What is difference between surface and transesophageal echocardiography?

Location. Surface echocardiogram-the ultrasound transducer is on the chest wall. In transesophageal echocardiogram, the transducer is placed down into the esophagus, much like an endoscopy. The imaging is clearer with transesophageal echo which helps when looking for prosthetic valves, clots or infected valves.