Magnetic resonance imaging assessment of fibrovascular ingrowth into porous polyethylene orbital implants

Abstract

To evaluate fibrovascular ingrowth into porous polyethylene orbital implants, using serial gadolinium (Gd)-enhanced magnetic resonance imaging (MRI). 40 rabbits were divided into two groups, according to the surgical techniques used. Group 1 underwent enucleation of one eye and Medpor implantation, group 2 underwent evisceration and Medpor implantation. All subjects from each group were examined via MRI, and the implants were assessed histologically on the first, second, fourth and eighth postoperative weeks. The degree to which fibrovascular ingrowth occurred was then assessed by measuring the Gd-enhanced portion via MRI, as well as by histologic examination. There was a significant correlation between the enhanced area on MRI and the fibrovascularized area observed upon histological examination in the two study groups (group 1: r = 0.850 P < 0.001, group 2: r = 0.788, P < 0.001). The area enhanced on MRI was 2.70% smaller in mean value than the fibrovascularized area observed upon histological examination. There was no differences in fibrovascular ingrowth between group 1 and 2. It was also found that there was no differences between the two groups with regard to the enhanced areas on MRI. Gd-enhanced MRI study proved to be an excellent method for the assessment of fibrovascular ingrowth into the Medpor orbital implants, after both enucleation and evisceration.