| 摘要 |
The echogenic characteristics of a needle 1 or catheter are enhanced by abubble-filled plastics stylet 2, (72, fig 7) which inserted in the bore 10 of the needle or catheter and is more effectively acoustically coupled to the inside of the needle or catheter. This is achieved in several different ways. In one arrangement, a liquid 3 or the like is introduced between the outside of the stylet 2 and the inside of the needle 1 or catheter. In another arrangement, the stylet (72, fig 7) is of a compressible material having a natural external diameter greater than the internal diameter of the needle or catheter so that the stylet is in compression within the needle or catheter. The stylet 72 may be stretched longitudinally by means of an extension rod 76 for insertion. |
