Monday, February 06, 2023

Vortex ultrasound tool breaks down blood clots in the brain

Good news! This new treatment option may make a huge positive difference in the outcomes of stroke events, between ending up in a permanent vegetative state or much better!

"... The device ... eliminated clots faster than existing techniques, and could restore blood flow through a completely blocked in vitro model of CVST in just 8 min. ...
In a technique known as sonothrombolysis, ultrasound is used to cavitate microbubbles surrounding a clot, causing it to break down. Compared with conventional anticoagulant or thrombolytic drugs that dissolve the blood clot, sonothrombolysis has potential to remarkably reduce the required treatment time. Previous strategies, however, have not been clinically effective when treating large, completely occluded veins or arteries. ...
The researchers created a vortex ultrasound transducer using a 2 x 2 array of small-aperture, low-frequency (1.8 MHz) piezoelectric transducers. Assembling the array with a quarter-wavelength (0.21 mm) shift between the forward-viewing surfaces of neighbouring transducers induces the physical phase delay required to generate a helical wavefront. ..."

From the abstract:
"This research aims to demonstrate a novel vortex ultrasound enabled endovascular thrombolysis method designed for treating cerebral venous sinus thrombosis (CVST). This is a topic of significant importance since current treatment modalities for CVST still fail in as many as 20-40% of the cases and the incidence of  CVST  has  increased  since  the  outbreak  of  the  COVID-19  pandemic.  Compared  with  conventional  anticoagulant or thrombolytic drugs, sonothrombolysis has the potential to remarkably shorten the required treatment  time  owing  to  the  direct  clot  targeting  with  acoustic  waves.  However,  previously  reported  strategies for sonothrombolysis have not demonstrated clinically meaningful outcomes (e.g., recanalization within 30 minutes) in treating large, completely occluded veins or arteries. In this paper, we demonstrated a  new  vortex  ultrasound  technique  for  endovascular  sonothrombolysis  utilizing  wave-matter interaction-induced shear stress to enhance the lytic rate substantially. Our in vitro experiment showed that the lytic rate was increased by at least 64.3 % compared with the nonvortex endovascular ultrasound treatment. A 23.1 g, 7.5 cm long, completely occluded invitro 3D model of acute CVST was fully recanalized within 8 minutes  with  a  record-high  lytic  rate  of  237.5  mg/min  for  acute  bovine  clot  in  vitro.  Furthermore,  we  confirmed that the vortex ultrasound causes no vessel wall damage over ex vivo bovine veins. This vortex ultrasound thrombolysis technique potentially presents a new life-saving tool for severe CVST cases that cannot be efficaciously treated using existing therapies."

Vortex ultrasound tool breaks down blood clots in the brain – Physics World




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