Calibration of diffuse correlation spectroscopy blood flow index with venous-occlusion diffuse optical spectroscopy in skeletal muscle

• Published in: Journal of biomedical optics Vol. 20; no. 12; p. 125005
• Main Authors: Li, Zhe, Baker, Wesley B, Parthasarathy, Ashwin B, Ko, Tiffany S, Wang, Detian, Schenkel, Steven, Durduran, Turgut, Li, Gang, Yodh, Arjun G
• Format: Journal Article
• Language: English
• Published: United States Society of Photo-Optical Instrumentation Engineers 01.12.2015
• Subjects: Adult; Blood flow; Calibration; Coefficients; Correlation; Diffusion; Female; Healthy Volunteers; Hemodynamics; Humans; Ischemia - pathology; Male; Monitoring; Muscle, Skeletal - blood supply; Muscles; Optics and Photonics; Oxygen Consumption - physiology; Regional Blood Flow; Reproducibility of Results; Research Papers: General; Spectrophotometry - methods; Spectroscopy; Spectroscopy, Near-Infrared - methods; near-infrared spectroscopy; venous occlusion; skeletal muscle; diffuse correlation spectroscopy; absolute blood flow; diffuse optical spectroscopy
• ISSN: 1083-3668; 1560-2281; 1560-2281
• DOI: 10.1117/1.JBO.20.12.125005

We investigate and assess the utility of a simple scheme for continuous absolute blood flow monitoring based on diffuse correlation spectroscopy (DCS). The scheme calibrates DCS using venous-occlusion diffuse optical spectroscopy (VO-DOS) measurements of arm muscle tissue at a single time-point. A calibration coefficient (γ) for the arm is determined, permitting conversion of DCS blood flow indices to absolute blood flow units, and a study of healthy adults (N=10) is carried out to ascertain the variability of γ. The average DCS calibration coefficient for the right (i.e., dominant) arm was γ=(1.24±0.15)×108 (mL·100  mL−1·min−1)/(cm2/s). However, variability can be significant and is apparent in our site-to-site and day-to-day repeated measurements. The peak hyperemic blood flow overshoot relative to baseline resting flow was also studied following arm-cuff ischemia; excellent agreement between VO-DOS and DCS was found (R2=0.95, slope=0.94±0.07, mean difference=−0.10±0.45). Finally, we show that incorporation of subject-specific absolute optical properties significantly improves blood flow calibration accuracy.