scholarly journals Photoacoustic Detection of Red Blood Cell Aggregation

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 ◽  
Rbc Aggregation

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.

scholarly journals Photoacoustic Detection of Red Blood Cell Aggregation

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 ◽  
Rbc Aggregation

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.

scholarly journals Photoacoustic ultrasound spectroscopy for assessing red blood cell aggregation and oxygenation

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 ◽  
Rbc Aggregation

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.

scholarly journals High frequency photoacoustic detection of red blood cell aggregation

2021 ◽  
Author(s):  
Fayruz Kibria
Keyword(s):  
Blood Cell ◽  
Red Blood Cell ◽  
High Frequency ◽  
Photoacoustic Imaging ◽  
Low Frequency ◽  
Cell Aggregation ◽  
Center Frequency ◽  
Photoacoustic Detection ◽  
Rbc Aggregation

Red blood cell (RBC) aggregation was correctly reported in early 1768 as the increased deposition for blood to form spots of red in pathological conditions. However only recently have there been advances in technology to allow possible detection of RBC aggregation in vivo. Photoacoustic imaging (PA) shows a promising future in the detection of simultaneous in vivo RBC aggregation and oxygen saturation. This work presents, for the first time, the results of investigating aggregated RBCs using high frequency (> 20 MHz) photoacoustic (PA) imaging. Aggregation was induced by using 3% w/v concentration of 70 kDa Dextran and PA measurements were taken by a 25 MHz center frequency transducer. It was found that the spectral slope (SS) of the photoacoustic signals decreased by ~0.25 dB/MHz with RBC aggregation. The results are consistent with the findings of low frequency PA RBC aggregation study which also reported decrease in SS with increased aggregation.

scholarly journals High frequency photoacoustic detection of red blood cell aggregation

2021 ◽  
Author(s):  
Fayruz Kibria
Keyword(s):  
Blood Cell ◽  
Red Blood Cell ◽  
High Frequency ◽  
Photoacoustic Imaging ◽  
Low Frequency ◽  
Cell Aggregation ◽  
Center Frequency ◽  
Photoacoustic Detection ◽  
Rbc Aggregation

Red blood cell (RBC) aggregation was correctly reported in early 1768 as the increased deposition for blood to form spots of red in pathological conditions. However only recently have there been advances in technology to allow possible detection of RBC aggregation in vivo. Photoacoustic imaging (PA) shows a promising future in the detection of simultaneous in vivo RBC aggregation and oxygen saturation. This work presents, for the first time, the results of investigating aggregated RBCs using high frequency (> 20 MHz) photoacoustic (PA) imaging. Aggregation was induced by using 3% w/v concentration of 70 kDa Dextran and PA measurements were taken by a 25 MHz center frequency transducer. It was found that the spectral slope (SS) of the photoacoustic signals decreased by ~0.25 dB/MHz with RBC aggregation. The results are consistent with the findings of low frequency PA RBC aggregation study which also reported decrease in SS with increased aggregation.

scholarly journals Photoacoustic ultrasound spectroscopy for assessing red blood cell aggregation and oxygenation

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 ◽  
Rbc Aggregation

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.

scholarly journals Photoacoustic ultrasound spectroscopy for assessing red blood cell aggregation and oxygenation

2021 ◽  
Author(s):  
Michael C. Kolios ◽  
Eno Hysi ◽  
Ratan K. Saha
Keyword(s):  
Blood Cell ◽  
Red Blood Cell ◽  
Aggregate Size ◽  
Cell Aggregation ◽  
Frequency Domain Analysis ◽  
Spectral Slope ◽  
Spectral Parameters ◽  
Oxygen Saturation Level ◽  
Oxygenation Level ◽  
Rbc Aggregation

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.

scholarly journals On the use of photoacoustics to detect red blood cell aggregation

2021 ◽  
Author(s):  
Michael C. Kolios
Keyword(s):  
Blood Cell ◽  
Red Blood Cell ◽  
Spectral Power ◽  
Aggregate Size ◽  
Cell Aggregation ◽  
Dominant Frequency ◽  
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.

Estimation of aggregate size of red blood cell by introducing reference power spectrum measured for hemispherical ultrafine wire

2021 ◽  
Author(s):  
Kyohei Higashiyama ◽  
Shohei MORI ◽  
Mototaka ARAKAWA ◽  
Satoshi Yashiro ◽  
Yasushi Ishigaki ◽  
...  
Keyword(s):  
Power Spectrum ◽  
Blood Cell ◽  
Red Blood Cell ◽  
Power Spectra ◽  
Aggregate Size ◽  
Posterior Wall ◽  
Size Estimation ◽  
Scattering Spectrum ◽  
Rbc Aggregation

Abstract Noninvasive measurement of the degree of red blood cell (RBC) aggregation is useful for evaluating blood properties. In the present paper, we proposed a method to estimate the size of RBC aggregates without using the power spectrum of the posterior wall by introducing a reference scattering spectrum. The reference power spectra were calculated using the power spectrum measured for an ultrafine wire with a hemispherical tip. They were applied to the size estimation of microparticles simulating RBC aggregates. The estimated sizes were close to the true values, which shows that the calculated reference power spectra were suitable for accurate size estimation. The proposed method was also applied to in vivo measurements, and the estimated sizes between at rest and in RBCs aggregated by avascularization were successfully differentiated. This demonstrates that the proposed method will be useful for estimating the size of RBC aggregates.

Sign in / Sign up

Export Citation Format

Share Document