Experimental Study of CT and MRI Detection of Intraocular Non-Metallic Foreign Bodies

Objective To discuss the value and limitation of CT and MRI in the detection of intraocular non metallic foreign bodies. Methods Eight kinds of non metallic foreign bodies (3-5mm) including wood (dry and wet),bamboo (dry and wet),cotton thread,plastic,glass and stone, were randomly lodged into 20 orbital regions of 10 dogs (intraocularly and extraocularly). CT and MRI scan were performed. Results Thirty of the 32 foreign bodies could be detected by computed tomography, the other two foreign bodies which could not be seen on CT films were wet wood and cotton thead. MRI was performed to the two dogs with the two foreign bodies and could detect them. Conclusion CT can detect most of the non metallic foreign bodies,but has some difficulties with medium density foreign bodies. MRI has a lot of advantages in dealing with these foreign bodies, which is a necessary complement to computed tomography.