目的:探讨3.0 T MRI肝脏加速容积采集(LAVA)技术在评估布-加综合征(BCS)患者侧支循环中的价值。方法:搜集经数字减影血管造影(DSA)确诊的40例BCS患者,回顾性分析其MRI LAVA影像资料,计算LAVA对BCS分型的诊断符合率;分析LAVA对常见肝内...目的:探讨3.0 T MRI肝脏加速容积采集(LAVA)技术在评估布-加综合征(BCS)患者侧支循环中的价值。方法:搜集经数字减影血管造影(DSA)确诊的40例BCS患者,回顾性分析其MRI LAVA影像资料,计算LAVA对BCS分型的诊断符合率;分析LAVA对常见肝内外侧支循环的检出率及侧支循环与BCS分型的相关性;采用Kappa检验评估LAVA与DSA对直径≥3.0 mm副肝静脉的检出一致性。结果:LAVA诊断下腔静脉阻塞型18例,肝静脉阻塞型13例,混合型9例;DSA证实下腔静脉阻塞型18例,肝静脉阻塞型15例,混合型7例;MRI LAVA对BCS分型的诊断符合率为95.0%(38/40)。LAVA显示奇/半奇静脉扩张33例(82.5%),副肝静脉扩张22例(55.0%),腹壁浅静脉扩张19例(47.5%),肝内交通支静脉扩张17例(42.5%),膈下静脉扩张9例(22.5%)。奇/半奇静脉侧支主要存在于下腔静脉梗阻型和混合型BCS(P<0.01,相关程度为0.595),而副肝静脉侧支主要存在于混合型BCS(P<0.01,相关程度为0.426)。LAVA检出副肝静脉31支,平均管径为(7.1±3.4)mm,LAVA与DSA对副肝静脉检出的一致性较好(Kappa值=0.767)。结论:MRI LAVA扫描技术在BCS分型诊断、侧支循环评估中具有重要价值,能为临床BCS的诊疗提供有用信息。展开更多
Based on the research of two geophone types （10 Hz moving-coil velocity and piezoelectric acceleration） and their velocity and acceleration parameters, frequency response functions have been determined, as well as t...Based on the research of two geophone types （10 Hz moving-coil velocity and piezoelectric acceleration） and their velocity and acceleration parameters, frequency response functions have been determined, as well as the differences between them. Also, shock- vibration tests have been accomplished, not only to explain the two shock response signal differences, but also to analyze the response signal characteristics and its ability to carry information. In addition, seismic data acquisition experiments have been carried out under comparable conditions in the field. A contrast analysis of shot gathers and stack profiles acquired with the two geophone types is given in this paper. The results show that the acceleration signal from the acceleration geophone has a better advantage in terms of high signal-to-noise ratio, high accuracy, high resolution, and quantity of information to better meet current and future requirements for seismic exploration.展开更多
文摘介绍了一种基于CPLD内置UFM(user flash memory)的嵌入式加速度数据采集系统,并给出了各个功能模块的实现方法。整个采集系统主要包括电荷放大器模块、信号调理模块、A/D转换模块、CPLD控制模块和电源模块。整个系统以EPM570T100C5为核心,由该CPLD控制A/D芯片MAX1311进行模数转换并根据相应的时序操作把转换到的数据存储到内置的UFM里。在设计电路板时,采用MAX II CPLD来合并逻辑和存储器(UFM),从而缩短了芯片至芯片延时,减小了电路板面积,降低了系统总成本。该系统可以稳定实现300k的采样速率,可以嵌入到设备内部进行加速度以及各种冲击信号的检测。
基金supported jointly by the National Natural Science Foundation Fund of China (No.40930418)Chinese government-funded scientific program of the Sino Probe Deep Exploration in China (SinoProbe03)the National Science and Technology Support Program Project (No. 2011BAB04B01)
文摘Based on the research of two geophone types （10 Hz moving-coil velocity and piezoelectric acceleration） and their velocity and acceleration parameters, frequency response functions have been determined, as well as the differences between them. Also, shock- vibration tests have been accomplished, not only to explain the two shock response signal differences, but also to analyze the response signal characteristics and its ability to carry information. In addition, seismic data acquisition experiments have been carried out under comparable conditions in the field. A contrast analysis of shot gathers and stack profiles acquired with the two geophone types is given in this paper. The results show that the acceleration signal from the acceleration geophone has a better advantage in terms of high signal-to-noise ratio, high accuracy, high resolution, and quantity of information to better meet current and future requirements for seismic exploration.
