Feasibility Study of High-Frequency Ultrasonic Blood Imaging in Human Radial Artery

Abstract

The present study investigates cyclic variation in blood echogenicity (CVBE) in vivo using high-frequency ultrasound (HFUS). Blood echogenicity (BE) and vessel diameter (VD) were obtained from cross-sectional B-mode images of the radial artery of six volunteers (three young and three old volunteers) acquired at a frequency of 20 MHz. The magnitudes of the cyclic variations in BE and VD were 0.83 ± 0.18 dB and 0.29 ± 0.05 mm, respectively. CVBE was observed to be out of phase with the cyclic variation in VD, which is known to be in phase with blood flow velocity. This result is different from those in previous studies, which were performed in the carotid artery at lower frequencies. In addition, the magnitude of CVBE in the older group (0.96 ± 0.05 dB) was higher than that in the younger group (0.63 ± 0.06 dB, p \ 0.005), whereas the magnitude of variation in VD was not significantly different between the two groups (p = 0.119). This feasibility study suggests that HFUS B-mode blood imaging of human small vessels is useful for the noninvasive measurement or monitoring of the dynamic variation of hemorheological properties in human blood.

Simultaneous measurement of erythrocyte aggregarion and oxygen saturation under in vitro pulsatile blood flow by high-frequency photoacoustics

“…This result can be interpreted as erythrocytes that aggregated and disaggregated during diastole and systole, respectively since the radial shear rate decreased and increase during diastole and systole, respectively. The out-of-phase relationship between EA and blood flow velocity was consistent with a previous study using high-frequency ultrasound [15]. …”

Simultaneous assessment of red blood cell aggregation and oxygen saturation under pulsatile flow using high-frequency photoacoustics

“…3. The cyclic variation in the US amplitude due to RBC aggregation was widely reported [13,20,21,[32][33][34][35].…”

“…The cyclic variation in the PAA induced by blood flow is most likely related to the cyclic variation in RBC aggregation induced by mean shear rate. Given that RBCs are the dominant absorbers in the flowing blood, the absorber size can vary periodically due to RBC aggregation and disaggregation respectively induced by the decrease and increase in the mean shear rate under pulsatile blood flow [21,[32][33][34][35].…”

Implementation of a Rotational Ultrasound Biomicroscopy System Equipped with a High-Frequency Angled Needle Transducer — Ex Vivo Ultrasound Imaging of Porcine Ocular Posterior Tissues

“…A cylindrical C-scan method was tried to get images at a certain depth by combining linear scanning and radial scanning [ 7 ]. Finally, a sectorial scanning method was tried in order to determine cyclic variations in blood echogenicity in the human radial artery [ 8 ].…”