Objective： To investigate the value of MR perfusion imaging in evaluating the curative effect of intervention treatment of hepatic cancer. Methods： 36 patients underwent MR perfusion imaging after intervention treat...Objective： To investigate the value of MR perfusion imaging in evaluating the curative effect of intervention treatment of hepatic cancer. Methods： 36 patients underwent MR perfusion imaging after intervention treatment. The quantization results were differed between carcinoma residue and benign tissue. And the diagnosis accuracy was judged, Results： There was a significant difference in mean MSI between residue tumor after surgery and the benign enhancement area. The timeintension curve of residue tumor was observed to ascend rapidly to reach the peak, whereas that of the enhancement tissue ascended slowly to reach the peak. The sensitivity and specificity of PWl on detection of residuary or recurrent tumor were 0.89 and 0.73 respectively. Conclusion： PWl is a very sensitive imaging technique that can be used to distinguish liver tissue condition after surgery. PWI contributed to early stage diagnosis and dynamic monitoring following HCC surgery.展开更多
Objective： To explore the application of MR perfusion-weighted imaging （PWI） in the benign and malignant prostate diseases, and evaluate the correlations of PWl features with vascular endothelial growth factor （V...Objective： To explore the application of MR perfusion-weighted imaging （PWI） in the benign and malignant prostate diseases, and evaluate the correlations of PWl features with vascular endothelial growth factor （VEGF） and microvessel density （MVD）. Methods： Seventy-four consecutive patients who were diagnosed clinically for the prostate diseases, including forty-four cases with benign prostate hyperplasia and thirty cases with prostatic cancer proved pathologically, were examined by PWI. MVD and VEGF were stained with immunohistochemical methods. Some parameters of PWl, including the steepest slope of signal intensity-time curve （SSmax） and the change in relaxation rate （ΔR2^＊ peak） at lesions, were analyzed. Correlation analysis was used to determine the relationship between the results of PWl and immunohistochemistry. Results： （1） In the benign prostate hyperplasia （BPH）, SSmax and ΔR2^＊ peak of perfusion curve were 34.2 ± 2.9 and 1.49 ± 0.11, respectively; however, in the prostatic cancer （Pca）, they were 58.6± 4.8 and 3.18 ±0.49 respectively; there were statistical differences （t = 2.16 and 2.31, P 〈 0.05）. （2） The VEGF and MVD expressions of thirty Pca patients were significantly higher than those of forty-four BPH patients （x2 = 28.64, P 〈 0.01; t = 21.2, P 〈 0.01）. MVD expressions of Pca and BPH groups showed positive associations with VEGF expressions （P 〈 0.01）. On MR perfusion-weighted imaging, SSmax and ΔR2^＊ peak showed associations with MVD and VEGF expressions （P 〈 0.01）. Conclusion： On MR perfusion-weighted imaging, SSmax and ΔR2^＊ peak can reflect MVD and VEGF expression levels in the benign and malignant prostate diseases and might be implied the tumor angiogenesis so as to distinguish benign from malignant and provide the important information for the surgeon to diagnose and treat the prostatic diseases.展开更多
In this paper we present a new version of Chen＇s system： a piecewise linear （PWL） Chert system of fractional-order. Via a sigmoid-like function, the discontinuous system is transformed into a continuous system. By...In this paper we present a new version of Chen＇s system： a piecewise linear （PWL） Chert system of fractional-order. Via a sigmoid-like function, the discontinuous system is transformed into a continuous system. By numerical simulations, we reveal chaotic behaviors and also multistability, i.e., the existence of small pararheter windows where, for some fixed bifurcation parameter and depending on initial conditions, coexistence of stable attractors and chaotic attractors is possible. Moreover, we show that by using an algorithm to switch the bifurcation parameter, the stable attractors can be numerically approximated.展开更多
Memristor is a newly found fourth circuit element for the next generation emerging nonvolatile memory technology. In this paper, design of new type of nonvolatile static random access memory cell is proposed by using ...Memristor is a newly found fourth circuit element for the next generation emerging nonvolatile memory technology. In this paper, design of new type of nonvolatile static random access memory cell is proposed by using a combination of memristor and complemented metal oxide semiconductor. Biolek memristor model and CMOS 180 nm technology are used to form a single cell. By introducing distinct binary logic to avoid safety margin is left for each binary logic output and enables better read/write data integrity. The total power consumption reduces from 0.407 mw (milli-watt) to 0.127 mw which is less than existing memristor based memory cell of the same CMOS technology. Read and write time is also significantly reduced. However, write time is higher than conventional 6T SRAM cell and can be reduced by increasing motion of electron in the memristor. The change of the memristor state is shown by applying piecewise linear input voltage.展开更多
文摘Objective： To investigate the value of MR perfusion imaging in evaluating the curative effect of intervention treatment of hepatic cancer. Methods： 36 patients underwent MR perfusion imaging after intervention treatment. The quantization results were differed between carcinoma residue and benign tissue. And the diagnosis accuracy was judged, Results： There was a significant difference in mean MSI between residue tumor after surgery and the benign enhancement area. The timeintension curve of residue tumor was observed to ascend rapidly to reach the peak, whereas that of the enhancement tissue ascended slowly to reach the peak. The sensitivity and specificity of PWl on detection of residuary or recurrent tumor were 0.89 and 0.73 respectively. Conclusion： PWl is a very sensitive imaging technique that can be used to distinguish liver tissue condition after surgery. PWI contributed to early stage diagnosis and dynamic monitoring following HCC surgery.
文摘Objective： To explore the application of MR perfusion-weighted imaging （PWI） in the benign and malignant prostate diseases, and evaluate the correlations of PWl features with vascular endothelial growth factor （VEGF） and microvessel density （MVD）. Methods： Seventy-four consecutive patients who were diagnosed clinically for the prostate diseases, including forty-four cases with benign prostate hyperplasia and thirty cases with prostatic cancer proved pathologically, were examined by PWI. MVD and VEGF were stained with immunohistochemical methods. Some parameters of PWl, including the steepest slope of signal intensity-time curve （SSmax） and the change in relaxation rate （ΔR2^＊ peak） at lesions, were analyzed. Correlation analysis was used to determine the relationship between the results of PWl and immunohistochemistry. Results： （1） In the benign prostate hyperplasia （BPH）, SSmax and ΔR2^＊ peak of perfusion curve were 34.2 ± 2.9 and 1.49 ± 0.11, respectively; however, in the prostatic cancer （Pca）, they were 58.6± 4.8 and 3.18 ±0.49 respectively; there were statistical differences （t = 2.16 and 2.31, P 〈 0.05）. （2） The VEGF and MVD expressions of thirty Pca patients were significantly higher than those of forty-four BPH patients （x2 = 28.64, P 〈 0.01; t = 21.2, P 〈 0.01）. MVD expressions of Pca and BPH groups showed positive associations with VEGF expressions （P 〈 0.01）. On MR perfusion-weighted imaging, SSmax and ΔR2^＊ peak showed associations with MVD and VEGF expressions （P 〈 0.01）. Conclusion： On MR perfusion-weighted imaging, SSmax and ΔR2^＊ peak can reflect MVD and VEGF expression levels in the benign and malignant prostate diseases and might be implied the tumor angiogenesis so as to distinguish benign from malignant and provide the important information for the surgeon to diagnose and treat the prostatic diseases.
文摘为解决低剂量计算机断层扫描(computedtomography,CT)重建图像时产生严重退化的问题,提出一种改进的非局部均值低剂量CT统计迭代重建算法。采用高斯滤波函数对含噪图像进行滤波,利用改进的非局部均值(non-local means,NLM)降噪模型做进一步降噪处理,通过空间邻近度因子和空间变化的滤波参数改进权值函数,得到新的降噪模型,把该模型应用到惩罚加权最小二乘(penalized weighted least square,PWLS)重建算法中,以期达到噪声抑制和边缘保持的良好效果。实验结果表明,该算法的重建图像可有效去除噪声,保护图像的边缘信息和细小结构。
基金funded by the European Regional Development Funding via RISC projectby CPER Region Haute Normandie France,the Australian Research Council via a Future Fellowship(FT110100896)Discovery Project(DP140100203)
文摘In this paper we present a new version of Chen＇s system： a piecewise linear （PWL） Chert system of fractional-order. Via a sigmoid-like function, the discontinuous system is transformed into a continuous system. By numerical simulations, we reveal chaotic behaviors and also multistability, i.e., the existence of small pararheter windows where, for some fixed bifurcation parameter and depending on initial conditions, coexistence of stable attractors and chaotic attractors is possible. Moreover, we show that by using an algorithm to switch the bifurcation parameter, the stable attractors can be numerically approximated.
文摘Memristor is a newly found fourth circuit element for the next generation emerging nonvolatile memory technology. In this paper, design of new type of nonvolatile static random access memory cell is proposed by using a combination of memristor and complemented metal oxide semiconductor. Biolek memristor model and CMOS 180 nm technology are used to form a single cell. By introducing distinct binary logic to avoid safety margin is left for each binary logic output and enables better read/write data integrity. The total power consumption reduces from 0.407 mw (milli-watt) to 0.127 mw which is less than existing memristor based memory cell of the same CMOS technology. Read and write time is also significantly reduced. However, write time is higher than conventional 6T SRAM cell and can be reduced by increasing motion of electron in the memristor. The change of the memristor state is shown by applying piecewise linear input voltage.
