Project Summary/Abstract
Timely diagnosis of stroke (ischemic vs. hemorrhagic) is critical to streamlining appropriate treatment and
achieving optimal clinical outcomes–minimizing damage to brain tissue and function. About 87% of strokes are
ischemic, with large vessel occlusions (LVOs) accounting for >90% of deaths among this subset. Patients with
LVOs are best treated with mechanical thrombectomy at a certified comprehensive stroke center (CSC) hospital
as soon as possible, but the nearest non-CSC stroke-care facility may lack this interventional catheterization
capability. Transcranial Doppler (TCD) ultrasound can measure vascular flow and detect LVOs, but current TCD
equipment has high operator dependence: to acquire a TCD signal, the user must simultaneously find the optimal
“acoustic window” of a patient’s skull and precisely align the ultrasound beam with the middle, anterior, or posterior
cerebral arteries.
We propose to design a transcranial ultrasound device that enables paramedics to identify LVOs quickly
and easily as part of stroke triage, to reduce the time to tPA and thrombectomy treatment delivery (by tens of
minutes to >1 hour) and improve ischemic stroke outcomes. This new TCD device will include a customized 2D
transducer array that can (1) sample and map trends in acoustic properties over an area of the skull and (2) detect
angled wavefronts from moving blood scatterers within the beam. To achieve this design, our team–consisting
primarily of undergraduates–will take thorough experimental acoustic measurements of ex vivo skull, acquire
transskull Doppler measurements on a custom phantom using a commercial array probe, and perform transskull
simulations of unique transducer array geometries. These efforts will pinpoint ideal acoustic windows and yield a
high-resolution, digital acoustic model of temporal skull, provide signals from which to refine an algorithm to guide
the placement and angle of a TCD transducer, and ultimately optimize the layout and operation of a custom 2D
array streamlined for TCD acquisition (and LVO detection) by untrained users.
This project will lead to further research (prototype fabrication and in vivo testing) and applications in detecting
and monitoring various neurological and cardiovascular conditions. Long-term, we envision cost-effective, user-
friendly TCD used in ambulatory care units across the country, and improved transcranial imaging and therapy
capabilities as well. The project will provide a closely mentored biomedical research experience to a diverse
set of undergraduates, whose success as researchers and role models will significantly impact and enhance the
research environment at the University of Memphis and collaborating institutions across the Mid-South.
