What procedure is used to visualize the contents of the mediastinum?

Mediastinoscopy is the correct procedure used to visualize the contents of the mediastinum, which is the area between the lungs that contains various vital structures, including the heart, aorta, esophagus, and trachea. This minimally invasive procedure involves making a small incision at the base of the neck and inserting a mediastinoscope—a thin, lighted tube equipped with a camera—to directly view and assess the mediastinal structures. This technique is particularly useful for diagnosing conditions such as lymphadenopathy, tumors, and other abnormalities within the mediastinum.

The other options serve different purposes or provide less direct visualization. For example, thoracotomy is a surgical procedure where the chest is opened, which allows for direct access to the thoracic cavity but is more invasive than necessary for visualizing the mediastinum alone. A chest X-ray can show the general contour and size of the mediastinum but lacks the detailed visualization offered by mediastinoscopy. Ultrasound can assist in evaluating some thoracic structures but is not typically used specifically to visualize the mediastinum as a standalone procedure. Thus, mediastinoscopy is the most effective and specialized technique for this particular purpose.