Real time monitoring of stroke using light and sound

Stroke is the second most common cause of death worldwide. In particular, ischemic stroke occurs when a blood vessel supplying blood to your brain is blocked. If treatment is delayed, a patient will have accelerated brain tissue damage; making it virtually impossible to recover. The existing technologies such as CT and MRI have limitations capturing any early vascular changes in real-time. Furthermore, animal model researches have limitations with scope and efficiency.

To solve this, the POSTECH research team developed a photoacoustic computed tomography (PACT) that combines light and ultrasound. The research team applied a complex scanning method that combines linear and rotational scanning to synthesize images from multiple angles into one. It is the same method used to take images from different directions and reconstitute them into a 3D image. Using this technology, the research team was able to non-invasively monitor cerebrovascular changes within small animals with the early stages of an ischemic stroke in real time; successfully analyzed vascular changes in a wide region with precision.

In addition, the team developed an algorithm that non-invasively observes hemoglobin and measures oxygen saturation in each blood vessel in real time by utilizing multi-wavelength photoacoustic imaging within a near-infrared region. This allowed the team to precisely monitor not only ischemic lesions but also collateral blood flow and neovascular changes. These results were proven reliable compared to the existing pathological tissue tests, and showed that the new PACT system can effectively track the vascular recovery process after stroke.

The POSTECH research team said, "The most significant result from this research is that we can now have precise observation of blood flow changes without using contrast." This will provide new experimental approaches not only for stroke treatment research but also for research on various neurological and vascular diseases."