In vitro randomized comparison of a standard and novel echogenic needle for ultrasonography-guided renal targeting

Urologists are becoming increasingly aware of the importance of pretreatment percutaneous renal biopsy of small renal cortical neoplasms. A barrier to the routine performance of ultrasonography-guided percutaneous renal biopsy has been the technical challenges associated with the procedure. We evaluated a new modified needle, which incorporates an echogenic needle tip designed to improve the needle tip's visibility under ultrasonographic visualization. We evaluated and compared the ultrasonographic imaging quality of the echogenic needle (EN) and a standard needle (SN).

Forty-eight participants were recruited to perform ultrasonography-guided needle targeting and drainage of a simulated cyst within a phantom model. The simulated cysts were embedded in an opaque gel mold. Each participant was blinded to the type of needle being deployed and was asked to identify and aspirate the simulated cyst with each needle under ultrasonography guidance. Each needle was tested at three ultrasound-aiming angles, (0, 15, and 30 degrees). The quality of needle visibility under ultrasonographic imaging was assessed via a questionnaire, including needle preference and a visibility score (1-10) at each aiming angle. Participants were stratified by level of ultrasound experience.

For each angle tested, the EN received higher visibility ratings. The mean visibility scores for the EN vs the SN were 6.44 vs 5.52 at 0 degrees (P=0.001), 7.77 vs 6.96 at 15 degrees (P=0.0004) and 8.33 vs 7.54 at 30 degrees (P=0.0001). Participants reported significantly greater comfort using the EN needle compared with the SN (P=0.001). These results held true regardless of the sequence of needle tested first. Also, there was a significant difference in visibility scores by angle (P=0.0001). Larger angles (30>15>0) resulted in higher scores.

In this in vitro trial, the application of the EN improved needle visibility for users of all levels of experience. Clinical correlation is pending.