Optical Techniques for Biomedical Engineering

A special issue of Bioengineering (ISSN 2306-5354). This special issue belongs to the section "Biomedical Engineering and Biomaterials".

Deadline for manuscript submissions: closed (31 December 2023) | Viewed by 8773

Special Issue Editor


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Guest Editor
Department of Electrical Engineering, Chang Gung University, Taipei 333, Taiwan
Interests: biophotonics; optical coherence tomography; laser speckle contrast imaging; laser surgery; biomedical engineering
Special Issues, Collections and Topics in MDPI journals

Special Issue Information

Dear Colleagues,

The Bioengineering journal is running a Special Issue titled “Optical Techniques for Biomedical Engineering”. Dr. Meng-Tsan Tsai and Dr. Ming-Che Chan are serving as Guest Editors for this Special Issue. Optical techniques are widely used for biomedical applications, including therapy, imaging, and sensing. With laser optics, biological tissue can be treated with high accuracy and few side effects. Optical imaging techniques such as fluorescence microscopy, multiphoton microscopy, harmonic microscopy, photoacoustic tomography, and optical coherence tomography are also implemented in various biological areas, with features of high resolution and high contrast. Moreover, optical sensing has become a solution for measuring physiological paraments such as pulsation, hemoglobin concentration, flow velocity, and so on.

This Special Issue aims to explore the research findings and technical developments in biophotonics, and papers on related applications in cells, animals, and human subjects are also encouraged. This Special Issue covers the following topics, including, but not limited to:

Laser therapy;

Optical coherence tomography;

Microscopy;

Diffuse and fluorescence tomography;

NIR spectroscopy;

Photoacoustic tomography;

Multispectral imaging and sensing;

Biosensors.

Review articles and regular research articles related to biomedical optics are welcome.

Dr. Meng-Tsan Tsai
Guest Editor

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Keywords

  • biomedical optics
  • laser therapy
  • microscopy
  • optical coherence tomography
  • spectroscopy
  • optical sensor

Published Papers (8 papers)

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Research

15 pages, 6261 KiB  
Article
Limb Volume Measurements: A Comparison of Circumferential Techniques and Optoelectronic Systems against Water Displacement
by Giovanni Farina, Manuela Galli, Leonardo Borsari, Andrea Aliverti, Ioannis Th. Paraskevopoulos and Antonella LoMauro
Bioengineering 2024, 11(4), 382; https://doi.org/10.3390/bioengineering11040382 - 15 Apr 2024
Viewed by 257
Abstract
Background. Accurate measurements of limb volumes are important for clinical reasons. We aimed to assess the reliability and validity of two centimetric and two optoelectronic techniques for limb volume measurements against water volumetry, defined as the gold standard. Methods. Five different measurement methods [...] Read more.
Background. Accurate measurements of limb volumes are important for clinical reasons. We aimed to assess the reliability and validity of two centimetric and two optoelectronic techniques for limb volume measurements against water volumetry, defined as the gold standard. Methods. Five different measurement methods were executed on the same day for each participant, namely water displacement, fixed-height (circumferences measured every 5 (10) cm for the upper (lower limb) centimetric technique, segmental centimetric technique (circumferences measured according to proportional height), optoelectronic plethysmography (OEP, based on a motion analysis system), and IGOODI Gate body scanner technology (which creates an accurate 3D avatar). Results. A population of 22 (15 lower limbs, 11 upper limbs, 8 unilateral upper limb lymphoedema, and 6 unilateral lower limb lymphoedema) participants was selected. Compared to water displacement, the fixed-height centimetric method, the segmental centimetric method, the OEP, and the IGOODI technique resulted in mean errors of 1.2, 0.86, −16.0, and 0.71%, respectively. The corresponding slopes (and regression coefficients) of the linear regression lines were 1.0002 (0.98), 1.0047 (0.99), 0.874 (0.94) and 0.9966 (0.99). Conclusion. The centimetric methods and the IGOODI system are accurate in measuring limb volume with an error of <2%. It is important to evaluate new objective and reliable techniques to improve diagnostic and follow-up possibilities. Full article
(This article belongs to the Special Issue Optical Techniques for Biomedical Engineering)
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12 pages, 7695 KiB  
Article
Endoscopic Hyperspectral Imaging System to Discriminate Tissue Characteristics in Tissue Phantom and Orthotopic Mouse Pancreatic Tumor Model
by Na Eun Mun, Thi Kim Chi Tran, Dong Hui Park, Jin Hee Im, Jae Il Park, Thanh Dat Le, Young Jin Moon, Seong-Young Kwon and Su Woong Yoo
Bioengineering 2024, 11(3), 208; https://doi.org/10.3390/bioengineering11030208 - 23 Feb 2024
Viewed by 870
Abstract
In this study, we developed an endoscopic hyperspectral imaging (eHSI) system and evaluated its performance in analyzing tissues within tissue phantoms and orthotopic mouse pancreatic tumor models. Our custom-built eHSI system incorporated a liquid crystal tunable filter. To assess its tissue discrimination capabilities, [...] Read more.
In this study, we developed an endoscopic hyperspectral imaging (eHSI) system and evaluated its performance in analyzing tissues within tissue phantoms and orthotopic mouse pancreatic tumor models. Our custom-built eHSI system incorporated a liquid crystal tunable filter. To assess its tissue discrimination capabilities, we acquired images of tissue phantoms, distinguishing between fat and muscle regions. The system underwent supervised training using labeled samples, and this classification model was then applied to other tissue phantom images for evaluation. In the tissue phantom experiment, the eHSI effectively differentiated muscle from fat and background tissues. The precision scores regarding fat tissue classification were 98.3% for the support vector machine, 97.7% for the neural network, and 96.0% with a light gradient-boosting machine algorithm, respectively. Furthermore, we applied the eHSI system to identify tumors within an orthotopic mouse pancreatic tumor model. The F-score of each pancreatic tumor-bearing model reached 73.1% for the KPC tumor model and 63.1% for the Pan02 tumor models. The refined imaging conditions and optimization of the fine-tuning of classification algorithms enhance the versatility and diagnostic efficacy of eHSI in biomedical applications. Full article
(This article belongs to the Special Issue Optical Techniques for Biomedical Engineering)
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12 pages, 11878 KiB  
Article
Feasibility of High-Cellular-Resolution Full-Field, Artificial-Intelligence-Assisted, Real-Time Optical Coherence Tomography in the Evaluation of Vitiligo: A Prospective Longitudinal Follow-Up Study
by Lai-Ying Lu, Yi-Ting Chen, I-Ling Chen, Yu-Chang Shih, Rosalie Tzu-Li Liu, Yi-Jing Lai and Chau Yee Ng
Bioengineering 2024, 11(2), 196; https://doi.org/10.3390/bioengineering11020196 - 19 Feb 2024
Viewed by 1016
Abstract
Vitiligo, a psychologically distressing pigmentary disorder characterized by white depigmented patches due to melanocyte loss, necessitates non-invasive tools for early detection and treatment response monitoring. High-cellular-resolution full-field optical coherence tomography (CRFF-OCT) is emerging in pigmentary disorder assessment, but its applicability in vitiligo repigmentation [...] Read more.
Vitiligo, a psychologically distressing pigmentary disorder characterized by white depigmented patches due to melanocyte loss, necessitates non-invasive tools for early detection and treatment response monitoring. High-cellular-resolution full-field optical coherence tomography (CRFF-OCT) is emerging in pigmentary disorder assessment, but its applicability in vitiligo repigmentation after tissue grafting remains unexplored. To investigate the feasibility of CRFF-OCT for evaluating vitiligo lesions following tissue grafting, our investigation involved ten vitiligo patients who underwent suction blister epidermal grafting and laser ablation at a tertiary center between 2021 and 2022. Over a six-month period, clinical features, dermoscopy, and photography data were recorded. Utilizing CRFF-OCT along with artificial intelligence (AI) applications, repigmentation features were captured and analyzed. The CRFF-OCT analysis revealed a distinct dark band in vitiligo lesion skin, indicating melanin loss. Grafted areas exhibited melanocytes with dendrites around the epidermal-dermal junction and hair follicles. CRFF-OCT demonstrated its efficacy in the early detection of melanocyte recovery and accurate melanin quantification. This study introduces CRFF-OCT as a real-time, non-invasive, and in vivo evaluation tool for assessing vitiligo repigmentation, offering valuable insights into pigmentary disorders and treatment responses. Full article
(This article belongs to the Special Issue Optical Techniques for Biomedical Engineering)
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15 pages, 3569 KiB  
Article
Advancing Barrett’s Esophagus Segmentation: A Deep-Learning Ensemble Approach with Data Augmentation and Model Collaboration
by Jiann-Der Lee and Chih Mao Tsai
Bioengineering 2024, 11(1), 47; https://doi.org/10.3390/bioengineering11010047 - 02 Jan 2024
Viewed by 961
Abstract
This approach provides a thorough investigation of Barrett’s esophagus segmentation using deep-learning methods. This study explores various U-Net model variants with different backbone architectures, focusing on how the choice of backbone influences segmentation accuracy. By employing rigorous data augmentation techniques and ensemble strategies, [...] Read more.
This approach provides a thorough investigation of Barrett’s esophagus segmentation using deep-learning methods. This study explores various U-Net model variants with different backbone architectures, focusing on how the choice of backbone influences segmentation accuracy. By employing rigorous data augmentation techniques and ensemble strategies, the goal is to achieve precise and robust segmentation results. Key findings include the superiority of DenseNet backbones, the importance of tailored data augmentation, and the adaptability of training U-Net models from scratch. Ensemble methods are shown to enhance segmentation accuracy, and a grid search is used to fine-tune ensemble weights. A comprehensive comparison with the popular Deeplabv3+ architecture emphasizes the role of dataset characteristics. Insights into training saturation help optimize resource utilization, and efficient ensembles consistently achieve high mean intersection over union (IoU) scores, approaching 0.94. This research marks a significant advancement in Barrett’s esophagus segmentation. Full article
(This article belongs to the Special Issue Optical Techniques for Biomedical Engineering)
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19 pages, 4071 KiB  
Article
Using Signal Features of Functional Near-Infrared Spectroscopy for Acute Physiological Score Estimation in ECMO Patients
by Hsiao-Huang Chang, Kai-Hsiang Hou, Ting-Wei Chiang, Yi-Min Wang and Chia-Wei Sun
Bioengineering 2024, 11(1), 26; https://doi.org/10.3390/bioengineering11010026 - 26 Dec 2023
Viewed by 895
Abstract
Extracorporeal membrane oxygenation (ECMO) is a vital emergency procedure providing respiratory and circulatory support to critically ill patients, especially those with compromised cardiopulmonary function. Its use has grown due to technological advances and clinical demand. Prolonged ECMO usage can lead to complications, necessitating [...] Read more.
Extracorporeal membrane oxygenation (ECMO) is a vital emergency procedure providing respiratory and circulatory support to critically ill patients, especially those with compromised cardiopulmonary function. Its use has grown due to technological advances and clinical demand. Prolonged ECMO usage can lead to complications, necessitating the timely assessment of peripheral microcirculation for an accurate physiological evaluation. This study utilizes non-invasive near-infrared spectroscopy (NIRS) to monitor knee-level microcirculation in ECMO patients. After processing oxygenation data, machine learning distinguishes high and low disease severity in the veno-venous (VV-ECMO) and veno-arterial (VA-ECMO) groups, with two clinical parameters enhancing the model performance. Both ECMO modes show promise in the clinical severity diagnosis. The research further explores statistical correlations between the oxygenation data and disease severity in diverse physiological conditions, revealing moderate correlations with the acute physiologic and chronic health evaluation (APACHE II) scores in the VV-ECMO and VA-ECMO groups. NIRS holds the potential for assessing patient condition improvements. Full article
(This article belongs to the Special Issue Optical Techniques for Biomedical Engineering)
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14 pages, 3678 KiB  
Article
Quantitative Evaluation of Caries and Calculus with Ultrahigh-Resolution Optical Coherence Tomography
by Tai-Ang Wang, Nguyễn Hoàng Trung, Hsiang-Chieh Lee, Cheng-Kuang Lee, Meng-Tsan Tsai and Yen-Li Wang
Bioengineering 2023, 10(11), 1317; https://doi.org/10.3390/bioengineering10111317 - 15 Nov 2023
Viewed by 1131
Abstract
Dental caries on the crown’s surface is caused by the interaction of bacteria and carbohydrates, which then gradually alter the tooth’s structure. In addition, calculus is the root of periodontal disease. Optical coherence tomography (OCT) has been considered to be a promising tool [...] Read more.
Dental caries on the crown’s surface is caused by the interaction of bacteria and carbohydrates, which then gradually alter the tooth’s structure. In addition, calculus is the root of periodontal disease. Optical coherence tomography (OCT) has been considered to be a promising tool for identifying dental caries; however, diagnosing dental caries in the early stage still remains challenging. In this study, we proposed an ultrahigh-resolution OCT (UHR-OCT) system with axial and transverse resolutions of 2.6 and 1.8 μm for differentiating the early-stage dental caries and calculus. The same teeth were also scanned by a conventional spectral-domain OCT (SD-OCT) system with an axial resolution of 7 μm. The results indicated that early-stage carious structures such as small cavities can be observed using UHR-OCT; however, the SD-OCT system with a lower resolution had difficulty identifying it. Moreover, the estimated surface roughness and the scattering coefficient of enamel were proposed for quantitatively differentiating the different stages of caries. Furthermore, the thickness of the calculus can be estimated from the UHR-OCT results. The results have demonstrated that UHR-OCT can detect caries and calculus in their early stages, showing that the proposed method for the quantitative evaluation of caries and calculus is potentially promising. Full article
(This article belongs to the Special Issue Optical Techniques for Biomedical Engineering)
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14 pages, 3715 KiB  
Article
A New Gas Analysis Method Based on Single-Beam Excitation Stimulated Raman Scattering in Hollow Core Photonic Crystal Fiber Enhanced Raman Spectroscopy
by Maryam Shirmohammad, Michael A. Short and Haishan Zeng
Bioengineering 2023, 10(10), 1161; https://doi.org/10.3390/bioengineering10101161 - 03 Oct 2023
Cited by 1 | Viewed by 1349
Abstract
We previously developed a hollow-core photonic crystal fiber (HCPCF) based Raman scattering enhancement technique for gas/human breath analysis. It enhances photon–gas molecule interactions significantly but is still based on CW laser excitation spontaneous Raman scattering, which is a low-probability phenomenon. In this work, [...] Read more.
We previously developed a hollow-core photonic crystal fiber (HCPCF) based Raman scattering enhancement technique for gas/human breath analysis. It enhances photon–gas molecule interactions significantly but is still based on CW laser excitation spontaneous Raman scattering, which is a low-probability phenomenon. In this work, we explored nanosecond/sub-nanosecond pulsed laser excitation in HCPCF based fiber enhanced Raman spectroscopy (FERS) and successfully induced stimulated Raman scattering (SRS) enhancement. Raman measurements of simple and complex gases were performed using the new system to assess its feasibility for gas analysis. We studied the gas Raman scattering characteristics, the relationship between Raman intensities and pump energies, and the energy threshold for the transition from spontaneous Raman scattering to SRS. H2, CO2, and propene (C3H6) were used as test gases. Our results demonstrated that a single-beam pulsed pump combined with FERS provides an effective Raman enhancement technique for gas analysis. Furthermore, an energy threshold for SRS initiation was experimentally observed. The SRS-capable FERS system, utilizing a single-beam pulsed pump, shows great potential for analyzing complex gases such as propene, which is a volatile organic compound (VOC) gas, serving as a biomarker in human breath for lung cancer and other human diseases. This work contributes to the advancement of gas analysis and opens alternative avenues for exploring novel Raman enhancement techniques. Full article
(This article belongs to the Special Issue Optical Techniques for Biomedical Engineering)
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10 pages, 1156 KiB  
Article
Efficacy of a Diode Vaginal Laser in the Treatment of the Genitourinary Syndrome of Menopause
by Marta Barba, Alice Cola, Desirèe De Vicari, Clarissa Costa, Arianna Petra Castelli, Silvia Volontè, Robert Fruscio and Matteo Frigerio
Bioengineering 2023, 10(10), 1158; https://doi.org/10.3390/bioengineering10101158 - 02 Oct 2023
Cited by 2 | Viewed by 1449
Abstract
Introduction: Genitourinary syndrome of menopause (GSM) and vulvovaginal atrophy (VVA) are the most frequent menopause-related clinical entities and are consistently included in the definition of pelvic floor disorders (PFDs). Nonhormonal therapies, such as lubricants and moisturizers, are indicated as first-line treatments, while the [...] Read more.
Introduction: Genitourinary syndrome of menopause (GSM) and vulvovaginal atrophy (VVA) are the most frequent menopause-related clinical entities and are consistently included in the definition of pelvic floor disorders (PFDs). Nonhormonal therapies, such as lubricants and moisturizers, are indicated as first-line treatments, while the “gold standard’’ is represented by topical estrogen products; however, in cancer survivors hormonal treatment is not indicated. For this reason, energy-based therapeutic approaches—for instance, through laser technologies—may be employed as alternative options in this kind of patient; however, there are no studies evaluating the efficacy of a pure diode vaginal laser in the treatment of GSM. As a consequence, with our study, we aimed to evaluate outpatient nonablative diode laser treatment in sexually active women, with contraindications, no response, or refusal of local estrogenic therapy. Methods: This prospective study included patients with GSM, aged ≥ 18 years old, with contraindications, or refusal of local estrogen therapies. Women were evaluated via the use of their Vaginal Health Index (VHI) scores, which consists of five measures: elasticity, fluid volume, pH, epithelial integrity, and moisture. Moreover, the intensity of VVA symptoms (vaginal burning, vaginal itching, vaginal dryness, dyspareunia, and dysuria) was measured using a 10 cm visual analog scale (VAS), where the left extreme of the scale (score = 0) indicated “absence of symptom” and the right indicated “symptom as bad as it could be” (score = 100). Sexual function was evaluated with the Female Sexual Function Index (FSFI-19) questionnaire. The treatment was performed using a Leonardo Dual diode laser (Biolitec Italia Srl, Milano, Italy). The laser treatment consisted of three sessions, one per month. One month after the third session, the VHI, symptom VAS, and FSFI-19 were re-evaluated. In addition, the Patient Global Impression of Improvement (PGI-I) questionnaire was collected. Results: Our study enrolled a total of 26 consecutive patients. All patients were either in menopause or under treatment with gonadotropin-releasing hormone (GnRH). None of the patients reported adverse effects after laser treatment. In total, 19 (73.1%) patients referred improvements of their symptoms according to PGI-I scores. All domains of the FSFI-19 questionnaire, significantly improved after the diode laser treatment. The mean VHI score increased by 3.2 points, from 12.2 to 15.4 (p < 0.001). Additionally, we documented a significant improvement in symptoms affecting the VAS score, from 69.2 to 43.5 points (p < 0.001). Conclusion: A diode vaginal laser is an effective and easily tolerated ambulatory procedure for vaginal functional restoration in the treatment of GSM and VVA. Full article
(This article belongs to the Special Issue Optical Techniques for Biomedical Engineering)
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