## 3 Results
### Comparison of Segmentation and Image Contrast  
Figure 2a,b show en-face projection images over 50 \(\upmu\)m for intensity and retardation data, respectively. Hyperscattering or turquoise pixels indicate amyloid-beta plaques. B-scans with manually segmented plaques highlighted as red and yellow dots are displayed in Figure 2c,d. Representative 3D renderings of the segmentations based on the intensity and phase retardation images are shown in Figure 2e,f, respectively. In Figure 2h, an overlay of both segmentation data sets is shown. Only few plaques appear in both data sets. The amount of plaques overlapping in both data sets was quantified as shown in Figure 2g. On average, 5% of the amyloid-beta plaques in all data sets were visualized by both contrast channels. Weber contrast was assessed in the intensity and retardation data sets based on the segmentation of both the intensity data (Int\({}_{\text{Seg}}\)) and retardation data (Ret\({}_{\text{Seg}}\)). As shown in Figure 3a, the image contrast of plaques was higher in intensity data and Int\({}_{\text{Seg}}\) compared to intensity data and Ret\({}_{\text{Seg}}\); however, no significance was found (\(p=0.8\)). The same analysis for the retardation values showed a significant contrast difference when comparing plaques segmented for retardation and intensity data (\(p=0.02\)), see Figure 3b. Additionally, the SNR was assessed in the intensity and retardation data sets based on the segmentation of both the intensity data (Int\({}_{\text{Seg}}\)) and retardation data (Ret\({}_{\text{Seg}}\)). A slightly higher difference for intensity images and Int\({}_{\text{Seg}}\) was observed compared to intensity images and Ret\({}_{\text{Seg}}\) (\(p=0.6\)). For retardation data and Ret\({}_{\text{Seg}}\), a higher SNR was calculated when compared to retardation images and Int\({}_{\text{Seg}}\) (\(p=0.06\)). A detailed overview of plaques segmented in all data sets is shown in Figure 4a. Figure 1: Visualization of amyloid-beta plaques in intensity and retardation optical coherence tomography (OCT) images. (**a**) Intensity en-face projection image averaged over a depth of 10 \(\upmu\)m starting 50 \(\upmu\)m underneath the tissue surface. (**b**) Representative intensity B-scan image. (**c**) Three-dimensional (3D) volume of intensity data. (**d**) Retardation en-face projection image averaged over 10 \(\upmu\)m starting 50 \(\upmu\)m underneath the tissue surface. (**e**) Representative retardation B-scan image. (**f**) 3D volume of retardation data. Figure 3: **(a)** The Weber contrast (WC) was calculated for all intensity data sets in linear scale. WC for the plaques segmented in the intensity data (Int\({}_{\text{Seg}}\)) compared to those segmented in the retardation data (Ret\({}_{\text{Seg}}\)) was evaluated. A slightly higher but not statistically significant difference for intensity data and Int\({}_{\text{Seg}}\) was observed compared to intensity data and Ret\({}_{\text{Seg}}\). (**b**) WC for the retardation data. Figure 2: Comparison of plaque segmentation in intensity and retardation data. (**a**) Maximum intensity en-face projection image. (**b**) Median retardation value en-face projection over 50 \(\upmu\)m. Color map: see Figure 1. (**c**) Intensity B-scan with segmented plaques shown in red. (**d**) Retardation B-scan with segmented plaques shown in yellow. (**e**) Representative 3D rendering of the segmented plaques in an intensity volume. (**f**) Representative 3D rendering of the segmented plaques in a retardation data set. (**g**) Quantification of total plaque overlap in every OCT and PS-OCT data set, i.e., plaques segmented in both contrast channels (m indicates the mean overlap). (**h**) Volumetric overlay of the intensity and retardation segmentations. Two yellow arrows highlight two plaques visible both in intensity and retardation image data. White pixels indicate plaques which are visible in both intensity and retardation data.