Endoscopic optical coherence tomography (eOCT), a depth-resolved, non-invasive, three-dimensional imaging technique, enables morphologic and functional examinations of the human tympanic membrane (TM) in vivo. To overcome the limitation of intensity-based OCT in tissue differentiation, light polarization is used here to assess collagen fibers as birefringent tissue. A fiber-based polarization-sensitive eOCT system was realized for first in vivo examinations of the TM’s collagen fiber layer, on which the acoustic and mechanical properties depend. By evaluating the local retardation, distinguishing the TM’s different tissues was possible and a comparison to microscopic ex vivo measurements was made.

Otitis media or middle-ear infection is a widespread bacterial/viral disease. Antibiotic-resistant bacteria within biofilms emerge during chronic ear infections and are challenging to treat. We explored Raman spectroscopy (RS) and Optical Coherence Tomography (OCT) to identify and compare unique spectroscopic and microstructural features from primary otopathogenic bacteria in colony, planktonic, and biofilm forms, in vitro. RS was utilized to identify biochemical fingerprints and OCT was used to generate depth-resolved 2D and 3D images to compare refractive indices and optical attenuation coefficients. A combined RS-OCT system will enable real-time visualization and diagnosis of bacterial OM at the point-of-care.

Several studies have already demonstrated that near infrared autofluorescence (NIRAF) detection can be reliably used to detect parathyroid glands (PGs) in adults. However, its scope remains unexplored in the pediatric population, who are more prone to accidental PG damage during neck surgeries. Our preliminary findings obtained from pediatric patients who underwent thyroidectomies, indicate a PG detection rate of 94.4% using NIRAF detection with a fiber-optic probe-based approach. Due to the complexities associated with surgeries performed through tiny neck incisions in the pediatric population, the fiber-optic probe-based NIRAF detection can be valuable for real-time label-free PG identification during pediatric neck surgeries.

In human airway, the ciliated cells and mucus are the first line of defense against inhaled pathogens and particulates, preventing them from invading the rest of the respiratory system. Ciliary dysfunction can quickly develop into a vulnerability for patients with acute and/or chronic diseases, including cystic fibrosis, asthma, chronic obstructive pulmonary disease, and primary cilia dyskinesia. Ciliary beating frequency (CBF) can provide a good standard for determining cilia functionality. In this study, we developed a homemade prototype front-facing endoscope based on a spectrally encoded interferometric microscopy (SEIM) system using a phase-resolved Doppler (PRD) algorithm to measure and map the ciliary beating frequency within an en face region. We evaluated the capability of assessing the CBF ex vivo. This study is the steppingstone to in-vivo studies and the translation of mapping spatial CBF in clinics.

We present a miniaturized ultrafast laser surgery probe for vocal fold restoration therapy. Previous benchtop studies have shown that sub-epithelial voids can be created within scarred vocal folds via ultrafast laser ablation to improve the localization of injected therapeutic biomaterials. Clinical translation of this laser surgery technique requires miniaturized high numerical aperture optical systems to treat scarred vocal folds within intact human larynges. The probe presented here provides the small form factors, high pulse energy delivery, and tight beam focusing required for sub-epithelial void formation in scarred vocal folds in vivo. We created large sub-epithelial voids within porcine hemilarynges and injected fluorescently-tagged hydrogels into these voids to demonstrate the probe’s expected performance in vivo. We conclude by discussing integration of the probe into a transportable system as well as future studies to assess clinical viability of this system.

Multispectral autofluorescence lifetime imaging (maFLIM) endoscopy can be used to clinically image a plurality of metabolic and biochemical autofluorescence biomarkers of oral precancer and cancer. We tested the hypothesis that maFLIM-derived autofluorescence biomarkers can be used as features in machine-learning models to automatically discriminate precancerous and cancerous from healthy oral tissue. Clinical widefield maFLIM endoscopy images of cancerous and precancerous oral lesions from 57 patients were acquired and used to develop and validate a computer-aided detection (CAD) system. This study demonstrates the potentials of a maFLIM endoscopy-based CAD system for automated in situ clinical detection of oral precancer and cancer.

Multispectral autofluorescence endoscopy is a non-invasive optical imaging modality that can provide contrast between malignant and benign oral tissue. We hypothesized that discrimination of cancerous and precancerous from benign oral lesions can be achieved through machine-learning (ML) models developed with multispectral autofluorescence intensity features. In vivo multispectral autofluorescence endoscopic images of benign, precancerous, and cancerous oral lesions were acquired from 67 patients and used to optimize ML models for discrimination between cancerous/precancerous and benign lesions. This study demonstrates the potentials of a ML-assisted system based on multispectral autofluorescence endoscopy for automated discrimination of cancerous and precancerous from benign oral lesions.

Increased cellular metabolic activity, a hallmark of malignant epithelial cells, can be quantified by imaging the oral tissue autofluorescence originated from the metabolic cofactors NADH and FAD. We report a novel multispectral autofluorescence lifetime imaging (maFLIM) handheld probe capable of simultaneous autofluorescence excitation at 375 nm (for NADH) and 445 nm (for FAD), and simultaneous multispectral time-resolved fluorescence measurement at four emission spectral channels. The performance of the dual-wavelength excitation maFLIM handheld probe was assessed by imaging fluorescent dye standards with well characterized fluorescence lifetimes, and the oral mucosa of human subjects in oral health care settings.

Increased cellular metabolic activity can be quantified by imaging the oral tissue autofluorescence originated from NADH and FAD. Clinical label-free metabolic imaging of oral epithelial cancer based on 375-nm excitation maFLIM endoscopy was recently demonstrated in patients presenting oral malignant lesions. A recently upgraded maFLIM endoscopy system enables simultaneous autofluorescence excitation at 375 nm (for NADH) and 445 nm (for FAD). This maFLIM endoscope is being used to clinically image healthy, benign, precancerous and cancerous oral lesions in oral health care settings. Comprehensive statistical analysis will be performed to identify new metabolic and biochemical autofluorescence biomarkers of oral epithelial cancer.

Concerning the usage of non-invasive optical techniques for oral cancer detection, the presented study dealt with the manual and semi-automatic measurement of oral epithelial thickness by means of optical coherence tomography (OCT). Here, a total of 3,510 OCT images out of seven areas of the oral cavity was analyzed. In the result, epithelial thickness varied from 77 µm to 704 µm. Beyond that, there was a good correlation between both methods (ρ = 0.71-0.96). With regard to clinical routine use, manual epithelial thickness measurement could be beneficial due to a currently lower time investment with comparable precision.