Prummel M F, Gerding M N, Zonneveld F W, Wiersinga W M
Department of Endocrinology & Metabolism, Academic Medical Center, University of Amsterdam, The Netherlands.
Clin Endocrinol (Oxf). 2001 Feb;54(2):205-9. doi: 10.1046/j.1365-2265.2001.01220.x.
Two-thirds of patients with Graves' ophthalmopathy (GO) respond to immunosuppressive treatment (prednisone or orbital irradiation), but one-third do not respond. Responders are likely to be in the active, oedematous stage of the eye disease, nonresponders in the inactive fibrotic stage. Clinical distinction between the two stages can be difficult. Quantitative magnetic resonance imaging (MRI) might be helpful in this respect, as T2 relaxation times are longer in oedematous than in fibrotic tissues.
Prospective study on quantitative orbital MRI in healthy subjects and patients with moderately severe GO, evaluating T2 relaxation time of extraocular muscles (EOM): (a) in patients vs. controls, and (b) in patients, as a predictor of outcome to orbital irradiation.
Nine healthy volunteers and 64 consecutive patients with moderately severe untreated GO, who were euthyroid for > or = 2 months and qualified for orbital irradiation. T2 relaxation times were measured at the site of the largest diameter in all eight EOM of each subject. Baseline T2 values in patients were related to outcome of radiotherapy, as assessed by an independent observer 6 months later according to predefined criteria.
T2 relaxation times of the eight EOM were longer in GO patients than in controls: median [range] 126 [52--250] vs. 88 [50--126] msec; P = 0.003. Per subject the single eye muscle with the longest T2 time was selected to represent active inflammation (excluding the lateral muscles for technical reasons). Again patients were different from controls: 160 [68--250] vs. 103 [86--115] msec, P < 0.001. In the group of 34 responders to subsequent radiotherapy, these T2 times tended to be longer than in the 30 nonresponding patients: 168 [108--250] vs. 138 [68--216] msec, P = 0.07. Using a cut-off value of 130 msec (derived from a receiver-operator-characteristics curve) a positive predictive value of 64% and a negative predictive value of 92% for the outcome of radiotherapy was calculated.
Quantitative orbital magnetic resonance imaging was found to be less accurate in predicting successful outcome of radiotherapy than expected. It seems more useful in detecting the fibrotic end-stage than the active stage of Graves' ophthalmopathy. It is therefore of limited use in the decision whether or not to apply immunosuppression in patients with moderately severe Graves' ophthalmopathy.
三分之二的格雷夫斯眼病（GO）患者对免疫抑制治疗（泼尼松或眼眶照射）有反应，但三分之一的患者无反应。有反应者可能处于眼病的活动期、水肿期，无反应者处于非活动纤维化期。这两个阶段的临床区分可能很困难。定量磁共振成像（MRI）在这方面可能会有帮助，因为水肿组织中的T2弛豫时间比纤维化组织中的更长。
对健康受试者和中度严重GO患者进行定量眼眶MRI的前瞻性研究，评估眼外肌（EOM）的T2弛豫时间：（a）患者与对照组相比；（b）在患者中，作为眼眶照射结果的预测指标。
9名健康志愿者和64例连续的中度严重未经治疗的GO患者，这些患者甲状腺功能正常≥2个月且符合眼眶照射条件。在每个受试者所有8条EOM的最大直径部位测量T2弛豫时间。患者的基线T2值与放疗结果相关，6个月后由一名独立观察者根据预定义标准进行评估。
GO患者8条EOM的T2弛豫时间比对照组更长：中位数[范围]126[52 - 250]毫秒对88[50 - 126]毫秒；P = 0.003。每个受试者选择T2时间最长的单眼肌肉代表活动性炎症（出于技术原因排除外侧肌肉）。患者与对照组再次存在差异：160[68 - 250]毫秒对103[86 - 115]毫秒，P < 0.001。在随后接受放疗的34名有反应者组中，这些T2时间往往比30名无反应患者的更长：168[108 - 250]毫秒对138[68 - 216]毫秒，P = 0.07。使用130毫秒的临界值（源自受试者工作特征曲线），计算出放疗结果的阳性预测值为64%，阴性预测值为92%。
发现定量眼眶磁共振成像在预测放疗成功结果方面不如预期准确。它在检测格雷夫斯眼病的纤维化终末期比活动期似乎更有用。因此，在决定是否对中度严重的格雷夫斯眼病患者应用免疫抑制方面，其用途有限。
