Unilateral vocal cord paralysis: a review of CT findings, mediastinal causes, and the course of the recurrent laryngeal nerves

Vocal cord paralysis (VCP) may be caused by a variety of mediastinal disease entities, including various neoplastic, inflammatory, and vascular conditions, and may be the presenting symptom of an otherwise clinically occult disease. Familiarity with the spectrum of thoracic diseases that can result in VCP and inclusion of the mediastinum to the level of the aorticopulmonary window (left side) or brachiocephalic artery (right side) in computed tomographic (CT) studies performed for VCP are essential. VCP can be reliably identified at CT by recognizing key findings at the level of the true vocal cords and aryepiglottic folds. Although there are a number of VCP mimics and imaging pitfalls, they can generally be avoided by carefully assessing the scan plane and level and evaluating for additional findings. By understanding and assessing the entire course of the vagus and recurrent laryngeal nerves, the radiologist can avoid missing causative lesions, many of which have a clinical significance far beyond that of the VCP itself.