CT Image In Localization Of Intraocular Foreign Body

Intraocular foreign bodies (IOFBs) is a common ocular trauma. The occurrence rate is very high, the danger to eyesight is serious. Because the foreign body stay lasting influence to the eyeball, in principle all foreign bodies inside the eye need to diagnose early and remove in good time, while attempting to preserve vision and restore ocular architecture. The accurate localization is the important assurance that the foreign body can be remove, preserve vision after an operation. The aim to remove IOFBs is not only to remove the IOFBs from eyeball, but also to protect and restore vision after IOFBs were removed by operation, and it's more important to patients with IOFBs. The localization is more accurate, the damage of the eyeball in operation is probably more small and the vision after operation is probably more good. CT scans is one of best method that shows the foreign body. It can offer very intuitionistic image data for clinic, help to design the operation scheme clinically in time, carry on the surgical operation accurately.Objective: By comparing the result of CT scans and X-ray in exam patients with IOFBs, to evaluate the value of Spiral CT scans in the diagnosis and treatment of IOFBs.Materials and Methods: Between February 6, 2006 and September 30, 2007 treated in Shenzhen Hospital attach Peking University. 34 cases with intraocular foreign bodies in single eye,25 of them were male, 9 of them were female, ages ranged from 8-53, with an average of 33.7 years old. All cases had vitreous opacity, 28 cases had traumatic cataract, 2 cases had retinal detachment, 1 case had endophthalmitis. The result were evaluated, compared with the type, location and amount of intraocular foreign bodies found in operations.Result: Multi-slice Spiral CT(MSCT) detected 34 cases, 23cases of metallic IOFBs with actinomorphic constructed defect, CT value between 1000 and 1500HU. 11 cases of non-metallic IOFBs, CT value between 100 and 180HU. X-ray exam detected 23 cases of single IOFBs and no multi IOFB. 20 cases of metallic IOFBs and 5 cases of non-metallic IOFBs. Operation: 32 cases were found foreign bodies in operations and 2 cases of ruptured globe were treated by enucleation. The types of IOFBs: 23 cases within pieces of metal, 7 cases within pieces of wood, 2 cases within pieces of glass, 2 cases within pieces of stone. The detective accuracy rate that examed by MSCT were better than X-ray. The detective accuracy rate of MSCT was 94.12%, and location accuracy rate was 100%. The detective accuracy rate of X-ray was 73.53%. there were significant difference between two techniques in statistics.CT value of foreign bodies: metal foreign bodies between 500-3000Hu(铜: 722-3071Hu, steel: 2491-3273Hu,铝: 371-847 Hu); non-metal foreign bodies between 95-400Hu(chinese: 219-418Hu, wood: 21-77Hu, bamboo: 0-100Hu, glass: 906-910Hu, stone: 750-900Hu), compare with CT value of normal eyes tissue: lens between 85-105Hu, vitreous between 17-24Hu, eye ball between 50-65Hu, optic nerve between 45-55Hu.Conclusion: Multi-slice Spiral CT is a better imaging method to detect and localize intraocular foreign bodies accurately. It gains an advantage over X-ray to diagnosis multi foreign bodies especially. Multi-slice Spiral CT can offer very intuitionistic image data for clinic, and help to make the surgery more accurately and successful.