Pressure modulation algorithm to separate cerebral hemodynamic signals from extracerebral artifacts

Baker, Wesley B.; Parthasarathy, Anand; Ko, Tiffany; Busch, David R.; Abramson, Kenneth; Tzeng, Shih Yu; Mesquita, Rickson C.; Durdurán, Turgut; Greenberg, Joel; Kung, David; Yodh, Arjun G.

doi:10.1117/1.nph.2.3.035004

Cited by 84 publications

(80 citation statements)

References 107 publications

(239 reference statements)

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“…The observed sensitivity of the DCS steady-state BFI measurement to scalp pressure is consistent with previous work and is indicative of scalp contamination in the DCS BFI measurement. 24,50 The insensitivity of the DCS PI measurement to scalp pressure, however, shows that scalp contamination is substantially less severe in the PI measurement. Future work is needed to better understand the theoretical explanation of this finding.…”

Section: Dcs Pi Measurements On Forehead Are Not Sensitive To Scalp Tmentioning

confidence: 99%

Influence of probe pressure on the pulsatile diffuse correlation spectroscopy blood flow signal on the forearm and forehead regions

Wang

Gao

et al. 2019

Neurophoton.

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In a pilot study of 11 healthy adults (24 to 39 years, all male), we characterize the influence of external probe pressure on optical diffuse correlation spectroscopy (DCS) measurements of pulsatile blood flow obtained on the forearm and forehead. For external probe pressure control, a hand inflatable air balloon is inserted between the tissue and an elastic strap. The air balloon is sequentially inflated to achieve a wide range of external probe pressures between 20 and 250 mmHg on the forearm and forehead, which are measured with a flexible pressure sensor underneath the probe. At each probe pressure, the pulsatility index (PI) of arteriole blood flow on the forehead and forearm is measured with DCS (2.1-cm source-detector separation). We observe a strong correlation between probe pressure and PI on the forearm (R ¼ 0.66, p < 0.001), but not on the forehead (R ¼ −0.11, p ¼ 0.4). The forearm measurements demonstrate the sensitivity of the DCS PI to skeletal muscle tissue pressure, whereas the forehead measurements indicate that DCS PI measurements are not sensitive to scalp tissue pressure. Note, in contrast to pulsatility, the time-averaged DCS blood flow index on the forehead was significantly correlated with probe pressure (R ¼ −0.55, p < 0.001). This pilot data appears to support the initiation of more comprehensive clinical studies on DCS to detect trends in internal pressure in brain and skeletal muscle.

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Section: Dcs Pi Measurements On Forehead Are Not Sensitive To Scalp Tmentioning

confidence: 99%

Influence of probe pressure on the pulsatile diffuse correlation spectroscopy blood flow signal on the forearm and forehead regions

Wang

Gao

et al. 2019

Neurophoton.

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“…Slab-layered models were proposed to reduce the partial volume effect (Jaillon et al , 2006; Li et al , 2005; Verdecchia et al , 2016). A recently developed method, “Modified Beer-Lambert law for blood flow”, has been proved to be effective in pressure modulation experiments to reduce the skin-effect on cerebral blood flow measurements (Baker et al , 2014; Baker et al , 2015). However, those methods ignored the influence of irregular tissue geometries.…”

Section: Summary and Future Perspectivesmentioning

confidence: 99%

Clinical applications of near-infrared diffuse correlation spectroscopy and tomography for tissue blood flow monitoring and imaging

Shang

2017

Physiol. Meas.

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Blood flow is one such available observable promoting a wealth of physiological insight both individually and in combination with other metrics. Near-infrared diffuse correlation spectroscopy (DCS) and, to a lesser extent, diffuse correlation tomography (DCT), have increasingly received interest over the past decade as noninvasive methods for tissue blood flow measurements and imaging. DCS/DCT offers several attractive features for tissue blood flow measurements/imaging such as noninvasiveness, portability, high temporal resolution, and relatively large penetration depth (up to several centimeters). This review first introduces the basic principle and instrumentation of DCS/DCT, followed by presenting clinical application examples of DCS/DCT for the diagnosis and therapeutic monitoring of diseases in a variety of organs/tissues including brain, skeletal muscle, and tumor. Clinical study results demonstrate technical versatility of DCS/DCT in providing important information for disease diagnosis and intervention monitoring.

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“…4 In our study, we did not explicitly control for the probe pressure; in future studies, this effect can be ameliorated by measurement and adjustment of pressure in situ and even by pressure modulation. 73 Another source of calibration error can arise from breakdown of the assumptions employed in VO-DOS measurements of BF. The simplest of these issues concerns the factor C, i.e., the concentration of hemoglobin in blood, which we assumed to be 14.1 g∕dL 35 for all subjects.…”

Section: Comparisonmentioning

confidence: 99%

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

Baker

Parthasarathy

et al. 2015

J. Biomed. Opt

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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)×10(8) (mL·100 mL(−1)·min(−1))/(cm(2)/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 (R(2)=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.

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Pressure modulation algorithm to separate cerebral hemodynamic signals from extracerebral artifacts

Cited by 84 publications

References 107 publications

Influence of probe pressure on the pulsatile diffuse correlation spectroscopy blood flow signal on the forearm and forehead regions

Influence of probe pressure on the pulsatile diffuse correlation spectroscopy blood flow signal on the forearm and forehead regions

Clinical applications of near-infrared diffuse correlation spectroscopy and tomography for tissue blood flow monitoring and imaging

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

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