靴式步态分析系统的应用研究

步态可以反应下肢功能状况及人们走路习惯。为此,下肢系统各类运动疾病都可引起步态变化。研究步态就是探讨下肢功能障碍因素,为矫形手术探讨科学原理,为疗效评定提供定量标准。为此,我们研制成靴式步态分析系统,以进行步态研究。靴式步态分     

人体行走时步态的生物力学研究进展

1　前言行走是人体日常生活中重复最多的一种整体性运动。直立行走的这种整体运动是人类长期进化的结果。现代测量技术的发展使我们有可能对人类行走时身体各部分 ,特别是下肢的运动和受力情况进行动态的数量化分析 ,这项工作逐渐发展为生物力学的一个特殊分支 ,并被定名为步态分析。步态分析对人体运动系统和神经系统疾病的病因分析和诊断 ,功能、疗效与残废评定 ,骨、关节假体与义肢设计 ,截瘫病人的行走功能重建等均有重要意义 ,已成为基础和临床研究中不可缺少的手段之一 ,在人类学、体育学和宇航学等领域也具有特殊的价值。步态生物力…     

用小波熵评价人体步态变化

目的 将小波熵应用于步态数据量化分析,探寻新的评价人体步态功能变化的特征参数.方法 运用 Bertec三维测力系统,采集10名青年被试者和10名老年被试者的足-地反作用力步态数据,采用离散正交小波变换分解被试组步态数据,定义相对小波能量和小波熵,用t-检验法分别检验基于两个被试组步态数据的相对小波能量及小波熵的差异,来评价人体步态功能变化.结果 基于两个被试组步态数据的相对小波能量差异显著;基于老年被试组步态数据的小波熵值明显低于基于青年被试组步态数据的小波熵值,显著性水平值P<0.05,基于两个被试组步态数据的小渡熵具有显著差异.结论 相对小波能量可提供步态数据中与人体步态功能内在变化相关的细节信息,小波熵能够表征人体步态内在动态变化程度,有望成为临床上可有效评估人体步态功能变化的特征参数.     

膝关节前交叉韧带损伤与重建术后的步态分析研究现状

膝关节运动在关节生物力学运动中最为复杂。行走是膝关节最为频繁的活动方式,也是在对膝关节生物力学分析中较易测量、能准确分析的运动方式。膝关节前交叉韧带(ACL)是膝关节重要的静力性稳定结构,其表面存在机械感受器,通过神经肌肉反射对动力性稳定结构即关节周围的肌群进行调节。ACL损伤后,反射弧的改变会引起膝周肌群肌力代偿性改变,进而产生步态的改变。这种步态的改变可以通过专业步态分析系统测量,能在定量的水平客观反映受试者膝关节行走时的功能状态。同样,ACL的解剖重建也会对膝关节的功能产生一定影响。因此对步态进行精确的…     

浅谈数字视频系统在医疗设备中的应用

目前，医疗视频系统在临床诊断和治疗中的应用非常广泛，随着科学技术的飞速发展，医疗设备的不断更新，视频系统已有效的应用于各种医疗设备上。模拟视频图象已逐步有数字视频图象所取代，质量可靠、清晰逼真的数字视频图象给医务人员提供了更加直观的诊断图象，可快速准确地找到病因，及时为病人解除病痛，为提高医疗技术水平发挥巨大的作用。     

计算机视频图象处理技术在动态生物医学图象研究中的应用

动态序列图象能够充分描述运动过程的特性与规律，但因数据量极大，分析研究具有一定的难度。我们将微机图象处理系统与视频摄录像设备结合，利用视频图象２４帧／秒的时序性，建立了一种动态生物医学图象处理分析系统，并运用该系统的对人体颈椎的三维运动过程和人体行走足底动态应力分布进行了测试分析，取得了良好结果，为生物医学中人体运动功能的定量检测、描述，体育运动的分析、评价，以及运动伤病的治疗与康复研究提供了一种新的有效途径。     

步态分析在矫形外科中的应用

步态分析是生物力学的特殊分支 ,是对人体行走时的肢体和关节活动进行运动学观察和动力学分析 ,提供一系列时间、几何、力学等参数值和曲线。其研究范围分为 3个方面 :(1)行走时肢体和关节活动的运动观察和分析 ;(2 )行走时足-地作用力的观察和分析 ;(3)行走时关节内应力分布和肌肉、韧带力的推算和分析。由于步态分析可将矫形外科检查中沿用已久的定性分析和直观描述转换为客观、精确的定量评定 ,因此 ,其在矫形外科的应用越来越广泛。1　步态分析用于建立正常人参数和曲线行走时一侧足跟着地至该足跟再次着地称为 1个步态周期 ,在 1个步态…     

Wallenberg综合征15例临床与MRI的关系

目的：分析Wallenberg综合征的临床和MRI关系。方法：采用临床和MRI对比分析的方法，分析Wallenberg综合征。结果：延髓上部病灶多为背外侧部梗塞或出血，延髓下部病灶多为外侧浅层梗塞，前者以明显吞咽困难、声音嘶哑、软腭麻痹和咽反射消失为主，后者以明显眩晕、眼球震颤和步态共济失调为主，二者均有恶心或呕吐、Horner征和面部及对侧颈以下的痛觉减退。结论：MRI可以帮助阐明Wallenberg综合征的解剖和临床表现的关系。     

MR黑血和白血技术诊断肥厚型心肌病的价值

目的：研究MR黑血和白血技术在诊断肥厚型心肌病中的价值。方法：采用心脏MR黑血和白血技术及多平面成像方式，对15例临床拟诊为肥厚型心肌病的患者进行检查。结果：MR黑白技术提供病变部位、厚度、信号、心腔形态、大小等信号。白血技术能反映心肌的运动，流出道有无狭窄及程度，二尖瓣有无返流等情况。多平面成像更全面了解病变的部位和范围，避免漏诊。MR的基本特征有室壁肥厚、心肌信号不均匀、左心室流出道狭窄、心肌运动不均匀、二尖瓣少量返流和心包积液等。结论：MR黑白和白血技术对肥厚型心肌病的诊断能提供更为准确、全面的影像学信息。     

步态与疾病

健康人步态端正挺直，肢体动作灵活自如。如果一个人的步态发生了改变，往往意味着维持身体平衡的系统受到损害，身体健康出现了问题，应及时到医院诊治。生活中常见的异常步态有以下几种： 小脑步态 主要表现为步行不稳、左右摇摆、步调不规则，在突然停顿或快速转身时尤为明显。这种步态常见于多发性脑动脉硬化、小脑肿瘤或变性等疾病。 共济失调步态 站立与步行困难，步行时常双眼注视足部与小腿，关节位置觉与音叉振动觉消失。此种步态可见于脊髓结核，脊髓、小脑变性，亚急性脊髓联合变性，慢性多发性神经病变等。 偏瘫步态 轻症偏…     

多功能直接数字化X线摄影系统的临床应用

目的探讨多功能直接数字化X线摄影系统(DDR)的临床应用,以期提高DDR的应用价值。方法利用EPEX型多功能DDR做常规摄影,随机调取1000张DDR影像,由3位高年资放射学者对影像进行分析,试图找出常用体位的最佳摄影方式。结果甲片率73.00%,乙片率22.70%,丙片率4.30%,废片率0%。结论DDR系统操作简单,成像快捷,影像质量好,有利于放射诊断。     

应用口腔数字成像系统诊断牙齿及牙周疾病的研究

目的：研究应用数字化成像系统检查牙齿和牙周的不同病变。材料和方法：应用国产口腔数字成像系统检查３４７颗牙齿的牙体和牙周病变。结果：口腔数字成像系统操作简便，放射剂量明显减少，获得的不同牙位和各种病变的图像质量基本优良，但影像覆盖范围小于常规Ｘ线牙片。结论：应用口腔数字成像系统可以满足临床诊断要求。     

The AAPM/RSNA physics tutorial for residents: digital fluoroscopy.

A digital fluoroscopy system is most commonly configured as a conventional fluoroscopy system (tube, table, image intensifier, video system) in which the analog video signal is converted to and stored as digital data. Other methods of acquiring the digital data (eg, digital or charge-coupled device video and flat-panel detectors) will become more prevalent in the future. Fundamental concepts related to digital imaging in general include binary numbers, pixels, and gray levels. Digital image data allow the convenient use of several image processing techniques including last image hold, gray-scale processing, temporal frame averaging, and edge enhancement. Real-time subtraction of digital fluoroscopic images after injection of contrast material has led to widespread use of digital subtraction angiography (DSA). Additional image processing techniques used with DSA include road mapping, image fade, mask pixel shift, frame summation, and vessel size measurement. Peripheral angiography performed with an automatic moving table allows imaging of the peripheral vasculature with a single contrast material injection.     

Digital image processing

Digital image processing is now commonplace in radiology, nuclear medicine and sonography. This article outlines underlying principles and concepts of digital image processing. After completing this article, readers should be able to: List the limitations of film-based imaging. Identify major components of a digital imaging system. Describe the history and application areas of digital image processing. Discuss image representation and the fundamentals of digital image processing. Outline digital image processing techniques and processing operations used in selected imaging modalities. Explain the basic concepts and visualization tools used in 3-D and virtual reality imaging. Recognize medical imaging informatics as a new area of specialization for radiologic technologists.     

Digital radiography: fundamentals and future potentials

Digital radiography consists of four major steps which include X-ray detection, digitization, image processing and display. Important parameters in digitization process is the pixel size and the number of grey levels which affect the quality of digitized images. A number of digital radiographic systems have been or are being developed which include the point-beam, line-beam, slot-beam and multiple slit-beam systems as well as conventional wide-beam systems such as image intensifier-TV system, storage phosphor system and film-based system. Important physical properties of digital radiographic systems are the sensitivity, resolution, noise, system response, scatter rejection, contrast sensitivity and image acquisition time. The resolution property is affected by the pixel size, sampling distance, display pixel size, image processing, detector response and X-ray beam characteristics. From ROC studies on chest images, the pixel size of approximately 0.2 mm and the corresponding image matrix of about 2,000 x 2,000 is considered optimal choice of these parameters. Future potentials of digital radiography are likely to be in the areas of computer-aided diagnosis (CAD) and PACS. Preliminary results obtained from recent studies on quantitative analysis of digital radiographic images are promising. The rms variation and the first moment of the texture of abnormal lungs with various interstitial diseases were clearly different from those of normal lungs. Automated detection scheme of nodules in chest images indicated approximately 70% true positive rates and a few false positives in each lung.(ABSTRACT TRUNCATED AT 250 WORDS)     

Digital skeletal radiography.

Skeletal radiography accounts for a large proportion of the plain film images generated in most radiology departments, yet it has been underemphasized in the investigation of digital imaging technologies. Unique features of skeletal radiography provide a challenge in the evaluation and investigation of digital skeletal imaging. This review summarizes the results of ongoing research in digital skeletal radiography. Elementary concepts of digital imaging are reviewed to provide a foundation for discussion of nominal contrast and resolution requirements for clinically useful digital skeletal radiography. Methods of acquiring digital skeletal images are reviewed, and digital image display, image compression, and basic image processing techniques are discussed with emphasis on specific skeletal applications.     

数字摄影DR系统图像质量控制技术探讨

作者结合临床实践对１００例实际照片和１０例模拟体照片进行技术分析，从（１）Ｘ线机性能；（２）摄影参数；（３）后处理技术；（４）胶片打印冲洗技术四个方面，详细阐述了影响数字摄影图像质量的有关因素。同时强调，严格设备调试和加强日常工作中冲洗质量管理是保证影像质量的重要环节。     

Digital radiography in urography

The clinical utility was evaluated of a computed radiographic system in urography. The system (FCR 101, Philips Medical Systems, Inc., Shelton, CT) is based on a photo-stimulatable phosphor screen (imaging plate) for X-ray image detection and storage. The X-ray information recorded on the imaging plate is converted into digital from and processed by means of a computer. After processing is completed, the digitized image is reversed back to analogic signals, which modulate the intensity of a laser beam scanning the image on a single-emulsion film (Fuji CR 633). Two hundred IVP's were obtained in four groups, of 50 patients each, with normal azotemic values by rapid infusion of a low osmolality contrast medium (iopamidol 150 mgI/ml). While conventional radiographs were performed on the first group of patients with the injection of 0.6 gI/kg body weight of contrast medium, digital examinations were carried out, in the remaining three groups, with the injection of 0.6, 0.3 and 0.12 gI/kg, respectively. The digital images were processed with the "Abdomen-routine" program. A specific algorithm was implemented in order to reduce the excessive contrast resolution of the bladder, which is due to the characteristics of the nonionic contrast medium and enhanced by the reading program. The image details were evaluated by two observers and then statistically analyzed with nonparametric tests. Statistical analysis did not show any difference in the quality of digital and screen-film images. Image processing improved some inadequate images, by reducing the contrast resolution of the bladder, and allowed a better detection of some details. Low doses (0.3 gI/kg) of a low osmolality (150 mgI/kg) contrast medium were enough to obtain good images. Another biological advantage was obtained by a consistent radiation dose reduction (about 40%).     

Digital radiography of the chest: state of the art

Digital image acquisition possesses a number of advantages over conventional systems in radiographic examination of the chest, the most important of which is its greater dynamic range. In addition, one digital images are acquired, they can be processed by computer in ways that cannot be rivalled by conventional analog techniques. Finally, digital images can be stored, retrieved and transmitted to local or remote sites. Here the status of the different digital systems employed in chest radiology and commonly used image processing techniques are reviewed. Also discussed are the current clinical applications of integrating digital chest radiography with a picture archiving and communication system (PACS) along with the difficulties typically encountered. Studies with a variety of digital techniques have been carried out on several fronts. Computer radiography based on photostimulabe phosphor (CR) has replaced screen-film imaging in certain applications (i.e. bedside imaging). However, CR has limitations, namely its poor X-ray utilisation efficiency at high X-ray tube voltages and sensitivity to scatter; therefore, it is not ideal for all applications. Recently, a dedicated digital chest unit with excellent X-ray utilisation efficiency at high X-ray tube potentials has been introduced. On the basis during the past decade, recommendations are made regarding the most desirable equipment specifications for dedicated and bedside digital chest radiography.     

Digital tomosynthesis: technique for electronic reconstructive tomography

A technique is described for obtaining tomographic images through retrospective reconstruction of digital data. The apparatus used for this technique, called digital tomosynthesis consists of a linear tomographic x-ray machine that has been modified by the addition of a fluoroscope and TV system, a video disk recorder, an analog-to-digital converter, and a small computer for data processing and manipulation. Video frames are collected and stored during a single tomographic sweep. The stored data are then digitized and retrospectively processed in the computer for reconstruction of any desired tomographic plane within the body. The major advantages of DTS include short patient study time, low radiation dose compared with conventional tomography, the ability to enhance the digitized image through manipulation of window and level display, and the applicability of this technique to dynamic studies such as angiotomography. Phantom studies show good diagnostic quality of the resulting images, and preliminary vascular studies in dogs indicate the clinical potential of this technique for use in digital subtraction angiotomography.