[In vitro and in vivo demonstrations of puncture instruments in the sonographic real time image. 1: Puncture needles].

The article reports on systematic sonographic examination of needles for aspiration biopsy in a waterbath and in an animal model. The in-vitro findings were found to be applicable to the in-vivo situations. Needles can be visualized almost true to construction in horizontal longitudinal view and produce an angle-like reflex at the tip in oblique longitudinal view. Roughening of the needle surface yields an amplification of contrast in the sonographic image. The same effect may be obtained by roughening the intraluminar parts of the needle. This is achieved by the corkscrew turns of the Nordenström needle or by means of stabilized air bubbles in gel form, the latter being interpreted as a kind of contrast substance. Internal inhomogenerization while maintaining a smooth exterior surface leads to contrast augmentation of the needle in the sonographic image without surface-induced traumatization during puncturing.