Abstract
Purpose: :
To demonstrate optimal scanning protocols and signal processing schemes in Optical Coherence Tomography data used for detection and visualisation of blood vessels in the retina and choroid. To compare joint Spectral and Time domain Optical Coherence Tomography technique based on a detection of Doppler beating frequencies with intensity decorrelation method. To demonstrate optimal en-face retinal flow maps calculated with those two methods.
Methods: :
Different scanning protocols were applied to visualise retinal and choroid layers in both fovea and optics disc area. Joint Spectral and Time domain detection and intensity decorrelation processing were applied to all of the data. Obtained vessels network maps were generated and compared in order to find optimal protocols for each technique.
Results: :
10 eyes from 5 healthy volunteers were measured using high speed FdOCT prototype. Flow maps computed from decorrelation and joint Spectral and Time domain OCT method will be demonstrated. Quantitative results of the comparison between two methods will be presented. New optimized ways of data visualization including new hue-saturation depth encoded color-scales will be shown. Independently flow maps of the vascular net including quantity information about velocities will be presented with another colour coded projection.
Conclusions: :
We found that images acquired with joint Spectral and Time Domain and decorrelation methods are mutually complement. Decorrelation method is highly selective while joint Spectral and Time domain OCT is more flexible for the use of different scanning protocols. The latter helps to extend the range of measured velocities one order of magnitude. By combining maps obtained using those two techniques we believe that we can image retinal and choroidal vasculature with higher accuracy increasing significantly amount of information. This in turn may potentially help in better understanding of physiological processes in the retina and choroid.
Keywords: imaging methods (CT, FA, ICG, MRI, OCT, RTA, SLO, ultrasound) • retina • image processing