Feasibility Study of Remote Contactless Perfusion Imaging with Consumer-Grade Mobile Camera

A non-invasive, contactless, inexpensive and easy-to-operate perfusion imaging method using a consumer-grade mobile camera (iPhone 8) developed in our group can visualise blood flow in tissue.

Ischemia was induced in one hand using a blood pressure cuff inflated over the systolic blood pressure to stop the blood flow. Using an iPhone, data was collected from 5 subjects, beginning with no occlusion (a baseline), followed by one hand occluded, and then release of the occlusion to restore blood circulation. This protocol was repeated for each hand for a total of 10 videos. The data were analysed to extract the oscillating and quasi-constant components of the photoplethysmogram signal representing blood flow. In addition, we introduced a scoring parameter to reflect perfusion (i.e., perfusion score).

The proposed perfusion score was used to create a pseudo colour map of perfusion across the protocol, demonstrating the ability to detect ischemia caused by occlusion. The difference in perfusion score was statistically significant between ischemia and baseline/recovery.

Pilot results on healthy volunteers demonstrate the feasibility of perfusion imaging using a consumer-grade camera. A further developed method can be used to assess the viability of transplanted tissue.