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.
In this paper we proposed a portable fluorescence microscopic imaging system to prevent iatrogenic biliary injuries from occurring during cholecystectomy due to misidentification of the cystic structures. The system consisted of a light source module, a CMOS camera, a Raspberry Pi computer and a 5 inch HDMI LCD. Specifically, the light source module was composed of 690 nm and 850 nm LEDs, allowing the CMOS camera to simultaneously acquire both fluorescence and background images. The system was controlled by Raspberry Pi using Python programming with the OpenCV library under Linux. We chose Indocyanine green(ICG) as a fluorescent contrast agent and then tested fluorescence intensities of the ICG aqueous solution at different concentration levels by our fluorescence microscopic system compared with the commercial Xenogen IVIS system. The spatial resolution of the proposed fluorescence microscopic imaging system was measured by a 1951 USAF resolution target and the dynamic response was evaluated quantitatively with an automatic displacement platform. Finally, we verified the technical feasibility of the proposed system in mouse models of bile duct, performing both correct and incorrect gallbladder resection. Our experiments showed that the proposed system can provide clear visualization of the confluence between the cystic duct and common bile duct or common hepatic duct, suggesting that this is a potential method for guiding cholecystectomy. The proposed portable system only cost a total of $300, potentially promoting its use in resource-limited settings.
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 (Ipar) acquired with the AOTF parallel to the polarization of illumination and the other image (Iper) 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.
Accurate and in vivo characterization of structural, functional, and molecular characteristics of biological tissue will facilitate quantitative diagnosis, therapeutic guidance, and outcome assessment in many clinical applications, such as wound healing, cancer surgery, and organ transplantation. We introduced and tested a multiview hyperspectral imaging technique for noninvasive topographic imaging of cutaneous wound oxygenation. The technique integrated a multiview module and a hyperspectral module in a single portable unit. Four plane mirrors were cohered to form a multiview reflective mirror set with a rectangular cross section. The mirror set was placed between a hyperspectral camera and the target biological tissue. For a single image acquisition task, a hyperspectral data cube with five views was obtained. The five-view hyperspectral image consisted of a main objective image and four reflective images. Three-dimensional (3-D) topography of the scene was achieved by correlating the matching pixels between the objective image and the reflective images. 3-D mapping of tissue oxygenation was achieved using a hyperspectral oxygenation algorithm. The multiview hyperspectral imaging technique was validated in a wound model, a tissue-simulating blood phantom, and in vivo biological tissue. The experimental results demonstrated the technical feasibility of using multiview hyperspectral imaging for 3-D topography of tissue functional properties.
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.
Hyperspectral reflectance imaging technique has been used for in vivo detection of cervical intraepithelial neoplasia. However, the clinical outcome of this technique is suboptimal owing to multiple limitations such as nonuniform illumination, high-cost and bulky setup, and time-consuming data acquisition and processing. To overcome these limitations, we acquired the hyperspectral data cube in a wavelength ranging from 600 to 800 nm and processed it by a wide gap second derivative analysis method. This method effectively reduced the image artifacts caused by nonuniform illumination and background absorption. Furthermore, with second derivative analysis, only three specific wavelengths (620, 696, and 772 nm) are needed for tissue classification with optimal separability. Clinical feasibility of the proposed image analysis and classification method was tested in a clinical trial where cervical hyperspectral images from three patients were used for classification analysis. Our proposed method successfully classified the cervix tissue into three categories of normal, inflammation and high-grade lesion. These classification results were coincident with those by an experienced gynecology oncologist after applying acetic acid. Our preliminary clinical study has demonstrated the technical feasibility for in vivo and noninvasive detection of cervical neoplasia without acetic acid. Further clinical research is needed in order to establish a large-scale diagnostic database and optimize the tissue classification technique.
We report a second derivative multispectral algorithm for quantitative assessment of cutaneous tissue oxygen saturation (StO2). The algorithm is based on a forward model of light transport in multilayered skin tissue and an inverse algorithm for StO2 reconstruction. Based on the forward simulation results, a parameter of a second derivative ratio (SDR) is derived as a function of cutaneous tissue StO2. The SDR function is optimized at a wavelength set of 544, 552, 568, 576, 592, and 600 nm so that cutaneous tissue StO2 can be derived with minimal artifacts by blood concentration, tissue scattering, and melanin concentration. The proposed multispectral StO2 imaging algorithm is verified in both benchtop and in vivo experiments. The experimental results show that the proposed multispectral imaging algorithm is able to map cutaneous tissue StO2 in high temporal resolution with reduced measurement artifacts induced by different skin conditions in comparison with other three commercial tissue oxygen measurement systems. These results indicate that the multispectral StO2 imaging technique has the potential for noninvasive and quantitative assessment of skin tissue oxygenation with a high temporal resolution.
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.
Cervical cancer is a prevalent disease in many developing countries. Colposcopy is the most common approach for screening cervical intraepithelial neoplasia (CIN). However, its clinical efficacy heavily relies on the examiner’s experience. Spectroscopy is a potentially effective method for noninvasive diagnosis of cervical neoplasia. In this paper, we introduce a hyperspectral imaging technique for noninvasive detection and quantitative analysis of cervical neoplasia. A hyperspectral camera is used to collect the reflectance images of the entire cervix under xenon lamp illumination, followed by standard colposcopy examination and cervical tissue biopsy at both normal and abnormal sites in different quadrants. The collected reflectance data are calibrated and the hyperspectral signals are extracted. Further spectral analysis and image processing works are carried out to classify tissue into different types based on the spectral characteristics at different stages of cervical intraepithelial neoplasia. The hyperspectral camera is also coupled with a lab microscope to acquire the hyperspectral transmittance images of the pathological slides. The in vivo and the in vitro imaging results are compared with clinical findings to assess the accuracy and efficacy of the method.
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, StO2) 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.
We describe a portable fluorescence goggle navigation system for cancer margin assessment during oncologic surgeries.
The system consists of a computer, a head mount display (HMD) device, a near infrared (NIR) CCD camera, a miniature
CMOS camera, and a 780 nm laser diode excitation light source. The fluorescence and the background images of the
surgical scene are acquired by the CCD camera and the CMOS camera respectively, co-registered, and displayed on the
HMD device in real-time. The spatial resolution and the co-registration deviation of the goggle navigation system are
evaluated quantitatively. The technical feasibility of the proposed goggle system is tested in an ex vivo tumor model.
Our experiments demonstrate the feasibility of using a goggle navigation system for intraoperative margin detection and
Obtaining three-dimensional (3D) information of biologic tissue is important in many medical applications. This paper
presents two methods for reconstructing 3D topography of biologic tissue: multiview imaging and structured light
illumination. For each method, the working principle is introduced, followed by experimental validation on a diabetic
foot model. To compare the performance characteristics of these two imaging methods, a coordinate measuring machine
(CMM) is used as a standard control. The wound surface topography of the diabetic foot model is measured by
multiview imaging and structured light illumination methods respectively and compared with the CMM measurements.
The comparison results show that the structured light illumination method is a promising technique for 3D topographic
imaging of biologic tissue.
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.
Accurate and in vivo characterization of structural, functional, and molecular characteristics of biological tissue will
facilitate quantitative diagnosis, therapeutic guidance, and outcome assessment in many clinical applications, such as
wound healing, cancer surgery, and organ transplantation. However, many clinical imaging systems have limitations and
fail to provide noninvasive, real time, and quantitative assessment of biological tissue in an operation room. To
overcome these limitations, we developed and tested a multiview hyperspectral imaging system. The multiview
hyperspectral imaging system integrated the multiview and the hyperspectral imaging techniques in a single portable
unit. Four plane mirrors are cohered together as a multiview reflective mirror set with a rectangular cross section. The
multiview reflective mirror set was placed between a hyperspectral camera and the measured biological tissue. For a
single image acquisition task, a hyperspectral data cube with five views was obtained. The five-view hyperspectral image
consisted of a main objective image and four reflective images. Three-dimensional topography of the scene was achieved
by correlating the matching pixels between the objective image and the reflective images. Three-dimensional mapping of
tissue oxygenation was achieved using a hyperspectral oxygenation algorithm. The multiview hyperspectral imaging
technique is currently under quantitative validation in a wound model, a tissue-simulating blood phantom, and an in vivo
biological tissue model. The preliminary results have demonstrated the technical feasibility of using multiview
hyperspectral imaging for three-dimensional topography of tissue functional properties.
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. Quantitative
assessment of wound tissue ischemia, perfusion, and inflammation provides critical information for appropriate
detection, staging, and treatment of chronic wounds. However, no method is available for noninvasive, simultaneous,
and quantitative imaging of these tissue parameters. We integrated hyperspectral, laser speckle, and thermographic
imaging modalities into a single setup for multimodal assessment of tissue oxygenation, perfusion, and inflammation
characteristics. Advanced algorithms were developed for accurate reconstruction of wound oxygenation and appropriate
co-registration between different imaging modalities. The multimodal wound imaging system was validated by an
ongoing clinical trials approved by OSU IRB. In the clinical trial, a wound of 3mm in diameter was introduced on a
healthy subject’s lower extremity and the healing process was serially monitored by the multimodal imaging setup. Our
experiments demonstrated the clinical usability of multimodal wound imaging.