目的探讨128层炫速双源CT血管造影(CTA)、尿路成像(CTU)联合应用在泌尿系统病变诊断中的价值。方法回顾性分析有临床症状并行双源CT的CTU病例128例,通过常规平扫、动脉期、实质期、排泌期扫描,三维后处理技术包括:多平面重建(MPR)、最...目的探讨128层炫速双源CT血管造影(CTA)、尿路成像(CTU)联合应用在泌尿系统病变诊断中的价值。方法回顾性分析有临床症状并行双源CT的CTU病例128例,通过常规平扫、动脉期、实质期、排泌期扫描,三维后处理技术包括:多平面重建(MPR)、最大密度投影(MIP)、曲面重建(CPR)及容积再现(VR),然后对获得影像进行分析。结果 CTA、CTU联合应用的扫描方法平均辐射剂量约12.04 m Gv;可成功优质重建出双肾、输尿管和膀胱的三维图像,血管系统与集合系统可以同时显影;通过旋转、放大等清晰显示全尿路及其局部细微结构、形态、走形及与周围组织的关系。结论 CTA、CTU联合应用在泌尿系统疾病的诊断和临床手术的制定等方面均有重要的应用价值。展开更多
In this paper,a genetic algorithm (GA) is investigated to deal with cell-by-cell dynamic spectrumallocation (DSA) in the heterogeneous scenario with temporal and spatial traffic demand changes,whichis also known as a ...In this paper,a genetic algorithm (GA) is investigated to deal with cell-by-cell dynamic spectrumallocation (DSA) in the heterogeneous scenario with temporal and spatial traffic demand changes,whichis also known as a difficult combinatorial optimization problem.A new two-dimensional chromosome encodingscheme is defined according to characteristics of the heterogeneous scenario,which prevents forminginvalid solutions during the genetic operation and enables much faster convergence.A novel randomcoloring gene generation function is presented which is the basic operation for initialization and mutationin the genetic algorithm.Simulative comparison demonstrates that the proposed GA-based cell-by-cellDSA outperforms the conventional contiguous DSA scheme both in terms of spectral efficiency gain andquality of service (QoS) satisfaction.展开更多
文摘目的探讨128层炫速双源CT血管造影(CTA)、尿路成像(CTU)联合应用在泌尿系统病变诊断中的价值。方法回顾性分析有临床症状并行双源CT的CTU病例128例,通过常规平扫、动脉期、实质期、排泌期扫描,三维后处理技术包括:多平面重建(MPR)、最大密度投影(MIP)、曲面重建(CPR)及容积再现(VR),然后对获得影像进行分析。结果 CTA、CTU联合应用的扫描方法平均辐射剂量约12.04 m Gv;可成功优质重建出双肾、输尿管和膀胱的三维图像,血管系统与集合系统可以同时显影;通过旋转、放大等清晰显示全尿路及其局部细微结构、形态、走形及与周围组织的关系。结论 CTA、CTU联合应用在泌尿系统疾病的诊断和临床手术的制定等方面均有重要的应用价值。
基金Supported by the National Basic Research Program of China (No. 2007CB310606)
文摘In this paper,a genetic algorithm (GA) is investigated to deal with cell-by-cell dynamic spectrumallocation (DSA) in the heterogeneous scenario with temporal and spatial traffic demand changes,whichis also known as a difficult combinatorial optimization problem.A new two-dimensional chromosome encodingscheme is defined according to characteristics of the heterogeneous scenario,which prevents forminginvalid solutions during the genetic operation and enables much faster convergence.A novel randomcoloring gene generation function is presented which is the basic operation for initialization and mutationin the genetic algorithm.Simulative comparison demonstrates that the proposed GA-based cell-by-cellDSA outperforms the conventional contiguous DSA scheme both in terms of spectral efficiency gain andquality of service (QoS) satisfaction.