With its rapid scanning time, high-spatial resolution, and multiplanar capability, contrast-enhanced neck CT conveniently allows imaging of the jugular foramen, the full extracranial course of the vagus nerve, direct imaging of the larynx, and assessment of the full extent of the recurrent laryngeal nerve when extended through the aortopulmonary window. Imaging protocols should include thin-cut high- resolution bone windows through the posterior skull base. Contrast should be administered. Noncontrast neck CT offers limited evaluation of the neck and may be an alternate option for this clinical scenario. There is no relevant literature to support the use of combined pre- and postcontrast imaging. Direct and indirect signs of vocal cord paralysis can be seen on CT [152]. CT may differentiate traumatic arytenoid dislocation from neurogenic paralysis [153]. Optimal evidence-based imaging algorithms in the setting of unilateral vocal cord paralysis without an apparent cause are not established. Several studies support the use of CT for detecting a cause for unilateral vocal cord paralysis with diagnostic yields ranging from 23.5% to 47.5% [155,157]. One study found CT had a higher diagnostic yield of 40% among patients >65 years of age [131]. In patients with a diagnosis of idiopathic vocal cord Cranial Neuropathy paralysis, repeat CT may be helpful to detect occult causes of paralysis [156]. Other studies report low diagnostic yields ranging from 0% to 6% [159-161]. Noninvasive virtual laryngoscopy using ultrahigh-resolution CT and cine MRI allowing the patient to perform phonation and breathing maneuvers during imaging are emerging technologies [162,163]. CTA Head and Neck There is no relevant literature to support the use of CTA in the evaluation of unilateral isolated vagal nerve palsy. FDG-PET/CT Skull Base to Mid-Thigh FDG-PET/CT is not routinely used in the initial evaluation of vocal cord paralysis or vagus nerve palsy.
Cranial Neuropathy. With its rapid scanning time, high-spatial resolution, and multiplanar capability, contrast-enhanced neck CT conveniently allows imaging of the jugular foramen, the full extracranial course of the vagus nerve, direct imaging of the larynx, and assessment of the full extent of the recurrent laryngeal nerve when extended through the aortopulmonary window. Imaging protocols should include thin-cut high- resolution bone windows through the posterior skull base. Contrast should be administered. Noncontrast neck CT offers limited evaluation of the neck and may be an alternate option for this clinical scenario. There is no relevant literature to support the use of combined pre- and postcontrast imaging. Direct and indirect signs of vocal cord paralysis can be seen on CT [152]. CT may differentiate traumatic arytenoid dislocation from neurogenic paralysis [153]. Optimal evidence-based imaging algorithms in the setting of unilateral vocal cord paralysis without an apparent cause are not established. Several studies support the use of CT for detecting a cause for unilateral vocal cord paralysis with diagnostic yields ranging from 23.5% to 47.5% [155,157]. One study found CT had a higher diagnostic yield of 40% among patients >65 years of age [131]. In patients with a diagnosis of idiopathic vocal cord Cranial Neuropathy paralysis, repeat CT may be helpful to detect occult causes of paralysis [156]. Other studies report low diagnostic yields ranging from 0% to 6% [159-161]. Noninvasive virtual laryngoscopy using ultrahigh-resolution CT and cine MRI allowing the patient to perform phonation and breathing maneuvers during imaging are emerging technologies [162,163]. CTA Head and Neck There is no relevant literature to support the use of CTA in the evaluation of unilateral isolated vagal nerve palsy. FDG-PET/CT Skull Base to Mid-Thigh FDG-PET/CT is not routinely used in the initial evaluation of vocal cord paralysis or vagus nerve palsy.