Browsing by Author "Lihachev, Alexey"

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    Autofluorescence imaging of the skin is an objective non-invasive technique for diagnosing pseudoxanthoma elasticum
    (2021) Farkas, Klára; Bozsányi, Szabolcs; Plázár, Dóra; Bánvölgyi, András; Fésűs, Luca; Anker, Pálma; Zakariás, Sára; Lihacova, Ilze; Lihachev, Alexey; Lange, Marta; Arányi, Tamás; Wikonkál, Norbert M.; Medvecz, Márta; Kiss, Norbert
    Pseudoxanthoma elasticum (PXE) is a rare multisystemic autosomal recessive connective tissue disease. In most cases, skin manifestations of PXE are the first to develop, followed later by severe ocular and cardiovascular complications. In our present study, in addition to dermoscopy, we introduced novel techniques, autofluorescence (AF) and diffuse reflectance (DR) imaging for the assessment of affected skin sites of five PXE patients. PXE-affected skin areas in most skin sites showed a previously observed pattern upon dermoscopic examination. With the novel imaging, PXE-affected skin lesions displayed high AF intensity. During our measurements, significantly higher mean, minimum and maximum AF intensity values were found in areas of PXE-affected skin when compared to uninvolved skin. Conversely, images acquired with the use of 660 and 940 nm illumination showed no mentionable difference. Our results demonstrate that AF imaging may be used in the in vivo diagnostics and quantification of the severity of the skin lesions of PXE patients. In addition, it is a safe, fast and cost-effective diagnostic method. AF imaging may be also used to objectively monitor the efficacy of the possible novel therapeutic approaches of PXE in the future.
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    Laser speckle imaging for visualization of hidden effects for early detection of antibacterial susceptibility in disc diffusion tests
    (2023-06-29) Balmages, Ilya; Reinis, Aigars; Kistkins, Svjatoslavs; Bliznuks, Dmitrijs; Plorina, Emilija V.; Lihachev, Alexey; Lihacova, Ilze; Department of Biology and Microbiology
    Rapid identification of effective antibiotic treatment is crucial for increasing patient survival and preventing the formation of new antibiotic-resistant bacteria due to preventative antibiotic use. Currently utilized “gold standard” methods require 16–24 h to determine the most appropriate antibiotic for the patient’s treatment. The proposed technique of laser speckle imaging with subpixel correlation analysis allows for identifying dynamics and changes in the zone of inhibition, which are impossible to observe with classical methods. Furthermore, it obtains the resulting zone of inhibition diameter earlier than the disk diffusion method which is recommended by the European Committee on Antimicrobial Susceptibility Testing (EUCAST). These results could improve mathematical models of changes in the diameter of the zone of inhibition around the disc containing the antimicrobial agent, thereby speeding up and facilitating epidemiological analysis.
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    Quantitative multispectral imaging differentiates melanoma from seborrheic keratosis
    (2021-08) Bozsányi, Szabolcs; Farkas, Klára; Bánvölgyi, András; Lőrincz, Kende; Fésűs, Luca; Anker, Pálma; Zakariás, Sára; Jobbágy, Antal; Lihacova, Ilze; Lihachev, Alexey; Lange, Marta; Bliznuks, Dmitrijs; Medvecz, Márta; Kiss, Norbert; Wikonkál, Norbert M.
    Melanoma is a melanocytic tumor that is responsible for the most skin cancer-related deaths. By contrast, seborrheic keratosis (SK) is a very common benign lesion with a clinical picture that may resemble melanoma. We used a multispectral imaging device to distinguish these two entities, with the use of autofluorescence imaging with 405 nm and diffuse reflectance imaging with 525 and 660 narrow-band LED illumination. We analyzed intensity descriptors of the acquired images. These included ratios of intensity values of different channels, standard deviation and minimum/maximum values of intensity of the lesions. The pattern of the lesions was also assessed with the use of particle analysis. We found significantly higher intensity values in SKs compared with melanoma, especially with the use of the autofluorescence channel. Moreover, we found a significantly higher number of particles with high fluorescence in SKs. We created a parameter, the SK index, using these values to differentiate melanoma from SK with a sensitivity of 91.9% and specificity of 57.0%. In conclusion, this imaging technique is potentially applicable to distinguish melanoma from SK based on the analysis of various quantitative parameters. For this application, multispectral imaging could be used as a screening tool by general physicians and non-experts in the everyday practice.
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    Visualization of keratin with diffuse reflectance and autofluorescence imaging and nonlinear optical microscopy in a rare keratinopathic ichthyosis
    (2021-02-02) Anker, Pálma; Fesűs, Luca; Kiss, Norbert; Noll, Judit; Becker, Krisztina; Kuroli, Enikő; Mayer, Balázs; Bozsányi, Szabolcs; Lőrincz, Kende; Lihacova, Ilze; Lihachev, Alexey; Lange, Marta; Wikonkal, Norbert; Medvecz, Márta
    Keratins are one of the main fluorophores of the skin. Keratinization disorders can lead to alterations in the optical properties of the skin. We set out to investigate a rare form of keratinopathic ichthyosis caused by KRT1 mutation with two different optical imaging methods. We used a newly developed light emitting diode (LED) based device to analyze autofluorescence signal at 405 nm excitation and diffuse reflectance at 526 nm in vivo. Mean autofluorescence intensity of the hyperkeratotic palmar skin was markedly higher in comparison to the healthy control (162.35 vs. 51.14). To further assess the skin status, we examined samples from affected skin areas ex vivo by nonlinear optical microscopy. Two-photon excited fluorescence and second-harmonic generation can visualize epidermal keratin and dermal collagen, respectively. We were able to visualize the structure of the epidermis and other skin changes caused by abnormal keratin formation. Taken together, we were able to show that such imaging modalities are useful for the diagnosis and follow-up of keratinopathic diseases.