Color and pulsed Doppler signatures of vascular bleeding

To develop ultrasound‐based methods for detection and localization of internal vascular bleeding, we investigated the bleeding signatures using color and pulsed Doppler. Under ultrasound guidance, femoral arteries (n=13) and veins (n=12) in seven pigs were catheterized with 6, 9, and 11 F catheters. Color and pulsed Doppler were acquired from the injury site and the surrounding positions after withdrawal of the catheter. The bleeding rates were 3.8–38 ml/s. Color Doppler revealed that the injured vessels were in spasm. The checkered color pattern at the injury site indicated flow turbulence. Pulsed Doppler spectrum of the color jet (extravasated blood) represented a unique arterial bleeding pattern with increased baseline velocity (from 0 up to 25.8 cm/s) and elevated systolic velocity (from 23.2 up to 62.5 cm/s) at the puncture site, as compared to the normal arterial pattern. Venous bleeding showed a narrow‐band vibration signal at the bleeding site. Local blood turbulence contained multiple velocity components which were illustrated as checkered color in color Doppler. Pulsed Doppler spectrum showed increased baseline due to turbulence and elevated velocity due to narrowed vessel. In future studies pulsed Doppler radio‐frequency data will be used to analyze bleeding patterns for detection and localization of internal bleeding.