Evaluation of hyperspectral imaging to quantify perfusion changes during the modified Allen test

Area of Science:

• Medical Imaging
• Biophysics
• Physiology

Background:

• Assessing hand perfusion is crucial for clinical decisions, particularly before arterial procedures.
• Current methods often rely on subjective visual inspection.
• Objective, noninvasive monitoring of microcirculation remains a challenge.

Observation:

• Hyperspectral imaging (HSI) was used to capture hand perfusion in 20 volunteers during modified Allen tests (MAT) and cuff occlusion.
• Key perfusion parameters including tissue hemoglobin index (THI), oxygenation (StO2), and near-infrared perfusion (NIR) were calculated.
• HSI demonstrated visible differences in perfusion states and generated quantitative data.

Findings:

• HSI parameters THI, StO2, and NIR correlated with physiological expectations during perfusion tests.
• The reperfusion index (RI) for THI was significantly higher (~3x) compared to StO2 and NIR (~1.25).
• The occlusion index (OI) was lowest for THI, indicating its sensitivity to perfusion changes.

Implications:

• HSI offers a noninvasive, objective method to evaluate hand perfusion, complementing the modified Allen test.
• The derived reperfusion index (RI) may aid in early detection of pathological perfusion disorders.
• HSI holds potential for microcirculation monitoring in critical care, transplants, and flap surgery.