Maximum A-posteriori Signal Recovery for OCT Angiography Image Generation
Channel: BVM Conference
Date: 25/06/2021

Optical coherence tomography angiography (OCTA) is a clinically promising modality to image retinal vasculature. For this end, optical coherence tomography (OCT) volumes are repeatedly scanned and intensity changes over time are used to compute OCTA images. Because of patient movement and variations in blood ow, OCTA data are prone to noise. To address this issue, we propose a novel iterative maximum a posteriori (MAP) signal recovery algorithm which generates OCTA volumes with reduced noise and improved image quality [1]. The proposed algorithm is based on the OCTA signal model and maximum likelihood estimate (MLE) by Ploner et al. [2]. The MLE was extended into a MAP estimate by using wavelet shrinkage and total variation minimization as regularizers. Reconstruction results are compared against ground truth OCTA data which were merged from six co-registered OCTA scans [3]. Significant improvements in signal-to-noise ratio and structural similarity were observed. The presented method is, to the best of our knowledge, the first use of Bayesian statistics for OCTA image generation.

References
1. Husvogt L, Ploner SB, Chen S, et al. Maximum a posteriori signal recovery for optical coherence tomography angiography image generation and denoising. Biomed Opt Express. 2021;12(1):55-68.
2. Ploner SB, Riess C, Schottenhamml J, et al. A Joint Probabilistic Model for Speckle Variance, Amplitude Decorrelation and Interframe Variance (IFV) Optical Coherence Tomography Angiography. Proc BVM. 2018; p. 98-102.
3. Ploner SB, Kraus MF, Moult EM, et al. Effcient and high accuracy 3-D OCT angiography motion correction in pathology. Biomed Opt Express. 2021 Jan;12(1):125-146.

Husvogt L. et al. (2021) Abstract: Maximum A-posteriori Signal Recovery for OCT Angiography Image Generation. In: Palm C., Deserno T.M., Handels H., Maier A., Maier-Hein K., Tolxdorff T. (eds) Bildverarbeitung für die Medizin 2021. Informatik aktuell. Springer Vieweg, Wiesbaden. https://doi.org/10.1007/978-3-658-33198-6_61