An ultrasound imaging transducer assembly enclosed in a fluid-resistant, acoustically- and electrically-insulated housing, designed to be inserted and positioned in the oesophagus to obtain ultrasound images of the heart and/or to navigate devices requiring ultrasound guidance and placement (e.g., endoscopy equipment or needle biopsy equipment). Also known as an oesophageal endosonography probe or transducer, it is composed of either a single transducer element or an array of transducer elements, i.e., piezoelectric element(s), active element(s), or crystal(s), and associated damping, backing, and matching layer materials. This is a reusable device.