Comparison among the imaging characteristics of the intravitreous wooden foreign body in rabbits

Objective: The intraocular foreign bodies (IOFBs) belong to the special ocular trauma. Diagnostic values (ultrasonography, CT/computed tomography and MRI/magnetic resonance imaging) of different imaging technologies for IOFBs in rabbit vitreous body were evaluated for clinical diagnosis. Methods: A total of 240 healthy rabbits were involved, 192 receiving the wooden IOFBs (f = 0.2 mm; different in lengths, materials and moisture states) implantation in the right vitreous. Imageological diagnosis was conducted 2 h, 2 weeks and 4 weeks after the surgery with the characteristics recorded and compared. Subsequently, the right eyebulb was extracted for pathological examination. Results: The detected IOFBs were punctate or linear low signals on MRI and showed strong echo of the light spot on sonogram. For 192 IOFBs, the detection rates were 49.5% and 71.4% for MRI and ultrasonography, respectively, with the minimum detectable length of 0.5 mm. The detection rates increased with the length. The detection rates of ultrasonography were significantly higher than those of MRI towards dry pine and China rose (P<0.05). Length was the major factor affecting the MRI detection rates, while the ultrasonography was unaffected by the length, material and moisture state. Detected diameters by MRI (0.227±0.045 mm) and the ultrasonography (0.250±0.050 mm) were extremely different from the actual diameter (P<0.001). Complication detection rates of IOFBs (Length = 2 mm) at 2 h, 2 w, and 4 w after the implantation among MRI, CT and ultrasonography differed insignificantly. Conclusion: MRI and ultrasonography were effective in diagnosing the IOFBs in rabbit ocular.