Abstract
Purpose To evaluate needle visibility in ultrasound under contrast mode conditions.
Materials and Methods Needle visibility was evaluated for bevel, EchoTip® and shaft of 18G Chiba biopsy needle with a 9 MHz linear probe (GE Logiq E9). Insertion angles varied between 30°(steep) and 90°(parallel to the probe surface). The acoustic output varied from 5–28%. 2 different contrast mode presets with either 'Amplitude Modulation' (Penetration) or 'Phase Inversion Harmonics' (High Resolution) were assessed. All other imaging parameters were kept constant. The visibility of bevel, EchoTip® and shaft was assessed for grayscale and color-coded images with a 3-point Likert-like scale (not, poorly, well visible) by 2 independent readers. The echogenicity of the needle bevel, EchoTip® and shaft was assessed in deciBel (dB) on the color-coded images.
Results With the parallel insertion angle, all needle areas were well visible. With steep insertion the EchoTip® was the only visible area. High Resolution was superior to Penetration (p<0.001). The visibility and echogenicity of the needle bevel (r
grayscale=0.109, pgrayscale=0.178; r
color-coded=0.236, pcolor-coded=0.266; r
dB=0.956, pdB=0.001), EchoTip® (r
grayscale+= 0.477, pgrayscale+= 0.018; r
color-coded=0.540, pcolor-coded+= 0.006; r
dB=0.911, pdB=0.001) and shaft (r
grayscale=0.124, pgrayscale=0.563; r
color-coded=0.061, pcolor-coded+= 0.775; r
dB+= 0.926, pdB=0.001) increased with increasing acoustic output. Grayscale images were superior to color-coded images for needle visibility (p=0.004).
Conclusion Parallel needle insertion, use of an echogenic tip, adequate choice of presets, increased acoustic output, and dual view of grayscale and color-coded images improve needle visibility in ultrasound under contrast mode conditions.
Key words
ultrasound - biopsy - contrast agents
