频域光相干断层扫描三种不同图像模式测量脉络膜厚度的差异比较

The differences of the choroidal thickness measured by spectral-domain optical coherence tomography in three kinds of imaging modes

目的比较3种不同图像模式测量的脉络膜厚度值差异。方法临床检查确诊的中心性浆液性脉络膜视网膜病变患者20例21只眼（A组）纳入研究。所有患眼视网膜倾斜且与水平线夹角大于5．0°。选取视网膜倾斜角度测量结果为视网膜水平的20例21只眼（B组）作为对照。2组间性别、年龄、等效球镜度数等比较，差异均无统计学意义（t=0．00、-0．345、0．489，P〉0．05）。频域光相干断层扫描增强扫描模式下分别在1：1像素、1：1μm、连续测量3种图像模式下测量其距离黄斑中心凹鼻侧或者颞侧1500“m处的脉络膜厚度。比较1：1像素模式、连续测量模式与1：1／zm模式测量的脉络膜厚度值的差异。结果A组1：1μm、1：1像素、连续测量图像模式测量所得脉络膜厚度分别为（304．81±87．74）、（342．86±91．43）、（307．86±89．35）μm。1：1像素图像模式测得的脉络膜厚度值比1：1μm图像模式测得的脉络膜厚度值显著增加，差异有统计学意义（t=-8．499，P〈0．01）；连续测量图像模式测得的脉络膜厚度值与1：1μm图像模式测得的脉络膜厚度值比较，差异无统计学意义（t=-0．790，P〉0．05）。B组1：1像素图像模式、连续测量图像模式脉络膜厚度测量值与1：1μm图像模式脉络膜厚度测量值比较，差异均无统计学意义（t=-1．521、-1．822，P〉0．05）。结论1：1像素图像模式测量的脉络膜厚度值偏大；1：1μm图像模式测量脉络膜厚度较为准确；连续测量图像模式提供了随访测量脉络膜厚度更方便准确的方法。

Objective To compare the differences in the choroidal thickness at 1500 #m nasal or temporal to the fovea between three measurements of different imaging modes. Methods In this retrospective study, 21 eyes from 20 patients diagnosed with central serous chorioretinopathy （CSC）, whose retinas tilt over 5. 0 degree to the horizontal line were included （retina tilt group）. The control group （retinal horizontal group） also included 21 eyes from 20 individuals whose retinas are horizontal indicated by retinal tilt angle measurement. There were no statistical significance （t=0.00, -0. 345, 0. 489; P〉0.05） in gender, age and spherical equivalent distributions between the two groups. The choroidal thickness at 1500μm nasal or temporal to the fovea was measured by spectral-domain optical coherence tomography （COT） enhanced depth scanning under three modes （1：1 pixel, 1：1 micron and continuous measurement）. The differences of ehoroidal thickness between these three measure modes were analyzed by a paired t test. Results The choroidal thickness was （304.81±87.74）, （342.86±91.43）, （307.86±89.35）μm respectively measured by 1 ： 1 pixel, 1 ： 1 micron and continuous measurement modes in retinal tilt group. The choroidal thickness measured by 1：1 pixel was increased compare to that by 1：1 micron, the difference was statistically significant （t =- 8. 499, P〈0.01）. The choroidal thickness measured by continuous measurement mode was the same of that by 1：1 micron, the difference was not statistically significant （t= -0. 790, P）0.05）. In retinal horizontal group, the choroidal thickness measured by these 3 modes was the same, the difference was not statistically significant （t =- 1. 521, -1.8Z2 ; P 〉 0.05）. Conclusions Spectralis OCT with 1：1 pixel mode exhibits horizontally compressed image, the values of ehoroidal thickness under tilted retinas measured by this condition were significantly greater than the true ones. The choroidal thickness measured by 1：1 micron mode measurement is more accurate. Continuous measurement mode provides more accurate and convenient choroidal thickness measurement during follow up of patients.