Abstract
Purpose: :
To evaluate image guided laser treatments using multiple imaging formats including optical coherence tomography (OCT) and fluorescein angiography onto the navigated retinal laser system.
Methods: :
We evaluated a new feature to the navigated retinal laser photocoagulation system which allows importation of images from various diagnostic imaging devices including spectral OCT. Once imported into the laser system, a registration tool accessed the image to be aligned with a reference image previously acquired on the navigated laser system. A minimum of 3 landmarks are needed with an average of 6 to overlay the image. A transformation and warping algorithm in the application attempts to scale and rotate the resultant layered image. Visual as well as internal confidence scale was used to determine adequate alignment. The resultant image was displayed and then used to specifically plan laser treatment applications corresponding to the image acquired on the laser delivery system.
Results: :
A total of 10 eyes from 10 patients underwent OCT imaging with the Spectralis instrument (Heidelberg Engineering, Vista, CA). These images were imported into the navigated laser photocoagulation system (Navilas, OD-OS, Teltow, Germany) where a baseline color fundus image was also obtained. The imported OCT image was successfully overlaid and registered onto the color fundus image by selecting 6 reference landmarks allowing treatment plans to be executed. All images were accurately aligned. The treatments were performed in comfortable infrared mode. Post-treatment color fundus photos were taken demonstrating accurate placement of laser applications corresponding to treatment plans.
Conclusions: :
Successful use of external imaging formats to plan and execute retinal laser photocoagulation was demonstrated. Laser treatments may now be custom planned, guided and performed using multiple imaging modalities including OCT. This may provide an alternative to fluorescein angiography guidance of macular laser photocoagulation treatment for diabetic macular edema and retinal edema due to retinal vascular disorders.
Keywords: laser • diabetic retinopathy • image processing