Effect of Neutrophil Extracellular Traps on Thrombolysis by tPA Characterized by Clot Mechanical Properties and CT Radiomics

Ischemic stroke, a leading cause of morbidity and mortality, often fails to achieve successful reperfusion following thrombolytic therapy with tissue plasminogen activator (tPA) or mechanical thrombectomy (MT). Clot composition, particularly mechanical stiffness, plays a critical role in treatment resistance. Neutrophil extracellular traps (NETs), DNA-based scaffolds released by neutrophils, contribute to clot stability and may influence thrombolysis efficacy and mechanical retrieval. This study investigates the impact of NETs on clot material properties and CT radiomic characteristics before and after tPA treatment. Using a NET-enriched clot analogue model induced by lipopolysaccharide (LPS), we performed thrombolysis experiments, mechanical testing (tensile and compressive), and microCT imaging. NET-rich clots exhibited greater mechanical resistance, with higher breaking strength and Young's modulus, and showed limited structural changes following tPA treatment. In contrast, NET-less clots exhibited significant softening after thrombolysis. Compression testing further demonstrated that tPA treatment increased clot stiffness in NET-rich clots but had no significant effect on NET-less clots. MicroCT imaging revealed distinct textural differences, with NET-rich clots appearing more homogeneous and resistant to post-thrombolysis structural alterations. Quantitative radiomic analysis identified multiple imaging features significantly correlated with clot mechanical properties, particularly for compressive modulus and stress. These findings highlight NETs as a key determinant of thrombolysis resistance and suggest that microCT radiomics may serve as a non-invasive tool to predict clot mechanics, potentially guiding MT strategies and improving stroke treatment outcomes.