数字式超声信号采集处理系统的设计与实现

作者设计了一种数字式的超声回波信号采集处理系统,采用高速、高精度的AD转换器,通过可编程逻辑器件(FPGA)芯片实现对射频信号的预处理,经过USB 2.0接口把数据传送到PC,在主机中完成对数据的后处理并最终显示处理结果,并给出了一个模拟多普勒血流测量的实例.此系统具有较高的灵活性和可移植性,可用于多种超声信号的采集与处理.     

超声血管增强技术对血管检测的体外模拟实验研究刘禧

目的通过体外模拟实验探讨超声血管增强技术（VET）在血管检测应用中的方法和价值。方法使用血流泵，分别模拟不同内径的表浅外周血管及脑血管血流状态，应用超声血管增强技术对模拟血管进行内径检测，应用不同VET级别、条件等观察成像效果，并与传统二维及彩色多普勒成像相对比。结果VET技术可以清晰显示模拟血管管壁及管腔细微结构，明显减低容积效应伪像，能够准确测量管腔内径。不同内径及深度的血管需选用不同的VET级别，模拟表浅血管选用2～3级、模拟脑血管选用4～5级时可清晰显示血管管腔。结论超声血管增强技术可提高血管显示能力和血管显示灵敏度，更清晰显示血管腔及准确测量内径。     

彩色及能量多普勒在药流术后诊断宫内残留的价值

目的 探讨彩色多普勒速度图(CDFI)和多普勒能量图(CDE)对药物流产后宫内残留物的诊断价值.方法 对经超声和尿HCG确诊宫内早孕的健康妇女,经药物流产后,见胚囊排出,2周内或2周以上仍有阴道出血,经二维超声、彩色多普勒速度图、多普勒能量图检查诊断宫内异常回声的75例病例图像进行回顾性分析,分别观察子宫大小、宫腔内情况及其与子宫肌壁血流情况.结果 宫内残留物58例显示宫腔内偏强回声,12例呈中低回声,5例呈混合回声,并在残留物基底部彩色多普勒可观察到血流信号或近宫腔处局部肌壁血流丰富区,多普勒能量图能提高血流信号的显示.28例子宫有不同程度增大.结论 彩色多普勒对药物流产后宫内残留物可显示特征性的改变,结合多普勒能量图更有利于超声诊断和临床治疗.     

经直肠超声对表面完全钙化的膀胱癌和膀胱嵌壁结石的鉴别诊断

目的 探讨经直肠超声在鉴别诊断位于膀胱三角区表面完全钙化的膀胱癌和膀胱嵌壁结石的价值.方法 对 47例病灶位于膀胱三角区的患者行经腹及经直肠超声检查,观察病灶活动度,对比分析两种检查途径的二维声像图、彩色多普勒血流成像（CDFI）及膀胱壁情况.结果 经腹超声检查膀胱癌和膀胱嵌壁结石均表现为膀胱腔内不移动强回声后伴声影.经直肠超声可清楚显示膀胱癌低回声肿块和表面强回声,该处膀胱壁层次不清,CDFI可见迂曲树枝状彩色血流信号自膀胱壁进入低回声内,可测及动脉血流频谱.膀胱嵌壁结石经直肠超声检查表现为强回声后伴声影,膀胱壁层次尚清楚,CDFI未探及彩色血流信号.膀胱癌经腹与经直肠超声检查结果比较差异有统计学意义（χ2＝56,P＜0.01）,嵌壁膀胱结石经腹与经直肠超声检查结果比较差异无统计学意义（P＞0.05）.结论 经直肠超声在鉴别诊断位于膀胱三角区表面完全钙化的膀胱癌和膀胱嵌壁结石中有重要价值.     

自动四维彩色容积超声在胎儿心脏检查中的应用

目的 探讨自动四维彩色容积超声在正常胎儿心脏检查中的应用价值.方法 对120例孕中期(18～23孕周)胎儿心脏进行四维容积扫查,在显示四腔心切面、启动彩色多普勒后采集胎儿胸部容积数据,利用超声自动多平面成像法自动获取3个诊断切面,分别为切面1(左心室流出道切面)、切面2(右心室流出道切面)及切面3(动脉导管弓切面),并采用超声断层显像法(TUI)显示所有切面的彩色血流图.对所有的容积数据进行分析并确定在每个容积数据中切面1～3是否正确显示.结果 通过自动四维彩色容积超声扫描,切面1～3的显示率分别为100%、96.67%、91.67%.切面1至少可在连续3个TUI图像上可靠显示,切面2和切面3均至少可在连续2个TUI图像上可靠显示.结论 自动四维彩色容积超声可自动获取胎儿心脏检查中所需的重要切面,显示率较高,并可观察相应切面的血流情况,显示效果良好.     

鳃裂囊肿的高频超声诊断与鉴别诊断价值

目的 探讨鳃裂囊肿的超声诊断与鉴别诊断价值.方法 回顾性分析与总结56例经手术和病理证实的鳃裂囊肿的高频彩色多普勒超声表现.结果 第一鳃裂7例,第二鳃裂48例,第三鳃裂1例,7例可显示瘘口.囊肿均为椭圆形或类圆形,囊壁多清晰规则,囊内多布有稀疏、密集不等的点状回声,其后方具有声增强效应;彩色多普勒超声显示囊内无血流信号,囊壁显示血流信号者仅9例.超声诊断符合率90.11%(完全符合42例,基本符合9例).结论 高频彩色多普勒超声能较准确地诊断与鉴别鳃裂囊肿,具有重要的临床价值.     

超声造影对正常动脉检测能力的实验研究

目的研究生理状态下彩色多普勒血流成像(CDFI)对不同深度血管血流的显示能力以及彩色多普勒超声造影(以下简称彩超造影)与实时灰阶谐波超声造影(以下简称谐波造影)的表现。方法动物选择普通家犬5只。使用意大利百胜Technos DU8超声诊断仪及SonoVue超声造影剂。二维超声分别显示犬的髂总动脉、髂外动脉、髂内动脉、股动脉及腋动脉,并测量内径,脉冲多普勒测量收缩期峰值流速(PSV)。人为增加血管深度,CDFI检查记录该深度状态的血流强度。至CDFI不能清晰显示血流时,分别利用彩超造影与谐波造影两种方法再次检测。彩超造影检测时记录血流强度及PSV。结果随着深度增加CDFI观察到的血流信号减弱,造影后血流信号均明显增强;造影后在同一部位检测到的PSV增加36.1%,两组数据比较有显著性差异;谐波造影显示注射造影剂后动脉管腔内回声迅速增强,能够清晰显示血管管壁与管腔的分界。结论造影剂的应用可明显提高CDFI对深部血流信号的检出,而谐波造影能更直观、准确地显示血管壁及流道的轮廓。     

膀胱癌能量多普勒血流与肿瘤浸润深度的相关性研究

目的：用能量多普勒超声技术检测膀胱癌的血流情况，与病理结果对比，评价能量多普勒超声诊断膀胱癌的临床价值。材料和方法：对60例膀胱癌患者进行能量多普勒超声检查，观察肿瘤内血流分布情况，进行血流分级，测量PSV、EDV、RI值；对术后肿瘤进行HE染色确定浸润深度。结果：能量多普勒超声显示的肿瘤内血流分级、与肿瘤浸润深度、邻近器官浸润在P=0．05水平上相关显著，相关系数r分别为0.318、0．355；RI值与肿瘤浸润深度在P=0．01水平上相关显著，相关系数r为0．540。RI值与邻近器官浸润在P=0．05水平上相关显著，相关系数r=0．282。随着肿瘤浸润深度加深，邻近器官浸润趋势增加，血流信号显示增多、RI值增高。PSV、EDV与肿瘤浸润深度无明显相关性。结论：膀胱癌内彩色血流愈丰富，肿瘤浸润深度愈深，浸润邻近器官深度愈增加，RI值也随之增高，表明RI值对膀胱癌的定性诊断有一定价值。     

淋巴管畸形的高频超声与彩色多普勒特点

目的 研究淋巴管畸形的高频超声及彩色多普勒超声表现特点并进行分析、总结.方法 应用高频超声及彩色多普勒超声对23例淋巴管畸形的二维灰阶超声声像图及彩色血流信号进行回顾性研究.超声扫查内容包括:病变大小、边界、内部回声、彩色血流信号及用脉冲多普勒测量血流速度.结果 17例淋巴管畸形(74%,17/23)位于颈部、颌下或腋下,6例位于其他部位;21例位于皮下组织内,其中3例同时累及真皮及肌层.13例大囊型淋巴管畸型,均显示为较大的无回声区,有分隔,壁光滑,其中2例大囊型合并感染,无回声区内有稀疏低回声;5例混合型淋巴管畸形,为淋巴管畸形和血管畸形混合存在,超声显示为大小不等的无回声区有分隔,合并局部微小无回声区或不规则的小的实性低回声区,其中3例侵及肌层;5例微囊型淋巴管畸形,超声显示以无回声区为主,内有少量的低回声区,形成囊实混合性病变.所有病例无回声区内彩色多普勒扫查均无彩色血流信号.8例大囊型及3例混合型淋巴管畸形周边扫查到彩色血流信号,2例微囊型内部实性低回声内显示有彩色血流信号.脉冲多普勒检查最大血流速度18～73 cm/s,阻力指数0.55～0.72.结论 淋巴管畸形的高频超声及彩色超声多普勒成像有显著的特点,以较大的无回声区为主,多发可有分隔,无回声区内无血流信号,大部分位于皮下组织内,基于以上特点,可确诊大部分病例,因而高频超声及彩色多普勒是诊断淋巴管畸形的较好方法.     

超声矢量血流成像联合奇异值分解滤波检测肝脏深部微血管内血流速度

目的 观察超声矢量流速成像（VFI）联合奇异值分解（SVD）滤波对检测肝脏深部微血管内血流速度的价值。方法 前瞻性对1例疑诊肝血管瘤患者采集肝脏灰阶超声、CDFI及超声造影（CEUS）图;对CEUS图行SVD滤波处理,以互相关算法分别获取基于灰阶超声、原始CEUS及经SVD滤波处理后CEUS的VFI,比较其检测肝脏微血管血流方向和速度的差异。结果 肝脏灰阶超声、原始CEUS及经SVD滤波处理后CEUS图的信噪比（SNR）分别为7.56、17.65及22.43 dB,对比组织比（CTR）分别为1.12、7.56及16.34 dB。相比基于灰阶超声和原始CEUS的VFI,经SVD滤波处理后CEUS的VFI可检出更高速、方向更均一的血流。SVD滤波处理前、后,VFI所测肝脏微血管内血流速度分别为1.91（0.81,4.11）及6.83（4.25,9.41）mm/s,差异有统计学意义（Z=-10.671,P<0.001）。结论 联合SVD滤波可显著提高VFI检测肝脏深部微血管内血流速度的效能。     

FPGA design and implementation for EIT data acquisition

OXBACT-5 was designed to meet the challenges involved in working in the intensive care hospital environment focussed particularly on thoracic imaging of patients with respiratory distress and chronic heart failure (CHF). The FPGA-based wireless LAN linked multi-channel EIT data acquisition system (DAS) providing 16 programmable excitation current channels and 64 voltage measurement channels is presented. It contains function modules of a PCI bus interface, direct digital synthesizers, dual-port memory blocks, digital demodulation and all the command and control logic in the FPGA. The whole EIT data acquisition system is fully programmable and reconfigurable from the host PC. The excitation frequency, excitation patterns, the measuring sequence and the gain of each measurement channel can be set from the host PC before each measurement. The demodulation is implemented in the FPGA chip to reduce the data rate between the DAS and the host PC. In addition, measurement process management is achieved in this FPGA chip. Complemented by analogue devices such as ADCs, DACs, analogue buffers and analogue multiplexers, the new FPGA-based EIT DAS system is implemented in a very compact way for bedside use in intensive care units of hospitals. It is intended for applications such as continuous respiration monitoring with data collection at 25 frames per second. Image reconstruction times depend on the choice of 2D or 3D imaging algorithms and the available processing power.     

基于PCI总线的磁共振成像数据采集卡设计

目的为小型磁共振成像装置设计专用的高速数据采集卡.方法采用高速模数转换器ADS 804对MRI复数模拟信号进行数字化采样,用静态存储器(SRAM)暂存这数字化信号数据.扫描完一幅图像数据后再把数据从SRAM读入计算机.对模数转换器ADC和静态存储器SRAM的所有逻辑控制信号包括写入ADC的地址均由现场可编程器件FPGA产生.对FPGA读、写和对AD的读出均使用并行总线,由PCI 9052总线控制器进行控制.结果用甚高速硬件描述语言Foundation 3.1软件对FPGA进行设计,并对其产生的控制逻辑电路进行了功能仿真模拟,得到了可行的结果.结论用硬件描述语言VHDL对FPGA进行数字逻辑电路设计是很方便的,修改纠错也很容易.     

A method for digitized flow-volume curves and expiratory resistance measurements using standard ventilatory equipment

Pulmonary resistance may be assessed in ventilated patients by analysis of passive expiratory pressure and flow properties of the respiratory system. Such measurements are generally complex and require specialized equipment. To facilitate expiratory airway mechanics measurements, we have developed a method for automatically recording and analyzing expiratory pressure flow curves in mechanically ventilated patients using standard ventilatory equipment and a personal computer. Simultaneous digital pressure, flow, and volume recordings are obtained with this system during exhalation. These values allow continuous calculation of ventilator circuitry and total system resistance, which could be used for assessing expiratory airway resistance in intubated patients. The accuracy of these methods was tested by comparison to standard analog recorder pressure-flow methods using two lung models as well as by testing in normal volunteers ventilated through a mouthpiece. In all situations (flows, pressures, and volumes) there was excellent correlation between data generated from the automatic digital method and standard analog methods (all r values > .9, slopes 0.9 to 1.02, P < .001, flow bias −0.02 L/min, flow precision 0.08 L/min, volume bias 0.008 L, volume precision 0.027 L). Expiratory resistance (using expiratory time-constant cord methods) also correlated well between automatic digital and standard analog analyses (r = .9, slope 0.98, P < .001). We found that expiratory flow limb resistances (airway, tubing, filters, and valves) were substantial (range, 5.5 to 14.0 cm H₂O/L/s) and are varied throughout the expiratory cycle. Therefore, measurement of expiratory-flow limb resistance is necessary for accurate clinical assessment of pulmonary resistance for any system analyzing expiratory flow mechanics in ventilated patients. We conclude that this simple and convenient method allows automatic and accurate construction of pulmonary expiratory flow properties and may enable measurement of passive expiratory resistance. Rapid and accurate measurements of expiratory lung mechanics may be possible at the bedside of ventilated patients using standard ventilatory equipment with these methods.     

Autologous blood injection intracoronary artery for treating slow‐flow and no‐reflow in acute coronary syndrome related to primary pci

Slow‐flow and no‐reflow phenomenon are taken to sudden loss of coronary artery flow, typically after stenting or angioplasty in primary PCI. Otherwise conventional therapy, we report a technique, which autologous blood into intracoronary to supply oxygen and break process thrombosis results in successfully management no‐reflow in primary PCI in ACS.     

Accuracy of velocity and shear rate measurements using pulsed Doppler ultrasound: a comparison of signal analysis techniques.

An experimental investigation was instituted to evaluate the performance of Doppler ultrasound signal processing techniques for measuring fluid velocity under well-defined flow conditions using a 10-MHz multigated pulsed ultrasound instrument. Conditions of fully developed flow in a rigid, circular tube were varied over a Reynolds number range between 500 and 8000. The velocity across the tube was determined using analog and digital zero crossing detectors and three digital spectrum estimators. Determination of the Doppler frequency from analog or digital zero crossing detectors gave accurate velocity values for laminar and moderately turbulent flow away from the wall (0.969 less than or equal to r less than or equal to 0.986). Three digital spectrum estimators, Fast Fourier Transform, Burg autoregressive method, and minimum variance method, were slightly more accurate than the zero crossing detector (0.984 less than or equal to r less than or equal to 0.994), especially at points close to the walls and with higher levels of turbulence. Steep velocity gradients and transit-time-effects from high velocities produced significantly larger errors in velocity measurement. Wall shear rate estimates were most precise when calculated using the position of the wall and two velocity points. The calculated wall shears were within 20%-30% of theoretically predicted values.     

基于PCI总线的MRI数字频率源设计

目的为小型磁共振成像(MRI)装置设计频率能够高速切换、相位和幅度可调的数字化频率源,同时产生成像需要的3路梯度波形.方法采用直接数字频率合成器件AD 9854,产生相位和幅度可调的高频信号;D/A转换器MAX527产生三路梯度信号;PCI 9052作为PCI总线到local控制端的桥;复杂可编程逻辑器件(CPLD)XC 95108对数据线、地址线和控制线进行译码后控制AD 9854和MAX 527.结果对由CPLD产生的数据和控制逻辑信号用专用的Modelsim软件进行了功能仿真和时序仿真,得到了可行的结果.结论VHDL具有强大的语言描述功能,非常适合单个模块的设计,而原理图输入方式则适合于各个模块的连接和有关时序调整的设计,采用VHDL和原理图结合的方法可以很方便地对CPLD的内部控制逻辑电路进行设计.     

Performance of a Digital PCO2/SpO2 Ear Sensor

OBJECTIVE: For determining the adequacy of ventilation, conventional pulse oximetry should be amended by PaCO2 (= arterial carbon dioxide partial pressure). This study investigates the precision of carbon dioxide measurements of the first digital ear-clip sensor providing continuous non-invasive monitoring of PaCO2, SpO2 (= functional arterial oxygen saturation as estimated with a pulse oximeter) and pulse rate and compares it to two conventional analog oximeters. METHODS: 30 hypoxemia episodes in 6 adult volunteers were investigated in a standardized protocol. Equipment: Masimo analog finger sensor, Nellcor analog ear sensor, SenTec digital ear sensor. RESULTS: The difference between PCO2 data (= PaCO2 estimated from the measured PcCO2 based on an algorithm by Severinghaus) (PcCO2 = cutaneous carbon dioxide pressure) and the PaCO2 is clinically unimportant. Therefore, we suggest, the two methods of estimating patient's carbon dioxide status can be used interchangeably. CONCLUSIONS: Combined digital SpO2/ PcCO2 ear sensors are very promising to allow for a fast and reliable monitoring of patient's oxygenation, hyper-/hypocapnia and ventilation with one single non-invasive probe. Optimal primary signal processing--amplification and digitalisation within the probe--allow for fast and reliable downstream signal processing algorithms. The resulting short SpO2 response times give the medical staff more time to take appropriate actions.     

Quantification of flow volume with a new digital three-dimensional color Doppler flow approach: an in vitro study.

OBJECTIVE: The quantification of flow stroke volume is important for evaluation of patients with cardiac dysfunction and cardiovascular disease. Three-dimensional digital color Doppler flow imaging allows the acquisition of flow data in an orientation approximately parallel to flow and analysis of the Doppler flow velocities perpendicular to flow (cross-sectional flow calculation). This in vitro study assessed the applicability of this method for quantifying cardiac output in a funnel-shaped tube model similar to mitral inflow or the left ventricular outflow tract. METHODS: A new digital three-dimensional color Doppler method was used to acquire Doppler flow information. Raw scan line data with digital velocity assignments were obtained on a conventional Doppler color flow imaging system with a 180 degrees rotating multiplanar transesophageal probe connected to a computer workstation. Nine stroke volumes (20-60 mL) with flow rates ranging from 1.5 to 5.28 L/min in a funnel-shaped pulsatile laminar flow model were studied. Three-dimensional flow rates were compared with standard-of-reference measurements of flow obtained from timed collection in a graduated cylinder and with an ultrasonic flow meter. RESULTS: Within the funnel tube, the flow volumes that were calculated from the first, second, and third depths and the average of all 3 depths correlated well with the actual flow rate (r = 0.97-0.99). Results from the middle and second levels and from the average of all 3 depths provided the closest fit to the actual flow rates (r = 0.99; y = 0.96x + 0.14; and r = 0.98; y = 1.14x - 0.43, respectively). CONCLUSIONS: Although a work in progress, this digital three-dimensional color Doppler flow measurement method is feasible, accurate, and simple, and it may offer in vivo evaluation of blood volume flow given a favorable orientation between the valve orifice and the scanning device.     

Development of an integrated filing system for endoscopic images

A new integrated filing system for endoscopic images has been developed, comprising a main image filing system and subsystems located at different stations. A hybrid filing system made up of both digital and analog filing devices was introduced to construct this system that combines the merits of the two filing methods. Each subsystem provided with a video processor, is equipped with a digital filing device, and routine images were recorded in the analog image filing device of the main system. The use of a multi-input adapter enabled simultaneous input of analog images from up to 8 video processors. Recorded magneto-optical disks make it possible to recall the digital images at any station in the hospital; the disks are copied without image degradation and also utilised for image processing. This system promises reliable storage and integrated, efficient management of endoscopic information. It also costs less to install than the so-called PACS (picture archiving and communication system), which connects all the stations of the hospital using optical fiber cables.