Oral lesions are conventionally diagnosed using white light endoscopy and histopathology. This can pose a challenge because the lesions may be difficult to visualise under white light illumination. Confocal laser endomicroscopy can be used for confocal fluorescence imaging of surface and subsurface cellular and tissue structures. To move toward real-time "virtual" biopsy of oral lesions, we interfaced an embedded computing system to a confocal laser endomicroscope to achieve a prototype three-dimensional (3-D) fluorescence imaging system. A field-programmable gated array computing platform was programmed to enable synchronization of cross-sectional image grabbing and Z-depth scanning, automate the acquisition of confocal image stacks and perform volume rendering. Fluorescence imaging of the human and murine oral cavities was carried out using the fluorescent dyes fluorescein sodium and hypericin. Volume rendering of cellular and tissue structures from the oral cavity demonstrate the potential of the system for 3-D fluorescence visualization of the oral cavity in real-time. We aim toward achieving a real-time virtual biopsy technique that can complement current diagnostic techniques and aid in targeted biopsy for better clinical outcomes.
Oral lesions are conventionally diagnosed using white light endoscopy and histopathology of biopsy samples. Oral
lesions are often flat and difficult to visualize under white light illumination. Moreover, histopathology is timeconsuming
and there is a need to develop minimally invasive optical biopsy techniques to complement current
techniques. Confocal laser endomicroscopy holds promise for virtual biopsy in disease diagnosis. This technique enables
fluorescence imaging of tissue structures at microscopic resolution. We have developed a prototype real-time 3-
dimensional (3D) imaging system using a laser endomicroscope interfaced with embedded computing. A Field-
Programmable Gate Array computing platform has been programmed to synchronize cross-sectional image grabbing and
Z-depth scanning, as well as automate acquisition of confocal image stacks. A PC was used for real-time volume
rendering of the confocal image stacks. We conducted pre-clinical and pilot clinical studies to image the murine and
human oral cavity. High quality volume renderings of the confocal image stacks were generated using 3D texture slicing.
Tissue morphology and 3D structures could be visualized. The results demonstrate the potential of the system for
diagnostic imaging of the oral cavity. This paves the way toward real-time virtual biopsy of oral lesions, with the aim to
achieve same-day diagnosis in a clinical setting.
Oral cancers are currently diagnosed using white light endoscopy and histopathology. However, oral tumours are mostly
superficial and can be difficult to visualise. Here we present the use of hypericin with fluorescence endoscopy and laser
confocal fluorescence endomicroscopy interfaced with embedded computing for the diagnosis of oral cancers.
Fluorescence imaging of oral lesions was carried out in the clinic using a fluorescence endoscope. The images were
analyzed to extract the red to blue (R/B) ratios to discriminate between tissue types. The results showed that the R/B
ratio is a good image parameter to discriminate between normal, hyperplastic and malignant oral tissue. We are also
developing an embedded, real-time computing system interfaced to a fluorescence endomicroscope for 3D visualization
of tumors, where synchronization of cross-sectional image grabbing and Z-depth scanning is realized through
programming a Field-Programmable Gate Array. In addition to the programming task, a proprietary control circuit has
been developed for the automated 3D reconstruction of fluorescence sections; and preliminary results from fluorescent
samples have demonstrated the potential of this system for real-time in vivo 3D visualization of tumours. This will
ultimately enable same-day clinical diagnosis to be achieved and further enhance the clinical usefulness of fluorescence
diagnostic imaging.
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