Laboratory assessment of ultrasonic needle and catheter visualization.

In the first portion of this experiment, seven different catheter materials were tested as to their sonographic visualization in vitro. While five of the seven catheter materials had good to excellent sonographic detection, nylon and polyethylene catheters were poorly visualized. Additionally, various methods of improved needle visualization were tested. Sonographic needle visualization was aided by a variety of methods including either roughening or scoring the outer needle or inner stylet and placement of a guidewire through the needle. When the needle was placed in solid tissue, injection of water through the needle tip was thought to be more advantageous for tip visualization than use of air as an acoustic marker.