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ABSTRACT: Optical coherence tomography (OCT) is being developed as a potentially valuable method for high-resolution cross-sectional imaging of the esophageal mucosal and submucosal layers. One potential application of OCT imaging is to identify subsquamous Barrett's epithelium in patients who have undergone ablative therapy, which is not visible on standard endoscopic examination. However, histologic correlation confirming the ability of OCT to image subsquamous Barrett's epithelium has yet to be performed.
Histologic correlation study.
To perform histologic correlation of ultrahigh-resolution optical coherence tomography (UHR-OCT) imaging for identification of subsquamous Barrett's epithelium.
Academic Medical Center (University of Washington, Seattle, WA).
Fourteen patients with pathologic biopsy specimens, proven to be high-grade dysplasia or adenocarcinoma underwent esophagectomy.
UHR-OCT imaging was performed on ex vivo esophagectomy specimens immediately after resection.
Correlation of UHR-OCT images with histologic images.
Subsquamous Barrett's epithelium was clearly identified by using UHR-OCT images and was confirmed by corresponding histology.
Difficulty distinguishing some subsquamous Barrett's glands from blood vessels in ex vivo tissue (because of the lack of blood flow) in some cases. Imaging was performed with a bench-top system.
Results from this study demonstrate that UHR-OCT imaging is capable of identifying subsquamous Barrett's epithelium.
Gastrointestinal endoscopy 10/2009; 71(2):223-30. · 6.71 Impact Factor
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05/2006;
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ABSTRACT: We present a photonic band gap (PBG) structure (or nonlinear photonic crystal) design for terahertz (THz) wave parametric generation, whose component materials have a small refractive index difference in the near infrared and a large index difference for THz waves. The structural dispersion of such a PBG structure is strong in the THz range but negligible in the optical range. The former allows the phase-matched pump wavelength to be placed in the near infrared to eliminate two-photon absorption of the pump and signal beams. The latter leads to a crystal layer fabrication tolerances of a few micrometers and traditional polishing methods are suitable for device fabrication. The added design flexibility also allows the use of the most efficient crystal orientations.
Optics Express 04/2006; 14(5):1933-41. · 3.59 Impact Factor
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ABSTRACT: Improved diagnostics capable of non-invasive detection of early stage carcinogenesis would benefit basic research, and potentially aid in clinical cancer diagnosis and management. The two-stage carcinogenesis protocol is widely used for studying the multi-stage nature of tumor development in mice and provides insight into tumor development in other animal models and humans. The objective of this study was to investigate the feasibility of non-invasive optical coherence tomography (OCT) for in vivo imaging of microanatomical changes in the epidermis and dermis during early carcinogenesis using a mouse skin model.
10 NIH mice were treated with DMBA and TPA following the well-established two-stage carcinogenesis protocol. OCT imaging of treated skin from live mice was performed at five time points (Week 4-8) after tumor initiation to reveal the structural changes in the epidermis and dermis associated with the earliest, premalignant stages of tumor development. OCT images were compared with histology findings. In addition, OCT signals were quantitatively analyzed to evaluate tissue optical property changes during early carcinogenesis.
Early structural changes in the epidermis, dermis and hair follicles during carcinogenesis were clearly delineated in vivo using OCT. OCT images correlated well with histological findings. Quantitative OCT signal analysis revealed a statistically significant change in the extinction coefficient for untreated (40.5 +/- 17.0 mm(-1)) and treated (9.6 +/- 3.6 mm(-1)) mouse epidermis (P < 0.005). The dermis extinction coefficient for the treated mouse skin (3.7 +/- 0.9 mm(-1)) was lower than the untreated one (4.7 +/- 1.6 mm(-1)), but was not statistically significant (P > 0.10). Furthermore, the papilloma extinction coefficient (2.9 +/- 0.3 mm(-1)) was significantly lower than the extinction coefficient for the treated epidermis (P < 0.005) and dermis (P < 0.01).
OCT is a viable tool for assessing the earliest stages of carcinogenesis and has potential for early detection of neoplasia in skin, as well as in epithelial linings of other organs.
Cancer biomarkers: section A of Disease markers 01/2006; 2(3-4):163-73. · 1.08 Impact Factor
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ABSTRACT: We describe a generic method to optimize the optical spectral throughput of a pair of acousto-optic modulators (AOM) which can be used for introducing a frequency shift in ultrahigh-resolution heterodyne optical coherence tomography. Systematic and quantitative analysis of a pair of AOMs indicates that a configuration with a spectral bandwidth of more than 200 nm at a center wavelength of 825 nm (tunable) can be achieved. Using a pair of AOMs in conjunction with a broadband low coherence light source, real-time imaging of biological tissues with an axial resolution ~3 microm (in air) has been experimentally demonstrated with a high-speed OCT system.
Optics Express 11/2005; 13(20):7816-22. · 3.59 Impact Factor
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ABSTRACT: We present an effective approach to manage dispersion compensation for a fiber-optic optical coherence tomography (OCT) imaging system in which an electro-optic (EO) phase modulator or an acousto-optic (AO) frequency modulator is used. To balance both the second and third order dispersion caused by the modulator, two independent optical components would be needed. The approach reported here combines a grating-lens delay line and an extra length of a single-mode optical fiber, enabling full compensation of the dispersion caused by the modulator up to the third order. Theoretical analysis of the proposed dispersion management scheme is provided. Experimental results confirmed the theoretical prediction and an optimal OCT axial resolution offered by the light source was recovered. The proposed method can potentially incorporate dynamic dispersion compensation for the sample during depth scanning.
Optics Express 12/2004; 12(24):5968-78. · 3.59 Impact Factor
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ABSTRACT: We developed a miniature endoscope that is capable of rapid lateral scanning and is suitable for real-time forward-imaging optical coherence tomography (OCT). The endoscope has an outer diameter of 2.4 mm, consisting of a miniature tubular lead zirconate titanate (PZT) actuator, a single-mode fiber-optic cantilever, and a graded-index lens. Rapid lateral scanning at 2.8 kHz is achieved when the fiber-optic cantilever is resonated with the PZT actuator. This allows OCT imaging to be performed by fast lateral beam scanning followed by slow depth scanning, which is different from the conventional OCT imaging sequence. Real-time OCT imaging with the endoscope operated in the new image acquisition sequence at 6 frames/s is demonstrated.
Optics Letters 09/2004; 29(15):1763-5. · 3.40 Impact Factor
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ABSTRACT: Ultrahigh-resolution optical coherence tomography (OCT) was used for noninvasive in vivo evaluation of the wound healing process. Cutaneous wounds were induced by 2.5-mm diameter full-thickness punch biopsies on the dorsal surface of seven mice. OCT imaging was performed to assess the structural characteristics associated with the healing process. The OCT results were compared to corresponding histology. Two automated quantitative analysis routines were implemented to identify the dermal-epidermal junction and segment the OCT images. Hallmarks of cutaneous wound healing such as wound size, epidermal migration, dermal-epidermal junction formation, and differences in wound composition were readily identified on the OCT images. Blister formation was also observed. Preliminary findings suggest OCT is a viable tool to noninvasively monitor wound healing in vivo.
Journal of Biomedical Optics 11(6):064002. · 3.16 Impact Factor
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ABSTRACT: We present a photonic band gap (PBG) structure design for terahertz (THz) wave parametric generation, which has crystal layer fabrication tolerance of a few micrometers and can be made with traditional polishing methods. This PBG structure consists of two component materials with a small refractive index difference at near infrared pump wavelengths and a large refractive index difference for THz waves. With this design the PBG device has optical properties very close to that of a bulk crystal in the near infrared, but photonic crystal features in the THz range, such as structural dispersion, which allows placement of the phase matched pump wavelength in the near infrared to eliminate two-photon absorption of the pump and signal beams. The added design flexibility also allows the use of the most efficient crystal orientations. Potential applications of this THz PBG structure are discussed
Aerospace Conference, 2006 IEEE;
