Although the phase-shift seismic processing method has characteristics of high accuracy, good stability, high efficiency, and high-dip imaging, it is not able to adapt to strong lateral velocity variation. To overcome...Although the phase-shift seismic processing method has characteristics of high accuracy, good stability, high efficiency, and high-dip imaging, it is not able to adapt to strong lateral velocity variation. To overcome this defect, a finite-difference method in the frequency-space domain is introduced in the migration process, because it can adapt to strong lateral velocity variation and the coefficient is optimized by a hybrid genetic and simulated annealing algorithm. The two measures improve the precision of the approximation dispersion equation. Thus, the imaging effect is improved for areas of high-dip structure and strong lateral velocity variation. The migration imaging of a 2-D SEG/EAGE salt dome model proves that a better imaging effect in these areas is achieved by optimized phase-shift migration operator plus a finite-difference method based on a hybrid genetic and simulated annealing algorithm. The method proposed in this paper is better than conventional methods in imaging of areas of high-dip angle and strong lateral velocity variation.展开更多
目的评价CT灰度直方图参数在鉴别<20 mm亚实性结节(SSNs)的肺腺癌病理亚型中的价值。方法回顾性分析经手术病理证实的肺腺癌患者73例共77个<20 mm SSNs,包括不典型腺瘤样增生(AAH)7个、原位腺癌(AIS)19个、微侵润性腺癌(MIA)4个...目的评价CT灰度直方图参数在鉴别<20 mm亚实性结节(SSNs)的肺腺癌病理亚型中的价值。方法回顾性分析经手术病理证实的肺腺癌患者73例共77个<20 mm SSNs,包括不典型腺瘤样增生(AAH)7个、原位腺癌(AIS)19个、微侵润性腺癌(MIA)4个、浸润性肺腺癌(IAC)47个,并分为AAH-MIA组和IAC组。比较分析这两组病理亚型的灰度直方图参数和结节最长径的差异,并行受试者工作特征曲线(ROC)分析,确定其诊断临界值及诊断效能。结果 CT灰度直方图纹理参数中的均值、方差、Perc.10%、Perc.50%、Perc.90%、Perc.99%在AAH-MIA组与IAC组之间的差异有统计学意义,ROC曲线分析均显示有较高的诊断效能,其中Perc.90%诊断效能最佳[曲线下面积(AUC)为0.813];结节最长径的组间差异也具有统计学意义。将Perc.90%与结节最长径建立简易联合诊断模型,其诊断敏感度93.6%,特异度70.0%,AUC值达0.866(P<0.001),联合诊断模型的诊断效能提高。通过ROC曲线分析,Perc.90%≥173.50和最大径≥15.37 mm的SSNs病理表现为IAC可能性大。结论 SSNs的CT灰度直方图参数有助于提高对肺腺癌类病变浸润程度的鉴别能力,联合使用灰度直方图和结节最长径比各自单独使用能更准确鉴别肺腺癌病理亚型,对指导临床治疗和判断预后有重要价值。展开更多
基金the Open Fund(PLC201104)of State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation (Chengdu University of Technology)the National Natural Science Foundation of China(No.61072073)the Key Project of Education Commission of Sichuan Province(No.10ZA072)
文摘Although the phase-shift seismic processing method has characteristics of high accuracy, good stability, high efficiency, and high-dip imaging, it is not able to adapt to strong lateral velocity variation. To overcome this defect, a finite-difference method in the frequency-space domain is introduced in the migration process, because it can adapt to strong lateral velocity variation and the coefficient is optimized by a hybrid genetic and simulated annealing algorithm. The two measures improve the precision of the approximation dispersion equation. Thus, the imaging effect is improved for areas of high-dip structure and strong lateral velocity variation. The migration imaging of a 2-D SEG/EAGE salt dome model proves that a better imaging effect in these areas is achieved by optimized phase-shift migration operator plus a finite-difference method based on a hybrid genetic and simulated annealing algorithm. The method proposed in this paper is better than conventional methods in imaging of areas of high-dip angle and strong lateral velocity variation.
