Bacterial infection is one of the major factors contributing to the compromised healing in chronic wounds. Sometimes bacteria biofilms formed on the wound are more resistant than adherent bacteria. Cold atmosphere plasma (CAP) has already shown its potential in contact-free disinfection, blood coagulation, and wound healing. In this study, we integrated a multimodal imaging system with a portable CAP device for image-guided treatment of infected wound in vivo and evaluated the antimicrobial effect on Pseudomonas aeruginosa sample in vitro.15 ICR mice were divided into three groups for therapeutic experiments:(1) control group with no infection nor treatment (2) infection group without treatment (3) infection group with treatment. For each mouse, a three millimeters punch biopsy was created on the dorsal skin. Infection was induced by Staphylococcus aureus inoculation one day post-wounding. The treated group was subjected to CAP for 2 min daily till day 13. For each group, five fixed wounds’ oxygenation and blood perfusion were evaluated daily till day 13 by a multimodal imaging system that integrates a multispectral imaging module and a laser speckle imaging module. In the research of relationship between therapeutic depth and sterilization effect on P.aeruginosa in agarose, we found that the CAP-generated reactive species reached the depth of 26.7μm at 30s and 41.6μm at 60s for anti-bacterial effects. Image-guided CAP therapy can be potentially used to control infection and facilitate the healing process of infected wounds.
Proc. SPIE. 9701, Multimodal Biomedical Imaging XI
KEYWORDS: Multimodal imaging, Tissues, Image segmentation, Image processing, Reflectivity, Multispectral imaging, Monte Carlo methods, Image enhancement, Cervical cancer, In vivo imaging, Algorithm development, RGB color model
Cervical cancer is the leading cause of cancer death for women in developing countries. Colposcopy plays an important role in early screening and detection of cervical intraepithelial neoplasia (CIN). In this paper, we developed a multimodal colposcopy system that combines multispectral reflectance, autofluorescence, and RGB imaging for in vivo detection of CIN, which is capable of dynamically recording multimodal data of the same region of interest (ROI). We studied the optical properties of cervical tissue to determine multi-wavelengths for different imaging modalities. Advanced algorithms based on the second derivative spectrum and the fluorescence intensity were developed to differentiate cervical tissue into two categories: squamous normal (SN) and high grade (HG) dysplasia. In the results, the kinetics of cervical reflectance and autofluorescence characteristics pre and post acetic acid application were observed and analyzed, and the image segmentation revealed good consistency with the gold standard of histopathology. Our pilot study demonstrated the clinical potential of this multimodal colposcopic system for in vivo detection of cervical cancer.
Vulvar lichen sclerosis (VLS) is a chronic, inflammatory and mucocutaneous disease of extragenital skin, which often goes undetected for years. The underlying causes are associated with the decrease of VEGF that reduces the blood oxygenation of vulva and the structural changes in the collagen fibrils, which can lead to scarring of the affected area. However, few methods are available for quantitative detection of VLS. Clinician’s examinations are subjective and may lead to misdiagnosis. Spectroscopy is a potentially effective method for noninvasive detection of VLS. In this paper, we developed a polarized, hyperspectral imaging system for quantitative assessment. The system utilized a hyperspectral camera to collect the reflectance images of the entire vulva under Xenon lamp illumination with and without a polarizer in front of the fiber. One image (I<sub>par</sub>) acquired with the AOTF parallel to the polarization of illumination and the other image (I<sub>per</sub>) acquired with the AOTF perpendicular to the illumination. This paper compares polarized images of VLS in a pilot clinical study. The collected reflectance data under Xenon lamp illumination without a polarizer are calibrated and the hyperspectral signals are extracted. An IRB approved clinical trial was carried out to evaluate the clinical utility for VLS detection. Our pilot study has demonstrated the technical potential of using this polarized hyperspectral imaging system for in vivo detection of vulvar lichen sclerosis.
We introduce a microfluidic approach to simulate tumor hypoxia and vascular anomaly. Polydimethylsiloxane (PDMS) phantoms with embedded microchannel networks were fabricated by a soft lithography process. A dialysis membrane was sandwiched between two PDMS slabs to simulate the controlled mass transport and oxygen metabolism. A tortuous microchannel network was fabricated to simulate tumor microvasculature. A dual-modal multispectral and laser speckle imaging system was used for oxygen and blood flow imaging in the tumor-simulating phantom. The imaging results were compared with those of the normal vasculature. Our experiments demonstrated the technical feasibility of simulating tumor hypoxia and vascular anomalies using the proposed PDMS phantom. Such a phantom fabrication technique may be potentially used to calibrate optical imaging devices, to study the mechanisms for tumor hypoxia and angiogenesis, and to optimize the drug delivery strategies.
Simultaneous and quantitative assessment of multiple tissue parameters may facilitate more effective diagnosis and therapy in many clinical applications, such as wound healing. However, existing wound assessment methods are typically subjective and qualitative, with the need for sequential data acquisition and coregistration between modalities, and lack of reliable standards for performance evaluation or calibration. To overcome these limitations, we developed a multimodal imaging system for quasi-simultaneous assessment of cutaneous tissue oxygenation and perfusion in a quantitative and noninvasive fashion. The system integrated multispectral and laser speckle imaging technologies into one experimental setup. Tissue oxygenation and perfusion were reconstructed by advanced algorithms. The accuracy and reliability of the imaging system were quantitatively validated in calibration experiments and a tissue-simulating phantom test. The experimental results were compared with a commercial oxygenation and perfusion monitor. Dynamic detection of cutaneous tissue oxygenation and perfusion was also demonstrated in vivo by a postocclusion reactive hyperemia procedure in a human subject and a wound healing process in a wounded mouse model. Our in vivo experiments not only validated the performance of the multimodal imaging system for cutaneous tissue oxygenation and perfusion imaging but also demonstrated its technical potential for wound healing assessment in clinical practice.
Quantitative assessment of wound tissue ischemia, perfusion, and inflammation provides critical information for appropriate detection, staging, and treatment of chronic wounds. However, few methods are available for simultaneous assessment of these tissue parameters in a noninvasive and quantitative fashion. We integrated hyperspectral, laser speckle, and thermographic imaging modalities in a single-experimental setup for multimodal assessment of tissue oxygenation, perfusion, and inflammation characteristics. Algorithms were developed for appropriate coregistration between wound images acquired by different imaging modalities at different times. The multimodal wound imaging system was validated in an occlusion experiment, where oxygenation and perfusion maps of a healthy subject’s upper extremity were continuously monitored during a postocclusive reactive hyperemia procedure and compared with standard measurements. The system was also tested in a clinical trial where a wound of three millimeters in diameter was introduced on a healthy subject’s lower extremity and the healing process was continuously monitored. Our in vivo experiments demonstrated the clinical feasibility of multimodal cutaneous wound imaging.
The wound healing process involves the reparative phases of inflammation, proliferation, and remodeling. Interrupting
any of these phases may result in chronically unhealed wounds, amputation, or even patient death. Despite the clinical
significance in chronic wound management, no effective methods have been developed for quantitative image-guided
treatment. We integrated a multimodal imaging system with a cold atmospheric plasma probe for image-guided
treatment of chronic wound. Multimodal imaging system offers a non-invasive, painless, simultaneous and quantitative
assessment of cutaneous wound healing. Cold atmospheric plasma accelerates the wound healing process through many
mechanisms including decontamination, coagulation and stimulation of the wound healing. The therapeutic effect of cold
atmospheric plasma is studied in vivo under the guidance of a multimodal imaging system. Cutaneous wounds are
created on the dorsal skin of the nude mice. During the healing process, the sample wound is treated by cold atmospheric
plasma at different controlled dosage, while the control wound is healed naturally. The multimodal imaging system
integrating a multispectral imaging module and a laser speckle imaging module is used to collect the information of
cutaneous tissue oxygenation (i.e. oxygen saturation, StO<sub>2</sub>) and blood perfusion simultaneously to assess and guide the plasma therapy. Our preliminary tests show that cold atmospheric plasma in combination with multimodal imaging
guidance has the potential to facilitate the healing of chronic wounds.
Simultaneous and quantitative assessment of skin functional characteristics in different modalities will facilitate diagnosis
and therapy in many clinical applications such as wound healing. However, many existing clinical practices and
multimodal imaging systems are subjective, qualitative, sequential for multimodal data collection, and need co-registration
between different modalities. To overcome these limitations, we developed a multimodal imaging system for quantitative,
non-invasive, and simultaneous imaging of cutaneous tissue oxygenation and blood perfusion parameters. The imaging
system integrated multispectral and laser speckle imaging technologies into one experimental setup. A Labview interface
was developed for equipment control, synchronization, and image acquisition. Advanced algorithms based on a wide gap
second derivative reflectometry and laser speckle contrast analysis (LASCA) were developed for accurate reconstruction
of tissue oxygenation and blood perfusion respectively. Quantitative calibration experiments and a new style of skinsimulating
phantom were designed to verify the accuracy and reliability of the imaging system. The experimental results
were compared with a Moor tissue oxygenation and perfusion monitor. For In vivo testing, a post-occlusion reactive
hyperemia (PORH) procedure in human subject and an ongoing wound healing monitoring experiment using dorsal
skinfold chamber models were conducted to validate the usability of our system for dynamic detection of oxygenation and
perfusion parameters. In this study, we have not only setup an advanced multimodal imaging system for cutaneous tissue
oxygenation and perfusion parameters but also elucidated its potential for wound healing assessment in clinical practice.