Magnetic resonance imaging versus bone scan for assessment of vascularization of the hydroxyapatite orbital implant.

We prospectively studied 10 patients who were status postenucleation and primary placement of the hydroxyapatite orbital implant. Both the technetium-99m bone scan and gadolinium-enhanced magnetic resonance images (MRI) were obtained on the same day at variable time points in the postoperative period in order to assess the degree of vascularization. Up to 78% of the bone scans were interpreted as being completely vascularized, while only 10% of the corresponding MRI scans were consistent with complete vascularization. Cost analysis showed that MRI was cost-effective imaging modality. We conclude that contrast-enhanced MRI provides a more accurate assessment of vascularization of the hydroxyapatite orbital implant when compared to bone scan.