Early vitreous changes in experimental proliferative vitreoretinopathy
S. Miglior, H. L. Kain, T. Libondi, R. G. Gonzalez, P. Barnett, J. M. Krauss and H. M. Cheng
Proton magnetic resonance imaging (MRI) was employed to obtain information
on early vitreal changes preceding ophthalmoscopically visible
proliferative vitreoretinopathy. Rabbits were injected close to the
posterior pole with a suspension of 250 000 cultured homologous
fibroblasts. The MRI was carried out using a 1.4-tesla (T) superconducting
imager (at a proton frequency of 61.4 MHz). The images were obtained over a
span of six days, prior to any detection of proliferative vitreoretinopathy
with ophthalmoscopy. As early as two days after injection, an area of
increased spin-spin relaxation time (T2) corresponding to the vitreal
injection site became visible. The MRI observations paralleled in vitro
changes in proton relaxation times (T1 [spin-lattice relaxation time] and
T2) after addition of beta-N-acetylglucosaminidase to the vitreous. Our
data suggest that hyaluronate disruption due to the activity of
fibroblastic enzymes may result in fibroblast dispersion and movement in
the vitreous and that MRI can provide early signs of vitreal changes that
lead to retinal detachment.