光学相干断层成像不同扫描信号强度对视盘RNFL厚度分析的影响

Effect of Different Scanning Signal Strength of Optical Coherence Tomography on the Analysis of Optic Disc RNFL Thickness

目的:比较不同信号强度下通过光学相干断层成像(OCT)采集的视盘视网膜神经纤维层(RNFL)厚度差异,讨论信号强度对其影响,为准确分析视盘RNFL提供依据。方法:系列病例研究。纳入2018年12月10日至2019年8月16日在陆军军医大学西南医院眼科进行OCT视盘扫描的患者90例(90眼),男43例,女47例,其中RNFL正常组30例(30眼),RNFL变薄组30例(30眼),RNFL增厚组30例(30眼),年龄(41.8±18.0)岁。所有患者屈光介质清楚,在采集过程中已获取了不同信号强度扫描图像,规定信号强度0~3为低信号,信号强度4~6为中信号,信号强度7~10为高信号,分别统计盘周3.46 mm直径RNFL平均厚度值及RNFL异常组在低信号与高信号强度下异常象限个数。组间年龄和性别比较分别采用单因素方差分析和χ^(2)检验进行分析;不同信号组间整体平均值之间的差异比较采用重复测量方差分析;不符合正态分布的采用Friedman秩和检验;异常组低信号强度与高信号强度之间异常的RNFL分布情况采用kappa检验分析一致性,kappa≥0.75表示一致性较好,kappa≤0.40表示一致性差。结果:RNFL正常组、RNFL变薄组和RNFL增厚组在不同信号强度下RNFL平均厚度的差异有统计学意义(正常组:F=137.78,P<0.001;变薄组:F=66.91,P<0.001;RNFL增厚组:χ^(2)=60.00,P<0.001)。在RNFL变薄组中,低信号强度与高信号强度下异常象限分布高度一致(kappa=0.88,P<0.001);在RNFL增厚组中,低信号强度与高信号强度下异常象限分布不存在一致性(kappa=0.20,P=0.009)。结论:OCT扫描的视盘RNFL平均厚度值因其信号强度变化而有差异,信号强度越高结果可靠度越高。低信号强度时可以确定变薄RNFL的象限分布,但是不能准确判定增厚RNFL的分布。

Objective:To collect optic disc retinal nerve fiber layer(RNFL)thickness by optical coherence tomography(OCT)in different signal strength(SS),and compare the differences between them,discuss the influence of SS on it,and provide basis for accurate analysis of optic disc RNFL.Methods:This case series stude included 90 patients with RNFL analysis in 90 eyes who had undergone OCT optic disc scanning in Department of Ophthalmology,South west Hospital,from December 2018 to August 2019 were selected,including 30 eyes in the RNFL normal group,30 eyes in the RNFL thinning group,and 30 eyes in the RNFL thickening group.Age(41.8±18.0)years old.All patients have clear refractive media.Scan images of different SS have been acquired during the collection process,Signal strength 0-3 is regarded as low SS,signal strength 4-6 is medium SS,signal strength 7-10 is high SS.The average value of 3.46 mm diameter RNFL and the number of abnormal quadrants of RNFL abnormal group under low SS and high SS were counted.The average age between groups was compared by single-factor ANOVA,the gender differences between different groups were compared by Chi square test,to compare the difference between the mean RNFL between different signal groups,the results were single-factor repeated measures ANOVA and those that did not conform to the normal distribution were tested by Friedman rank-sum test,and the abnormal RNFL distribution between the low signal group and the high signal group was analyzed by the kappa consistency test,and the kappa≥0.75 indicated that the consistency was good,and the kappa≤0.4.indicated the consistency difference.Results:The difference in the average thickness of RNFL under different signal strength is statistically significant,in the normal RNFL group(F=137.78,P<0.001),in the thinning RNFL group(F=66.91,P<0.001),in the RNFL thickening group(χ^(2)=60.00,P<0.001).In the analysis of RNFL thinning group,the distribution of abnormal quadrants under low signal strength and high signal strength was highly consistent(kappa=0.88,P<0.001).In the analysis of RNFL thickening group,the distribution of abnormal quadrants under low signal strength and high signal strength was not significantly consistent(kappa=0.20,P=0.009).Conclusion:The average RNFL value of the optic disc OCT scan is correlated with the SS.The higher the SS,the higher the reliability of the result.At low SS,the quadrant distribution of thinned RNFL can be determined,but the distribution of thickened RNFL cannot be determined accurately.