Abstract Number: Esoc2026ys65 Dual Ultrasound/Photoacoustic Imaging for Ex Vivo Characterization of Carotid Atherosclerotic Plaques: Study Protocol and Preliminary Feasibility

Abstract Background and aims The severity of carotid artery stenosis is currently the main criterion for indication of revascularization treatment for stroke prevention. However, stroke risk is influenced by plaque vulnerability—specifically the presence of a lipid-rich necrotic core, intra-plaque hemorrhage, and inflammation. Current imaging modalities (Duplex Ultrasound –DUS-, CTA, MRA) have limited sensitivity for these specific components. Dual ultrasound/photoacoustic systems provide multimodal characterization by combining high-resolution structural data with optical absorption contrast. Ultrasound provides geometrically accurate morphology and internal echogenic patterns, while photoacoustic imaging enables selective sensitivity to blood-containing regions and detection of other molecular components. We propose a study to validate a novel, portable, and low-cost ultrasound/photoacoustic system to identify plaque vulnerability. We hypothesize that it will demonstrate high correlation with histological vulnerability markers, potentially offering a new, accessible, and radiation-free tool for precise risk stratification in clinical practice. Methods A prospective, observational, analytical study involving consecutive patients undergoing carotid endarterectomy. Pre-operative plaque characterization includes DUS and CTA, classified according to Plaque-RADS. Immediately post-surgery, fresh specimens undergo ultrasound/photoacoustic acquisition using a portable system based on pulsed laser diodes. Histological and immunohistochemical analysis is performed to quantify lipid content (Oil Red O/Sudan), inflammation (CD68), neovascularization (CD31/CD34), and hemorrhage (Glycophorin A), alongside Hematoxylin-Eosin staining. Optoacoustic signals will be correlated spatially and quantitatively with histological findings and pre-operative imaging (CTA/Ultrasound). Results Recruitment is ongoing (n=39) with a target sample size of 50 plaques. The acquisition protocol and histological processing have been standardized, and preliminary ex vivo imaging has confirmed technical feasibility. Conflict of interest Eduardo Mariño: nothing to disclose