Microvasculature visualization in OCT data
The purpose of the project is to evaluate the OCT data of processing methods, in order to quantitatively or qualitatively visualize blood vessels. There are known many OCT methods for blood flow visualization in the literature. One of them, a method proposed by our group, is called joint spectral and time domain Optical Coherence Tomography (STdOCT) and is based on Doppler frequency beating analysis. This quantitative method has proved its applicability for three-dimensional visualization of retinal blood vessels. In this project STdOCT is used as a reference to other methods. It has been shown that STdOCT has an advantage to another widely used phase-resolved method. The project aims at studying another class of methods based on only intensity information analysis in order to visualize microvasculature.
Ultrahigh-speed beam engineering for improved light delivery
Optical imaging is an emerging technology which offers unprecedented ability to visualize the internal structure of the objects even with submicrometer resolution. Optical modalities have found numerous applications especially in biomedicine, where they can differentiate tissues without exogenous contrast or demonstrate ability to probe physiological properties of tissues. With these features, optical imaging technologies are becoming powerful clinical tools for non-invasive and objective diagnosis, guided treatment and monitoring therapies.
The objective of this project is to apply ultrahigh-speed modulation of the light beam wavefront in time and space in order to improve the performance of the imaging systems. We perform both theoretical and experimental investigations of the control of the parameters of the imaging systems such as numerical aperture, resolution and depth of focus using high-speed.
The project will impact the improvements in the performance of optical instrumentation that serves as a key step in developing tools for more efficient visualization of biological objects and other samples.
High-speed optical coherence tomography imaging and biometry of the anterior segment of the eye
Optical Coherence Tomography (OCT) is a modality analogous to ultrasound imaging, except that it generates images using echoes of light. OCT uses low coherence interferometry to obtain two-dimensional cross-sectional and three-dimensional volumetric images with micrometer resolution. OCT has a number of features which make it extremely attractive as a diagnostic imaging modality. These include a unique micron scale image resolution and possibility of real time imaging without removing tissue, which are extremely powerful for diagnosis of pathology of biological tissues. OCT has become a standard medical imaging modality in ophthalmology since it can generate images of retinal pathology with higher resolution than any other non-invasive technique.
The purpose of this project is to bring together advanced instrumentation for Fourier-domain OCT with the innovative image analysis and segmentation algorithms for better visualization and biometric measurement of the anterior segment of the eye. In collaboration with our clinical partners, we are implementing cutting-edge technologies involving modern photonics (broadband light sources, fiber-optic components, optical design), high-speed electronics, and advanced image processing to optimize the visualization of the ocular anterior segment.
The resulting methods and approaches will also allow us to develop novel tools for quantitative evaluation of progression and evaluation of new treatment modalities of the anterior segment of the eye.
Spatio-temporal optical coherence manipulation.
The research area concerns some base aspects of nature of light. In order to control an optical field in sample plane a novel method of interferometric spatiotemporal optical coherence manipulation is developed. It involves modulating the phase of the spectral degree of coherence (μ) in order to adjust the effective coherence properties of the light beam. This method shall give possibility to improve an optical imaging through strongly scattering media like biological tissues.
Structural and functional OCT imaging using STdOCT
The research conducted by dr Szkulmowski is focused on applications of Spectral and Time domain OCT (STdOCT) to:
- flow velocity estimation in phantoms and in-vivo samples,
- total flow estimation,
- removing complex ambiguity,
- removing speckle noise,
- increasing image quality in OCT imaging.
The aim of the research is to create single tool to comprehensive imaging of structure and functions of living tissue.
Fig. Speckle reduction in OCT images of human optic nerve head area. a, b – without speckle reduction; c, d – after speckle reduction.
Fig. Image quality improvement with different data averaging techniques. N – number of averaged OCT spectra to obtain one line of tomogram.
P. Stremplewski & K. Komar
Fundus autofluorescence imaging and two photon processes in native dyes in human eye.
We are looking for specific reactions of native fluorophores on light. Mostly we focus on excited state dynamics of lipofuscin. In order to distinguish between flurophores in fundus, we put effort to perform fundus imaging relied on pump and probe scheme. Together with fundus imaging, we perform spectral analysis of lipofuscins, especially excited state transmission measurements.
FAF images of fundus taken with our device, with extremely low intensity of excitation beam. All presented images are single frames, without averaging.