Tuesday, September 20, 2022

Ultrasound technique captures micron-scale images of brain activity

Amazing stuff! Absolutely stunning what ultrasound imaging can do! And it is all noninvasive!

"Researchers ... have now developed a method called functional ultrasound localization microscopy (fULM) that can capture cerebral activity at the micron scale. The team published the first micron-scale, whole-brain images of rodent vascular activity ... along with a detailed explanation of the fULM image acquisition and analysis procedures.  ...
Unlike invasive electrophysiological or optical approaches to study brain function at the microscopic scale, ultrasound localization microscopy (ULM) can be non-invasive. The imaging technology tracks biocompatible micron-sized microbubbles injected into the blood circulation and by accumulating the tracks of millions of microbubbles, reconstructed images can reveal subtle changes in the cerebral blood volume with micron-sized accuracy, across large fields-of-view. ...
In addition to imaging the brain microvasculature, the technique detects local brain activation by calculating the number and speed of microbubbles passing in each vessel. When a brain region activates, neurovascular coupling causes the blood volume to increase locally, dilating the vessels and allowing more microbubbles to pass. ..."

From the abstract:
"... Ultrasound localization microscopy (ULM) has achieved transcranial imaging of cerebrovascular flow, up to micrometre scales, by localizing intravenously injected microbubbles; however, the long acquisition time required to detect microbubbles within microscopic vessels has so far restricted ULM application mainly to microvasculature structural imaging. Here we show how ULM can be modified to quantify functional hyperemia dynamically during brain activation reaching a 6.5-µm spatial and 1-s temporal resolution in deep regions of the rat brain."

Ultrasound technique captures micron-scale images of brain activity – Physics World


Fig. 1: Functional ULM reveals brain-wide hyperemia at a microscopic scale during brain activation.


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