Relative ultrasonographic echogenicity of standard, dimpled, and polymeric-coated needles

PURPOSE: To use quantitative ultrasonographic measurements to compare the e ffect of a polymeric coating designed to increase needle echogenicity to co mmercially available needles. MATERIALS AND METHODS: Commercially available standard smooth and dimpled e chogenic tip 21-gauge needles established reference levels of echogenicity in gelatin-based and turkey breast phantoms, Examples of both types of need les were coated with a thin polymeric film that utilizes entrapped microbub bles of air on its surface to increase echogenicity, Samples of each type i n both coated and noncoated versions were placed in phantoms in matched pos itions and imaged with clinical ultrasound machines, Similar numbers of eac h category were evaluated at various angles of insonation for a total of 10 9 images. Similar numbers of each category were imaged at B-minute interval s for up to 38 minutes for a total of 226 images. Images were recorded, dig itized, and evaluated for relative echo strength in arbitrary echogenic bri ghtness units. RESULTS: Coating increased peak echogenicity over the entire needle to a le vel that closely approximates the peak echogenicity of dimpled needle tips (means: dimpled = 834, coated smooth = 803, coated dimpled = 823; P = .54), Smooth is lower than this group at 468 (P = .0001), Representative area ec hogenicity increased with coating or dimpling (smooth = 377 vs coated smoot h = 778, coated dimpled = 690, dimpled = 775; P = .0001), Coating increased peak values 74% and area values 95% compared to smooth. Decreased angles o f insonation moderately reduced echogenicity on coated smooth, coated dimpl ed, and dimpled, while it decreased to below good visibility threshold on s tandard smooth needles. The echogenicity of the coated needles fades in sal ine with time (l%/min). CONCLUSION: Objective measurements show that this coating significantly inc reases echogenicity of entire needles to match that obtained with a dimpled tip.