In many ultrafast imaging applications, the reduced field-of-view（r FOV） technique is often used to enhance the spatial resolution and field inhomogeneity immunity of the images. The stationary-phase characteristic ...In many ultrafast imaging applications, the reduced field-of-view（r FOV） technique is often used to enhance the spatial resolution and field inhomogeneity immunity of the images. The stationary-phase characteristic of the spatiotemporallyencoded（SPEN） method offers an inherent applicability to r FOV imaging. In this study, a flexible r FOV imaging method is presented and the superiority of the SPEN approach in r FOV imaging is demonstrated. The proposed method is validated with phantom and in vivo rat experiments, including cardiac imaging and contrast-enhanced perfusion imaging. For comparison, the echo planar imaging（EPI） experiments with orthogonal RF excitation are also performed. The results show that the signal-to-noise ratios of the images acquired by the proposed method can be higher than those obtained with the r FOV EPI. Moreover, the proposed method shows better performance in the cardiac imaging and perfusion imaging of rat kidney, and it can scan one or more regions of interest（ROIs） with high spatial resolution in a single shot. It might be a favorable solution to ultrafast imaging applications in cases with severe susceptibility heterogeneities, such as cardiac imaging and perfusion imaging. Furthermore, it might be promising in applications with separate ROIs, such as mammary and limb imaging.展开更多
基金Project supported by the National Natural Science Foundation of China(Grant Nos.11474236,81171331,and U1232212)
文摘In many ultrafast imaging applications, the reduced field-of-view（r FOV） technique is often used to enhance the spatial resolution and field inhomogeneity immunity of the images. The stationary-phase characteristic of the spatiotemporallyencoded（SPEN） method offers an inherent applicability to r FOV imaging. In this study, a flexible r FOV imaging method is presented and the superiority of the SPEN approach in r FOV imaging is demonstrated. The proposed method is validated with phantom and in vivo rat experiments, including cardiac imaging and contrast-enhanced perfusion imaging. For comparison, the echo planar imaging（EPI） experiments with orthogonal RF excitation are also performed. The results show that the signal-to-noise ratios of the images acquired by the proposed method can be higher than those obtained with the r FOV EPI. Moreover, the proposed method shows better performance in the cardiac imaging and perfusion imaging of rat kidney, and it can scan one or more regions of interest（ROIs） with high spatial resolution in a single shot. It might be a favorable solution to ultrafast imaging applications in cases with severe susceptibility heterogeneities, such as cardiac imaging and perfusion imaging. Furthermore, it might be promising in applications with separate ROIs, such as mammary and limb imaging.
文摘针对传统应用飞机内部时分指令/响应型多路串行数据总线(MIL-STD-1553B:Military Standard 1553 Bus)需要大量外围芯片的问题,在研究MIL-STD-1553总线协议的基础上,实现一种以现场可编程逻辑器件(FPGA:Field Programmable Gate Array)为核心的1553B接口模块。综合分析了FPGA控制1553B总线的原理和过程,给出了FPGA控制通用串行总线(USB:Universal Serial Bus)的实现方法。采用变压器耦合的方式,通过HI-1567转换器,将信号送入FPGA中,利用FPGA内部丰富的逻辑资源完成对总线数据的采集、编解码以及与PC(Personal Computer)机的通信,并将FPGA接收到的数据信息显示在PC机上。实验结果表明,该设计方案完成了总线数据的发送和接收,实现了总线数据的正确传输,不但减少了大量的外围电路,而且提高了系统的可靠性和实时性。
