In vitromicroscopic imaging of enhanced thrombolysis with 120-kHz ultrasound in a human clot model

Substantial enhancement of recombinant tissue plasminogen activator (rt-PA) thrombolysis can be achieved with ultrasound, suggesting its use as an adjunctive treatment in thrombolytic therapy for stroke. A microscopic visualization method was used to measure the lysis of human whole-blood clots treated with human fresh frozen plasma (HFFP), rt-PA, and 120-kHz ultrasound for 30 min at $\text{T=37\hspace{0.05em}°}\mathrm{C}.$ The clot–plasma interface was imaged using an inverted optical microscope and the thrombolytic front analyzed as a function of time. Ultrasound treatment significantly enhanced the mean lytic rate from 0.5 to 3.4 μm/min (a 580% change) compared with rt-PA treatment alone.