Endosonography, also called endoscopic ultrasound, is a specialized technique that combines endoscopy with ultrasound by placing a small ultrasound transducer at the tip of an endoscope or similar instrument. By positioning the transducer inside the body, much closer to the target organ than external ultrasound can achieve, endosonography produces higher-resolution images with less interference from bone and gas. Common applications include transrectal ultrasound of the prostate, endoscopic ultrasound of the pancreas and bile ducts through the stomach wall, and transesophageal echocardiography of the heart through the esophagus. Endosonography can also guide fine needle aspiration biopsies of lesions that are difficult to reach from outside the body.
Sonography Term