title: Using CT to localize side and level of vocal cord paralysis.
abstract: OBJECTIVE
  The purpose of our study was to assess the relative accuracy of imaging findings related to peripheral recurrent nerve paralysis on axial CT studies of the neck. Also assessed were imaging findings of a central vagal neuropathy.
  
  
  METHODS
  We retrospectively identified 40 patients who had clinically diagnosed vocal cord paralysis and had undergone CT. Eight imaging signs of vocal cord paralysis were assessed, and an imaging distinction between a central or peripheral vagal neuropathy was made by evaluating asymmetric dilatation of the oropharynx with thinning of the constrictor muscles. In two patients, we studied the use of reformatted coronal images from a multidetector CT scanner.
  
  
  RESULTS
  For unilateral vocal cord paralysis, the most sensitive imaging findings were ipsilateral pyriform sinus dilatation, medial positioning and thickening of the ipsilateral aryepiglottic fold, and ipsilateral laryngeal ventricle dilatation. In two patients, coronal reformatted images aided the diagnosis by better showing flattening of the subglottic arch. Imaging findings allowed localization of a central vagal neuropathy in four patients.
  
  
  CONCLUSIONS
  Three reliable imaging findings associated with vocal cord paralysis were identified on routine axial CT studies: ipsilateral pyriform sinus dilatation, medial positioning and thickening of the ipsilateral aryepiglottic fold, and ipsilateral laryngeal ventricle dilatation. Coronal reformatted images of the larynx may be helpful, but they are not necessary in 95% of patients. Ipsilateral pharyngeal constrictor muscle atrophy is a helpful imaging finding to localize a more central vagal neuropathy. Our findings can aid radiologists in identifying peripheral and central vagal neuropathy in patients who present for CT of the neck who have a normal voice and are without a history suggestive of a vagal problem.
authors.affiliation: Department of Radiology, Tri-Service General Hospital, National Defense Medical Center, Taipei, Taiwan.
authors.forename: Shy-Chyi
authors.initials: SC
authors.lastname: Chin
authors.forename: Simon
authors.initials: S
authors.lastname: Edelstein
authors.forename: Cheng-Yu
authors.initials: CY
authors.lastname: Chen
authors.forename: Peter M
authors.initials: PM
authors.lastname: Som
mesh_terms: D005260:Female; D007839:Functional Laterality / Q000502:physiology; D006801:Humans; D007830:Larynx / Q000000981:diagnostic imaging; D008297:Male; D008875:Middle Aged; D009133:Muscular Atrophy / Q000000981:diagnostic imaging; D010609:Pharyngeal Muscles / Q000000981:diagnostic imaging; D012189:Retrospective Studies; D012680:Sensitivity and Specificity; D036542:Tomography, Spiral Computed; D020421:Vagus Nerve Diseases / Q000000981:diagnostic imaging; D014826:Vocal Cord Paralysis / Q000000981:diagnostic imaging* / Q000209:etiology; D014827:Vocal Cords / Q000000981:diagnostic imaging