Speeg-Schatz C, Scheiber C, Passard C, Grucker D
Ophthalmology Clinic, University Hospital, Strasbourg, France.
Binocul Vis Strabismus Q. 1998;13(2):105-14.
To improve existing MRI (Magnetic Resonance Imaging) methods of assessing ocular motility in horizontal gaze by using a multi-static fast imaging T2W MRI sequence, preventing patient head motion and convergence of the eyes during the study for the diagnosis and management of complex paralytic strabismus.
A turbo-RARE image of the orbits was acquired in a set plane each time the patient fixed on a virtual image of one of 15 LEDs (Light Emitting Diodes). Positioning and securing the head was by a security cushion with an 8 degree tilt of the 25 cm quadrature head coil. After completion of the study (5 minutes) the MRI images were transferred to a work station and on to a magnetic-video tape to be replayed in cine mode on a PC using standard software. The qualitative analysis was completed by the study of quantitative parameters: visual axis, minor axis of the lens, the lines and angles of the horizontal rectus muscles with the optic nerve and the visual axis. We used digital image analysis to measure the cross-sectional areas of these muscles and also to determine muscle volumes. Twenty normal volunteers and 3 cases of oculomotor palsies were so studied.
The experimental setup allowed us to obtain: 1) rapid (14 s) and high resolution images (256 x 196 x 3 mm); 2) which were free artifacts; 3) with no detectable eye convergence; 4) in which the lateral and medial rectus muscles and anatomical details of the orbit were clearly depicted; 5) from which additional functional information was obtained from the cine loop analysis; 6) wherein the visual axes did not converge during horizontal versions; 7) which permitted horizontal rectus muscle angles to be followed during contraction and relaxation; and 8) allowed the cross-sectional area of the four rectus muscles to be compared during contraction and relaxation (difference of 0.2 cm2).
This method will provide useful functional quantitative information in the evaluation of ocular motility disorders. The procedure is readily clinically applicable
通过使用多静态快速成像T2加权磁共振成像（MRI）序列，改进现有的评估水平注视时眼球运动的MRI方法，在研究过程中防止患者头部移动和眼睛集合，以用于复杂麻痹性斜视的诊断和治疗。
每次患者注视15个发光二极管（LED）之一的虚拟图像时，在设定平面获取眼眶的快速自旋回波图像。通过带有25厘米正交头线圈、倾斜8度的安全垫来定位和固定头部。研究完成后（5分钟），将MRI图像传输到工作站，并转存到磁录像带上，以便使用标准软件在个人电脑上以电影模式回放。通过研究定量参数完成定性分析：视轴、晶状体短轴、水平直肌与视神经及视轴的线条和角度。我们使用数字图像分析来测量这些肌肉的横截面积，并确定肌肉体积。对20名正常志愿者和3例动眼神经麻痹患者进行了此项研究。
该实验装置使我们能够获得：1）快速（14秒）且高分辨率的图像（256×196×3毫米）；2）无伪影；3）无明显的眼睛集合；4）清晰显示外侧和内侧直肌以及眼眶的解剖细节；5）通过电影环分析可获得额外的功能信息；6）水平扫视期间视轴不集合；7）允许在收缩和放松过程中跟踪水平直肌角度；8）能够比较四条直肌在收缩和放松过程中的横截面积（相差0.2平方厘米）。
该方法在评估眼球运动障碍方面将提供有用的功能定量信息。该程序在临床上易于应用。
