Blood-ocular barrier damage: use of contrast-enhanced MRI

The blood-ocular barrier (BOB) shares similar neuroepithelial origin, microanatomy and functions with the blood-brain barrier. There are many natural (e. g. diabetes, hypertension) or iatrogenic (chemotherapy, retinal photocoagulation) conditions which can cause a BOB breakdown, resulting in visual acuity impairment or loss. The authors examined 42 patients affected by BOB damage in different pathological conditions. All patients previously underwent a conventional fluoroangiographic (FA) study. Nine patients with normal FA exam were evaluated also. Despite normal MRI findings immediately after Gd-DTPA injection, contrast leakage into the vitreous body or into the aqueous fluid was demonstrated in delayed scans (40-50 min after contrast administration), proving the existence of a BOB damage (sensitively 94 %). Although FA exam remains the choice modality in BOB breakdown demonstration, we propose MRI as a useful diagnostic tool when optic media opacity (cataract, haemovitreous, intraocular silicon oil) occurs, preventing direct retinal fundus imaging and/or an early screening tool.