Combining anticoagulation and rtPA therapy induces carotid artery embolization. Electrolytic injury of the left carotid artery in C57BL/6 male mice was performed in a separate mouse cohort, with animals administered the platelet label DyLight488 before electrolytic injury (where indicated). (A) Real-time imaging of thrombolysis was conducted post-carotid occlusion, using the mouse carotid artery transilluminator, as described in the Methods. Thrombolytic therapy (vehicle control, rtPA, rtPA/argatroban) was delivered IV at 15 minutes’ post-occlusion and imaging conducted for 60 minutes after treatment onset. Images presented are 1 example, from 30 to 58 minutes’ posttreatment onset (platelets = white; erythrocytes = red). Inset: Embolization events at 48 minutes (48’00’’) posttreatment onset, with platelet mass outlined by broken lines, and quantification of embolization incidence presented in panel B. (C) Global cerebral perfusion (LCSI) was assessed pre-injury (baseline) and 90 minutes’ post-occlusion for the same mouse presented in panel A. The carotid artery was confirmed to be patent immediately before and immediately after collection of the LSCI reading. (D) At 90 minutes’ post-occlusion, the brain from the mouse depicted in panels A and C was excised and imaged with a Nikon AZ100 Multizoom Macroscope (i, ii) and postimaging processing performed by using Nikon NIS-Element’s Clarify.ai algorithm module. (ii) Confocal imaging of platelet embolus was performed by using a Leica SP8 confocal system and the three-dimensional data set acquired by using LAS X (version 3.5.7). Three-dimensional data were rendered by using Imaris version 9.8. Treatment dosing regimens: rtPA (10 mg/kg [1/9 mg/kg bolus/infusion over 30 minutes]); argatroban (80 µg/kg bolus; 40 µg/kg/min infusion over 60 minutes). Scale bars = 1 mm (panel Di); 30 = µm (panel Dii).