目的：报告1例甲状腺相关性眼病的非典型CT扫描表现。 方法：一位64岁的中国女性出现复视3mo，无视力模糊。14a前她曾患甲状腺功能亢进症伴多结节甲状腺肿并行甲状腺切除术。眼科检查发现双眼下斜视并向上注视受限。左眼red desaturation并Ⅰ级相对性瞳孔传入障碍。 T3，T4和促甲状腺激素(thyroid stimulating hormone,TSH)正常。 TSH受体、抗体水平高，与Graves病一致。 磁共振成像(magnetic resonance imaging,MRI)显示双下直肌弥漫性增大，肌腱受累。 结果：给予几周期静脉注射甲基强的松龙继之以口服强的松后视力无提高，反之继续下降。行左眼眼眶减压术，术后其左眼视力有所改善。 结论：有肌腱受累的眼外肌增大不能排除甲状腺相关性眼眶病(thyroid assciated orbitopathy, TAO)的可能。

AIM: To report an atypical CT scan finding of thyroid eye disease. METHODS: A 64 years old Chinese lady presented with diplopia for 3 months without blurring of vision. She had been diagnosed as thyrotoxicosis with multinodular goitre 14 years back and thyroidectomy was done 14 years ago. Eye examination revealed both eye hypotropia with restricted up gaze movement. There was presence of red desaturation on her left eye with grade I relative afferent pupillary defect. Hormone profile showed normal triiodothyronine (T3), tetraiodothyronine (T4) and thyroid stimulating hormone(TSH). TSH receptor antibody was high which was consistent with Graves’disease. Magnetic resonance imaging(MRI) showed diffused enlargement of both inferior rectus muscle with tendon involvement. RESULTS: Few cycle of intravenous methylprednisolone followed by oral prednisolone were given but left eye vision deteriorated in spite of medical treatment. Left eye orbital decompression was done and her left eye visual acuity was improved after the surgery. CONCLUSION: Extraocular muscle enlargement with tendon involvement does not exclude possibility of thyroid associated orbitopathy (TAO).