眼眶磁共振成像T2-Mapping诊断活动性Graves眼病的临床应用

The diagnostic value of orbital magnetic resonance imaging T2-Mapping in patients with active Graves＇ ophthalmopathy

目的 探讨眼眶磁共振成像（MRI）在诊断活动性Graves眼病（GO）以及评估糖皮质激素疗效中的临床价值。方法 2011年3月至2012年6月同济医院内分泌科和眼科收治的106例GO患者，以临床活动性评分（CAS）≥3或CAS〈3分为活动性GO或非活动性GO，眼眶MRI T2-Mapping测量眼外肌T2弛豫时间（T2 relaxation time, T2RT）（ms）和肌面积（mm2 ），分析T2RT和肌面积与CAS、眼球活动度、复视、突眼度、视力和眼内压等的相关关系。比较甲基强的松龙（甲强龙）治疗中-重活动性GO前后T2RT和肌面积变化。结果 活动性GO平均T2RT（88.9±13.8）和平均肌面积（58.1±23.8）大于非活动性GO（分别为80.6±10.0和46.2±18.6, P〈0.01），两者大于正常眼对照组（分别为76.2±4.7和30.3±6.1, P〈0.01）， 最大T2RT（107.8±14.2）与最大肌面积（89.9±29.8）正相关（P〈0.01），两者分别与CAS、眼球活动度降低、复视、突眼度增加及视力下降正相关（P〈0.01），与眼球自发性痛、眼球运动痛、眼睑红斑及眼内压增高负相关或无相关（P〉0.05）。T2RT延长的中-重GO患者，即使1≤CAS〈3，对甲强龙治疗仍有积极反应。甲强龙改善眼部症状的同时，显著降低了最大T2RT（99.0±17.6）和最大肌面积（70.2±25.1）。结论 T2RT延长，尤其在同一条眼外肌上伴肌面积增大，是眼外肌急性炎症的标志，联合CAS可提高诊断敏感度，并预测甲强龙的疗效。

Objective To study the clinical value of orbital magnetic resonance imaging（MRI） in diagnosis and making a judgment about the curative effect of glucocorticoid in patients with Graves＇ ophthalmopathy （GO）. Methods A total of 106 patients with GO were divided into active GO group or inactive GO group according to whether clinical activity score（CAS） ≥3 or not, respectively. T2 relaxation times（T2RTs） （ms） and areas（ mm2 ） of four extra-ocular muscles （EOMs） （superior, inferior, medial, and lateral rectus） were directly measured by MRI T2-Mapping. Correlation analysis of T2RTs and areas with eyeball motility, diplopia, exophthalmus, visual acuity and intraocular pressure （ IOP ） were also performed. The T2RTs and areas of EOMs before and after intravenous methylprednisolone（ iv MP） pulse therapy were recorded, respectively. Results The mean T2RTs （ 88.9 ± 13.8 ） and mean areas（ 58.1 ± 23.8 ） of EOMs in active GO were significantly greater than those in inactive GO （80.6 ± 10.0 and 46.2 ± 18.6, respectively）, bing both significantly greater than those in volunteers with normal eyes （ 76.2 ± 4.7 and 30.3 ± 6.1, respectively） （ P〈0.01 ）. Maximal T2RTs and maximal areas of EOMs showed significant positive correlation（ P〈0.01 ） , and both were positively correlated weakly with CAS, reduced movement of eyeball, diplopia, exophthalmus and loss of visual acuity （P〈 0.01 ）. On the contrary, maximal T2RTs and maximal areas of EOMs showed negative correlation or no correlation with spontaneous retrobulbar pain, painful eye movement, redness of eyelids and abnormal IOP. Even if 1 ≤CAS〈3, ophthalmic symptoms and signs also showed a positive responses to iv MP in patients with moderate to severe GO as long as prolonged T2RTs occurred at least in one of EOMs. The maximal T2RTs, maximal areas, mean T2RTs and mean areas of EOMs were significantly decreased at the end of iv MP treatment, meanwhile ophthalmic symptoms and signs were obviously improved. Conclusions Prolonged T2RTs, especially accompanied by enlarged area on the identical EOMs is an remarkable symbols of acute inflamed muscles. The findings suggested that the use of prolonged rT2RTs can improve diagnostic sensitivity and predict the curative effect of iv MP in patients with moderate to severe GO and CAS ≥ 1.