Engineering Minute

Engineering Minute – Infrared Blood Flow Monitor Detects Stroke

A collaboration between research teams at the Army Medical University and China Academy of Engineering Physics has lead to the development of an infrared blood flow monitor that could help physicians diagnose strokes. The inexpensive and compact device uses a combination of near-infrared diffuse optical spectroscopy and correlation spectroscopy to monitor a patient's blood flow. The technique analyzes light scattered from tissues to determine the amount of oxygen and blood within an area as well as analyzes fluctuations in tissue-scattered light to measure blood flow index. Their work was recently published in the journal AIP Advances


“We can measure blood volume, blood oxygenation and blood flow using suitable near-infrared techniques,” says Liguo Zhu, a collaborating author of the study. 

In the experiment, the blood circulation of the forearm was obstructed by the arm cuff for three minutes.
In the experiment, the blood circulation of the forearm was obstructed by the arm cuff for three minutes. Credit: American Institute of Physics


From the American Institute of Physics article: "To test their instrument, the authors strapped a device probe to a human subject’s forearm, then inflated an arm cuff around the subject’s bicep to block off blood circulation. The authors found that the measured light attenuated, or reduced in intensity, as blood flow was cut off and brightened again when the arm cuff was removed — mirroring the decrease and subsequent increase in oxygen and blood at the probe area. At the same time, the measured autocorrelation, or time lag, function decayed less rapidly when blood flow was cut off, showing that blood was moving more slowly through the area.

The team’s device can record a comprehensive profile of a body part’s hemodynamics, or blood circulation, said Hua Feng, another author on the study. This capability contrasts those of previous instruments, which could only characterize certain aspects of blood flow. Feng added that devices should measure as many 'hemodynamic parameters' as necessary to obtain an accurate diagnosis, as 'the hemodynamics of stroke is complex.'"


Read more about the infrared blood flow monitor that diagnoses stroke at the American Institute of Physics