CT眼眶结构定量分析在甲状腺相关性眼病活动性评价中的作用

 目的 通过便于操作的方法分析CT图像眼外肌增粗情况，评估其与甲状腺相关性眼病（TAO）活动性的相关性，以提供客观的评价指标。设计 回顾性病例对照研究。研究对象 116例TAO患者及30例正常对照眼眶CT影像学资料。方法 利用autoCAD软件计算球后2 mm处各条眼外肌横截面积、眼眶面积以及眼球突出度，分析其与临床活动性评分（CAS）的相关性，通过受试者工作特征曲线（ROC）明确其对于疾病活动性的诊断价值。主要指标 眼外肌总横截面积/眼眶面积（OM/TOA）、眼球突出度、CAS评分。结果 TAO组患者球后2 mm处上直肌、下直肌、内直肌、外直肌横截面积以及OM/TOA比值分别为（56.39±22.77）mm²、（43.72±16.63）mm²、（43.51±13.70）mm²、（34.15±7.05）mm²和0.21±0.043，均大于正常对照组的（28.47±2.30）mm²、（22.53±2.5）mm²、（28.21±1.66）mm²、（28.21±1.66）mm²和0.15±0.017（P均<0.001）。OM/TOA比值与CAS评分成正相关（r=0.593，P<0.001），眼球突出度与CAS评分无相关性（r=0.086，P=0.361）。依据ROC曲线下面积，得出上述比值≥0.18时判断TAO处于活动期的诊断效果最优，其敏感度为89.0%，特异度为53.5%（曲线下面积=0.761，P<0.001）。结论 CT图像上球后2 mm处OM/TOA比值作为一种客观的定量指标，可以对TAO的活动性进行判别，且操作相对简单，联合CAS评分，可较准确地评估病情。（眼科，2018, 27： 333-337）

Quantitative analysis of orbit structure on computed tomography to assess the activity of thyroid associated ophthalmopathy

 Objective To analyze the extraocular muscle thickening on computed tomography (CT) images using easy methods and assess its correlation with the activity of thyroid associated ophthalmopathy（TAO） to provide objective evaluation indicators. Design Retrospective case-control study. Participants 116 cases of TAO patients and 30 cases of normal control were included. Method Auto-CAD software was used to calculate the cross-sectional area of eye muscles, total orbit coronal area and exophthalmos at 2 mm behind the eyeball, and its correlation with clinical activity score（CAS） was analyzed. The receiver operating characteristic curve (ROC) was used to determine the diagnostic value of these CT parameters for the disease activity. Main Outcome Measures Orbital extraocular muscle coronal area/total orbit coronal area ratio (OM/TOA ratio), exophthalmos, CAS. Results The cross-sectional area of the superior rectus muscle, inferior rectus muscle, medial rectus muscle, lateral rectus muscle, and the OM/TOA ratio in the TAO group was 56.39±22.77 mm², 43.72±16.63 mm², 43.51±13.70 mm², 34.15±7.05 mm² and 0.21±0.043 respectively. These parameters were significantly greater than that in the normal control group (28.47±2.30 mm², 22.53±2.5 mm², 28.21±1.66 mm², 28.21±1.66 mm² and 0.15±0.017 respectively) (all P<0.001). The OM/TOA ratio was positively correlated with the CAS (r=0.593, P<0.001). There was no significant correlation between the exophthalmos and the CAS(r=0.086, P=0.361). The cutoff value of OM/TOA ratio 0.18 was the best for detection TAO as active, with sensitivity 89.0% and the specificity 53.5% (area under the curve=0.761, P<0.001). Conclusion The OM/TOA ratio at 2 mm behind the eyeball on the CT image can be used as an objective quantitative parameter for assessing the TAO activity. Combined with CAS, it can be used for accurately assessing the disease and guiding treatment. （Ophthalmol CHN, 2018, 27： 333-337）