Ultrasound-Based Three-Dimensional Microangiography for Repeated Noninvasive Imaging of Neovascularization

Figure 2

Quadratic averaging (Q-Avg) to enhance blood signal in B-mode ultrasound images: (a) stack of traditional B-mode images revealing some vessel structures with a relatively low signal-to-noise ratio; (b) Q-Avg results in blood-enhanced angiography; (c) flow velocity map generated from correlation between signal intensity at selected points (shown as purple dots in (b)) and flow velocity measured at the same positions with pulsed wave Doppler; (d) correlation plot; (e and f) color and power Doppler imaging allow for flow mapping with less sensitivity than quadratic averaging and these techniques are unable to reveal flow perpendicular to the sound direction (compared with arrowheads in (c)); (g) flow phantom measurements showed no statistically significant correlation between signal intensity in quadratic averaged frames and flow velocity in spite that this was indicated on in vivo measurements (d); (h) stack of B-mode images revealing the flow phantom catheter; (i) Q-Avg of the B-mode images obtained at a perfusion speed of 15.85 mm/s. Orange circle: superficial ROI. Red circle: central ROI. Blue circle: Profound ROI. Green circle: total lumen ROI.