经直肠前列腺超声造影参数成像预测前列腺癌的临床研究

目的评价经直肠前列腺超声造影参数成像对临床怀疑前列腺癌但超声没有发现明确病灶患者前列腺癌预测的临床应用价值。方法对30名血清PSA升高而灰阶超声没有发现明确病灶的患者在同天先后行经直肠前列腺超声造影及经直肠超声引导下前列腺穿刺活检的操作。造影图像切面选择在前列腺底部、中部及尖部与穿刺部位保持在同一切面,超声造影及穿刺活检由同一名医师承担。采用SonoProstate软件进行参数成像并分析造影参数图像。统计分析参数图像结果与病理结果。结果19例病理证实为前列腺癌的病例中参数成像方法诊断15例,11例病理证实为前列腺增生的病例中参数成像方法诊断9例。前列腺超声造影参数成像与超声引导下前列腺穿刺活检术对前列腺癌的预测无统计学差异(P=0.687)。结论对血清PSA升高但灰阶超声未发现明确前列腺病灶的患者,经直肠前列腺超声造影参数成像有助于提示前列腺癌可疑部位并指导前列腺穿刺活检。     

Simultaneous nonrigid registration, segmentation, and tumor detection in MRI guided cervical cancer radiation therapy

External beam radiation therapy (EBRT) for the treatment of cancer enables accurate placement of radiation dose on the cancerous region. However, the deformation of soft tissue during the course of treatment, such as in cervical cancer, presents significant challenges for the delineation of the target volume and other structures of interest. Furthermore, the presence and regression of pathologies such as tumors may violate registration constraints and cause registration errors. In this paper, automatic segmentation, nonrigid registration and tumor detection in cervical magnetic resonance (MR) data are addressed simultaneously using a unified Bayesian framework. The proposed novel method can generate a tumor probability map while progressively identifying the boundary of an organ of interest based on the achieved nonrigid transformation. The method is able to handle the challenges of significant tumor regression and its effect on surrounding tissues. The new method was compared to various currently existing algorithms on a set of 36 MR data from six patients, each patient has six T2-weighted MR cervical images. The results show that the proposed approach achieves an accuracy comparable to manual segmentation and it significantly outperforms the existing registration algorithms. In addition, the tumor detection result generated by the proposed method has a high agreement with manual delineation by a qualified clinician.     

Toward multiple catheters detection in fluoroscopic image guided interventions

Catheters are routinely inserted via vessels to cavities of the heart during fluoroscopic image guided interventions for electrophysiology (EP) procedures such as ablation. During such interventions, the catheter undergoes nonrigid deformation due to physician interaction, patient's breathing, and cardiac motions. EP clinical applications can benefit from fast and accurate automatic catheter tracking in the fluoroscopic images. The typical low quality in fluoroscopic images and the presence of other medical instruments in the scene make the automatic detection and tracking of catheters in clinical environments very challenging. Toward the development of such an application, a robust and efficient method for detecting and tracking the catheter sheath is developed. The proposed approach exploits the clinical setup knowledge to constrain the search space while boosting both tracking speed and accuracy, and is based on a computationally efficient framework to trace the sheath and simultaneously detect one or multiple catheter tips. The algorithm is based on a modification of the fast marching weighted distance computation that efficiently calculates, on the fly, important geodesic properties in relevant regions of the image. This is followed by a cascade classifier for detecting the catheter tips. The proposed technique is validated on 1107 fluoroscopic images acquired on multiple patients across four different clinics, achieving multiple catheter tracking at a rate of 10 images/s with a very low false positive rate of 1.06.     

基于超声导波的水下管道缺陷检测

文中介绍一套可拆式传感器系统设计与制作,利用超声导波原理对水下管道的腐蚀进行检测,基于厚度剪切模式的压电陶瓷和可拆式固定装置组成,可拆式传感器系统包括传感器PZT特别设计,并且可以把传感器装置夹在要检测的管道上。当对水下设备的管道进行了一系列的测试,结果表明传感器系统能够有效地激发和接收T（0,1）模式的超声导波,由于T（0,1）模式超声导波能够在水下管道上长距离传播,因此适用于缺陷检测。人为缺口的回波信号与缺口的尺寸以及位置具有良好的相关性。研究表明这一可拆式传感器系统能够利用导波有效地对水下管道进行检测。     

A gradient guided search algorithm for multiuser detection

This paper introduces a new multiuser detection algorithm based on a gradient guided search that can achieve near-optimum performance while its implementation complexity is linear in the number of users. The new algorithm attempts to perform jointly optimum multiuser detection by updating one user's bit decision each iteration in the best possible way. When a decorrelating multiuser detector is employed to initialize the proposed algorithm, in all cases tested the gradient guided search converges to a solution with performance very close to optimum. Further, tests indicate that the proposed algorithm provides excellent performance for cases where other suboptimum algorithms perform poorly. Although we focus only on synchronous multiuser detection, the algorithm is equally applicable to asynchronous multiuser detection problems     

Salient video cube guided nighttime vehicle braking event detection

In nighttime driving brake lights are particularly important because they offer a warning signal to prevent potential collisions. In this work, we propose a novel visual-based approach for nighttime brake light detection using three-dimensional Nakagami imaging to analyze tail lights of vehicles in front. Rather than heuristic features, such as symmetry of taillights and appearance of the third brake light, the proposed approach extracts invariant features by modeling the scattering of brake lights, thus allowing detection to proceed in a part-based manner. Experiments from extensive datasets show that the proposed system can effectively detect vehicle braking under different lighting and traffic conditions, making it a realistic option for real-world applications.     

基于显著特征引导的红外舰船目标快速分割方法研究

分割的难度可以利用关于视觉任务的知识来降低。在分析现有分割方法的基础上,提出了一种用目标的显著特征来限定分割区域的分割方法,使基于类间方差的门限法得以应用。同时,考虑了红外图像中船体与发动机等区域存在不同灰度分布的情况,定义了局部分割准则。实验结果证明所提出的方法能成功完成红外舰船目标分割,并能应用于实时舰船目标检测与识别。     

超声联合神经刺激器引导下臂丛神经阻滞在上肢手术中的应用

目的：探讨超声联合神经刺激器引导下臂丛神经阻滞在上肢手术中的应用效果。方法：选择上肢手术120例,随机分为3组,每组40例。A组为传统方法定位组,B组为神经刺激器定位组,C组为超声联合神经刺激器定位组。观察三组的臂丛神经阻滞麻醉起效时间、麻醉效果、麻醉持续时间、静脉辅助用药情况、不良反应（穿刺针误入血管、局麻药毒性反应、神经损伤、气胸）。结果：C组麻醉起效时间短于A组及B组（P＜0．05）,C组麻醉效果优于A组及B组（P＜0．05）,C组麻醉持续时间长于A组（P＜0．05）,C组静脉辅助用药少于A组及B组（P＜0．05）, C组不良反应发生率小于A组及B组（P＜0．05）。结论：在上肢手术中使用超声联合神经刺激器引导下臂丛神经阻滞麻醉效果好,不良反应发生率低,值得临床推广。     

绝缘子表面裂纹激光超声检测简

为了实现在役绝缘子裂纹的带电检测,采用脉冲激光非接触方式在瓷瓶表面激励超声波,用宽带超声换能器接收声波,并用这种非接触发射-接触接收声波的方法,对含有人工刻槽的棕釉高压瓷质绝缘子表面裂纹进行了检测实验,通过可视化成像检测系统,对声波在被检样品中传播的动态波形进行了实时观察,获得缺陷最大振幅图。结果表明,该方法在绝缘子裂纹远程检测方面具有适用性,且检测不受绝缘子复杂曲面形状的影响。     

基于超声导波的无缝线路断轨检测系统

随着高速铁路的快速发展,无缝线路在轨道交通领域的应用也越来越广泛,断轨的发生机率也随之变高。目前我国主要使用探伤车和轨道电路等方法检测断轨,但是存在诸多缺点。近年来,利用超声导波检测无缝线路断轨取得了长足的发展。文中设计了一种基于超声导波的断轨检测系统,具有断轨实时检测、数据上传、报警等功能,能够快速确定故障区间。在实际线路上进行了断轨检测实验,实现了以1 km为单位检测区间的断轨检测,误报率小于1%。     

超声图像中胎儿股骨的自动检测与测量

首先利用灰度、形状信息从Ｂ超图像中分割出股骨的候选区域,根据候选区域周围组织确定股骨区域。再利用边缘信息找出股骨的端点,计算出股骨长度,文中提出的方法不需人工干预,避免了重复枯燥的测量和人工测量误差,所需时间短,准确。     

Displacement estimation with co-registered ultrasound for image guided neurosurgery: a quantitative in vivo porcine study

Brain shift during open cranial surgery presents a challenge for maintaining registration with image-guidance systems. Ultrasound (US) is a convenient intraoperative imaging modality that may be a useful tool in detecting tissue shift and updating preoperative images based on intraoperative measurements of brain deformation. We have quantitatively evaluated the ability of spatially tracked freehand US to detect displacement of implanted markers in a series of three in vivo porcine experiments, where both US and computed tomography (CT) image acquisitions were obtained before and after deforming the brain. Marker displacements ranged from 0.5 to 8.5 mm. Comparisons between CT and US measurements showed a mean target localization error of 1.5 mm, and a mean vector error for displacement of 1.1 mm. Mean error in the magnitude of displacement was 0.6 mm. For one of the animals studied, the US data was used in conjunction with a biomechanical model to nonrigidly re-register a baseline CT to the deformed brain. The mean error between the actual and deformed CT's was found to be on average 1.2 and 1.9 mm at the marker locations depending on the extent of the deformation induced. These findings indicate the potential accuracy in coregistered freehand US displacement tracking in brain tissue and suggest that the resulting information can be used to drive a modeling re-registration strategy to comparable levels of agreement.     

激光制导武器目标光斑检测系统设计与实现

为了实现激光制导武器目标光斑检测系统对远距离的来袭激光光斑的捕获与定位,采用机器视觉检测技术设计并实现全数字化、实时、高精度的激光检测系统。系统针对CMOS探测器采集到的激光光斑图像,采用硬件实现改进的快速二维中值滤波算法进行图像滤波处理,最大类间方差算法进行灰度图像阈值分割,灰度重心法进行中心提取,实现了精确中心定位。实验验证和误差分析表明,该系统具有很强的抗干扰性及精确的坐标定位,坐标误差在1mm以内。     

Automatic detection of breast nodule in the ultrasound images using CNN

Breast cancer is the most common cancer among women worldwide.Ultrasound is widely used as a harmless test for early breast cancer screening.The ultrasound network(USNet) model is presented.It is an improved object detection model specifically for breast nodule detection on ultrasound images.USNet improved the backbone network,optimized the generation of feature maps,and adjusted the loss function.Finally,USNet trained with real clinical data.The evaluation results show that the trained model has strong nodule detection ability.The mean average precision(mAP) value can reach 0.734 9.The nodule detection rate is 95.11%,and the in situ cancer detection rate is 79.65%.At the same time,detection speed can reach 27.3 frame per second(FPS),and the video data can be processed in real time.     

Edge detection in ultrasound imagery using the instantaneous coefficient of variation

The instantaneous coefficient of variation (ICOV) edge detector, based on normalized gradient and Laplacian operators, has been proposed for edge detection in ultrasound images. In this paper, the edge detection and localization performance of the ICOV-squared (ICOVS) detector are examined. First, a simplified version of the ICOVS detector, the normalized gradient magnitude squared, is scrutinized in order to reveal the statistical performance of edge detection and localization in speckled ultrasound imagery. Both the probability of detection and the probability of false alarm are evaluated for the detector. Edge localization is characterized by the position of the peak and the 3-dB width of the detector response. Then, the speckle-edge response of the ICOVS as applied to a realistic edge model is studied. Through theoretical analysis, we reveal the compensatory effects of the normalized Laplacian operator in the ICOV edge detector for edge-localization error. An ICOV-based edge-detection algorithm is implemented in which the ICOV detector is embedded in a diffusion coefficient in an anisotropic diffusion process. Experiments with real ultrasound images have shown that the proposed algorithm is effective in extracting edges in the presence of speckle. Quantitatively, the ICOVS provides a lower localization error, and qualitatively, a dramatic improvement in edge-detection performance over an existing edge-detection method for speckled imagery.     

基于衍射横波的裂纹激光超声检测方法

为了评估表面开口裂纹, 采用激光超声衍射横波的方法测量其参量。激光激励的横波传播至裂纹尖端产生衍射信号, 随后被处于裂纹另一侧的传感器所接收。依据不同接收点衍射横波的渡越时间, 推导出裂纹参量的计算公式; 模拟分析了横波在工件中的传播过程, 搭建了裂纹的激光超声测量实验系统, 并采集了衍射横波数据。结果表明, 在有效的检测范围内, 测量值与实际值之间的误差在5%之内。该结果可促进激光超声在表面裂纹检测中的应用。     

Embolic Doppler ultrasound signal detection using discrete wavelet transform

Asymptomatic circulating emboli can be detected by Doppler ultrasound. Embolic Doppler ultrasound signals are short duration transient like signals. The wavelet transform is an ideal method for analysis and detection of such signals by optimizing time-frequency resolution. We propose a detection system based on the discrete wavelet transform (DWT) and study some parameters, which might be useful for describing embolic signals (ES). We used a fast DWT algorithm based on the Daubechies eighth-order wavelet filters with eight scales. In order to evaluate feasibility of the DWT of ES, two independent data sets, each comprising of short segments containing an ES (N=100), artifact (N=100) or Doppler speckle (DS) (N=100), were used. After applying the DWT to the data, several parameters were evaluated. The threshold values used for both data sets were optimized using the first data set. While the DWT coefficients resulting from artifacts dominantly appear at the higher scales (five, six, seven, and eight), the DWT coefficients at the lower scales (one, two, three, and four) are mainly dominated by ES and DS. The DWT is able to filter out most of the artifacts inherently during the transform process. For the first data set, 98 out of 100 ES were detected as ES. For the second data set, 95 out of 100 ES were detected as ES when the same threshold values were used. The algorithm was also tested with a third data set comprising 202 normal ES; 198 signals were detected as ES.     

边缘信息引导多级尺度特征融合的显著性目标检测方法

针对基于FCN和U型网络架构的深度学习显著性目标检测方法提取的显著性图存在边界不清晰和结构不完整的问题,文中提出了一种基于边缘信息引导多级尺度特征融合网络(EGMFNet)。EGMFNet使用多通道融合残差块(RCFBlock)以嵌套的U型网络架构作为主干模型。同时,在网络的较低层级引入具有边缘信息引导的全局空间注意力模块(EGSAM)以增强空间特征及边缘特征。此外,在损失函数中引入了图像边界损失,用于提升显著性图的质量并在学习过程中保留更加清晰的边界。在四个基准数据集上进行实验,实验结果表明,文中方法的F值较典型方法提升1.5%、2.7%、1.8%和1.6%,验证了EGMFNet网络模型的有效性。     

Micro-emboli detection: an ultrasound Doppler signal processing viewpoint

Several studies have been carried out in the last twenty years on the characterization and detection of cerebral artery emboli. From the detection point of view, the existing methods are largely based on the classical Fourier analysis of which the well known limitations provide poor accuracy. This paper first recalls existing methods based on Fourier, Wigner-Ville and wavelet approaches. It then presents new emboli detection methods based on parametric signal processing approaches. The basic idea of these parametric methods is to compare the Doppler embolic signal to its autoregressive model. The detection principle consists in constructing a decision information which contains the signature of the micro-embolus being sought. The detection is finally evaluated using receiver operating characteristic (ROC) curves. Comparison between the new methods and classical approaches is performed using a realistic embolic signal simulation. Furthermore, to validate our theoretical study, we tested our new algorithms using in vivo signals. This comparison shows the significant inaccuracy of existing methods to detect micro-emboli.     

基于ICS1702的超声导波检测系统电源管理设计

电源部分是超声导波检测系统的关键组成部分,良好的电源管理系统是保证检测系统正常工作的基础。为适应野外检测条件,实现检测系统的小型化、便携化,文中以电源管理芯片ICS1702为核心,提出了一种用于超声导波检测系统的电源管理设计方法,并设计了相关的硬件和软件部分。实验证明该电路具有控制简单,成本低的优点,实现了电源的小型化,为超声导波检测仪的便携式提供了可能。