Cross-sectional Imaging Anatomy and Pathologic Conditions Affecting Thoracic Nerves.

While in many cases they are not directly visualized, awareness of the thoracic nerves and their courses at cross-sectional imaging is important for radiologists. An understanding of the normal function of each nerve is important, as many patients present with neurologic signs and symptoms that can be used to reinforce search patterns for disease and detection of supportive radiologic abnormalities. In the case of primary neoplasms, understanding the expected presence of a nerve in the location of a mass can enhance and improve the accuracy of differential diagnoses. Even in the absence of neurologic symptoms, secondary involvement of these structures by malignancy or close proximity to other intrathoracic disease can prompt significant alterations in oncologic or surgical management. The major components of the thoracic nervous system with which the thoracic radiologist must be familiar are the phrenic, vagus, recurrent laryngeal, intercostal, and long thoracic nerves in addition to the sympathetic chain and brachial plexus. The anatomic structure and course of each component are described including its major functions. Major clinical signs and symptoms attributable to nerve dysfunction or disease are reviewed as well as any associated radiologic signs. Emphasis is placed on primary and secondary malignant involvement of the nerves and iatrogenic and traumatic injuries. Online supplemental material is available for this article. ©RSNA, 2016.

Imaging of the Patient with Thoracic Outlet Syndrome.

Patients with symptoms from compression of the neurovascular bundle in the thoracic outlet are described as having thoracic outlet syndrome (TOS), which is best thought of as three conditions classified according to which structures are involved. The purpose of this article is to review the role of imaging in evaluation of patients with TOS, beginning with diagnosis and extending through postoperative management. While diagnosis of TOS still rests on the patient's presenting history and physical examination, imaging examinations are helpful in supporting the diagnosis, delineating abnormal anatomy, determining which structures are compressed, identifying the site of compression, and excluding other diagnoses. Magnetic resonance imaging is the noninvasive imaging modality of choice in evaluating patients with suspected TOS, but computed tomography also plays an important role, particularly in delineating bone anatomy. Evidence of vascular damage is required to make the diagnosis of TOS at imaging. Dynamic compression of the axillosubclavian vessels at the thoracic outlet can be a finding supportive of the diagnosis of TOS but is not a stand-alone diagnostic criterion, as it can be seen in patients without TOS. As diagnosis and treatment of TOS increase, radiologists will increasingly encounter the TOS patient after decompression surgery. Recognition of the expected postoperative appearance of these patients is critical, as is an understanding of the imaging findings of potential short- and long-term complications. (©)RSNA, 2016.