Karol Karnowski

Karol Karnowski
University of Western Australia | UWA · Optical and Biomedical Engineering (OBEL)

PhD

About

91
Publications
7,664
Reads
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796
Citations
Citations since 2017
63 Research Items
501 Citations
2017201820192020202120222023020406080100
2017201820192020202120222023020406080100
2017201820192020202120222023020406080100
2017201820192020202120222023020406080100
Additional affiliations
May 2013 - present
Nicolaus Copernicus University
Position
  • Professor (Assistant)

Publications

Publications (91)
Article
the last decade, 3D printing systems have greatly evolved both in terms of processable materials and printing resolutions, becoming a top seed technology for many academic and industrial applications. Nevertheless, manufacturing polymeric materials characterized by a trabecular porosity and functionally graded architecture—where both the local poro...
Article
Full-text available
All-fiber-optic imaging microendoscopes are emerging as an important tool in bioimaging studies, but physical limitations constrain the achievable beam characteristics of designs using a single focusing element. These constraints are especially relevant for applications that require a long working distance, high resolution, and/or minimal probe dia...
Article
Mammographic breast density is a strong breast cancer risk factor, and its routine clinical measurement could potentially be used to identify women at higher risk of breast cancer and/or monitor primary prevention strategies. Previous reports of optical breast spectroscopy (OBS), a novel approach to measuring breast density, demonstrated that it is...
Article
Full-text available
Background: Noninvasive assessment of metabolic processes that sustain regeneration of human retinal visual pigments (visual cycle) is essential to improve ophthalmic diagnostics and to accelerate development of new treatments to counter retinal diseases. Fluorescent vitamin A derivatives, which are the chemical intermediates of these processes, a...
Article
Full-text available
Many bioimaging studies, including those in engineered tissue constructs, intravital microscopy in animal models, and medical imaging in humans, require cellular-resolution imaging of structures deep within a sample. Yet, many of the current approaches are limited in terms of resolution, but also in invasiveness, repeatable imaging of the same loca...
Conference Paper
OCT imaging of dynamic samples can give rise to significant misleading axial motion artifacts, depending on system specifications. Here, we investigate the axial shift phenomena in low-cost swept-source OCT dynamic measurements and simulations.
Conference Paper
Full-text available
Corneal biomechanics plays a fundamental role in the genesis and progression of corneal pathologies, such as keratoconus. It also contributes to corneal remodelling after corneal surgery, and it affects the measurement accuracy of glaucoma biomarkers, such as the intraocular pressure (IOP). Air-puff induced corneal deformation imaging reveals infor...
Article
Full-text available
Corneal biomechanics plays a fundamental role in the genesis and progression of corneal pathologies, such as keratoconus, in corneal remodeling after corneal surgery, and in affecting the measurement accuracy of glaucoma biomarkers, such as the intraocular pressure (IOP). Air-puff induced corneal deformation imaging reveals information highlighting...
Article
Full-text available
Significance: To advance our understanding of the contrast observed when imaging with polarization-sensitive optical coherence tomography (PS-OCT) and its correlation with oral cancerous pathologies, a detailed comparison with histology provided via ex vivo fixed tissue is required. The effects of tissue fixation, however, on such polarization-bas...
Article
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We present in-vivo imaging of the mouse brain using custom made Gaussian beam optical coherence microscopy (OCM) with 800nm wavelength. We applied new instrumentation to longitudinal imaging of the glioblastoma (GBM) tumor microvasculature in the mouse brain. We have introduced new morphometric biomarkers that enable quantitative analysis of the de...
Article
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Purpose: To introduce a new approach for keratoconus detection based on corneal microstructure observed in vivo derived from a single Scheimpflug image. Methods: Scheimpflug single-image snapshots from 25 control subjects and 25 keratoconus eyes were analyzed; from each group, five subjects were randomly selected to provide out-of-sample data. E...
Conference Paper
Full-text available
Purpose : Ocular biomechanical simulations show that air-puff induced corneal deformation imaging (APCDI) can reveal pathological asymmetric responses, as in eccentric keratoconus. Such asymmetries often go undetected when monitoring deformation on only one meridian (Birkenfeld et al., IOVS, 2019), as is the case with commercial instruments. We pre...
Article
We show that polarization‐sensitive optical coherence tomography angiography (PS‐OCTA) based on full Jones matrix assessment of speckle decorrelation offers improved contrast and depth of vessel imaging over conventional OCTA. We determine how best to combine the individual Jones matrix elements and compare the resulting image quality to that of a...
Article
The organization of fibrillar tissue on the micrometer scale carries direct implications for health and disease but remains difficult to assess in vivo. Polarization-sensitive optical coherence tomography measures birefringence, which relates to the microscopic arrangement of fibrillar tissue components. Here, we demonstrate a critical improvement...
Article
Purpose: We introduce a new approach to assess the properties of corneal microstructure in vivo of healthy control and keratoconus eyes, based on statistical modeling of light intensity distribution from Scheimpflug images. Methods: Twenty participants (10 mild keratoconus and 10 control eyes) were included in this study. Corneal biomechanics wa...
Article
It is challenging to recover local optic axis orientation from samples probed with fiber-based polarization-sensitive optical coherence tomography (PS-OCT). In addition to the effect of preceding tissue layers, the transmission through fiber and system elements, and imperfect system alignment, need to be compensated. Here, we present a method to re...
Article
Full-text available
Application of the air‐puff swept source OCT (SS‐OCT) instrument to determine the influence of viscoelasticity on the relation between overall the air‐puff force and corneal apex displacement of porcine corneas ex vivo is demonstrated. Simultaneous recording of time‐evolution of the tissue displacement and air pulse stimulus allows obtaining valuab...
Article
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We employ optical coherence tomography (OCT) and optical coherence microscopy (OCM) to study conjunctival lymphatics in porcine eyes ex vivo. This study is a precursor to the development of in vivo imaging of the collecting lymphatics for potentially guiding and monitoring glaucoma filtration surgery. OCT scans at 1300 nm and higher‐resolution OCM...
Article
Standard optical systems in ophthalmology are strictly dedicated either to retinal or to anterior segment imaging due to the refractive properties of the eye. We demonstrate a swept source optical coherence tomography platform with an electrically tunable lens (ETL) for versatile 3D in vivo imaging of both the eye’s anterior segment and the retina....
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In this paper, we describe a technique capable of visualizing mechanical properties at the cellular scale deep in living tissue, by incorporating a gradient-index (GRIN)-lens micro-endoscope into an ultrahigh-resolution optical coherence elastography system. The optical system, after the endoscope, has a lateral resolution of 1.6 µm and an axial re...
Article
Full-text available
Imaging of living cells based on traditional fluorescence and confocal laser scanning microscopy has delivered an enormous amount of information critical for understanding biological processes in single cells. However, the requirement for a high numerical aperture and fluorescent markers still limits researchers’ ability to visualize the cellular a...
Conference Paper
Polarisation sensitive optical coherence tomography (PS-OCT) offers additional intrinsic contrast to probe differences between healthy tissue and cancer that are often barely visible due to limited scattering contrast in an OCT image. PS-OCT reconstructs tissue birefringence from phase-sensitive measurements of orthogonal polarisation components of...
Conference Paper
Optical coherence tomography (OCT) has been the most revolutionary diagnostic tool in eye care over the past 20 years. This paper reviews the current status and future directions of OCT in ophthalmic application.
Conference Paper
In this paper, we use swept source optical coherence tomography combined with air-puff module (air-puff SS-OCT) to investigate the properties of the cornea. During OCT measurement the cornea was stimulated by short, air pulse, and corneal response was recorded. In this preliminary study, the air-puff SS-OCT instrument was applied to measure behavio...
Conference Paper
Optical coherence elastography (OCE) is emerging as a potentially useful tool in the identification of a number of diseases. In our group, we are developing OCE techniques based on compressive loading. Typically, these techniques employ a quasi-static mechanical load introduced by uniaxially compressing a sample with a rigid plate. The resulting de...
Conference Paper
Availability of the long-depth-range OCT systems enables comprehensive structural imaging of the eye and extraction of biometric parameters characterizing the entire eye. Several approaches have been developed to perform OCT imaging with extended depth ranges. In particular, current SS-OCT technology seems to be suited to visualize both anterior an...
Conference Paper
We present a comprehensive imaging methodology for 3D structural and functional measurements of fertilized mouse oocytes. In contrary to methods used for mouse zygote imaging so far OCT provides 3D data without z axis movement of sample or objective lens. Furthermore, complex scanning protocols used in this study give access to different scales of...
Conference Paper
A novel, time-resolved interferometric technique is presented allowing the reconstruction of the complex electric field output of a fast frequency swept laser in a single-shot measurement. The power of the technique is demonstrated by examining a short cavity swept source designed for optical coherence tomography applications, with a spectral bandw...
Article
The labial minor salivary glands (LSGs) play a role in medical research and practice due to their superficial location and involvement in both systemic and localized diseases. Swept-source optical coherence tomography (OCT) is a noninvasive modality that enables in vivo, micrometer resolution, wide-field three-dimensional imaging in seconds. A purp...
Article
Full-text available
A novel, time-resolved interferometric technique is presented that allows the reconstruction of the complex electric field output of a swept source laser in a single-shot measurement. The power of the technique is demonstrated by examining a short cavity swept source designed for optical coherence tomography (OCT) applications with a spectral width...
Conference Paper
Full-text available
Tunable semiconductor laser for 1025-1095 nm spectral range is developed based on the InGaAs semiconductor optical amplifier and a narrow band-pass acousto-optic tunable filter in a fiber ring cavity. Mode-hop-free sweeping with tuning speeds of up to 104 nm/s was demonstrated. Instantaneous linewidth is in the range of 0.06-0.15 nm, side-mode supp...
Conference Paper
We analyse the dynamical behaviour of a short cavity OCT swept-source laser experimentally and theoretically. Mode-hopping, sliding frequency mode-locking and chaos are all observed during the laser sweep period. Heterodyne measurements of laser dynamics allows some insight into the behaviour of the laser, while interferometric techniques allow the...
Article
Full-text available
The labial minor salivary glands (LSGs) are easily accessible mucus-secreting structures of the alimentary tract that may provide new information on the basis of gastrointestinal complications of cystic fibrosis (CF). It was shown that they are destructed in the course of cystic fibrosis. We employed wide-field, micrometer resolution in vivo optica...
Conference Paper
Swept-source optical coherence tomography is a new approach in metrology of contact lenses. We developed this method and used to preliminary study evaluation of possible long-term effects of contact lenses wear on vision quality.
Article
We demonstrate swept source optical coherence tomography (OCT) imaging of contact lenses (CLs) in a wet cell and comprehensive quantitative characterization of CLs from volumetric OCT datasets. The approach is based on a technique developed for lens autopositioning and autoleveling enabled by lateral capillary interactions between the wet cell wall...
Article
Full-text available
We investigate the behaviour of a short cavity swept source laser with an intra cavity swept filter both experimentally and theoretically. We characterise the behaviour of the device with real-time intensity measurements using a fast digital oscilloscope, showing several distinct regimes, most notably regions of mode-hopping, frequency sliding mode...
Conference Paper
In vivo 3D-OCT imaging of the lower lip mucosa and labial salivary glands (LSGs) is demonstrated in cystic fibrosis (CF) patients. Surface density of LSGs in CF patients is statistically lower than in healthy subjects.
Article
Full-text available
Three-dimensional imaging of the mucosa of the lower lip and labial minor salivary glands is demonstrated in vivo using swept source optical coherence tomography (OCT) system at 1310 nm with modified interface. Volumetric data sets of the inner surface of the lower lip covering ~230 mm(2) field are obtained from patients with Sjögren's syndrome and...
Conference Paper
In presented method combination of Fourier and Time domain detection enables to broaden the effective bandwidth for time dependent Doppler signal that allows for using higher-order Bessel functions to calculate unambiguously the vibration amplitudes.
Article
We show results of a project which focuses on detection of activity in neural tissue with Optical Coherence Tomography (OCT) methods. Experiments were performed in neural cords dissected from the American cockroach (Periplaneta americana L.). Functional OCT imaging was performed with ultrahigh resolution spectral / Fourier domain OCT system (axial...