Optimized Optical Coherence Tomography Imaging With Hough Transform-Based Fixed-Pattern Noise Reduction

Xin

et al. 2020

Lasers Surg Med

Self Cite

Background and Objectives Laser‐induced thermal injuries are a heavily researched topic in laser medicine and biomedicine. To explore the quantitative biological effects of laser‐induced injury repair, we propose an optical imaging‐based in vivo evaluation method and discuss the injury effect and repair characteristics of skin tissue. Study Design/Materials and Methods A supercontinumm laser (spectrum width ranged from 400 to 2400 nm) was used to irradiate live mice. The radiation doses were set as 32.85, 65.69, 98.4, and 197.08 J/cm2. Laser‐induced cutaneous thermal injuries were observed and measured after laser radiation. Optical coherence tomography (OCT) was used to image the injured spots. The optical attenuation coefficient (OAC) was computed using a Fourier‐domain algorithm. Three‐dimensional (3D) visualizations of the injured spots in the OCT images were constructed to qualitatively demonstrate the degree of the thermal injury at different times. The corresponding pathological changes of the skin injuries were observed dynamically. Results Under increasing radiation doses, the injured spots, which ranged in degree from mild to severe, appeared accordingly. The mean OAC value of normal skin was 1.15 ± 0.01 mm−1. The mean values of the OAC maps in the region of interests (ROIs) were 0.88 ± 0.05, 0.91 ± 0.02, 0.93 ± 0.04, and 0.98 ± 0.08 mm−1 at each of the four radiation levels, respectively. Additionally, the 3D OCT visualization showed a directed view of the injured spots and the healing process and was used as a qualitative evaluation method. The OCT images and pathological results showed that the damage tended to vary across all groups, but this trend tended to weaken as the radiation dose increased. Conclusion Optical imaging provides an in vivo noninvasive and real‐time evaluation method to comprehensively quantify supercontinuum laser‐induced thermal injuries and wound healing. The OACs and 3D visualizations of the OCT cubic data enable the areas of the direct injured spots to be measured and the inner structure to be viewed. The results obtained with these techniques indicate that the skin injuries are aggravated and tissue repair trends weaken as the radiation doses increase. This method would have a potential application for laser‐medicine and laser‐biological effects in the future. Lasers Surg. Med. © 2020 Wiley Periodicals LLC

Section: Materials and Experimental Methodsmentioning

confidence: 99%

Quantitative and Qualitative Evaluation of Supercontinuum Laser‐Induced Cutaneous Thermal Injuries and Their Repair With OCT Images

Xin

et al. 2020

Lasers Surg Med

Self Cite

“…The OCT image analysis of the radiated biological tissues was first preprocessed through speckle noise reduction 42 and fixed mode noise reduction. 43 The volumetric OCT images included 250 A-scans, 460 B-scans, and 200 Cscans, thus forming a volumetric data set of 250 × 460 × 200 pixels, with a size of approximately 2.5 mm × 10 mm × 8 mm. The optical attenuation coefficient (OAC) was computed as in our previous method; 44 that is, it can form an en face region of approximately 10 mm × 10 mm.…”

Section: Oct Imaging Visualization and Characterizationmentioning

confidence: 99%

Quantitative investigation of laser ablation based on real‐time temperature variations and OCT images for laser treatment applications

et al. 2021

Lasers Surg Med

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Background and Objective: Lasers are widely employed in clinical applications. In vivo monitoring of real-time information about different-wavelength laser surgeries would provide important surgical feedback for surgeons or clinical therapy instruments. However, the quantitative effect of laser ablation or vaporization still needs to be further explored and investigated. Here, we investigate and quantitatively evaluate the ablation variations and morphological changes of two laser ablation models: point-and sweeping-based models. Methods: An infrared thermal imager was used to monitor the temperature variations, and curve fitting was used to build the relationship between the laser radiation duration/sweeping speed and quantitative parameters of the ablated areas. Optical coherence tomography (OCT) images were used to visualize the inner structure and evaluate the depth of the ablated craters. Optical attenuation coefficients (OACs) were computed to characterize the normal and ablated tissues.Results: The results demonstrated that there was a good linear relationship between radiation duration and temperature variation. Similarly, a linear relationship was observed between the sweeping speed and quantitative parameters of craters or scratches (width and depth). The mean OAC of normal tissues was significantly distinguished from the mean OACs of the ablated craters or scratches. Conclusion: Laser ablation was investigated based on a quantitative parameter analysis, thermal detection, and OCT imaging, and the results successfully demonstrated that there is a linear relationship between the laser parameters and quantitative parameters of the ablated tissues under the current settings. Such technology could be used to provide quantitative solutions for exploring the lasertissue biological effect and improve the performance of medical image-guided laser ablation in the future.

“…The image acquisition rate was approximately 60 frames per second. OCT images were preprocessed using the related algorithms [32] to reduce the fixed mode noise. The OCT images of the burnt tissues were acquired (Fig.…”

Section: Oct Image Preprocessing and Oac Computationmentioning

confidence: 99%

Evaluation of a 3.8-µm laser-induced skin injury and their repair with in vivo OCT imaging and noninvasive monitoring

Wang

et al. 2021

Lasers Med Sci

Self Cite

To explore a 3.8-µm laser-induced damage and wound healing effect, we propose using optical coherence tomography (OCT) and a noninvasive monitoring-based in vivo evaluation method to quantitatively and qualitatively analyze the time-dependent biological effect of a 3.8-µm laser. The optical attenuation coefficient (OAC) is computed using a Fourier-domain algorithm. Three-dimensional (3-D) visualization of OCT images has been implemented to visualize the burnt spots. Furthermore, the burnt spots from the 3-D volumetric data was segmented and visualized, and the quantitative parameters of the burnt spots, such as the mean OACs, areas, and volumes, were computed. Then, OCT images and histological sections were analyzed to compare the structural changes. Within a certain radiation range, there is a linear relationship between radiation dose and temperature. Dermoscopic images, OCT images, and histological sections showed that, within a certain dose range, as the radiation doses increased, the cutaneous damage became more serious. One hour after laser radiation, the mean OACs increased and then decreased; the areas of burnt spots always increased and were 0.95 ± 0.07,