Multispectral imaging of nailfold capillaries using light-emitting diode illumination

Area of Science:

• Biomedical Optics
• Medical Imaging
• Microcirculation Research

Background:

• Video capillaroscopy visualizes nailfold capillary morphology for diagnosing connective tissue diseases but lacks physiological data.
• Assessing hemoglobin oxygenation in capillaries could enhance diagnostic sensitivity and track microvascular disease progression.

Purpose of the Study:

• To design, construct, and validate a cost-effective multispectral imaging (MSI) system.
• To utilize light-emitting diode (LED) illumination for assessing relative hemoglobin oxygenation in nailfold capillaries.

Main Methods:

• Designed and modeled an LED ring light, fabricating it with four LED colors on a custom PCB.
• Characterized the experimental system against the illumination model.
• Evaluated system feasibility for oximetry using a blood phantom with variable oxygenation and imaged nailfold capillaries in a healthy subject.

Main Results:

• Illumination modeling closely matched the constructed system's performance.
• The MSI system demonstrated sensitivity to hemoglobin oxygenation changes in the blood phantom.
• Nailfold capillary imaging yielded morphological properties comparable to gold-standard systems.

Conclusions:

• LED-based MSI offers a low-cost method for imaging nailfold capillaries.
• This approach provides valuable insights into capillary blood oxygenation.
• Potential for improved diagnosis and monitoring of microvascular conditions.