A chest ultrasound is a noninvasive diagnostic exam that produces images, which used to assess the organs and structures within the chest, such as the lungs, mediastinum (area in the chest containing the heart, aorta, trachea, esophagus, thymus, and lymph nodes), and pleural space (space between the lungs and the interior wall of the chest). Ultrasound technology allows quick visualization of the chest organs and structures from outside the body. Ultrasound may also be used to assess blood flow to chest organs.