Automated combination of optical coherence tomography images and fundus images

We discuss approaches to combining multimodal multidimensional images, namely, three-dimensional optical coherence tomography (OCT) data and two-dimensional color images of the fundus. Registration of these two modalities can help to adjust the position of the obtained OCT images on the retina. Some existing approaches to matching fundus images are based on finding key points that are considered invariant to affine transformations and are common to the two images. However, errors in the identification of such points can lead to registration errors. There are also methods for iterative adjustment of conversion parameters, but they are based on some manual settings. In this paper, we propose a method based on a full or partial search of possible combinations of the OCT image transformation to find the best approximation of the true transformation. The best approximation is determined using a measure of comparison of preprocessed image pixels. Further, the obtained transformations are compared with the available true transformations to assess the quality of the algorithm. The structure of the work includes: pre-processing of OCT and fundus images with the extraction of blood vessels, random search or grid search over possible transformation parameters (shift, rotation and scaling), and evaluation of the quality of the algorithm.

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Non-invasive three-dimensional thickness analysis of oral epithelium based on optical coherence tomography—development and diagnostic performance

Heliyon ◽

10.1016/j.heliyon.2021.e06645 ◽

2021 ◽

Vol 7 (4) ◽

pp. e06645

Author(s):

Charlotte Theresa Trebing ◽

Sinan Sen ◽

Stefan Rues ◽

Christopher Herpel ◽

Maria Schöllhorn ◽

...

Keyword(s):

Optical Coherence Tomography ◽

Diagnostic Performance ◽

Three Dimensional ◽

Oral Epithelium ◽

Optical Coherence ◽

Non Invasive

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Three-dimensional segmentation and depth-encoded visualization of choroidal vasculature using swept-source optical coherence tomography

Experimental Biology and Medicine ◽

10.1177/15353702211028540 ◽

2021 ◽

pp. 153537022110285

Author(s):

Hao Zhou ◽

Tommaso Bacci ◽

K Bailey Freund ◽

Ruikang K Wang

Keyword(s):

Optical Coherence Tomography ◽

Three Dimensional ◽

Age Related Macular Degeneration ◽

Optical Coherence ◽

Full Thickness ◽

Swept Source ◽

Automated Method ◽

Choroidal Imaging ◽

Choroidal Vasculature ◽

Choroidal Vessels

The choroid provides nutritional support for the retinal pigment epithelium and photoreceptors. Choroidal dysfunction plays a major role in several of the most important causes of vision loss including age-related macular degeneration, myopic degeneration, and pachychoroid diseases such as central serous chorioretinopathy and polypoidal choroidal vasculopathy. We describe an imaging technique using depth-resolved swept-source optical coherence tomography (SS-OCT) that provides full-thickness three-dimensional (3D) visualization of choroidal anatomy including topographical features of individual vessels. Enrolled subjects with different clinical manifestations within the pachychoroid disease spectrum underwent 15 mm × 9 mm volume scans centered on the fovea. A fully automated method segmented the choroidal vessels using their hyporeflective lumens. Binarized choroidal vessels were rendered in a 3D viewer as a vascular network within a choroidal slab. The network of choroidal vessels was color depth-encoded with a reference to the Bruch’s membrane segmentation. Topographical features of the choroidal vasculature were characterized and compared with choroidal imaging obtained with indocyanine green angiography (ICGA) from the same subject. The en face SS-OCT projections of the larger choroid vessels closely resembled to that obtained with ICGA, with the automated SS-OCT approach proving additional depth-encoded 3D information. In 16 eyes with pachychoroid disease, the SS-OCT approach added clinically relevant structural details, including choroidal thickness and vessel depth, which the ICGA studies could not provide. Our technique appears to advance the in vivo visualization of the full-thickness choroid, successfully reveals the topographical features of choroidal vasculature, and shows potential for further quantitative analysis when compared with other choroidal imaging techniques. This improved visualization of choroidal vasculature and its 3D structure should provide an insight into choroid-related disease mechanisms as well as their responses to treatment.

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