Real time monitoring of stroke using light and sound

Every year, millions of people die from stroke. In order to win against this disease which occurs the moment when a blood vessel is blocked in brain, a POSTECH research team made a breakthrough with a cutting-edge technology combining 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."

This research was conducted by the following members:

- Professor Yong-Joo Ahn from the Department of Convergence IT Engineering, and the School of Convergence Science and Technology

- Professor Chul-Hong Kim from the Department of Electrical Engineering, Department of Convergence IT Engineering, Department of Mechanical Engineering, and the Graduate School of Convergence Science and Technology

- Ji-Woong Kim from the Department of Convergence IT Engineering integrated course

- Joo-Young Kwon from the School of Convergence Science and Technology integrated course

- Dr. Seoung-Wook Choi (Ph.D., Stanford University) from POSTECH Institute of Artificial Intelligence

- Hyun-Seo Jeon of the Department of Convergence IT Engineering integrated course

- Min-Sik Seong of the Department of Mechanical Engineering integrated course

- Research team of Chengbo Liu and Rongkang Gao from the Chinese Academy of Sciences

This research was recently published in "Advanced Science," one of the international scientific academic journals.

This research was hosted by the BK21 FOUR project of the National Research Foundation of Korea, the ICAN program hosted by the Ministry of Science and ICT and the Institute of Information & communications Technology Planning & Evaluation, medical device industry promotion project of the Korea Medical Device Industry Association, health and medical treatment technology R&D project supported by the Korea Health Industry Development Institute with funds from the Ministry of Health and Welfare, Glocal University 30, and financial support from the Hyundai Motor Company Chung Mong-Koo Foundation.