Cadera W, Bloom J N, Karlik S, Viirre E
TLC Northwest Eye, Seattle, Wash., USA.
Can J Ophthalmol. 1997 Jun;32(4):250-3.
The pathophysiology of double elevator palsy is poorly understood. We assessed two patients with this condition using magnetic resonance imaging (MRI) to evaluate the appearance of the extraocular muscles.
Cross-sectional study.
Radiology department of a university-affiliated hospital in London, Ont.
Two patients from a private ophthalmology practice who had undergone complete transpositions of the horizontal rectus muscles to treat hypotropia associated with double elevator palsy.
MRI. A volume scanning technique was used to obtain maximum information about the muscles.
Appearance of the extraocular muscles.
In both patients MRI showed decreased volume of the superior rectus muscle on the affected side. The other rectus muscles were normal. This suggested either congenital hypoplasia or paresis of the involved superior rectus muscle. In addition, the full tendon transpositions of the medial and lateral recti did not appreciably change the middle and deep orbital pathways of the transposed horizontal rectus muscles.
MRI may be a useful adjunct to saccadic velocity assessments in differentiating between primary inferior rectus restriction, primary superior rectus paresis and congenital supranuclear elevator deficiency.
双上转肌麻痹的病理生理学机制尚不清楚。我们使用磁共振成像（MRI）对两名患有此病的患者进行评估，以观察眼外肌的表现。
横断面研究。
安大略省伦敦市一家大学附属医院的放射科。
两名来自私人眼科诊所的患者，他们接受了水平直肌完全移位术以治疗与双上转肌麻痹相关的下斜视。
MRI。采用容积扫描技术以获取有关肌肉的最大信息量。
眼外肌的表现。
两名患者的MRI均显示患侧上直肌体积减小。其他直肌正常。这提示受累上直肌存在先天性发育不全或麻痹。此外，内直肌和外直肌的完全肌腱移位并未明显改变移位后的水平直肌在眼眶中部和深部的走行路径。
在区分原发性下直肌受限、原发性上直肌麻痹和先天性核上性上转肌功能不足方面，MRI可能是对扫视速度评估的有用辅助手段。
