Ultrahigh Speed Fourier Domain OCT Imaging of the Rodent Retinal Structure and Blood Flow

Abstract

Purpose: : To demonstrate ultrahigh speed OCT structural and functional imaging of the rodent retina. This study demonstrates 800nm spectral / Fourier domain OCT imaging at 70,000 axial scans per second and 1050nm swept source / Fourier domain OCT imaging at 200,000 axial scans per second in the rodent retina. Ultrahigh speed Fourier domain OCT enables novel protocols which can be used for imaging rodent retinal structure and measuring retinal blood flow in vivo.

Methods: : An ultrahigh speed, ultrahigh resolution spectral / Fourier domain OCT prototype instrument operating at 800nm using new high speed CMOS imaging technology and an ultrahigh speed swept source / Fourier domain OCT prototype instrument operating at 1050nm using new scanning laser technology were developed. The prototype instruments were used to image the retinal structure and blood flow in rodents.

Results: : Ultrahigh speed imaging enables high pixel density 3D-OCT data with minimal eye motion artifacts. Image processing methods such as image registration can reduce residual motion artifacts and improve signal to noise ratio. Ultrahigh resolution imaging at 800nm show thin retinal features clearly. Imaging at 1050nm wavelengths provides enhanced penetration in the optic nerve and lamina cribrosa. Ultrahigh speed OCT systems enable measuring axial flow velocities of up to 50mm/s.

Conclusions: : Ultrahigh speed imaging of the rodent retinal structure and blood flow was demonstrated. 3D-OCT data sets obtained at high speeds show reduced motion artifacts. Image registration corrects residual motion and improves image quality. Doppler OCT provides non-invasive quantitative measurements of retinal blood flow in vivo and may benefit studies of diseases such as glaucoma and diabetic retinopathy.

Keywords: imaging methods (CT, FA, ICG, MRI, OCT, RTA, SLO, ultrasound) • retina • blood supply