In this thesis the development of a miniaturized phased array ultrasound transducer
is described. The application of this transducer in the field of echocardiology
is devoted to transesophageal cross-sectional scanning of the heart and its great
vessels. The enormous increase in diagnostic applications of ultrasound over the
last three decades is particularly due to the non-invasive character of this technique.
Consequently the developments of transcutaneous scanning techniques have
outnumbered all other possibilities, but researchers have continuously been investigating
the alternatives of scanning organs from within the human body. In those
patients in whom inhibiting factors preclude adequate diagnostic information to
be obtained transcutaneously, alternative scanning techniques still may-provide
vital information.
For cardiac imaging two possibilities exist to enter the human body, invasively
by means of a catheter or 'non-invasively' by means of an endoscope. In Chapter I,
the introduction, our early experiences with a catheter-mounted scanning system
are described. The limited possibilities of such a system combined with the
inherent technological complications, as well as the invasive character of such a
technique favoured the search for a different approach. The idea to advance in the
catheter direction was never left but first the experience gained has been applied to
transesophageal scanning with an endoscope-mounted transducer as described in this thesis