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Show 360 Spatial Frequency Domain Imaging of a Facial Tissue Phantom of Known Optical Properties Stephanie Kirk 1, Shijun Sung 2, Kaylyn Mattick 2, Miranda An 2, Divya Devineni 2, Gordon Kennedy 3, Anthony Durkin 3, Lilangi Ediriwickrema 3 University of California Irvine, 2 University of California Irvine, School of Medicine, 3 Beckman Laser Institute, University of California Irvine 1 Introduction: Spatial frequency domain imaging (SFDI) is a wide-field optical imaging modality that applies patterned illumination at multiple center wavelengths (470-851 nm) to quantify the properties and chromophore concentrations of sub-surface tissue. Its application to the periocular region facilitates mechanistic understanding of inflammatory conditions such as thyroid eye disease (TED) by quantifying parameters such as tissue oxy- and deoxy hemoglobin concentrations (hence oxygen saturation). The periocular anatomy is unique due to complex ocular adnexal anatomy. We, therefore, explored the potential geometric impact of neighboring bony (nasal process of the maxilla, nasal bone, supraorbital rim, lateral zygoma) and soft tissue (nasal cartilage and anterior projection, brow ptosis) regions on the validity of SFDI measurements by imaging a fabricated facial phantom. Methods: We cast a polydimethylsiloxane-based tissue-simulating facial phantom having homogeneous known optical properties. The phantom was placed on a chin rest and imaged nine times from two positions; ‘en face’ and ‘side profile’. Between each pair of measurements, the phantom was removed and replaced on the chin rest. The flat back of the phantom was measured after being removed and replaced on a cart 15 times. Mean optical properties were calculated for 4 5x5 mm regions of interest (ROIs): inferior temporal, inferior nasal, superior temporal, and forehead control. Results: The measured absorption and reduced scattering coefficients are reproducible when comparing the facial phantom to those of its flat posterior surface. ROIs were not distinct (two sample test p-value >0.05), and the imaging orientation (‘en face’ vs. ‘side profile’) did not impact the measurements. Conclusions: This study demonstrates that the periocular profile with its elevation and adjacent structures does not impact, or bias SFDI measurements at the ROI locations selected, suggesting promise for imaging the periocular region of human subjects and obtaining biological indices of tissue optical characteristics and chromophore distribution. References: None provided. Keywords: Diagnostic tests (ERG, VER, OCT, HRT, mfERG, etc), Orbit/ocular pathology, Neuro-ophth & systemic disease ( eg. MS, MG, thyroid) Financial Disclosures: Stephanie Kirk; Shijun Sung; Kaylyn Mattick; Miranda An; Divya Devineni; Gordon Kennedy; Anthony Durkin: Dr. Durkin has a financial interest in Modulating Imaging, Inc., which developed the Reflect RS(TM). However, Dr. Durkin does participate in the management of Modulated Imaging and has not shared these results with that company. Conflicts of interest have been disclosed and managed in accordance with the University of California and NIH Policies.; Lilangi Ediriwickrema Grant Support: NIH and UC Irvine’s Translational Science (UCI ICTS NIH KL2 Grant KL2 TR001416) Research to Prevent Blindness unrestricted grant to UCI Ophthalmology National Institute of General Medical Sciences (NIGMS) Grant No. R01GM108634 Contact Information: Stephanie Kirk, kirksd@uci.edu 2024 Annual Meeting Syllabus | 515 |
