Ultrasound transducers.

Sonography is facing a new technological revolution. Recent advances in ultrasound technology are increasing spatial, contrast and vascular resolution. Transducers play an important role in achieving these improvements; their technology is widely reviewed in this paper. Physics and technology relate to image quality and its clinical potentials. Large annular arrays made the progression of imaging quality; they are still a very good choice for scanning superficial structures. New broadband linear arrays approach their quality and allow to visualize the flow within very small vessels; they permit new harmonic imaging that reduces image noise and clutter caused by the body wall. New advances include digital beamformers that work at their best when coupled with broadband technology. New multi-layer and multi-array scanheads improve the signal-to-noise ratio and increase the transmitted energy. New transducers and imaging algorithms allow real-time acquisition of large fields of view and even of three-dimensional volumes. Further refinement of two-dimensional matrix transducers will produce high-definition volumetric images. Evolution in transducers technology permits to interrogate the vessels with higher Doppler frequencies extending the anatomical perception and opening new fields of investigation.