Cullen Cheryl, Kendall Edward, Cui Jie, Colleaux Kevin, Grahn Bruce
Department of Small Animal Clinical Sciences, Western College of Veterinary Medicine, University of Saskatchewan, Saskatoon, Canada.
Graefes Arch Clin Exp Ophthalmol. 2002 May;240(5):393-402. doi: 10.1007/s00417-002-0434-6. Epub 2002 Apr 3.
The study was performed to determine (1) whether intravitreous ferromagnetic foreign bodies (FBs) are sufficiently mobile in a magnetic field to induce acute injury in vivo, and (2) whether the length of time from implantation of the intravitreous FB affects mobility.
A 3 mm x 0.72 mm magnetic FB (MFB) and a non-magnetic metallic FB (NMFB) of similar dimensions were surgically implanted into the right and left eyes, respectively, of 20 New Zealand white rabbits. On days 0 (FB implantation) and 30, all rabbits underwent computed tomography (CT) prior to and immediately following exposure to a 1.5-tesla (T) magnetic field. Pre- and post-magnetic field CT image FB angles and distances, together with ophthalmic examinations, were used to assess FB mobility. Rabbits were killed at 31 days. The globes were processed for light microscopy (LM) and scanning electron microscopy (SEM).
Angle measurements revealed that the MFBs developed significant angular motion and were scattered more widely than NMFBs on the day of FB implantation and 30 days later, although the angular motion and scatter of MFBs were less on day 30. There were no significant differences among distance measurements for MFBs or NMFBs on or between days 0 and 30. Throughout the 30-day study, ophthalmic examinations revealed dorso-ventral FB movement and focal vitreous degeneration and retinal hemorrhage within both MFB- and NMFB-containing globes. Mild vitreous hemorrhage was noted around a NMFB. Focal retinal degeneration was confirmed by LM ( n=1 MFB). SEM revealed intravitreous erythrocytes and spindle cells adjacent to all FBs examined.
(1) Angle measurements show that MFBs are significantly mobile when exposed to a 1.5-T magnetic field on the same day as FB implantation and 30 days later. (2) Angular mobility of MFBs is less at 30 days. (3) Magnetic field exposure did not induce ocular injury in MFB-containing globes. (4) Intravitreous metallic FB retention induces ocular pathologic changes.
本研究旨在确定：（1）玻璃体内铁磁性异物（FBs）在磁场中是否具有足够的移动性，从而在体内诱发急性损伤；（2）玻璃体内FB植入后的时间长短是否会影响其移动性。
将一个3毫米×0.72毫米的磁性FB（MFB）和一个尺寸相似的非磁性金属FB（NMFB）分别通过手术植入20只新西兰白兔的右眼和左眼。在第0天（FB植入日）和第30天，所有兔子在暴露于1.5特斯拉（T）磁场之前和之后立即进行计算机断层扫描（CT）。利用磁场前后CT图像中的FB角度和距离，以及眼科检查来评估FB的移动性。在第31天处死兔子。将眼球进行处理以进行光学显微镜（LM）和扫描电子显微镜（SEM）检查。
角度测量显示，在FB植入日及30天后，MFB产生了显著的角向运动，并且比NMFB散布得更广泛，尽管MFB在第30天的角向运动和散布程度较小。在第0天和第30天或这两天之间，MFB或NMFB的距离测量结果没有显著差异。在整个30天的研究中，眼科检查显示，在含有MFB和NMFB的眼球内均出现了FB的背腹向移动以及局灶性玻璃体变性和视网膜出血。在一个NMFB周围观察到轻度玻璃体出血。通过LM（n = 1个MFB）证实了局灶性视网膜变性。SEM显示，在所有检查的FB附近均有玻璃体内红细胞和梭形细胞。
（1）角度测量表明，在FB植入日及30天后，当暴露于1.5-T磁场时，MFB具有显著的移动性。（2）MFB在第30天的角向移动性较小。（3）磁场暴露未在含有MFB的眼球中诱发眼损伤。（4）玻璃体内金属FB的存留会诱发眼部病理改变。
