MR-Guided Focused Ultrasound for Acute Stroke

Recent developments in thrombolysis therapy using tissue Plasminogen Activator (tPA) in combination with ultrasound for noninvasive stroke treatment are of great excitement.1–5 The first clinical trials have been successfully initiated, demonstrating the potential benefit of transcranial ultrasound in combination with tPA as an effective vessel recanalizing treatment strategy.6–10 The use of tPA, however, is limited because of its various exclusion criteria, its availability, and its costs. Depending on the literature, the number of patients with stroke receiving tPA treatment ranges between 1.6%11 and 9%,12 averaging 3% to 4% worldwide. Hence, novel treatment options in stroke are in high demand. Neurointerventional methods for mechanical clot retrieval in acute stroke show great potential13–16 but are currently limited to highly specialized centers. Alternative strategies to treat stroke noninvasively and in the absence of tPA might be provided by innovative ultrasound technologies, such as transcranial focused ultrasound (FUS). First investigations in this regard have emphasized the high potential of successful clot lysis in combination with17,18 but, more so, in the absence of tPA.19,20 Very recently, successful transcranial clot lysis within seconds and without the use of tPA has been demonstrated using one of the first transcranial FUS head systems worldwide, designed for therapeutic FUS applications in humans.21In the following report, the results of recent in vitro studies, first in vivo data using a novel sonothrombolysis model, and a future concept for …