Effects of scan circle displacement in optical coherence tomography retinal nerve fibre layer thickness measurement: a RNFL modelling study
Effects of scan circle displacement in optical coherence tomography retinal nerve fibre layer thickness measurement: a RNFL modelling study
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DOI：
10.1038/eye.2008.258
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发表时间：
2009-06-01
期刊：
影响因子：
3.9
通讯作者：
Leung, C. K. S.
中科院分区：
文献类型：
--
作者：
Cheung, C. Y. L.;Yiu, C. K. F.;Leung, C. K. S.
目的应用三次样条模型研究光学相干断层扫描（OCT）扫描环位移对视网膜神经纤维层（RNFL）测量误差的影响。在每个受试者中随机选择一只眼睛，通过采取16个不同大小的圆形扫描（扫描半径范围从1到2.5 mm）来测量视盘周围的RNFL厚度。利用平滑样条近似的数学模型构建每只眼睛的RNFL轮廓。扫描圈（直径3.4 mm）RNFL测量（总平均、上级、鼻侧、下侧和颞侧RNFL厚度）（上级、鼻上、鼻下、鼻下、颞下、颞下和颞上）移位不同距离（0.1、0.2、0.3、0.4、0.5、0.6和0.7 mm），并与“参考标准”进行比较，其中扫描圆以视盘为中心。RNFL测量误差计算为（RNFL厚度（（位移））- RNFL厚度结果平均、上级、鼻侧、下侧和颞侧RNFL测量误差分别为2.3 ± 2.0、4.9 ± 4.5、4.1 ± 3.8、6.2 ± 7.6、4.9 ± 4.5、4.1 ± 3.8和6.2 ± 7.6。在0.1 mm扫描圆位移时为3.8 ± 3.5 μ m，在0.7 mm扫描圆位移时为12.1 ± 11.4、27.8 ± 18.4、21.7 ± 18.6、34.8 ± 22.9和15.2 ± 10.7 μ m。中心扫描圆与偏移扫描圆测量的平均厚度和象限RNFL厚度差异有显著性（P < 0.001）。RNFL测量误差随距离的增加而单调增加，且这种变化具有方向依赖性。结论RNFL测量误差随扫描位移的方向和距离而变化。上级和下级RNFL测量值最容易受到扫描位移误差的影响，而平均RNFL厚度最不容易受到影响。获得良好居中的扫描对于OCT中可靠的RNFL测量是必不可少的。Eye（2009）23，1436-1441; doi：10.1038/eye.2008.258; 2008年9月19日在线发表
Objective To study the effect of optical coherence tomography (OCT) scan circle displacement on retinal nerve fibre layer (RNFL) measurement errors using cubic spline models.Methods Forty-nine normal subjects were included in the analysis. In one randomly selected eye in each subject, RNFL thickness around the optic disc was measured by taking 16 circular scans of different sizes (scan radius ranged from 1 to 2.5 mm). The RNFL profile in each eye was constructed with a mathematical model using a smoothing spline approximation. Scan circle (diameter 3.4 mm) RNFL measurements (total average, superior, nasal, inferior, and temporal RNFL thicknesses) obtained from eight directions (superior, superonasal, nasal, inferonasal, inferior, inferotemporal, temporal, and superotemporal) displaced at different distances (0.1, 0.2, 0.3, 0.4, 0.5, 0.6, and 0.7 mm) from the disc centre were then computed by a computer program and compared to the 'reference standard' where the scan circle is centred at the optic disc. RNFL measurement error was calculated as the absolute of (RNFL thickness ((displaced)) - RNFL thickness ((reference standard))).Results The respective mean average, superior, nasal, inferior, and temporal RNFL measurement errors were 2.3 +/- 2.0, 4.9 +/- 4.5, 4.1 +/- 3.8, 6.2 +/- 7.6, and 3.8 +/- 3.5 mu m upon 0.1 mm scan circle displacement, and 12.1 +/- 11.4, 27.8 +/- 18.4, 21.7 +/- 18.6, 34.8 +/- 22.9, and 15.2 +/- 10.7 mu m upon 0.7 mm scan circle displacement. Significant differences of average and quadrant RNFL thicknesses were evident between centred and displaced scan circle measurements (all with P < 0.001). RNFL measurement error increased in a monotonic fashion with increasing distance away from the disc and the change was direction-dependent.Conclusions RNFL measurement error varies with the direction and distance of scan displacement. The superior and the inferior RNFL measurements are most vulnerable to scan displacement errors, whereas the average RNFL thickness is the least susceptible. Obtaining a well-centred scan is essential for reliable RNFL measurement in OCT. Eye (2009) 23, 1436-1441; doi:10.1038/eye.2008.258; published online 19 September 2008