Preliminary photoacoustic imaging of the human radial artery for simultaneous assessment of red blood cell aggregation and oxygen saturation in vivo
Bibliographic record
Abstract
Our group has previously demonstrated that lower shear rate in the pulsatile blood flow yields greater red blood cell (RBC) aggregation which in turn results in a higher oxygen saturation (sO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> ) level and a higher photoacoustic (PA) signal. Higher shear rates led to disaggregation thereby decreasing the PA signal amplitude and the sO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> . These results suggest that the interrelationship between the sO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> and RBC aggregation may provide a new biomarker in the diagnosis of diseases that alter blood rheological properties. In this paper, we present a pilot study where high-frequency photoacoustic imaging (PAI) is used for the simultaneous assessment of RBC aggregation and sO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> in vivo in the human radial artery (RA). The ultrasound (US) and PA images in the RA were acquired using a US/PA imaging system equipped with a 21 MHz linear-array probe (Vevo LAZR; LZ250, FUJIFILM VisualSonics, Canada), varying the wavelength of optical illumination (700, 750, 800, 850 and 900 nm). The blood flow velocity at the RA was assessed by pulsed wave Doppler in the same device. The PA signals inside the RA were observed at all wavelengths. The PA power increased with the illumination wavelength. At each wavelength, the PA power varied as function of time. The phase of variation in PA signals was inversely proportional to that in systolic blood flow velocity. The sO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> is proportional to the cell surface area exposed to the surrounding media, and RBC aggregation decreases the exposed area of the aggregate. As such, the sO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> was higher for aggregated cells (diastolic state) than single cells (systolic state). This PAI study of RA RBC aggregation and sO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> in vivo is the first attempt to study the hemodynamics and physiological function of RBC, which can be used as a potential tool for the diagnosis of blood flow conditions in the RA.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.000 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one teacher head, not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".