AIM:To assess the effect of experimentally induced anisometropia on binocularity in normal adults with glassesfree three-dimensional(3D)technique.METHODS:Totally 54 healthy medical students with normal binocularity in...AIM:To assess the effect of experimentally induced anisometropia on binocularity in normal adults with glassesfree three-dimensional(3D)technique.METHODS:Totally 54 healthy medical students with normal binocularity in the cross-sectional study were enrolled.Anisometropia was induced by placing trail lenses over the right eye,in 0.5 D steps including lenses of-0.5,-1,-1.5,-2,-2.5 D(hyperopic anisometropia)and lenses of+0.5,+1,+1.5,+2,+2.5 D(myopic anisometropia).The glasses-free 3D technique was used to evaluated not only fine stereopsis,but also coarse stereopsis,dynamic stereopsis,foveal suppression,and peripheral suppression in these subjects.One-way analysis of variance was used to compare quantitative data such as fine stereopsis,coarse stereopsis.Pearson’s Chi-square test was performed to compare categorical data such as dynamic stereopsis,foveal suppression and peripheral suppression.RESULTS:The subjects showed a statistically significant decline in fine stereopsis,coarse stereopsis,and dynamic stereopsis with increasing levels of anisometropia(P<0.001).Binocularity was af fected when induced anisometropia was more than 1 D(P<0.05).Foveal suppression and peripheral suppression were evident and increased in proportion to anisometropia(P<0.001).CONCLUSION:The relatively low degrees of anisometropia may have a potentially significant effect on high-grade binocular interaction.The mechanisms underlying the defect of binocularity seem to involve not only foveal suppression,but also peripheral suppression.展开更多
目的:对比三维多回波恢复梯度回波(3D MERGE)、三维可变反转角快速自旋回波(3D SPACE STIR)序列在腰椎间盘突出症(LDH)检查中的应用效果。方法:选择2020年1月~2022年11月收治的135例LDH患者,回顾性分析患者临床和磁共振成像(MRI)资料,...目的:对比三维多回波恢复梯度回波(3D MERGE)、三维可变反转角快速自旋回波(3D SPACE STIR)序列在腰椎间盘突出症(LDH)检查中的应用效果。方法:选择2020年1月~2022年11月收治的135例LDH患者,回顾性分析患者临床和磁共振成像(MRI)资料,所有患者均接受常规MRI扫描及3D MERGE、3D SPACE STIR序列扫描,对比3D MERGE、3D SPACE STIR序列测量神经根直径的一致性,评价两种序列的图像质量参数[信噪比(SNR)、对比噪声比(CNR)]、图像清晰度评分。结果:3D MERGE和3D SPACE STIR序列测量的L3~S1神经根直径比较差异无统计学意义(P>0.05),且两组序列测量的L3、L4、L5和S1直径均显示出较高相关性(r=0.957,0.986,0.975,0.972,P<0.05);3D MERGE序列的SNR及CNR均高于3D SPACE STIR序列,神经根显示分级、图像清晰度评分优于3D SPACE STIR序列,差异有统计学意义(P<0.05)。结论:3D MERGE、3D SPACE STIR序列在LDH神经根直径测量中具有极高一致性,3D MERGE序列较3D SPACE STIR序列能够更清晰显示神经跟的解剖形态,图像质量更好。展开更多
高斯噪声是闪光图像中的主要噪声,将在密度反演等后续处理中被放大,严重影响密度重建及客体边界提取结果,因此,消高斯噪声是闪光图像消噪研究的重点内容。针对闪光照相图像噪声及照相客体轴旋转对称的特点,研究了基于三维块匹配滤波(Blo...高斯噪声是闪光图像中的主要噪声,将在密度反演等后续处理中被放大,严重影响密度重建及客体边界提取结果,因此,消高斯噪声是闪光图像消噪研究的重点内容。针对闪光照相图像噪声及照相客体轴旋转对称的特点,研究了基于三维块匹配滤波(Block Matching and 3D Filtering,BM3D)的闪光照相图像消噪算法,针对闪光照相图像中难以获得更高质量相似块的缺陷,在不破坏噪声独立性的情况下,通过对含噪退化图像进行旋转与镜像操作,增加了提供相似块的图像来源。同时,通过引入图像块的灰度变换,降低了原有相似性要求中的灰度值要求,提高了形状相似的要求,增加了获得高质量相似块的能力。图像的消噪结果表明,由于相似块的质量得到保证,用于闪光图像消噪的改进BM3D方法取得了更好的消噪效果。展开更多
基金Supported by Sichuan Science and Technology Program (No.23NSFSC0856)。
文摘AIM:To assess the effect of experimentally induced anisometropia on binocularity in normal adults with glassesfree three-dimensional(3D)technique.METHODS:Totally 54 healthy medical students with normal binocularity in the cross-sectional study were enrolled.Anisometropia was induced by placing trail lenses over the right eye,in 0.5 D steps including lenses of-0.5,-1,-1.5,-2,-2.5 D(hyperopic anisometropia)and lenses of+0.5,+1,+1.5,+2,+2.5 D(myopic anisometropia).The glasses-free 3D technique was used to evaluated not only fine stereopsis,but also coarse stereopsis,dynamic stereopsis,foveal suppression,and peripheral suppression in these subjects.One-way analysis of variance was used to compare quantitative data such as fine stereopsis,coarse stereopsis.Pearson’s Chi-square test was performed to compare categorical data such as dynamic stereopsis,foveal suppression and peripheral suppression.RESULTS:The subjects showed a statistically significant decline in fine stereopsis,coarse stereopsis,and dynamic stereopsis with increasing levels of anisometropia(P<0.001).Binocularity was af fected when induced anisometropia was more than 1 D(P<0.05).Foveal suppression and peripheral suppression were evident and increased in proportion to anisometropia(P<0.001).CONCLUSION:The relatively low degrees of anisometropia may have a potentially significant effect on high-grade binocular interaction.The mechanisms underlying the defect of binocularity seem to involve not only foveal suppression,but also peripheral suppression.
文摘目的:对比三维多回波恢复梯度回波(3D MERGE)、三维可变反转角快速自旋回波(3D SPACE STIR)序列在腰椎间盘突出症(LDH)检查中的应用效果。方法:选择2020年1月~2022年11月收治的135例LDH患者,回顾性分析患者临床和磁共振成像(MRI)资料,所有患者均接受常规MRI扫描及3D MERGE、3D SPACE STIR序列扫描,对比3D MERGE、3D SPACE STIR序列测量神经根直径的一致性,评价两种序列的图像质量参数[信噪比(SNR)、对比噪声比(CNR)]、图像清晰度评分。结果:3D MERGE和3D SPACE STIR序列测量的L3~S1神经根直径比较差异无统计学意义(P>0.05),且两组序列测量的L3、L4、L5和S1直径均显示出较高相关性(r=0.957,0.986,0.975,0.972,P<0.05);3D MERGE序列的SNR及CNR均高于3D SPACE STIR序列,神经根显示分级、图像清晰度评分优于3D SPACE STIR序列,差异有统计学意义(P<0.05)。结论:3D MERGE、3D SPACE STIR序列在LDH神经根直径测量中具有极高一致性,3D MERGE序列较3D SPACE STIR序列能够更清晰显示神经跟的解剖形态,图像质量更好。
文摘高斯噪声是闪光图像中的主要噪声,将在密度反演等后续处理中被放大,严重影响密度重建及客体边界提取结果,因此,消高斯噪声是闪光图像消噪研究的重点内容。针对闪光照相图像噪声及照相客体轴旋转对称的特点,研究了基于三维块匹配滤波(Block Matching and 3D Filtering,BM3D)的闪光照相图像消噪算法,针对闪光照相图像中难以获得更高质量相似块的缺陷,在不破坏噪声独立性的情况下,通过对含噪退化图像进行旋转与镜像操作,增加了提供相似块的图像来源。同时,通过引入图像块的灰度变换,降低了原有相似性要求中的灰度值要求,提高了形状相似的要求,增加了获得高质量相似块的能力。图像的消噪结果表明,由于相似块的质量得到保证,用于闪光图像消噪的改进BM3D方法取得了更好的消噪效果。
