Direct assessment of extracerebral signal contamination on optical measurements of cerebral blood flow, oxygenation, and metabolism

• DOI: 10.1117/1.nph.7.4.045002
• Publication Date: 2020-10-07T08:07:51Z
• Authors: Daniel Milej; Androu Abdalmalak; Ajay Rajaram; Keith St. Lawrence
• Keywords: 610; Brain imaging; Dynamic contrast-enhanced measurements; Time-resolved measurements; Research Papers; 01 natural sciences; Indocyanine green; Near-infrared spectroscopy; 0103 physical sciences; Diffuse reflectance; Diffuse correlation spectroscopy

Significance: Near-infrared spectroscopy (NIRS) combined with diffuse correlation (DCS) provides a noninvasive approach for monitoring cerebral blood flow (CBF), oxygenation, and oxygen metabolism. However, these methods are vulnerable to signal contamination from the scalp. Our work evaluated of reducing impact this using time-resolved (TR) NIRS multidistance (MD) DCS. Aim: The magnitude scalp was by measuring flow, metabolic responses global hemodynamic challenge. Contamination assessed collecting data without impeding flow. Approach: Experiments involved healthy participants. A pneumatic tourniquet used cause ischemia, as confirmed contrast-enhanced NIRS, computerized gas system generate hypercapnic Results: Comparing acquired demonstrated that TR-NIRS technique could reduce contributions in signals up 4 times (rSD = 3 cm) 6 cm). Similarly, brain be separated analyzing MD DCS multilayer model. Using techniques, there no change metabolism during hypercapnia, expected, despite large increases CBF oxygenation. Conclusion: NIRS/DCS can accurately monitor appropriate enhancement depth sensitivity, highlighting potential techniques neuromonitoring.