High-resolution magnetic resonance imaging evaluation of blood-retinal barrier integrity following transscleral diode laser treatment

E. L. Arrindell, J. C. Wu, M. D. Wolf, S. Nanda, D. P. Han, E. C. Wong, G. W. Abrams, W. F. Mieler and J. S. Hyde
Department of Ophthalmology, Medical College of Wisconsin, Milwaukee.

OBJECTIVE: To compare the effects of contact transscleral diode laser treatment and retinal cryotherapy on blood-retinal barrier integrity with the use of high-resolution magnetic resonance imaging techniques with constant infusion of gadolinium-diethylenetriaminepentaacetic acid (Gd-DTPA). METHODS: Transscleral diode laser photocoagulation and retinal cryotherapy were used to treat equivalent areas of the inferior retinal periphery of pigmented rabbits. Magnetic resonance imaging time-course studies with measurement of signal enhancements due to Gd-DTPA leakage were conducted 2 and 15 days following treatment. RESULTS: Two days following treatment, cryotherapy-treated eyes exhibited a mean (+/- SD) effective Gd-DTPA permeability coefficient of 4.6 +/- 0.8 x 10(-6) cm/s; in comparison, diode laser-treated eyes exhibited 1.6 x 1.4 x 10(-6) cm/s effective permeability. Significant decreases in the effective permeability were also noted 15 days after treatment in both groups. CONCLUSIONS: Transscleral contact probe diode laser photocoagulation induces less disruption of the blood-retinal barrier than does conventional cryotherapy. In addition, the continuous infusion method of Gd-DTPA delivery is a reliable and easily interpretable alternative to the commonly used bolus injection approach.