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Magnetic resonance imaging findings of microphthalmos
Abstract
Purpose: To evaluate MR imaging findings of congenital micrhthalmos.
Materials and Methods: MR imaging findings of 15 cases with microphthalmos confirmed by follow-up results were retrospectively analyzed. MR imaging was performed in 15 patients, in which 3 cases were performed with postcontrast T1-weighted imaging.
Results: Among the 15 cases, unilateral microphthalmo was found in 13 cases, while bilateral microphthalmoes was found in the other two. Small eyeball with posterior choroidal defect at the site of the optic disk was found in 10 eyes among the total of 17 eyes (15 cases, 17 eyes)，accompanied a cyst with long T1 long T2 signal outstretching from the defect. For the other cases, one congenital microphthalmos with orbital cyst, five microphthalmoes with PHPV, and one simple microphthalmos were found.
Conclusions: MRI can display the microphthalmos and other dysplasia in orbit, contributing to diagnosis and therapy.
Keywords: microphthalmos, magnetic resonance imaging, diagnosis
先天性小眼球(microphthalmos)临床较少见，其影像学表现特别是磁共振表现报道较少，本文总结2004年～2006年在我院就诊的15例先天性小眼球磁共振表现，初步探讨其诊断和鉴别诊断要点,为临床诊断和治疗提供依据。
材料和方法
1 材料：收集2004年～2006年在我院就诊的15例（17只眼）先天性小眼球资料，其中男9例，女6例，年龄最小6个月，最大53岁，中位年龄4岁。发生于一侧眼球13例，发生于两侧眼球3例。主要临床表现：瞳孔发白5例，视物不清4例，斜视3例，视物不清伴斜视1例，眼内陷、角膜发灰1例，自幼眼睁不开1例。
2 MRI检查方法：采用GE Signa twinspeed 1.5T MR扫描仪、相控阵头线圈和/或眼表面线圈，小于等于5岁的病人在扫描前半小时口服水合氯醛在睡眠状态行MRI检查，对大于5岁者瞩扫描过程中安静、闭目，扫描时均采用仰卧位，用海绵垫对头部进行固定。15例行平扫，3例还行增强扫描。15例使用头线圈，1例还同时使用眼表面线圈。采用快速自旋回波序列横断面T1WI、T2WI，冠状面及斜矢状面T1WI，T1WI TR/TE：600/11.1 ms，T2WI TR/TE：3000/120 ms，层厚4.0mm，层间距0.5mm， FOV 18 cm×18cm，矩阵 288×224，激励次数 2，带宽 20.8KHz。横断面和斜矢状面基线平行于视神经长轴方向，冠状面垂直于额叶底部，常规采集12层。
结 果
1、小眼球伴视乳头缺损10只眼，MRI表现（图1）为眼球体积小，视乳头区眼球壁不连续，相应位置可见一长T1长T2信号囊样结构突出于眼球之外，并与视神经相连，3例行增强扫描者，囊样结构均未见强化。囊样结构呈三角形2例，圆形1例，呈以窄颈与眼球相连的类圆形7例；位于视盘区正后方8例，位于视盘和视神经下方1例，位于视盘区后方视神经上下两侧1例。囊样结构小于眼球体积者9例，囊样结构大于眼球体积者1例。伴视网膜脱离3例。伴晶体改变8例，其中晶体体积增大、变凸6例，晶体体积减小、形态不规则2例。患侧眶腔减小6例，扩大2例，体积无明显改变2例。
2、小眼球并眶内囊肿1只眼，MRI表现（图2）为眼球体积明显减小，失去正常形态，呈短T2信号，晶体结构未见，眶内可见一体积较大不规则形囊样结构填充，视神经明显变细。
3、小眼球伴永存原始玻璃体增生症（PHPV）5只眼，MRI表现（图3）为眼球体积小，晶体后方与视盘之间可见管状或圆锥状软组织影(Cloqet’s管),在T1WI和T2WI上与玻璃体相比均呈低信号。1例同时使用头线圈和眼表面线圈，后者显示病变形态和边缘更清晰。
4、单纯性小眼球1只眼，MRI表现（图4）为眼球体积略小，眼球壁完整，晶体减小，形态不规则，前房变浅。
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