Treated Needles

Abstract

We sought to compare needle visualization and diagnostic yield rates resulting from the use of several commercially available treated needles in sonographically guided biopsies. We conducted a randomized prospective study in which 61 patients (42 women and 19 men; mean age, 57 years; range, 19-84 years) were assigned to undergo biopsies (37 thyroid and 24 liver, 2 passes per patient) with 1 of 4 different 22-gauge needles: Teflon coated, etched tip, echogenic polymer coated, and untreated. Two blinded radiologists independently scored needle shaft and tip visualization from 0 (no visualization) to 4 (excellent visualization). After blinded cytologic evaluation, the individual passes were rated as adequate or inadequate for establishing a tissue diagnosis. The echogenic polymer-coated needle had the highest mean score +/- SD for visualization of both the shaft (3.4 +/- 0.90) and tip (3.5 +/- 0.87) compared with the untreated (shaft, 2.2 +/- 0.77; P = 0.003; tip, 2.8 +/- 0.92; P = 0.01), Teflon-coated (shaft, 2.7 +/- 0.94; tip, 3.1 +/- 0.75), and etched tip (shaft, 3.0 +/- 0.82; tip, 3.0 +/- 0.56) needles. Diagnostic yield rates for the 4 different needle types were 75.0% for the echogenic polymer-coated, 64.7% for the Teflon-coated, 56.3% for the etched tip, and 75.0% for the untreated needles (no significant difference). The echogenic polymer-coated needle was the best visualized of all needles evaluated, both treated and untreated. No significant difference was found in diagnostic yield rates, but that may be reflective of the relatively small sample size.