Abstract
Purpose::
To describe advantages of enhanced Fourier domain optical coherence tomography (FD-OCT) imaging by using multiple scan averaging in retinal diseases.
Methods::
A prototype high-speed OCT system was fabricated for patient examinations based on FD-OCT. The system has a sensitivity of 98 dB, an air axial resolution of 6.1 µm, and an acquisition rate of ~18,700 axial scans per second. A set of repetitive 12 B-scan images at identical retinal location were averaged using custom software after rejecting some images that contain lateral eye motion to enhance FD-OCT imaging. .The averaged FD-OCT image was compared with single FD-OCT scan and conventional OCT images.
Results::
One hundred one eyes of 84 patients with various retinal diseases that involve the macula were examined, and 483 set of scans were performed. Noise reduction was effective by averaging more than four images. In 406 of 483 set of scans (84.1%), effective amount of image were able to be acquired. In general, the boundaries of each retinal layer became more clearly defined. Especially, highly reflective four lines in the photoreceptor and RPE-BM-choriocapillaris complex are better discernible. Averaged images successfully depicted the structures that could not be clearly identified in a single FD-OCT image due to various reasons, such as opaque media and retinal pathologies. They enhanced especially the fine structures and pathological changes in the photoreceptor layers and sub-RPE lesions in unfavorable conditions.
Conclusions::
Multiple scan averaging FD-OCT imaging is an easy and practical method to improve retinal image quality. This image processing technique has the potential to enhance the utility of FD-OCT-based instrument, thereby facilitating the interpretation of tomographic pathological features and contributing to the improvement of diagnosis and management of retinal disease.
Keywords: imaging methods (CT, FA, ICG, MRI, OCT, RTA, SLO, ultrasound) • retina • image processing