目的:利用光学相干断层扫描血管成像技术(OCTA)观察视网膜静脉阻塞患者黄斑区浅层和深层视网膜毛细血管丛血流密度、中心凹无血管区(FAZ)面积、黄斑中心凹厚度(CMT)等的变化,并分析其与视功能的相关性。方法:本组54例(眼)视网膜静脉阻塞...目的:利用光学相干断层扫描血管成像技术(OCTA)观察视网膜静脉阻塞患者黄斑区浅层和深层视网膜毛细血管丛血流密度、中心凹无血管区(FAZ)面积、黄斑中心凹厚度(CMT)等的变化,并分析其与视功能的相关性。方法:本组54例(眼)视网膜静脉阻塞(RVO)患者,其中34例(眼)视网膜分支静脉阻塞,20例(眼)视网膜中央静脉阻塞;健康对照组19例(眼),通过OCTA在以视网膜黄斑中心凹为中心的3 mm ×3 mm区域进行扫描,比较分析患眼、对侧眼及健康对照眼在FAZ面积、黄斑区血流密度、CMT的变化,分析其与最佳矫正视力(BCVA)的相关性。结果:患眼的FAZ面积均大于对侧眼和对照眼(P 【0.01, P 【0.05),且FAZ面积与logMAR BCVA呈正相关;患眼黄斑区浅层和深层的血流密度明显低于对侧眼和对照眼(P 【0.001, P 【0.001),且浅层及深层的血流密度均与logMAR BCVA呈负相关;患眼的CMT均较对侧眼及正常眼增厚(P 【0.001, P 【0.001)。结论:OCTA对于检测RVO黄斑区浅层和深层视网膜血流密度、FAZ面积等相关指标具有无创、便捷、准确的优点。RVO患者患眼较对侧眼及正常对照眼在浅层及深层视网膜血流密度和浅层FAZ面积均有改变,且FAZ面积和血流密度与RVO眼的最佳矫正视力相关。展开更多
A dust concentration imaging system based on optical tomography is proposed to monitor concentration variations of coal dust in a mine.Concentration profiles,rather than just a point value,of coal dust concentrations ...A dust concentration imaging system based on optical tomography is proposed to monitor concentration variations of coal dust in a mine.Concentration profiles,rather than just a point value,of coal dust concentrations are the goal of this method.An optical sensor array is employed to realize an optical sensing field of the coal dust concentration during on-line monitoring.A novel image reconstruction algorithm,called the simultaneous iterative reconstruction technique(SIRT),is compared to the well known linear,back projection algorithm(LBP).The SIRT was applied to the present problem and tested by modeling.The disadvantage of the SIRT is a slow speed but some improvements have been made by adding a weighting function that reduces the relative error to 1.7% from 3.1% for 50 iterations.The results of image reconstruction are presented for both simulated and real objects.They prove that the optical tomography technique,based on a multi-source fan projection scheme,can be an effective approach for estimating coal dust distribution.This system can be applied in real time for continuous measurements in a mine.展开更多
文摘目的:利用光学相干断层扫描血管成像技术(OCTA)观察视网膜静脉阻塞患者黄斑区浅层和深层视网膜毛细血管丛血流密度、中心凹无血管区(FAZ)面积、黄斑中心凹厚度(CMT)等的变化,并分析其与视功能的相关性。方法:本组54例(眼)视网膜静脉阻塞(RVO)患者,其中34例(眼)视网膜分支静脉阻塞,20例(眼)视网膜中央静脉阻塞;健康对照组19例(眼),通过OCTA在以视网膜黄斑中心凹为中心的3 mm ×3 mm区域进行扫描,比较分析患眼、对侧眼及健康对照眼在FAZ面积、黄斑区血流密度、CMT的变化,分析其与最佳矫正视力(BCVA)的相关性。结果:患眼的FAZ面积均大于对侧眼和对照眼(P 【0.01, P 【0.05),且FAZ面积与logMAR BCVA呈正相关;患眼黄斑区浅层和深层的血流密度明显低于对侧眼和对照眼(P 【0.001, P 【0.001),且浅层及深层的血流密度均与logMAR BCVA呈负相关;患眼的CMT均较对侧眼及正常眼增厚(P 【0.001, P 【0.001)。结论:OCTA对于检测RVO黄斑区浅层和深层视网膜血流密度、FAZ面积等相关指标具有无创、便捷、准确的优点。RVO患者患眼较对侧眼及正常对照眼在浅层及深层视网膜血流密度和浅层FAZ面积均有改变,且FAZ面积和血流密度与RVO眼的最佳矫正视力相关。
基金supported by the Key Project in the National Science & Technology Pillar Program during the twelfth Five-Year Planperiod (No. SQ2012BAJY3504-08)
文摘A dust concentration imaging system based on optical tomography is proposed to monitor concentration variations of coal dust in a mine.Concentration profiles,rather than just a point value,of coal dust concentrations are the goal of this method.An optical sensor array is employed to realize an optical sensing field of the coal dust concentration during on-line monitoring.A novel image reconstruction algorithm,called the simultaneous iterative reconstruction technique(SIRT),is compared to the well known linear,back projection algorithm(LBP).The SIRT was applied to the present problem and tested by modeling.The disadvantage of the SIRT is a slow speed but some improvements have been made by adding a weighting function that reduces the relative error to 1.7% from 3.1% for 50 iterations.The results of image reconstruction are presented for both simulated and real objects.They prove that the optical tomography technique,based on a multi-source fan projection scheme,can be an effective approach for estimating coal dust distribution.This system can be applied in real time for continuous measurements in a mine.
