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S. Pfaffenberger, B. Devcic-Kuhar, C. Kollmann, S.P. Kastl, C. Kaun, W.S. Speidl, T.W. Weiss, S. Demyanets, R. Ullrich, H. Sochor, C. Wöber, J. Zeitlhofer, K. Huber, M. Gröschl, E. Benes, G. Maurer, J. Wojta, M. Gottsauner-Wolf:
"Can a Commercial Diagnostic Ultrasound Device Accelerate Thrombolysis ?: An In Vitro Skull Model";
Stroke, 36 (2005), 124 - 128.

Background and Purpose: Recently 3 clinical trials revealed encouraging results in recanalization and clinical outcome in acute stroke patients when 2 MHz transcranial Doppler monitoring was applied. This study investigated whether a 1.8-MHz commercial diagnostic ultrasound device has the potential to facilitate thrombolysis using an in vitro stroke model.
Methods: Duplex-Doppler, continuous wave-Doppler and pulsed wave(PW)-Doppler were compared on their impact on recombinant tissue plasminogen activator (rt-PA)-mediated thrombolysis. Blood clots were transtemporally sonicated in a human stroke model. Furthermore, ultrasound attenuation of 5 temporal bones of different thicknesses was determined.
Results: In comparison only significantly PW-Doppler accelerated rt-PA-mediated thrombolysis significantly. Without temporal bone, PW-Doppler plus rt-PA showed a significant enhancement in relative clot weight loss of 23.7% when compared to clots treated with rt-PA only (33.9%±5.5% versus 27.4%±5.2%; P<0.0005). Ultrasound attenuation measurements revealed decreases of the output intensity of 86.8% (8.8dB) up to 99.2% (21.2dB) depending on temporal bone thicknesses (1.91 to 5.01mm).
Conclusion: Without temporal bone, PW-Doppler significantly enhanced thrombolysis.. However, because of a high attenuation of ultrasound by temporal bone, no thrombolytic effect was observed in our in vitro model, although Doppler imaging through the same temporal bone was still possible.

http://aleph.ub.tuwien.ac.at/F?base=tuw01&func=find-c&ccl_term=AC05937965