title: CT assessment of vocal cord medialization.
abstract: OBJECTIVE
  Unilateral vocal cord paralysis (UVCP) occurs after iatrogenic injury or disease process and is associated with dysphonia and aspiration. Various surgical options are available for treatment of UVCP, including vocal cord medialization thyroplasty and injection laryngoplasty. These augmentative procedures improve phonation and airway protection. Our purpose was to demonstrate the CT appearance of implants used for the treatment of UVCP.
  
  
  METHODS
  Twelve patients treated surgically for UVCP were studied with helical CT. The vocal cords were augmented by using Silastic implants (n = 7), polytetrafluoroethylene (Gore-Tex) implants (n = 2), Teflon injections (n = 2), or fat injection (n = 1). Augmented vocal cords were characterized by size, shape, and Hounsfield units (HU). Two other patients with failed medialization thyroplasty were evaluated for the position of the extruded implant relative to the paralyzed vocal cord.
  
  
  RESULTS
  The 7 Silastic implants were triangular and hyperattenuated (293.4 +/- 90.4 HU). The 2 Gore-Tex implants were heterogeneous with lobulated medial margins and were hyperattenuating (320 and 414 HU). The injected materials demonstrated ovoid/masslike configurations: the 2 Teflon injections were hyperattenuated (107 and 429 HU), and the fat injection was hypoattenuated (-102 HU). Inferior displacement of the implant was demonstrated relative to the true vocal cord in 2 patients with failed Silastic thyroplasties.
  
  
  CONCLUSIONS
  CT can distinguish various types of vocal cord augmentation. Silastic implants are recognized by their characteristic triangular configuration. The Gore-Tex implants had unique heterogeneous attenuation with lobulated medial margins. Fat and Teflon injections both appear ovoid/masslike. Teflon injection should not be mistaken for tumor.
authors.affiliation: Division of Diagnostic Imaging, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA. vakumarmd@yahoo.com
authors.forename: V A
authors.initials: VA
authors.lastname: Kumar
authors.forename: J S
authors.initials: JS
authors.lastname: Lewin
authors.forename: L E
authors.initials: LE
authors.lastname: Ginsberg
mesh_terms: D000273:Adipose Tissue / Q000637:transplantation*; D000328:Adult; D000368:Aged; D004129:Dimethylpolysiloxanes; D005260:Female; D006801:Humans; D007089:Image Enhancement; D007091:Image Processing, Computer-Assisted; D008297:Male; D008875:Middle Aged; D010043:Outcome and Process Assessment, Health Care; D010348:Patient Care Team; D011138:Polytetrafluoroethylene; D011183:Postoperative Complications / Q000000981:diagnostic imaging*; D019919:Prosthesis Implantation; D012008:Recurrence; D012086:Reoperation; D012189:Retrospective Studies; D012828:Silicones; D014057:Tomography, X-Ray Computed; D014826:Vocal Cord Paralysis / Q000000981:diagnostic imaging / Q000209:etiology / Q000601:surgery*
chemical_list: D004129:Dimethylpolysiloxanes; D012828:Silicones; C013830:baysilon; D011138:Polytetrafluoroethylene