On the use of photoacoustics to detect red blood cell aggregation

Theoretical Predictions ◽

Rbc Aggregation ◽

Simulation Results

The feasibility of detecting red blood cell (RBC) aggregation with photoacoustics (PAs) was investigated theoretically and experimentally using human and porcine RBCs. The theoretical PA signals and spectra generated from such samples were examined for several hematocrit levels and aggregates sizes. The effect of a finite transducer bandwidth on the received PA signal was also examined. The simulation results suggest that the dominant frequency of the PA signals from non-aggregated RBCs decreases towards clinical frequency ranges as the aggregate size increases. The experimentally measured mean spectral power increased by ~6 dB for the largest aggregate compared to the non-aggregated samples. Such results confirm the theoretical predictions and illustrate the potential of using PA imaging for detecting RBC aggregation.

Photoacoustic ultrasound spectroscopy for assessing red blood cell aggregation and oxygenation

10.32920/14636592 ◽

2021 ◽

Author(s):

Michael C. Kolios

Keyword(s):

Blood Cell ◽

Red Blood Cell ◽

Aggregate Size ◽

Cell Aggregation ◽

Frequency Domain Analysis ◽

Spectral Slope ◽

Spectral Parameters ◽

Oxygen Saturation Level ◽

Oxygenation Level ◽

Red blood cell (RBC) aggregation and oxygenation are important markers for a variety of blood disorders. No current technique is capable of simultaneously measuring aggregation/oxygenation levels noninvasively. We propose using photoacoustic ultrasound spectroscopy (PAUS) for assessing both phenomena. This technique relies on frequency-domain analysis of the PA signals by extracting parameters such as the ultrasound spectral slope and the midband fit. To investigate the effect of hematocrit, aggregation, and oxygenation levels on PAUS parameters, a Monte Carlo-based theoretical model and an experimental protocol using porcine RBCs were developed. The samples were illuminated at 750 and 1064 nm and changes in the PAUS parameters were compared to the oxygen-dependent optical absorption coefficients to assess the oxygenation level. Good agreement between the theoretical and experimental spectral parameters was obtained for the spectral slope of the nonaggregated spectra (∼0.3 dB/MHz∼0.3 dB/MHz). The experimental midband fit increased by ∼5 dB∼5 dB for the largest aggregate size. Based on the analysis of the PA signals, the oxygen saturation level of the most aggregated sample was >20%>20% greater than the nonaggregated sample. The results provide a framework for using PA signals’ spectroscopic parameters for monitoring the aggregation and oxygenation levels of RBCs.

Red blood cell (RBC) aggregation and its influence on non-Newtonian nature of blood in microvasculature

Journal of Modeling in Mechanics and Materials ◽

10.1515/jmmm-2016-0157 ◽

2017 ◽

Vol 1 (1) ◽

Author(s):

Chitra Murali ◽

Perumal Nithiarasu

Keyword(s):

Blood Flow ◽

Blood Cell ◽

Red Blood Cell ◽

Cell Aggregation ◽

Time Dependent ◽

Shear Rates ◽

Significant Difference ◽

Rbc Aggregation ◽

Rouleaux Formation

AbstractA robust computational model is proposed to investigate the non-Newtonian nature of blood flow due to rouleaux formation in microvasculature. The model consists of appropriate forces responsible for red blood cell (RBC) aggregation in the microvasculature, tracking of RBCs, and coupling between plasma flow and RBCs. The RBC aggregation results have been compared against the available data. The importance of different hydrodynamic forces on red blood cell aggregation has been delineated by comparing the time dependent path of the RBCs. The rheological changes to the blood flow have been investigated under different shear rates and hematocrit values and quantified with and without RBC aggregation. The results obtained in terms of wall shear stress (WSS) and blood viscosity indicate a significant difference between Newtonian and powerlaw fluid assumptions.

Effects of increased plasma viscosity and red blood cell aggregation on blood viscosity in vivo

AJP Heart and Circulatory Physiology ◽

10.1152/ajpheart.1981.241.4.h513 ◽

1981 ◽

Vol 241 (4) ◽

pp. H513-H518 ◽

Cited By ~ 9

Author(s):

L. Gustafsson ◽

L. Appelgren ◽

H. E. Myrvold

Keyword(s):

Blood Cell ◽

Red Blood Cell ◽

Apparent Viscosity ◽

Cell Aggregation ◽

Plasma Viscosity ◽

Pressure Flow ◽

The effects of increased plasma viscosity and induced red blood cell (RBC) aggregation on apparent viscosity of blood in vivo in the skeletal muscle of the dog were studied. Apparent viscosity in vivo was determined in the isolated and vasodilated calf muscles of one hindlimb by comparing pressure-flow relationships for RBC suspensions with pressure-flow relationships for a Newtonian solution of known viscosity. RBC suspensions of increased plasma viscosity with and without RBC aggregation were obtained by substituting plasma with isoviscous solutions of high- and low-molecular-weight dextran in saline. Hematocrits of the suspensions were adjusted to either 45 or 60%. The viscosities of the suspensions in vitro were determined in a Wells-Brookfield viscometer. Apparent viscosity of blood in vivo was found to be mainly dependent on the viscosity of plasma. RBC aggregation had no significant influence on the viscosity in vivo.

Photoacoustic Detection of Red Blood Cell Aggregation

10.32920/ryerson.14663541.v1 ◽

2021 ◽

Author(s):

Eno Hysi

Keyword(s):

Blood Cell ◽

Oxygen Saturation ◽

Red Blood Cell ◽

Photoacoustic Imaging ◽

Power Spectra ◽

Aggregate Size ◽

Cell Aggregation ◽

Spectral Slope ◽

Photoacoustic Detection ◽

The potential of photoacoustic imaging for detecting red blood cell (RBC) aggregation is explored. Enhanced aggregation is observed in disorders such as diabetes impairing oxygen release into tissue. Simultaneous measurements of aggregation and oxygenation levels cannot be made using current tools. Photoacoustic detection of aggregation and assessment of oxygen saturation was investigated. A theoretical and experimental model of aggregation was developed using human and porcine RBCs. Frequency-domain analysis of the PA signals was used to derive the spectral slope and midband fit of the normalized power spectra for various hematorit and aggregation conditions. Oxygen saturation was assessed using multiple wavelengths of illumination. The experimental spectral slope (~0.3 dB/MHz) for non-aggregated samples agreed with the theory decreasing with increasing aggregate size. The midband fit increased by ~5 dB when the aggregate size reached the largest level while the oxygen saturation increased by > 20%. These results suggest that photoacoustic-radio-frequency-spectroscopic-parameters have the potential to monitor RBC aggregation and oxygenation level.

Photoacoustic Detection of Red Blood Cell Aggregation

10.32920/ryerson.14663541 ◽

2021 ◽

Author(s):

Eno Hysi

Keyword(s):

Blood Cell ◽

Oxygen Saturation ◽

Red Blood Cell ◽

Photoacoustic Imaging ◽

Power Spectra ◽

Aggregate Size ◽

Cell Aggregation ◽

Spectral Slope ◽

Photoacoustic Detection ◽

The potential of photoacoustic imaging for detecting red blood cell (RBC) aggregation is explored. Enhanced aggregation is observed in disorders such as diabetes impairing oxygen release into tissue. Simultaneous measurements of aggregation and oxygenation levels cannot be made using current tools. Photoacoustic detection of aggregation and assessment of oxygen saturation was investigated. A theoretical and experimental model of aggregation was developed using human and porcine RBCs. Frequency-domain analysis of the PA signals was used to derive the spectral slope and midband fit of the normalized power spectra for various hematorit and aggregation conditions. Oxygen saturation was assessed using multiple wavelengths of illumination. The experimental spectral slope (~0.3 dB/MHz) for non-aggregated samples agreed with the theory decreasing with increasing aggregate size. The midband fit increased by ~5 dB when the aggregate size reached the largest level while the oxygen saturation increased by > 20%. These results suggest that photoacoustic-radio-frequency-spectroscopic-parameters have the potential to monitor RBC aggregation and oxygenation level.

Photoacoustic ultrasound spectroscopy for assessing red blood cell aggregation and oxygenation

10.32920/14636592.v1 ◽

2021 ◽

Author(s):

Michael C. Kolios

Keyword(s):

Blood Cell ◽

Red Blood Cell ◽

Aggregate Size ◽

Cell Aggregation ◽

Frequency Domain Analysis ◽

Spectral Slope ◽

Spectral Parameters ◽

Oxygen Saturation Level ◽

Oxygenation Level ◽

Red blood cell (RBC) aggregation and oxygenation are important markers for a variety of blood disorders. No current technique is capable of simultaneously measuring aggregation/oxygenation levels noninvasively. We propose using photoacoustic ultrasound spectroscopy (PAUS) for assessing both phenomena. This technique relies on frequency-domain analysis of the PA signals by extracting parameters such as the ultrasound spectral slope and the midband fit. To investigate the effect of hematocrit, aggregation, and oxygenation levels on PAUS parameters, a Monte Carlo-based theoretical model and an experimental protocol using porcine RBCs were developed. The samples were illuminated at 750 and 1064 nm and changes in the PAUS parameters were compared to the oxygen-dependent optical absorption coefficients to assess the oxygenation level. Good agreement between the theoretical and experimental spectral parameters was obtained for the spectral slope of the nonaggregated spectra (∼0.3 dB/MHz∼0.3 dB/MHz). The experimental midband fit increased by ∼5 dB∼5 dB for the largest aggregate size. Based on the analysis of the PA signals, the oxygen saturation level of the most aggregated sample was >20%>20% greater than the nonaggregated sample. The results provide a framework for using PA signals’ spectroscopic parameters for monitoring the aggregation and oxygenation levels of RBCs.

The Effect of Glucose and Poloxamer 188 on Red-Blood-Cell Aggregation

Metabolites ◽

10.3390/metabo11120886 ◽

2021 ◽

Vol 11 (12) ◽

pp. 886

Author(s):

Alicja Szołna-Chodór ◽

Bronisław Grzegorzewski

Keyword(s):

Mechanical Properties ◽

Blood Cell ◽

Red Blood Cell ◽

Cell Aggregation ◽

Aggregation Index ◽

Poloxamer 188 ◽

Rbc Aggregation ◽

Effect Of Glucose ◽

Blood Cell Aggregation

Glucose metabolism disorders contribute to the development of various diseases. Numerous studies show that these disorders not only change the normal values of biochemical parameters but also affect the mechanical properties of blood. To show the influence of glucose and poloxamer 188 (P188) on the mechanical properties of a red-blood-cell (RBC) suspension, we studied the aggregation of the cells. To show the mechanisms of the mechanical properties of blood, we studied the effects of glucose and poloxamer 188 (P188) on red-blood-cell aggregation. We used a model in which cells were suspended in a dextran 70 solution at a concentration of 2 g/dL with glucose and P188 at concentrations of 0–3 g/dL and 0–3 mg/mL, respectively. RBC aggregation was determined using an aggregometer, and measurements were performed every 4 min for 1 h. Such a procedure enabled the incubation of RBCs in solution. The aggregation index determined from the obtained syllectograms was used as a measure of aggregation. Both the presence of glucose and that of P188 increased the aggregation index with the incubation time until saturation was reached. The time needed for the saturation of the aggregation index increased with increasing glucose and P188 concentrations. As the concentrations of these components increased, the joint effect of glucose and P188 increased the weakening of RBC aggregation. The mechanisms of the observed changes in RBC aggregation in glucose and P188 solutions are discussed.

Parameters of red blood cell aggregation as correlates of the inflammatory state

AJP Heart and Circulatory Physiology ◽

10.1152/ajpheart.2001.280.5.h1982 ◽

2001 ◽

Vol 280 (5) ◽

pp. H1982-H1988 ◽

Cited By ~ 84

Author(s):

R. Ben Ami ◽

G. Barshtein ◽

D. Zeltser ◽

Y. Goldberg ◽

I. Shapira ◽

...

Keyword(s):

Shear Stress ◽

Blood Cell ◽

Red Blood Cell ◽

Aggregate Size ◽

Cell Aggregation ◽

Aggregate Fraction ◽

Plasma Factor ◽

Cellular Factors ◽

Rbc Aggregation ◽

Aggregation Parameters

To identify clinically relevant parameters of red blood cell (RBC) aggregation, we examined correlations of aggregation parameters with C-reactive protein and fibrinogen in unstable angina (UA), acute myocardial infarction (AMI), and bacterial infection (BI). Aggregation parameters were derived from the distribution of RBC population into aggregate sizes (cells per aggregate) and changing of the distribution by flow-derived shear stress. Increased aggregation was observed in the following order: UA, AMI, and BI. The best correlation was obtained by integration of large aggregate fraction as a function of shear stress. To differentiate plasmatic from cellular factors in RBC aggregation, we determined the aggregation in the presence and absence of plasma and formulated a “plasma factor” (PF) ranging from 0 to 1. In AMI the enhanced aggregation was entirely due to PF (PF = 1), whereas in UA and BI it was due to both plasmatic and cellular factors (0 ≤ PF ≤ 1). It is proposed that clinically relevant parameters of RBC aggregation should express both RBC aggregate size distribution and aggregate resistance to disaggregation and distinguish between plasmatic and cellular factors.

A synergistic effect of albumin and fibrinogen on immunoglobulin-induced red blood cell aggregation

AJP Heart and Circulatory Physiology ◽

10.1152/ajpheart.00128.2003 ◽

2003 ◽

Vol 285 (6) ◽

pp. H2663-H2669 ◽

Cited By ~ 49

Author(s):

Ronen Ben-Ami ◽

Gershon Barshtein ◽

Tamar Mardi ◽

Varda Deutch ◽

Ori Elkayam ◽

...

Keyword(s):

Blood Cell ◽

Red Blood Cell ◽

Cell Aggregation ◽

High Plasma ◽

Plasma Albumin ◽

Rbc Aggregation ◽

Thrombotic Complications ◽

Therapeutic Administration

Therapeutic administration of immunoglobulins (Ig) has the potential to precipitate thrombotic events. This phenomenon may be explained by red blood cell (RBC) aggregation, which can be potentiated by Ig. The contribution of plasma albumin and fibrinogen to Ig-induced RBC aggregation is unclear. We examined RBC aggregation in three settings: 1) patients receiving therapeutic infusions of Ig; 2) patients receiving plasma supplemented in vitro with Ig; and 3) patients receiving RBC suspensions in standard buffer with varying concentrations of albumin, Ig, and fibrinogen. Ig infusion augmented aggregation of RBCs from patients with normal or high plasma levels of albumin but decreased aggregation in those with lower plasma albumin concentrations. In vitro, RBC aggregation was significantly increased only when all three components, fibrinogen, albumin, and Ig, were present at or above normal concentrations in the suspension but was unaffected when any one of the components was absent from the suspension. Our results suggest a three-way interaction among fibrinogen, Ig, and albumin that synergistically induces RBC aggregation in plasma. Understanding these interactions may help predict clinically important phenomena related to RBC aggregation, such as thrombotic complications of Ig infusion.