Effects of Needle and Catheter Size on Commercially Available Ultrasound Contrast Agents

Objectives To investigate effects of needle and catheter size on in vitro ultrasound contrast agent (UCA) enhancement and concentrations using 4 commercially available UCAs. Methods Definity (Lantheus Medical Imaging, North Billerica, MA), Optison (GE Healthcare, Princeton, NJ), SonoVue (Bracco SA, Geneva, Switzerland), and Sonazoid (GE Healthcare, Oslo, Norway) were investigated. The UCA was injected via a 1‐mL syringe (BD, Franklin Lakes, NJ) into a 3‐way stopcock (Smith Medical, Dublin, OH) and flushed with 10 mL of saline through an 18‐cm infusion extension tube connected to either a 16‐, 18‐, 20‐, 22‐, or 24‐gauge catheter (BD) or an 18‐, 20‐, 21‐, or 25‐gauge needle (BD). In vitro enhancement was determined in a flow phantom (ATS Laboratories, Bridgeport, CT), and microbubble concentrations were determined using an LSRII flow cytometer (BD Biosciences, San Jose, CA). Results Significant decreases in enhancement and microbubble concentrations were observed for all 4 UCAs (P < .001) when administration was performed through a 25‐gauge needle. No statistically significant differences in enhancement or concentrations were observed between all catheter sizes and 18‐ to 21‐gauge needles for SonoVue and Sonazoid. Definity and Optison administration through a 24‐gauge catheter resulted in a significant loss of enhancement (P < .02), although these differences were not significant on flow cytometry. Conclusions Administration of commercial UCAs in a clinical scenario is possible with catheters or needles smaller than 20 gauge, although the minimal allowable size appears to be UCA specific.