Enhancement of cerebrospinal fluid tracer movement by the application of pulsed transcranial focused ultrasound

Seung Schik Yoo, Hyun Chul Kim, Jaeho Kim, Evgenii Kim, Kavin Kowsari, Jared Van Reet, Kyungho Yoon

Research output: Contribution to journalArticlepeer-review

3 Citations (Scopus)


Efficient transport of solutes in the cerebrospinal fluid (CSF) plays a critical role in their clearance from the brain. Convective bulk flow of solutes in the CSF in the perivascular space (PVS) is considered one of the important mechanisms behind solute movement in the brain, before their ultimate drainage to the systemic lymphatic system. Acoustic pressure waves can impose radiation force on a medium in its path, inducing localized and directional fluidic flow, known as acoustic streaming. We transcranially applied low-intensity focused ultrasound (FUS) to rats that received an intracisternal injection of fluorescent CSF tracers (dextran and ovalbumin, having two different molecular weights–Mw). The sonication pulsing parameter was determined on the set that propelled the aqueous solution of toluidine blue O dye into a porous media (melamine foam) at the highest level of infiltration. Fluorescence imaging of the brain showed that application of FUS increased the uptake of ovalbumin at the sonicated plane, particularly around the ventricles, whereas the uptake of high-Mw dextran was unaffected. Numerical simulation showed that the effects of sonication were non-thermal. Sonication did not alter the animals’ behavior or disrupt the blood-brain barrier (BBB) while yielding normal brain histology. The results suggest that FUS may serve as a new non-invasive means to promote interstitial CSF solute transport in a region-specific manner without disrupting the BBB, providing potential for enhanced clearance of waste products from the brain.

Original languageEnglish
Article number12940
JournalScientific reports
Issue number1
Publication statusPublished - 2022 Dec

Bibliographical note

Funding Information:
We thank Dr. Wonhye Lee for participating in acquisition of computed tomography of rodent skulls. We thank work was partially supported by National Aeronautics and Space Administration (NASA) grant NNX16AO69A-T0415 (to SSY). The funder had no role in study design, data collection, data analysis, and decision to publish or preparation of the manuscript.

Publisher Copyright:
© 2022, The Author(s).

All Science Journal Classification (ASJC) codes

  • General


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