation assessment of spine deformity with free-hand 3-D ultrasound imaging. This paper presents a fully automatic method to evaluate the spine curve in VPI images corresponding to different projection depth of the volumetric ultrasound, thus making it possible to analyze 3-D spine deformity. The new automatic method is based on prior knowledge about the geometric arrangement of the spinous processes. The frequency bandwidth of log-Gabor filters is adaptively adjusted to calculate the oriented phase congruency, facilitating the segmentation of the spinous column profile. And the spine curvature angle is finally calculated according to the inflection points of the curve over the segmented spinous column profile. The performance of the automatic method is evaluated on spine VPI images among patients with different scoliotic angles. The curvature angles obtained using the proposed method have a high linear correlation with those by the manual method (r = 0.90, p < 0.001) and X-ray Cobb's method (r = 0.87, p < 0.001). The feasibility of 3-D spine deformity assessment is also demonstrated using VPI images corresponding to various projection depth. The results suggest that this method can substantially improve the recognition of the spinous column profile, especially facilitating the applications of 3-D spine deformity assessment.


Assuntos
Imageamento Tridimensional , Curvaturas da Coluna Vertebral/diagnóstico por imagem , Adolescente , Adulto , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Ultrassonografia/métodos , Adulto Jovem
8.
Math Biosci Eng ; 17(1): 654-668, 2019 10 22.
Artigo em Inglês | MEDLINE | ID: mdl-31731370

RESUMO

In this paper, a three-dimensional (3D) shape measurement method based on structured light field imaging is proposed, which contributes to the biomedical imaging. Generally, light field imaging is challenging to accomplish the 3D shape measurement accurately, as the slope estimation method based on radiance consistency is inaccurate. Taking into consideration the special modulation of structured light field, we utilize the phase information to substitute the phase consistency for the radiance consistency in epi-polar image (EPI) at first. Therefore, the 3D coordinates are derived after light field calibration, but the results are coarse due to slope estimation error and need to be corrected. Furthermore, the 3D coordinates refinement is performed based on relationship between the structured light field image and DMD image of the projector, which allows to improve the performance of the 3D shape measurement. The necessary light field camera calibration is described to generalize its application. Subsequently, the effectiveness of the proposed method is demonstrated with a sculpture and compared to the results of a conventional PMP system.

9.
Math Biosci Eng ; 17(1): 776-788, 2019 10 31.
Artigo em Inglês | MEDLINE | ID: mdl-31731376

RESUMO

This study proposed a new automatic measurement method of spinal curvature on ultrasound coronal images in adolescent idiopathic scoliosis (AIS). After preprocessing of Gaussian enhancement, the symmetric information of the image was extracted using the phase congruency. Then bony features were segmented from the soft tissues and background using the greyscale polarity. The morphological methods of image erosion and top-bottom-hat transformation, and geometric moment were utilized to identify the spinous column profile from the transverse processes. Finally, the spine deformity curve was obtained using robust regression. In-vivo experiments based on AIS patients were performed to evaluate the performance of the developed method. The comparison results revealed there was a significant correlation (y=0.81x, r=0.86) and good agreement between the new automatic method and the manual measurement method. It can be expected that this novel method may help to provide effective and objective deformity assessment method during the ultrasound scanning for AIS patients.


Assuntos
Diagnóstico por Computador/métodos , Processamento de Imagem Assistida por Computador/métodos , Reconhecimento Automatizado de Padrão , Escoliose/diagnóstico por imagem , Curvaturas da Coluna Vertebral/diagnóstico por imagem , Adolescente , Algoritmos , Humanos , Modelos Estatísticos , Distribuição Normal , Análise de Regressão , Coluna Vertebral/diagnóstico por imagem , Ultrassonografia , Adulto Jovem
10.
Math Biosci Eng ; 16(3): 1067-1081, 2019 02 15.
Artigo em Inglês | MEDLINE | ID: mdl-30947409

RESUMO

Applying ultrasound for scoliosis assessment has been an attractive topic over the past decade. This study proposed a new fast 3-D ultrasound projection imaging method to evaluate the spine deformity. A narrow-band rendering method was used to generate the coronal images based on B-mode images and their corresponding positional data. The non-planar reslicing method, which followed the natural spine curve, was used to project the complete spine data into the coronal image. The repeatability of the new method was tested. A comparison experiment on the reconstructed images and the processing time between the conventional 3-D rendering method and the developed projection imaging method was also performed among 70 patients with scoliosis. The intra- and inter-operator tests results demonstrated very good repeatability (ICC ≥ 0.90). The mean processing times for the developed projection method and conventional rendering method were 15.07 ± 0.03 s and 130.31 ± 35.07 s, respectively. The angle measurement results showed a high correlation (y = 0.984x, r = 0.954) between the images obtained using the two methods. The above results indicated that the developed projection imaging method could greatly decrease the processing time while preserving the comparative image quality. It can be expected that this novel method may help to provide fast 3-D ultrasound diagnosis of scoliosis in clinics.


Assuntos
Processamento de Imagem Assistida por Computador/métodos , Imageamento Tridimensional/métodos , Escoliose/diagnóstico por imagem , Coluna Vertebral/diagnóstico por imagem , Ultrassonografia/métodos , Adolescente , Feminino , Humanos , Masculino , Variações Dependentes do Observador , Reprodutibilidade dos Testes , Adulto Jovem
11.
Biomed Res Int ; 2018: 3697835, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-29750152

RESUMO

Displacement of the myotendinous junction (MTJ) obtained by ultrasound imaging is crucial to quantify the interactive length changes of muscles and tendons for understanding the mechanics and pathological conditions of the muscle-tendon unit during motion. However, the lack of a reliable automatic measurement method restricts its application in human motion analysis. This paper presents an automated measurement of MTJ displacement using prior knowledge on tendinous tissues and MTJ, precluding the influence of nontendinous components on the estimation of MTJ displacement. It is based on the perception of tendinous features from musculoskeletal ultrasound images using Radon transform and thresholding methods, with information about the symmetric measures obtained from phase congruency. The displacement of MTJ is achieved by tracking manually marked points on tendinous tissues with the Lucas-Kanade optical flow algorithm applied over the segmented MTJ region. The performance of this method was evaluated on ultrasound images of the gastrocnemius obtained from 10 healthy subjects (26.0 ± 2.9 years of age). Waveform similarity between the manual and automatic measurements was assessed by calculating the overall similarity with the coefficient of multiple correlation (CMC). In vivo experiments demonstrated that MTJ tracking with the proposed method (CMC = 0.97 ± 0.02) was more consistent with the manual measurements than existing optical flow tracking methods (CMC = 0.79 ± 0.11). This study demonstrated that the proposed method was robust to the interference of nontendinous components, resulting in a more reliable measurement of MTJ displacement, which may facilitate further research and applications related to the architectural change of muscles and tendons.


Assuntos
Músculo Esquelético/diagnóstico por imagem , Tendões/diagnóstico por imagem , Adulto , Algoritmos , Feminino , Humanos , Masculino , Ultrassonografia/métodos
12.
PLoS One ; 12(12): e0190141, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-29267389

RESUMO

BACKGROUND: Spinal flexibility is an essential parameter for clinical decision making on the patients with adolescent idiopathic scoliosis (AIS). Various methods are proposed to assess spinal flexibility, but which assessment method is more effective to predict the effect of orthotic treatment is unclear. OBJECTIVE: To investigate an effective assessment method of spinal flexibility to predict the initial in-orthosis correction, among the supine, prone, sitting with lateral bending and prone with lateral bending positions. METHODS: Thirty-five patients with AIS (mean Cobb angle: 28° ± 7°; mean age: 12 ± 2 years; Risser sign: 0-2) were recruited. Before orthosis fitting, spinal flexibility was assessed by an ultrasound system in 4 positions (apart from standing) including supine, prone, sitting with lateral bending and prone with lateral bending. After orthosis fitting, the initial in-orthosis correction was routinely assessed by whole spine standing radiograph. Comparisons and correlation analyses were performed between the spinal flexibility in the 4 positions and the initial in-orthosis correction. RESULTS: The mean in-orthosis correction was 41% while the mean curve correction (spinal flexibility) in the 4 studied positions were 40% (supine), 42% (prone), 127% (prone with lateral bending) and 143% (sitting with lateral bending). The correlation coefficients between initial in-orthosis correction and curve correction (spinal flexibility) in the 4 studied positions were r = 0.66 (supine), r = 0.75 (prone), r = 0.03 (prone with lateral bending) and r = 0.04 (sitting with lateral bending). CONCLUSIONS: The spinal flexibility in the prone position is the closest to and most correlated with the initial in-orthosis correction among the 4 studied positions. Thus, the prone position could be an effective method to predict the initial effect of orthotic treatment on the patients with AIS.


Assuntos
Aparelhos Ortopédicos , Escoliose/fisiopatologia , Coluna Vertebral/fisiopatologia , Adolescente , Criança , Feminino , Humanos , Masculino , Escoliose/diagnóstico por imagem , Escoliose/terapia
13.
Biomed Res Int ; 2017: 6783824, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-29457033

RESUMO

Skeletal muscles are essential to the gender-specific characteristics of human movements. Sonomyography, a new signal for quantifying muscle activation, is of great benefit to understand muscle function through monitoring the real-time muscle architectural changes. The purpose of this pilot study was to investigate gender differences in the architectural changes of gastronomies muscle and tendon by using sonomyography during performing two-legged calf raising exercises. A motion analysis system was developed to extract sonomyography from ultrasound images together with kinematic and kinetic measurements. Tiny fascicle length changes among seven male subjects were observed at the initial part of calf raising, whereas the fascicle of seven female subjects shortened immediately. This result suggested that men would generate higher mechanical power output of plantar flexors to regulate their heavier body mass. In addition, the larger regression coefficient between the fascicle length and muscle force for the male subjects implied that higher muscle stiffness for the men was required in demand of maintaining their heavier body economically. The findings from the current study suggested that the body mass might play a factor in the gender difference in structural changes of muscle and tendon during motion. The sonomyography may provide valuable information in the understanding of the gender difference in human movements.


Assuntos
Tendão do Calcâneo/crescimento & desenvolvimento , Músculo Esquelético/crescimento & desenvolvimento , Ultrassonografia/métodos , Tendão do Calcâneo/diagnóstico por imagem , Adulto , Articulação do Tornozelo/diagnóstico por imagem , Articulação do Tornozelo/fisiologia , Fenômenos Biomecânicos/fisiologia , Exercício Físico/fisiologia , Feminino , Humanos , Contração Isométrica/fisiologia , Movimento/fisiologia , Contração Muscular/fisiologia , Músculo Esquelético/diagnóstico por imagem , Projetos Piloto , Fatores Sexuais
14.
Man Ther ; 26: 70-76, 2016 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-27497646

RESUMO

BACKGROUND: Transverse friction massage (TFM), as an often used technique by therapists, is known for its effect in reducing the pain and loosing the scar tissues. Nevertheless, its effects on neuromotor driving mechanism including the electromechanical delay (EMD), force transmission and excitation-contraction (EC) coupling which could be used as markers of stiffness changes, has not been computed using ultrafast ultrasound (US) when combined with external sensors. AIM: Hence, the aim of this study was to find out produced neuromotor changes associated to stiffness when TFM was applied over Quadriceps femoris (QF) tendon in healthy subjcets. METHODS: Fourteen healthy males and fifteen age-gender matched controls were recruited. Surface EMG (sEMG), ultrafast US and Force sensors were synchronized and signals were analyzed to depict the time delays corresponding to EC coupling, force transmission, EMD, torque and rate of force development (RFD). RESULTS: TFM has been found to increase the time corresponding to EC coupling and EMD, whilst, reducing the time belonging to force transmission during the voluntary muscle contractions. CONCLUSIONS: A detection of the increased time of EC coupling from muscle itself would suggest that TFM applied over the tendon shows an influence on changing the neuro-motor driving mechanism possibly via afferent pathways and therefore decreasing the active muscle stiffness. On the other hand, detection of decreased time belonging to force transmission during voluntary contraction would suggest that TFM increases the stiffness of tendon, caused by faster force transmission along non-contractile elements. Torque and RFD have not been influenced by TFM.


Assuntos
Fricção/fisiologia , Massagem , Contração Muscular/fisiologia , Músculo Quadríceps/fisiologia , Adulto , Idoso , Idoso de 80 Anos ou mais , Feminino , Humanos , Masculino , Pessoa de Meia-Idade
15.
Artigo em Inglês | MEDLINE | ID: mdl-27299162

RESUMO

BACKGROUND: Radiographic evaluation for patients with scoliosis using Cobb method is the current gold standard, but radiography has radiation hazards. Several groups have recently demonstrated the feasibility of using 3D ultrasound for the evaluation of scoliosis. Ultrasound imaging is radiation-free, comparatively more accessible, and inexpensive. However, a reliable and valid 3D ultrasound system ready for clinical scoliosis assessment has not yet been reported. Scolioscan is a newly developed system targeted for scoliosis assessment in clinics by using coronal images of spine generated by a 3D ultrasound volume projection imaging method. The aim of this study is to test the reliability of spine deformity measurement of Scolioscan and its validity compared to the gold standard Cobb angle measurements from radiography in adolescent idiopathic scoliosis (AIS) patients. METHODS: Prospective study divided into two stages: 1) Investigation of intra- and inter- reliability between two operators for acquiring images using Scolioscan and among three raters for measuring spinal curves from those images; 2) Correlation between the Cobb angle obtained from radiography by a medical doctor and the spine curve angle obtained using Scolioscan (Scolioscan angle). The raters for ultrasound images and the doctors for evaluating radiographic images were mutually blinded. The two stages of tests involved 20 (80 % females, total of 26 angles, age of 16.4 ± 2.7 years, and Cobb angle of 27.6 ± 11.8°) and 49 (69 % female, 73 angles, 15.8 ± 2.7 years and 24.8 ± 9.7°) AIS patients, respectively. Intra-class correlation coefficients (ICC) and Bland-Altman plots and root-mean-square differences (RMS) were employed to determine correlations, which interpreted based on defined criteria. RESULTS: We demonstrated a very good intra-rater and intra-operator reliability for Scolioscan angle measurement with ICC larger than 0.94 and 0.88, respectively. Very good inter-rater and inter-operator reliability was also demonstrated, with both ICC larger than 0.87. For the thoracic deformity measurement, the RMS were 2.5 and 3.3° in the intra- and inter-operator tests, and 1.5 and 3.6° in the intra- and inter-rater tests, respectively. The RMS differences were 3.1, 3.1, 1.6, 3.7° in the intra- and inter-operator and intra- and inter-rater tests, respectively, for the lumbar angle measurement. Moderate to strong correlations (R(2) > 0.72) were observed between the Scolioscan angles and Cobb angles for both the thoracic and lumbar regions. It was noted that the Scolioscan angle slightly underestimated the spinal deformity in comparison with Cobb angle, and an overall regression equation y = 1.1797x (R(2) = 0.76) could be used to translate the Scolioscan angle (x) to Cobb angle (y) for this group of patients. The RMS difference between Scolioscan angle and Cobb angle was 4.7 and 6.2°, with and without the correlation using the overall regression equation. CONCLUSIONS: We showed that Scolioscan is reliable for measuring coronal deformity for patients with AIS and appears promising in screening large numbers of patients, for progress monitoring, and evaluation of treatment outcomes. Due to it being radiation-free and relatively low-cost, Scolioscan has potential to be widely implemented and may contribute to reducing radiation dose during serial monitoring.

16.
IEEE Trans Biomed Eng ; 62(12): 2828-36, 2015 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-26087480

RESUMO

GOAL: The fascicle length obtained by ultrasound imaging is one of the crucial muscle architecture parameters for understanding the contraction mechanics and pathological conditions of muscles. However, the lack of a reliable automatic measurement method restricts the application of the fascicle length for the analysis of the muscle function, as frame-by-frame manual measurement is time-consuming. In this study, we propose an automatic measurement method to preclude the influence of nonfascicle components on the estimation of the fascicle length by using motion estimation of fascicle structures. METHODS: The method starts with image segmentation using the cohesiveness of fascicle orientation as a feature, obtaining the fascicle change by tracking manually marked points on the fascicular path with the Lucas-Kanade optical flow algorithm applied on the segmented image. RESULTS: The performance of this method was evaluated on ultrasound images of the gastrocnemius obtained from seven healthy subjects (34.4 ± 5.0 years). Waveform similarity between the manual and dynamic measurements was assessed by calculating the overall similarity with the coefficient of multiple correlations (CMC). In vivo experiments demonstrated that fascicle tracking with the orientation-sensitive segmentation (CMC = 0.97 ± 0.01) was more consistent with the manual measurements than existing automatic methods (CMC = 0.87 ± 0.10). CONCLUSION: Our method was robust to the interference of nonfascicle components, resulting in a more reliable measurement of the fascicle length. SIGNIFICANCE: The proposed method may facilitate further research and applications related to real-time architectural change of muscles.


Assuntos
Processamento de Imagem Assistida por Computador/métodos , Músculo Esquelético/diagnóstico por imagem , Adulto , Algoritmos , Humanos , Músculo Esquelético/anatomia & histologia , Músculo Esquelético/fisiologia , Ultrassonografia
17.
Orthop Surg ; 7(1): 57-65, 2015 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-25708037

RESUMO

OBJECTIVE: To assess the ability of whole body vibration (WBV) with the kidney-tonifying herbal Fufang (Bushen Zhuanggu Granules, BZG) to prevent osteoporosis in ovariectomized rats. METHODS: Fifty 6-month-old female Sprague Dawley rats were divided into five groups: sham-operated (SHAM), ovariectomized (OVX), OVX with WBV (OVX + WBV), OVX with BZG (OVX + BZG), OVX with both WBV and BZG (OVX + WBV + BZG). The SHAM group received normal saline. After 12 weeks of treatment, the rats were killed, their serum concentrations of osteopontin (OPN), receptor activator of nuclear factor kappa-B ligand RANKL and bone turnover markers assayed and bone mineral density (BMD), histomorphometry and bone strength evaluated. RESULTS: Concentrations of OPN were significantly lower in the SHAM, OVX + WBV and OVX + WBV + BZG groups at 12 weeks, whereas concentrations of RANKL had decreased significantly in the SHAM, OVX + WBV, OVX + BZG and OVX + WBV + BZG groups. In the OVX + WBV, OVX + BZG and OVX + WBV + BZG groups the amount of bone turnover had been significantly antagonized. Compared with OVX group, BMD, % trabecular area (Tb.Ar), number of trabeculae (Tb.N) and assessed biomechanical variables were higher in OVX+WBV group, whereas and BMD, %Tb.Ar, Tb.N, maximal load and yield load were higher in the OVX + BZG group. All tested indices were significantly lower in the OVX + WBV and OVX + BZG groups than in the OVX + WBV + BZG group. CONCLUSION: Either WBV or BZG alone prevents OVX-induced bone loss. However, BZG enhances the effect of WBV by further enhancing BMD, bone architecture and strength.


Assuntos
Conservadores da Densidade Óssea/uso terapêutico , Medicamentos de Ervas Chinesas/uso terapêutico , Osteoporose/prevenção & controle , Ovariectomia , Complicações Pós-Operatórias/prevenção & controle , Vibração/uso terapêutico , Animais , Terapia Combinada , Feminino , Osteoporose/etiologia , Distribuição Aleatória , Ratos , Ratos Sprague-Dawley , Resultado do Tratamento
18.
J Surg Res ; 195(1): 246-56, 2015 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-25634828

RESUMO

BACKGROUND: According to some clinical studies, insufficient cement distribution (ID) in the fractured area and asymmetrical cement distribution around the fractured area were thought to be the reasons for unrelieved pain and recollapse after percutaneous vertebral augmentation (PVA) in the treatment of symptomatic osteoporotic vertebral compression fractures. METHODS: Finite element methods were used to investigate the biomechanical variance among three patterns of cement distribution (ID and sufficient cement distribution in the fractured area and asymmetrical cement distribution around the fractured area including upward [BU] and downward [BD] cement distribution). RESULTS: Compared with fractured vertebra before PVA, distribution of von Mises stress in the cancellous bone was transferred to be concentrated at the cancellous bone surrounding cement after PVA, whereas it was not changed in the cortical bone. Compared with sufficient cement distribution group, maximum von Mises stress in the cancellous bone and cortical bone and maximum displacement of augmented vertebra increased significantly in the ID group, whereas asymmetrical cement distribution around the fractured area in BU and BD groups mainly increased maximum von Mises stress in the cancellous bone significantly. Similar results could be seen in all loading conditions. CONCLUSIONS: ID in the fractured area may lead to unrelieved pain after PVA in the treatment of symptomatic osteoporotic vertebral compression fractures as maximum displacement of augmented vertebral body increased significantly. Both ID in the fractured area and asymmetrical cement distribution around the fractured area are more likely to induce recollapse of augmented vertebra because they increased maximum von Mises stress in the cancellous bone and cortical bone of augmented vertebra significantly.


Assuntos
Cimentos Ósseos , Fraturas por Compressão/terapia , Modelos Biológicos , Fraturas por Osteoporose/terapia , Fraturas da Coluna Vertebral/terapia , Fenômenos Biomecânicos , Análise de Elementos Finitos , Humanos , Imageamento Tridimensional
19.
IEEE Trans Med Imaging ; 34(8): 1760-8, 2015 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-25594962

RESUMO

The standing radiograph is used as a gold standard to diagnose spinal deformity including scoliosis, a medical condition defined as lateral spine curvature > 10°. However, the health concern of X-ray and large inter-observer variation of measurements on X-ray images have significantly restricted its application, particularly for scoliosis screening and close follow-up for adolescent patients. In this study, a radiation-free freehand 3-D ultrasound system was developed for scoliosis assessment using a volume projection imaging method. Based on the obtained coronal view images, two measurement methods were proposed using transverse process and spinous profile as landmarks, respectively. As a reliability study, 36 subjects (age: 30.1 ±14.5; male: 12; female: 24) with different degrees of scoliosis were scanned using the system to test the inter- and intra-observer repeatability. The intra- and inter-observer tests indicated that the new assessment methods were repeatable, with ICC larger than 0.92. Small intra- and inter-observer variations of measuring spine curvature were observed for the two measurement methods (intra-: 1.4 ±1.0° and 1.4 ±1.1°; inter-: 2.2 ±1.6° and 2.5 ±1.6°). The results also showed that the spinal curvature obtained by the new method had good linear correlations with X-ray Cobb's method (R2 = 0.8, p < 0.001, 29 subjects). These results suggested that the ultrasound volume projection imaging method can be a promising approach for the assessment of scoliosis, and further research should be followed up to demonstrate its potential clinical applications for mass screening and curve progression and treatment outcome monitoring of scoliosis patients.


Assuntos
Imageamento Tridimensional/métodos , Escoliose/diagnóstico por imagem , Coluna Vertebral/diagnóstico por imagem , Adolescente , Adulto , Algoritmos , Feminino , Humanos , Masculino , Radiografia , Ultrassonografia , Adulto Jovem
20.
Ultrasonics ; 57: 72-83, 2015 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-25465963

RESUMO

Muscle imaging is a promising field of research to understand the biological and bioelectrical characteristics of muscles through the observation of muscle architectural change. Sonomyography (SMG) is a technique which can quantify the real-time architectural change of muscles under different contractions and motions with ultrasound imaging. The pennation angle and fascicle length are two crucial SMG parameters to understand the contraction mechanics at muscle level, but they have to be manually detected on ultrasound images frame by frame. In this study, we proposed an automatic method to quantitatively identify pennation angle and fascicle length of gastrocnemius (GM) muscle based on multi-resolution analysis and line feature extraction, which could overcome the limitations of tedious and time-consuming manual measurement. The method started with convolving Gabor wavelet specially designed for enhancing the line-like structure detection in GM ultrasound image. The resulting image was then used to detect the fascicles and aponeuroses for calculating the pennation angle and fascicle length with the consideration of their distribution in ultrasound image. The performance of this method was tested on computer simulated images and experimental images in vivo obtained from normal subjects. Tests on synthetic images showed that the method could identify the fascicle orientation with an average error less than 0.1°. The result of in vivo experiment showed a good agreement between the results obtained by the automatic and the manual measurements (r=0.94±0.03; p<0.001, and r=0.95±0.02, p<0.001). Furthermore, a significant correlation between the ankle angle and pennation angle (r=0.89±0.05; p<0.001) and fascicle length (r=-0.90±0.04; p<0.001) was found for the ankle plantar flexion. This study demonstrated that the proposed method was able to automatically measure the pennation angle and fascicle length of GM ultrasound images, which made it feasible to investigate muscle-level mechanics more comprehensively in vivo.


Assuntos
Modelos Biológicos , Contração Muscular/fisiologia , Músculo Esquelético/diagnóstico por imagem , Músculo Esquelético/fisiologia , Adulto , Algoritmos , Tornozelo/anatomia & histologia , Tornozelo/fisiologia , Simulação por Computador , Estudos de Viabilidade , Feminino , Ondas de Choque de Alta Energia , Humanos , Masculino , Músculo Esquelético/anatomia & histologia , Imagens de Fantasmas , Amplitude de Movimento Articular/fisiologia , Valores de Referência , Ultrassonografia
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