Noncontact diffuse correlation spectroscopy for noninvasive deep tissue blood flow measurement

Area of Science:

• Biomedical Optics
• Medical Instrumentation
• Physiology

Background:

• Accurate blood flow measurement is vital for diagnosing and monitoring various medical conditions.
• Existing methods for blood flow assessment, such as diffuse correlation spectroscopy (DCS), often require physical contact, limiting their application in certain tissues.
• Noncontact measurement techniques are needed to overcome limitations associated with probe-tissue interaction and to assess blood flow in vulnerable or soft tissues.

Purpose of the Study:

• To develop and validate a noncontact diffuse correlation spectroscopy (DCS) probe for measuring blood flow.
• To assess the performance of the noncontact probe in comparison to a traditional contact probe.
• To evaluate the potential of noncontact DCS for applications in vulnerable and soft tissues.

Main Methods:

• Development of a noncontact DCS probe featuring separated optical paths for source and detector to minimize interference.
• Calibration of the noncontact probe against a contact probe using a tissue-like phantom solution.
• Validation of the noncontact probe's performance through concurrent measurements with a contact probe in human muscle tissues.

Main Results:

• The noncontact DCS probe demonstrated a unique design allowing for large source-detector separations, enabling deep tissue measurements.
• High correlation was observed between the noncontact and contact probes in both phantom (R(2)=0.89) and real-tissue (R(2)=0.77) measurements, confirming accuracy.
• The noncontact probe successfully measured blood flow changes without distorting tissue properties.

Conclusions:

• The developed noncontact DCS probe is a promising tool for accurate blood flow assessment.
• This technology can be applied to measure blood flow in vulnerable tissues, such as pressure ulcers, and soft tissues, like the breast.
• Noncontact DCS offers a non-invasive approach to monitor tissue hemodynamics without compromising tissue integrity.