Handheld Spatial Frequency Domain Imaging using Spiral Illumination for Skin Imaging

Skin pathologies affect one in four Americans and their diagnosis often requires expert consultation and invasive procedures. Our team has recently focused on one such conditional called systemic sclerosis (SSc), which is a debilitating autoimmune connective tissue disease, with the highest mortality among all autoimmune diseases, exceeding that of lupus as well as cancers including breast and melanoma. Early diagnosis and identification of high-risk patients is of vital importance as early therapeutic intervention significantly improves survival. Dermal thickening and skin tightening are cardinal features of the disease, but these are often subtle in early phases, leading to delays in the diagnosis and missed opportunities for early intervention. Unfortunately, there are no objective and repeatable methods to detect small but clinically meaningful changes in skin involvement. There is a pressing need to find a better method to monitor skin in SSc. We have recently shown that spatial-frequency domain imaging (SFDI) holds promise for revealing the degree of skin involvement in SSc. SFDI is a non-invasive and label free optical technique that generates widefield images of tissue optical properties (absorption (μa) and reduced scattering coefficients (μs´)). Our team was the first to apply SFDI in SSc, and our preliminary data show that: 1) μs´ can detect skin changes missed by expert manual palpation; 2) μs´ correlates well with skin thickness, histologic parameters, and manual palpation; 3) μs´ can detect longitudinal skin changes in patients. While these results are promising, the specific skin features identified by μs´ remain unclear. Additionally, SFDI is currently a benchtop technology, not suited for everyday use in clinical settings. We have recently discovered that the use of a rotating spiral pattern can simultaneously provide highly accurate measurements of optical properties while greatly simplifying device design, opening the door to handheld and endoscopic applications. Additionally, the rotating pattern intrinsically provides measurements of scattering anisotropy, which provides additional diagnostic information. We will leverage these innovations to develop the first clinical handheld SFDI system that provides point-of-care measurements of SSc (Aim 1), which will serve as a testbed for validating this technology while opening the door for use in other diseases. The design will be informed by a feature selection analysis performed on our preliminary data to identify the imaging parameters that correlate with key metrics of skin involvement across a diverse patient population. Next, we will develop a processing pipeline to provide a real-time measurement to the clinical provider (Aim 2). Benchmarks include full body imaging in <10 min. Finally, we will validate handheld SFDI in SSc patients (Aim 3). N=75 SSc patients and N= 36 matched healthy controls will be assessed. If successful, this project will provide an easy-to-use and scalable device that can be used for multi-site clinical studies for SSc and many other skin diseases. Furthermore, the spiral pattern SFDI technique developed here may have applications beyond this proposal, especially in endoscopy and multimodal imaging. Project Number: 1R01EB037660-01 | Fiscal Year: 2025 | NIH Institute/Center: National Institute of Biomedical Imaging and Bioengineering (NIBIB) | Principal Investigator: Darren Roblyer (+1 co-PI) | Institution: BOSTON UNIVERSITY (CHARLES RIVER CAMPUS), BOSTON, MA | Award Amount: $619,926 | Activity Code: R01 | Study Section: Imaging Technology Development Study Section[ITD] View on NIH RePORTER: https://reporter.nih.gov/project-details/1R01EB03766001