动态增强核磁技术对评定甲状腺相关眼病病程的价值

The value of DCE-MRI in assessing the course of thyroid associated ophthalmopathy

目的探讨动态增强核磁技术（DCE—MRI）测量眼外肌参数指标用于评定甲状腺相关眼病（TAO）临床病程的可行性。方法回顾性系列病例研究。选取2011年3月至2012年10月在天津市第一中心医院治疗的136例双眼受累的TAO患者，男性64例，女性72例，年龄24．0～65．0岁，平均年龄（40．5±10．9）岁。根据临床活动度评分（GaS）标准，将136例TAO患者分为活动期组（88例）和非活动期组（48例），40例健康志愿者为对照组。所有受试者行MRI及DCE—MRI眼眶扫描。记录每条眼外肌的信号特点；利用西门子3．0T后处理工作站绘制每条直肌的时间．信号强度曲线（TIC）分析计算参数，并评估相应的诊断价值。参数包括早期强化系数（EEC）、峰值强化系数（Emax）和清除系数（WCsmin）。3组间信号强度分布采用Kruskal—Wallis秩和检验，多组间两两比较采用Nemenyi法检验。3组动态增强核磁技术参数比较（早期强化系数、峰值强化系数和清除系数）采用单因素方差分析，多组间两两比较采用Bonferronit检验。采用受试者_T作特征曲线分析平均EEC、平均Emax和WC5min对TAO的诊断价值。结果活动期组88例患者的高信号患者45例占51．1％，等信号23例占26．1％，低信号20例占22．7％，与非活动期组和健康对照组3组间T。WI不同信号强度眼外肌（高信号、中等信号、低信号）分布比例差异有统计学意义（Х^2=9．20，P〈0．05）。TAO组各条眼外肌的EEC、Emax和WC5min均明显小于健康对照组（P〈0．05），其中TAO活动期组各条眼外肌的EEC分别是0．63±0．06、0．61±0．05、0．56±0．09、0．57±0．09，非活动期组的各条眼外肌的EEC分别是0．49±0．05、0．50±0．08、0．57±0．10、0．55±0．09。TAO活动期组各条眼外肌的Emax分别是1．35±0．09、1．28±0．09、1．21±0．17、1．25±0．10，非活动期组的各条眼外肌Emax分别是1．04±0．06、1．05±0．10、1．20±0．19、1．16±0．11。TAO活动期组各条眼外肌的WC5min分别是0．13±0．03、0．13±0．03、0．13±0．06、0．13±0．03，非活动期组的各条眼外肌WC5min分别是0．08±0．02、0．79±0．03、0．11±0．06、0．09±0．03。非活动期组内直肌和下直肌的EEC、Emax及WC5min与上直肌的WC5min均明显小于活动期组（P〈0．05），两组间外直肌和上直肌的EEC、Emax及外直肌的WC5min比较差异无统计学意义（P〉0．05）。受试者工作特征曲线分析平均EEC、平均Emax和平均WC5min的相应曲线下的面积分别为0．771，0．879，0．898。结论DCE—MRI测量眼外肌参数可显示TAO患者的临床活动情况，可考虑作为TAO活动分期的量化指标。

Objective To explore the feasibility of the semi-quantitative rectus extraocular muscle （EOM） parameters of dynamic contrast-enhanced magetic resonance imaging （DCE-MRI） in assessing the clinical course of thyroid associated ophthalmopathy （TAO）. Methods It was a retrospective case series study. A total of 136 cases of TAO were recruited from March 2011 to October 2012 in the Tianjin the first center hospital including 63 males and 72 females, aged 24.0-65.0 years, with an average age of （40.5±10.9） years. Forty healthy volunteers were recruited as control group （CG）. According to clinical activity score （CAS）, all TAO patients were divided into 2 groups, activity group （AG） and inactivity group （IAG）. MRI and DCE-MRI orbit scan were performed in each subject. Drew time-intensity curves （TIC） by Siemens 3.0 MR （syngo） post-processing workstation. The semi-quantitative parameters of DCE-MRI were calculated. The semi-quantitative paramters based on TIC include early enhancement coefficient （EEC）, maximum enhancement coefficient （Emax） and wash-out coefficient （WC5min）. Kruskal-Wallis H rank test was used for comparing signal intensity among 3 groups, and Nemenyi test for pairwise comparison between groups. The DCE-MRI parameters （EEC, Emax, WC5min,） among groups were compared by one-way ANOVA, and Bonferroni t test is for pairwise comparison between groups. The diagnostic value of mean EEC, mean Emax, WC5min for assessment of the clinical course in TAO was analyzed by ROC curve. Results There were significant difference in signal intensity （SI） of rectus EOM on T2WI among CG, AG and IAG, which is significantly different in 88 cases of AG including 45 cases of high intensity 51.1%, 23 cases of moderate intensity 26.1%, and 20 cases of low intensity 22.7%,compared with CG and IAG. EEC （P〈0.05）, Emax and WC5min values of rectus EOM of TAO group were significantly lower than those of CG（P〈0.05）, which values of rectus EOM of TAO active group of EEC are 0.63±0.06,0.61±0.05,0.56±0.09,0.57±0.09, and values of rectus EOM of TAO inactive group of EEC are 0.49±0.05,0.50±0.08,0.57±0.10,0.55±0.09. The values of rectus EOM of TAO active group of Emax are 1.35±0.09, 1.28±0.09, 1.21±0.17,1.25±0.10, and the values of rectus EOM of TAO inactive group of Emax are 1.04±0.06,1.05±0.10,1.20±0.19,1.16±0.11. The values of rectus EOM of TAO active group of WC5 mi, are 0.13±0.03,0.13±0.03,0.13±0.06,0.13±0.03 and the values of rectus EOM of TAO inactive group of WC5min are 0.08±0.02,0.79±0.03,0.11±0.06,0.09± 0.03. EEC （Х^2=9.20, P〈0.05）, Emax and WC5min values of rectus EOM of TAO group were significantly lower than those of CG （P〈0.05）. EEC, Emax and WC5min, values of medial rectus and inferior rectus EOM of IAG were significantly lower than those of AG（P〈0.05）. WC5min, values of superior rectus EOM of IAG were significantly lower than those of AG （P〈0.05）. There were no differences in EEC and Emax values of lateral rectus and superior rectus EOM between IAG and AG （P〉0.05）. There were no differences in WC5min, values of lateral rectus EOM between IAG and AG （P〉0.05）. The area under the curve （AUC） were 0.771, 0.879, 0.898 for mean EEC, mean Emax, and mean WC5min, respectively. Conclusion The semi-quantitative paramters of DCE-MRI can show the clinical activity of TAO patients and can be considered as the quantitative index of TAO activity staging.