Ultrasonografia Endoscópica

Endoscopic ultrasonography (EUS) has evolved from a diagnostic imaging modality to one that can also be used for invasive diagnostic and therapeutic procedures. These advances are largely due to the introduction of linear scanning instruments that can be used to place devices into the ultrasound plane of view, permitting various interventions to be performed. The ability of EUS to guide a biopsy needle into lesions that are too small to be identified by computed tomography or magnetic resonance imaging, or too well encased by surrounding vascular structures to allow percutaneous biopsy, secures its role in a variety of clinical settings. Indications for EUS-guided fine-needle aspiration (EUS-FNA) include biopsy of mucosal and submucosal lesions in which prior conventional endoscopic biopsies have been nondiagnostic. The procedure is most commonly used to sample peri-intestinal structures such as lymph nodes and masses in the pancreas, liver, adrenal gland, and bile duct. It has also been used to aspirate peritoneal and pleural fluid. Endoscopic ultrasonography is used to establish the stages of tumors of the gastrointestinal track, pancreas and biliary ducts, being its main use to establish the stages of esophageal, gastric and rectal tumors. Some studies have shown that Endoscopic Sonography is the most exact imaging modality to determine the depth of the tumor invasion with a preoperative certainty between 80 to 90%, when compared with a histological specimen. Using ultrasound endoscopic sonography it cannot be distinguished with certainty whether the process is inflammatory or neoplastic. Likewise, ultrasonographic sonography has proved to be ineffective in determining the stages of lymphatic nodules, for the nodule had to be localized and identified as benign or malign. <a id="