Filling of Fine and Core Biopsy Needles With the Contrast Agent Sulfur Hexafluoride: Ex Vivo and in vitro Evaluation of Ultrasound Needle Visibility.

OBJECTIVES

To investigate whether the ex vivo and in vitro ultrasound visibility of fine needles (FNs) and core biopsy needles (CNBs) can be improved by filling them with an ultrasound contrast agent.

METHODS

After needle filling with the contrast agent sulfur hexafluoride, punctures with FNs and CBNs were recorded in the B-mode and contrast-specific imaging mode (10 observations in each of the 4 groups). Recordings were made in both butchered bovine liver (experiment I) and a water bath (experiment II). Air and normal saline were used as controls (total n = 120 for each experiment). In experiment I, 4 ultrasound specialists subjectively assessed the relative needle visibility in the recordings by using an arbitrary scale (integers 0-10). In experiment II, the contrast-to-noise ratio was calculated for both the entire needle course and the needle tip area.

RESULTS

In experiment I, subjective visibility was increased compared with both controls only for CBNs in the contrast-specific imaging mode (P < .01). In experiment II, the contrast-to-noise ratio for both the entire needle course and the needle tip area increased compared with both controls for both FNs and CBNs in the contrast-specific imaging mode (P < .05).

CONCLUSIONS

Ultrasound contrast agent needle filling is a promising new method to increase the visibility of CBNs in the contrast-specific imaging mode. This finding needs to be confirmed in vivo before its clinical value can be assessed.