A Systemic embolization model in a rat with real-time micro-fluoroscopy for direct quantification of thrombolysis.

Recanalization after intravenous thrombolysis remains incomplete in many stroke patients, highlighting the need for standardized preclinical methods to evaluate thrombolytic therapies. We developed a rat systemic embolization model combined with high-resolution micro-fluoroscopy enabling direct, real-time, and quantitative assessment of thrombolysis in vivo. Human fibrin-based BaSO₄ labeled clots were introduced into the abdominal aorta (three clots/animal) to assess alteplase (rtPA) efficacy at doses of 0.9 and 5 mg/kg/h. Micro-CT imaging served as a reference modality. Micro-fluoroscopy continuously visualized clot dissolution, detecting a mean of two clots per animal. Thrombolysis resulted in a dose-dependent reduction in clot area (mean ± SD; -46 ± 26% and -81 ± 22% for 0.9 and 5 mg/kg/h rtPA, respectively, versus -21 ± 14% in controls). Measurement reliability was high (ICC = 0.89), and concordance with micro-CT supported concurrent validity. The model demonstrated predictive and construct validity, and offers technically feasible, reproducible, and standardized platform for pharmacodynamic evaluation of thrombolytic agents.•A systemic embolization model with C-arm micro-fluoroscopy enables direct, real-time visualization of thrombolysis in vivo.•Applying multiple clots per animal reduces the total number of animals required.•The model allows standardized, reproducible testing of thrombolytics with translational relevance.