Comprehensive Optimization of Interferometric Diffusing Wave Spectroscopy (iDWS)

TL;DR

This paper enhances interferometric diffusing wave spectroscopy (iDWS) for noninvasive cerebral blood flow measurement, optimizing system parameters and demonstrating improved performance in adult humans and clinical settings.

Contribution

The study systematically optimizes iDWS parameters and demonstrates its capability for stable, high-sensitivity cerebral blood flow monitoring in adults and clinical environments.

Findings

Successful pulsatile CBFi monitoring at 4-4.5 cm source-collector separation.

System stability achieved with optimized hardware and data processing.

Preliminary clinical measurements in Neuro ICU show promising results.

Abstract

It has been shown that light speckle fluctuations provide a means for noninvasive measurements of cerebral blood flow index (CBFi). While conventional Diffuse Correlation Spectroscopy (DCS) provides marginal brain sensitivity for CBFi in adult humans, new techniques have recently emerged to improve diffuse light throughput and thus, brain sensitivity. Here we further optimize one such approach, interferometric diffusing wave spectroscopy (iDWS), with respect to number of independent channels, camera duty cycle and full well capacity, incident power, noise and artifact mitigation, and data processing. We build the system on a cart and define conditions for stable operation. We show pulsatile CBFi monitoring at 4-4.5 cm source-collector separation in adults with moderate pigmentation (Fitzpatrick 4). We also report preliminary clinical measurements in the Neuro Intensive Care Unit (Neuro ICU). These results push the boundaries of iDWS CBFi monitoring performance beyond previous reports.