Handheld Spatial Frequency Domain Imaging (SFDI) to measure skin involvement in Scleroderma

Boston University (Charles River Campus), Boston MA

Investigators

Abstract

PROJECT SUMMARY Scleroderma, or systemic sclerosis (SSc) is a chronic, autoimmune disorder, characterized by skin and internal organ fibrosis. There are no uniformly effective therapies for SSc, which suffers from the highest mortality of all autoimmune diseases, with a 10-year survival rate of 62-65%. Early diagnosis enables timely intervention, potentially preventing internal organ damage and improving survival. The extent and progression of skin involvement is a predictor for future organ complications and survival. Accurately assessing the degree of skin thickening in patients with SSc is thus of vital importance, and one of the primary outcome measures in SSc clinical trials. The current clinical standard of scleroderma skin assessment is the modified Rodnan Skin Score (mRSS). mRSS is an integer score between 0-3, assigned to different regions of the body based on subjective assessment of skin thickening by clinical palpation. mRSS is an unreliable metric, with intrinsic technical challenges such as a poor inter-observer variability and uncertainty regarding its sensitivity to longitudinal changes. There is a need for a reliable, objective and quantitative metric to assess skin involvement in scleroderma. In this project, Spatial Frequency Domain Imaging (SFDI), a non-invasive, wide-field diffuse optical imaging technique is proposed as an objective, repeatable and quantitative alternate to mRSS. SFDI uses near infrared light to generate widefield images of tissue optical properties (diffuse reflectance (Rd), absorption (µa) and reduced scattering coefficients (μs′)) at subsurface depths. Preliminary clinical data shows that μs′ and Rd can differentiate between patient and control groups, correlate well with mRSS, and detect sub- clinical changes in early SSc. To advance SFDI towards a usable research and clinical device for SSc, this project aims to build a handheld SFDI device and validate its use for SSc skin assessment. For clinical translation, this device will need to reliably measure all regions of the body quickly and provide real-time information to the clinician. Using a new innovation developed in our lab that employs a rotating spiral pattern for SFDI to measure both optical properties and scattering anisotropy, a simplified, hand-held clinical device will be developed. Next, a processing pipeline will be developed, which will provide a real time SSc “score” to the clinical provider. Finally, the device will be validated on a cohort of SSc patients and controls. This project aims to develop an easy-to-use and scalable device that would improve clinicians’ ability to monitor SSc, develop treatment plans, and could be used for multi-site clinical studies for SSc and other skin diseases.