Optimal set-up for ultrasound guided punctures using new scanner applications: an in-vitro study.

Objective: To investigate if US-visualisation of the needle tip echo during US-guided punctures could be improved by use of new technological applications. Method: an US-guided 18 G Trocar needle was inserted into targets of a puncture phantom. The punctures were performed in series of 10 using different settings of the US-scanner (GE Logic 700 Expert). At 7-cm of puncture depth the quality of the echo was tested using four different settings; normal (N), N+automatic tissue optimising (ATO), coded harmonic imaging (CHI), CHI+ATO and at 13-cm of puncture depths six different settings; N, N+ATO, coded excitation (CE), CE+ATO, CHI, CHI+ATO. In total 100 (40+60) images were randomly numbered and read independently by three radiologists with regard to scoring of the quality of the echoes from the needle tip, needle shaft and the target. Results: US visualisation of the needle tip was significantly (P<0.005) improved as compared to normal settings (N) when the settings of ATO and CE were used. CHI resulted in the lowest score. A high agreement between observers was registered. Similar results were registered with regard to scorings from the needle shaft and target. Conclusion: Not only changes of needle designs and puncture techniques can enhance echoes from the needle but also changes in the settings of the US-scanner with the use of new technological applications can improve visualisation of the needle echo.