Early and present examples of intraluminal ultrasonic echography

Although one of the great merits of medical application of ultrasound is the non-invasive character of the technique, there are several examples in which an invasive or semi-invasive application can be useful. Probably due to then poor sensitivity of the piezoelectric crystals some very early invasive echo applications are based on tubeor catheter-mounted echo elements. Echo-endoscopy for the inspection of body cavities dates back to the fifties. Not much later investigators began to develop intra-esophageal probes for inspection of the heart and great vessels. Transesophageal echography has become very important in cardiology today. Intravascular echo imaging has gained much interest. Such a technique would be very helpful in the diagnosis of obstructive arterial disease and the evaluation of therapeutic intervention. This echo technique has been suggested for steering of catheter-based desobstruction methods. A few examples of combined echo and desobstruction techniques as reported in literature are mentioned. With high-frequency intravascular real-time imaging it is possible to observe detailed information on arterial wall, fibrotic proliferation and atherosclerotic plaque.