Combined Photoacoustic and Ultrasound Imaging for Enabling Quantitative Evaluation of Hidradenitis Suppurativa - PROJECT SUMMARY/ABSTRACT: Hidradenitis suppurativa (HS), which affects approximately 6 million people in the United States, is a debilitating chronic inflammatory disease of the skin and subcutaneous tissue. HS presents as painful abscesses, boils, nodules, and fistulous tracts and patients with HS had the highest morbidity of all skin diseases. Treatment plans can average 14 years with patients trying multiple options to find relief. Even excisional surgeries have a high recurrence rate. Currently, clinical assessments of HS are accomplished through visual inspection and palpation, which underestimate disease stage and severity. Histological analysis identifies changes in vascularization, emerging fluid buildups, emerging tunnels, and structural changes in collagen, keratin and lipids not visible by clinical inspection. Ultrasound (US) imaging can aid in HS diagnosis and staging, but is infrequently used in the United States and is limited to detection of structural defects. Using optical excitation and acoustic detection, photoacoustic (PA) imaging has the capability to detect many biomarkers of HS identified by histology and could aid in HS diagnosis and treatment planning. The PI, an expert on PA imaging, has led a number of observational trials involving human imaging and has gathered input from dermatologists, pathologists, radiologists and HS surgeons on desired specifications for an HS imaging system. Here, he has assembled a strong team which has the background, experience and expertise to design, develop and test a portable PA/US imaging system with an easy-to-use hand-held probe for HS. The system, which will collect and analyze PA/US 3D volumes of an entire skin section, will include an algorithm that will automatically generate an HS likelihood map that calculates probability of HS involvement voxel-by-voxel across an entire imaging area. This goal will be accomplished through three Specific Aims: 1) Development of a 3D PA/US system with a hand-held probe to create volumetric data from HS lesions. The system and all components will be designed, optimized, and tested. 2) Identify and validate HS-specific PA biomarkers and use them to generate HS likelihood maps. We will collect PA/US data from subjects with HS and quantify biomarkers associated with HS. The biomarkers will then be used to generate a likelihood map, whose accuracy will be validated using healthy controls and histology data. 3) Demonstrate capability of 3D PA/US for (a) planning excisional surgeries by comparing PA proposed surgical volumes with 3D projections of the surgeon’s photographed surgical outline and (b) analyzing effectiveness of pharmaceutical treatments by comparing likelihood scores with clinical scores of treatment response. Impact. HS is typically assessed by visual inspection, palpation, and patient history. The proposed PA/US imaging system and associated HS-detection algorithm (the likelihood map) not only holds promise for reducing HS morbidity in direct clinical use by enabling more accurate surgeries and better-targeted pharmacological treatments, but will also assist future HS investigators to develop more effective drugs and individualized therapeutic strategies.
