Per Thunswärd: Contrast agent needle priming: Impact on sonographic needle visibility and potential for CT biopsy site confirmation

Abstract

Needle visualization in ultrasound-guided procedures can be challenging, particularly in contrast-specific imaging-mode. While diagnostic accuracy during CT-guided transthoracic lung biopsies is generally high, non-diagnostic results still occur and could potentially be reduced through image-based confirmation of whether the target was hit as intended. Two needle priming applications aimed at addressing these challenges were evaluated: (1) using the ultrasound contrast agent (USCA) sulfur hexafluoride to enhance needle visibility during ultrasound-guided procedures, and (2) using iodine contrast media to confirm biopsy locations during CT-guided procedures. 

Paper I: Fine needles and separable core biopsy needles were primed with USCA. Punctures were performed in butchered bovine liver and a water bath model, followed by an evaluation of needle visibility. Results were mixed in B-mode, while USCA priming consistently improved needle visibility in contrast-specific imaging-mode for core biopsy needles but not for fine needles.

Paper II: Core biopsy needles of the side-notch type (used with reusable instruments) were primed with two different concentrations of iodine contrast media using a membrane device. In CT-guided biopsies with these primed needles, high-attenuation traces at biopsy sites were successfully created in a blood pudding phantom model, with superior results at the higher contrast agent concentration.

Paper III: USCA priming was performed using a 1 mL syringe on difficult-to-separate and non-separable core biopsy needles, as well as coaxial introducer needles. Needle visibility was evaluated in a water bath model. USCA priming, almost without exception, enhanced visibility in contrast-specific imaging-mode.

Paper IV: Non-separable core biopsy needles were primed as in Paper III and evaluated in an in vivo porcine model. USCA priming, with few exceptions, improved needle visibility in contrast-specific imaging-mode but slightly worsened it in B-mode. 

These findings support the clinical use of USCA needle priming for ultrasound-guided core biopsy procedures performed in contrast-specific imaging-mode where needle visibility is limited. However, the results do not support its use in B-mode. Iodine contrast agent needle priming showed promise for confirming biopsy locations during CT-guided procedures, but further in vivo validation is required. The method’s clinical value is, however, uncertain, as newer, lighter full-core biopsy guns seem to offer a simpler solution.