Dixon技术在甲状腺相关性眼病早期视神经改变评估中的价值

The value of Dixon in the evaluation of early optic nerve changes in patients with thyroid-associated ophthalmopathy

目的:探讨Dixon技术在甲状腺相关性眼病(thyroid-associated ophthalmopathy,TAO)早期视神经改变评估中的价值。方法:回顾性分析28例TAO患者和15例健康志愿者的临床和影像学资料。测量并比较两组视神经信号强度比值(signal intensity ratio,SIR)、视神经含水量(water fraction,WF)以及视力的差异。采用Spearman’s相关分析评估病例组视神经SIR、WF值与临床参数的相关性。使用受试者工作特征曲线评估视神经SIR、WF值鉴别TAO与健康对照组视神经的效能。结果:TAO组视力显著低于对照组(P=0.024),视神经SIR值和WF值均显著高于对照组(P=0.008;P=0.003)。TAO组视神经SIR值和WF值均与临床活动度评分呈正相关(r=0.369,P=0.005;r=0.420,P=0.001)。以WF值>0.914为阈值判断视神经异常,可获得最优的鉴别效能及特异度(曲线下面积=0.694,敏感度35.7%,特异度93.3%)。联合WF值>0.914和SIR值>1.903判断视神经异常,鉴别效能及敏感度进一步提高(曲线下面积=0.729,敏感度75.0%,特异度63.3%)。结论:Dixon技术可用于评估TAO早期视神经改变。

Objective:To detect the value of Dixon in evaluating early optic nerve changes in the patients with thyroid-associated ophthalmopathy(TAO).Methods:The clinical and imaging data of 28 consecutive TAO patients and 15 healthy controls were retrospectively analyzed.Signal intensity ratio(SIR),water fraction(WF)of optic nerve and visual acuity were collected and compared between TAO and healthy groups.The correlations between the SIR and WF value of optic nerve and clinical indicators were analyzed using Spearman’s correlation analysis.Receiver operating characteristic curve analysis was applied to assess the discriminating performance of SIR and WF value.Results:TAO group had significantly lower visual acuity and higher SIR and WF values of optic nerve than those of healthy group(P<0.05).SIR and WF value of optic nerve correlated positively with clinical activity score(r=0.369,P=0.005;r=0.420,P=0.001).Setting a cut-off WF value of 0.914 enabled optimal efficiency and specificity for discriminating optic nerves between TAOs and HCs(area under curve,0.694;sensitivity,35.7%;specificity,93.3%).Combining SIR and WF values of optic nerves,discriminating efficiency and sensitivity were further improved(area under curve,0.729;sensitivity,75.0%;specificity,63.3%).Conclusion:Dixon technique is suggested to be used in the evaluation of early optic nerve changes in TAO patients.