12 research outputs found
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Intra-operative point-of-procedure delineation of oral cancer margins using optical coherence tomography.
ObjectivesSurgical margin status is a significant determinant of treatment outcome in oral cancer. Negative surgical margins can decrease the loco-regional recurrence by five-fold. The current standard of care of intraoperative clinical examination supplemented by histological frozen section, can result in a risk of positive margins from 5 to 17 percent. In this study, we attempted to assess the utility of intraoperative optical coherence tomography (OCT) imaging with automated diagnostic algorithm to improve on the current method of clinical evaluation of surgical margin in oral cancer.Materials and methodsWe have used a modified handheld OCT device with automated algorithm based diagnostic platform for imaging. Intraoperatively, images of 125 sites were captured from multiple zones around the tumor of oral cancer patients (n = 14) and compared with the clinical and pathologic diagnosis.ResultsOCT showed sensitivity and specificity of 100%, equivalent to histological diagnosis (kappa, ĸ = 0.922), in detection of malignancy within tumor and tumor margin areas. In comparison, for dysplastic lesions, OCT-based detection showed a sensitivity of 92.5% and specificity of 68.8% and a moderate concordance with histopathology diagnosis (ĸ = 0.59). Additionally, the OCT scores could significantly differentiate squamous cell carcinoma (SCC) from dysplastic lesions (mild/moderate/severe; p ≤ 0.005) as well as the latter from the non-dysplastic lesions (p ≤ 0.05).ConclusionThe current challenges associated with clinical examination-based margin assessment could be improved with intra-operative OCT imaging. OCT is capable of identifying microscopic tumor at the surgical margins and demonstrated the feasibility of mapping of field cancerization around the tumor
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Developing Optical Biometrics Using Optical Coherence Tomography for Medical Screening and Diagnosis
Optical coherence tomography (OCT), a non-invasive, high-resolution imaging modality, has seen an increasing role as a clinical diagnostic, screening, and therapeutic imaging method over the years. Medical specialties such as ophthalmology, interventional cardiology and gastroenterology have been able to take full advantage of OCT’s minimally invasive near-cellular depth resolution to stage and diagnose different disease states and medical conditions. Although we have seen a wide spread use of OCT in the aforementioned specialties, there remains a plethora of medical specialties that could potentially benefit from the use of a non-invasive, high-resolution imaging modality. This thesis concentrates on developing the use of OCT and analytical image processing methods to address clinical unmet needs in interventional pulmonology, head and neck cancer and dermatology. The work presented will specifically discuss nosocomial ventilator associated pneumonia, oral squamous cell carcinoma (SCC), and androgenic alopecia (AA) respectively. Each medical condition studied required a unique imaging system and imaging probe to properly assess the presented clinical need. Ventilator associated pneumonia (VAP) utilized a high-speed Fourier domain OCT (FD-OCT) imaging system with side-viewing probe, a microscope-based fluorescence lifetime imaging (FLIM) system, and a bench top terahertz spectroscopy system. Using the three imaging modalities, the macroscopic structure of bacterial biofilm in-situ as well as biofilm bacterial phenotype composition could be resolved. OSCC required the development of a portable low-cost spectral domain OCT(SD-OCT) imaging system and low-profile forward viewing scanning probe to transport the system overseas to Bangalore, India where oral cancer has a high prevalence. Using intensity-based OCT as compared to the histology gold standard, differences between normal, dysplastic and malignant oral mucosa were determined. Lastly, androgenic alopecia better known as male or female pattern baldness, utilized a larger 3D scanning hand held microscope probe that provided a wide field of view yet a high lateral resolution to observe differences in hair shaft and hair follicle structure between varying stages of balding.Structural intensity-based OCT biomarkers are effective in analyzing various disease conditions, as evidence by the clinical OCT imaging applications. These biomarkers provide a means of assessing and staging the state of the medical condition in the spectrum between normal and abnormal. With such an imaging tool and outlook, physicians could further guide medical intervention, determine treatment efficacy and monitor disease progression
Optical Coherence Tomography as an Oral Cancer Screening Adjunct in a Low Resource Settings
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Developing Optical Biometrics Using Optical Coherence Tomography for Medical Screening and Diagnosis
Optical coherence tomography (OCT), a non-invasive, high-resolution imaging modality, has seen an increasing role as a clinical diagnostic, screening, and therapeutic imaging method over the years. Medical specialties such as ophthalmology, interventional cardiology and gastroenterology have been able to take full advantage of OCT’s minimally invasive near-cellular depth resolution to stage and diagnose different disease states and medical conditions. Although we have seen a wide spread use of OCT in the aforementioned specialties, there remains a plethora of medical specialties that could potentially benefit from the use of a non-invasive, high-resolution imaging modality. This thesis concentrates on developing the use of OCT and analytical image processing methods to address clinical unmet needs in interventional pulmonology, head and neck cancer and dermatology. The work presented will specifically discuss nosocomial ventilator associated pneumonia, oral squamous cell carcinoma (SCC), and androgenic alopecia (AA) respectively. Each medical condition studied required a unique imaging system and imaging probe to properly assess the presented clinical need. Ventilator associated pneumonia (VAP) utilized a high-speed Fourier domain OCT (FD-OCT) imaging system with side-viewing probe, a microscope-based fluorescence lifetime imaging (FLIM) system, and a bench top terahertz spectroscopy system. Using the three imaging modalities, the macroscopic structure of bacterial biofilm in-situ as well as biofilm bacterial phenotype composition could be resolved. OSCC required the development of a portable low-cost spectral domain OCT(SD-OCT) imaging system and low-profile forward viewing scanning probe to transport the system overseas to Bangalore, India where oral cancer has a high prevalence. Using intensity-based OCT as compared to the histology gold standard, differences between normal, dysplastic and malignant oral mucosa were determined. Lastly, androgenic alopecia better known as male or female pattern baldness, utilized a larger 3D scanning hand held microscope probe that provided a wide field of view yet a high lateral resolution to observe differences in hair shaft and hair follicle structure between varying stages of balding.Structural intensity-based OCT biomarkers are effective in analyzing various disease conditions, as evidence by the clinical OCT imaging applications. These biomarkers provide a means of assessing and staging the state of the medical condition in the spectrum between normal and abnormal. With such an imaging tool and outlook, physicians could further guide medical intervention, determine treatment efficacy and monitor disease progression
Intravascular Optical Coherence Tomography for Characterization of Atherosclerosis with a 1.7 Micron Swept-Source Laser.
The main cause of acute coronary events, such as thrombosis, is the rupture of atherosclerotic plaques. Typical intravascular optical coherence tomography (IVOCT) imaging systems that utilize a 1.3 μm swept source laser are often used for identifying fibrous cap thickness of plaques, yet cannot provide adequate depth penetration to resolve the size of the lipid pool. Here, we present a novel IVOCT system with a 1.7 μm center wavelength swept light source that can readily penetrate deeper into the tissue because of the longer wavelength and allows for better identification of plaques due to the lipid absorption spectrum at 1.7 μm. Using this system, we have imaged a human coronary artery to evaluate the performance of the novel OCT system and verified the results by hematoxylin and eosin (H&E) histology. The significantly improved imaging depth and better identification sensitivity suggest that the 1.7 μm OCT system holds great potential that can be further translated for in-vivo applications of atherosclerosis characterization
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High-Speed Integrated Endoscopic Photoacoustic and Ultrasound Imaging System.
Endoscopic integrated photoacoustic and ultrasound imaging has the potential for early detection of the cancer in the gastrointestinal tract. Currently, slow imaging speed is one of the limitations for clinical translation. Here, we developed a high speed integrated endoscopic PA and US imaging system, which is able to perform PA and US imaging simultaneously up to 50 frames per second. Using this system, the architectural morphology and vasculature of the rectum wall were visualized from a Sprague Dawley rat in-vivo
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High-Speed Integrated Endoscopic Photoacoustic and Ultrasound Imaging System.
Endoscopic integrated photoacoustic and ultrasound imaging has the potential for early detection of the cancer in the gastrointestinal tract. Currently, slow imaging speed is one of the limitations for clinical translation. Here, we developed a high speed integrated endoscopic PA and US imaging system, which is able to perform PA and US imaging simultaneously up to 50 frames per second. Using this system, the architectural morphology and vasculature of the rectum wall were visualized from a Sprague Dawley rat in-vivo
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Visualization of ex vivo rabbit olfactory mucosa and foramina with three-dimensional optical coherence tomography
There is increasing interest in developing a minimally invasive imaging modality to safely evaluate dynamic microscopic changes of the olfactory mucosa and cribriform foramina. Herein, we utilized three-dimensional (3D) optical coherence tomography (OCT) to characterize the ex vivo stratified substructure of olfactory mucosa in rabbits and create 3D reconstructed images of olfactory foramina. Olfactory mucosa and cribriform plates from four New Zealand White rabbits were dissected and imaged using two swept-source OCT systems: (1) 1.3-µm (μm) center wavelength, 100-nm bandwidth, 200-kHz sweep rate, and (2) 1.7-μm center wavelength, 120-nm bandwidth, 90-kHz sweep rate. Volumetric OCT images were compiled to create a 3D reconstruction of the cribriform plate. The ability of OCT to distinguish the olfactory mucosa substructure and foramina was compared to histology. To estimate imaging penetration depth of each system, the first-order exponential decays of depth-resolved intensity were calculated and compared using a paired t-test. Three-dimensional OCT depicted the stratified layered structures within the olfactory mucosa correlating with histology. The epithelium and lamina propria were measured to be 32 μm and 107 μm in 1.3-μm OCT compared to 30 μm and 105 μm in histology. Olfactory foramina were visualized via 3D reconstruction. The 1.7-μm system provided greater depth penetration compared to the 1.3-μm system, allowing for improved foramina visualization. We have shown that OCT can be used to image non-pathologic olfactory mucosa and foramina. Implications for this work include diagnostic and therapeutic potentials for neurorhinological and neurodegenerative diseases
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Intra-operative point-of-procedure delineation of oral cancer margins using optical coherence tomography.
ObjectivesSurgical margin status is a significant determinant of treatment outcome in oral cancer. Negative surgical margins can decrease the loco-regional recurrence by five-fold. The current standard of care of intraoperative clinical examination supplemented by histological frozen section, can result in a risk of positive margins from 5 to 17 percent. In this study, we attempted to assess the utility of intraoperative optical coherence tomography (OCT) imaging with automated diagnostic algorithm to improve on the current method of clinical evaluation of surgical margin in oral cancer.Materials and methodsWe have used a modified handheld OCT device with automated algorithm based diagnostic platform for imaging. Intraoperatively, images of 125 sites were captured from multiple zones around the tumor of oral cancer patients (n = 14) and compared with the clinical and pathologic diagnosis.ResultsOCT showed sensitivity and specificity of 100%, equivalent to histological diagnosis (kappa, ĸ = 0.922), in detection of malignancy within tumor and tumor margin areas. In comparison, for dysplastic lesions, OCT-based detection showed a sensitivity of 92.5% and specificity of 68.8% and a moderate concordance with histopathology diagnosis (ĸ = 0.59). Additionally, the OCT scores could significantly differentiate squamous cell carcinoma (SCC) from dysplastic lesions (mild/moderate/severe; p ≤ 0.005) as well as the latter from the non-dysplastic lesions (p ≤ 0.05).ConclusionThe current challenges associated with clinical examination-based margin assessment could be improved with intra-operative OCT imaging. OCT is capable of identifying microscopic tumor at the surgical margins and demonstrated the feasibility of mapping of field cancerization around the tumor