Design and construction of an esophageal phased array probe

The clinical urge for echocardiographic data from patients with inadequate image quality at the precordial examination has initiated the development of transesophageal scanning techniques. The orientation of heart structures with respect to the transducer position in the esophagus, the absence of interfering structures in the soundbeam and the constraints imposed by the anatomy of the esophagus result in a different set of parameters for the optimization of the transducer and its assembly. In this article, the design and construction of a miniaturized 5 MHz phased array transducer optimized for transesophageal scanning is described. Relevant parameters and their influence on the design will be discussed, such as: bandwidth, sensitivity, resolution (in three dimensions), focal depth and the production method.