应用HR—MRI对正常人眼球容积及眼外肌测量的研究

Study on normal ophthalmic tissues among ocular volume and extraocular muscles structure measurement by high-resolution MRI

目的应用HR—MRI技术对正常人眼球容积及眼外肌进行活体生物测量，获取在活体状态下正常人眼球容积及眼外肌的精确数值，为眼科研究、教学及临床诊断提供参数数据。方法临床实验分析研究。收集2012年11月至2013年12月正常受试者100名（200只眼眶），其中男性50名，女性50名，行HR—MRI眼眶扫描，应用图像处理软件进行相关参数测量眼球容积及眼外肌肌腹最大径层面的水平径及垂直径。结果玻璃体腔容积（4．51±0．26）cm3，与“眼科测量正常值”比较，差异无统计学意义（P=0．148）；球内总容积、前房容积、晶状体容积分别为（5．05±0．21）cm3、（0．24±0．26）cm3、（0．23＋0．14）cm3，与“眼科测量正常值”比较，差异有统计学意义（P〈O．01）。正常人两侧眼外肌对称，最大径线层面各眼外肌短径：下直肌〉内直肌〉上直肌〉外直肌，长径：外直肌〉内直肌〉上直肌〉下直肌。结论HR—MRI可较好地应用于活体眼球容积及眼外肌肌腹的测量，并可与“眼科测量正常值”进行对照；判断眼外肌可利用双侧眼外肌对称性及眼外肌粗细规律来判断。

Objective To measure the ocular volume and extraocular muscles of healthy people using the HR-magnetic resonance imaging （MRI） technology, to provide parameters support for eye research, teaching and diagnosis. Methods The study collected 100 cases of normal subjects （200 eyes） from November 2012 to December 2013, 50 male cases, 50 female cases, accepted line HR-or- bital MRI, and image processing software was applied to morphology and statistical analysis. The ex- traocular muscles, muscle belly level horizontal diameter and maximum diameter vertical diameter were measured. Results The volume of the vitreous cavity （4.51±0.26）cm3 was little different from the anatomic normal value （P=0.148）; The volumes of the ocular globe, the anterior chamber, and the lens cavity were （5.05±0.21）cm3, （0.24±0.26）cm3, （0.23±0.14）cm3, with no statistic differences com- pared with those of the anatomic normal values. The extraocular muscles of normal Chinese were symmetrical on the two sides. The relationships of the short diameters of extraocular muscles in the Maximum Planes were： IR〉MR〉SR〉LR. That of the long diameters of extraocular muscles were： IR〉 MR〉SR〉IR. Conclusions MRI can be used for measuring ocular volume and sizes of extraocular muscles. Compared with the anatomic normal value, the sizes of extraocular muscles can also be as- sessed by the symmetry on the two sides and by observing the usual rule of extraocular muscles.