In vivo photoacoustic assessment of the oxygen saturation changes in the human radial artery: a preliminary study associated with age

Abstract

Significance: We demonstrate the potential of probing the sO 2 change under blood flow in vivo using photoacoustic (PA) imaging and sheds light on the complex relationship between RBC aggregation and oxygen delivery. Aim: To conduct in vivo assessments of the sO 2 in the radial artery of healthy volunteers and simultaneously probe the relation between the sO 2 and hemodynamic behavior such as red blood cell (RBC) aggregation. Approach: The effects of PA-based measurements of blood hemodynamics were studied as a function of the subjects' age (20s, 30s, and 40s). The pulsatile blood flow in the human radial artery of 12 healthy subjects was imaged in the 700 to 900 nm optical wavelength range using a linear array-based PA system. Results: The PA power when blood velocity is minimum (Pa max) was larger than the one attained at maximum blood velocity (Pa min), consistent with predictions based on the cyclical variation of RBC aggregation during pulsatile flow. The difference between Pa min and Pa max at 800 nm (ΔPa 800) increased with age (1.7, 2.2, and 2.6 dB for age group of 20s, 30s, and 40s, respectively). The sO 2 computed from Pa max was larger than the one from Pa min. Conclusions: The ΔPa 800 increased with participant age. The ΔPa 800 metric could be a surrogate of noninvasively monitoring the age-induced changes in RBC aggregation. The sO 2 change during a cycle of pulsatile blood flow also increased with age, demonstrating that RBC aggregation can affect the sO 2 change.

Evaluation of Tracheal Stenosis in Rabbits Using Multispectral Optoacoustic Tomography

“…Endobronchial OCT, as a new method for airway image in both animal (Mahmood et al, 2006;Lin et al, 2013;Lee et al, 2014) and human (Balakrishnan et al, 2018;Goorsenberg et al, 2018;Kozlowski et al, 2019) may cause airway mucosa injury or aggravate airway stenosis, due to its invasive detection. Furthermore, PAT and MSOT could be an accurate imaging modality for assessment of blood vessel diseases (Yang et al, 2019;Bok et al, 2021;Karlas et al, 2021), highlighting the potential of them as a new tool to evaluate structural and functional information in tubular structures like artery, vein, trachea and bowel. Here we have developed a new non-invasive PAT-based method with high temporal and spatial resolution, which is capable of acquiring structural and functional information of trachea.…”

“…More recently, MSOT is found to be a method with a multitude of possible applications ranging from the small animal studies, to clinical imaging applications (Taruttis et al, 2013;Anne et al, 2020;Karlas et al, 2021), indicating its ability of providing potent structural, functional, and molecular information. Furthermore, PAT and MSOT could be an accurate imaging modality for assessment of blood vessels diseases in vivo (Yang et al, 2019;Bok et al, 2021;Karlas et al, 2021), highlighting the potential of them as a new tool to evaluate structural and functional information in tubular structures like artery, vein, trachea and bowel.…”

Monitoring Blood Clot Formation and Lysis in Vitro Using High Frequency Photoacoustics

“…This has been used previously to determine blood oxygenation in human renal arteries in vivo. [80] By switching the laser source in this work to a tunable multiwavelength source, blood oxygenation measurements are possible while simultaneously detecting clotting and lysis. Another useful parameter that can be measured using multispectral imaging is hemoglobin concentration, which can be used as part of the test developed in this work to determine if a patient is anemic.…”

Optoacoustic biomarkers of lipids, hemorrhage and inflammation in carotid atherosclerosis

“…In another work, raster-scan optoacoustic mesoscopy (RSOM) demonstrated capability to assess vascular anomalies, such as capillary malformations (CMs) and infantile hemangiomas (IHs) before and after the application of a corresponding treatment (15). Regarding larger arteries, optoacoustics has been also employed in imaging, for example, the radial artery morphology and oxygenation (16,17). Nevertheless, arteries such as the radial are quite superficial (depth of 2-3 mm under the skin), a feature that facilitates their imaging using optoacoustics, a technology affected by light attenuation with increasing depth.…”