Ocular and cerebral metastases in the VX2 rabbit tumor model: contrast-enhanced MR imaging

Ocular and cerebral metastases developed after the inoculation of a VX2 tumor cell suspension into the internal carotid artery of 15 rabbits. The hematogenous spread of tumor cells resulted in ocular metastases in 13 of 15 animals (86.7%) and cerebral system metastases in 14 of 15 animals (93%). Magnetic resonance (MR) imaging with Gd-DTPA demonstrated early disruption of the blood-ocular barrier and blood-brain barrier 5-7 days after infusion of tumor cells. Quantitative assessment of contrast enhancement revealed a mean increase in signal intensity of 145% +/- 51% in the anterior chambers, 102% +/- 70% for choroidal metastases, and 51% +/- 29% for central nervous system (CNS) metastases. These results indicate that contrast-enhanced MR imaging can be used to demonstrate a loss of blood-ocular barrier integrity that is similar to the breakdown of the blood-brain barrier associated with metastatic tumors to the CNS and eye.