title: MR imaging of thyroglossal duct cysts in adults.
abstract: OBJECTIVE
  To describe the magnetic resonance (MR) features of thyroglossal duct cysts (TDC) in adults.
  
  
  METHODS
  Sixteen patients with TDC underwent MR imaging to obtain T1- and T2-weighted images and T2-weighted fat saturation images. In addition, contrast enhanced images were obtained in five patients.
  
  
  RESULTS
  The signal intensity of TDC was of that of a simple cyst in seven (44%) patients, yielding high signal intensity on T2- and low signal intensity on T1-weighted images. In nine (56%), the signal intensity was either intermediate or high on T1-weighted images, the T2 signal intensity in these cases being high (7), intermediate (1) or low (1). Enhancement of the wall of the cyst was present in three of five (60%) patients. All 16 TDC were located at or just to one side of the midline and 12 were embedded in the strap muscles. All TDC were infrahyoid in location but 11 also extended superiorly to be directly related to the hyoid. At the hyoid the cystic component was immediately posterior (6) anterior (3) or anterior and posterior (2) to the bone. Intralaryngeal extension was present in eight (50%) patients. A suprahyoid tract was identified in three patients. The thyroid gland was in a normal location in all patients.
  
  
  CONCLUSIONS
  Thyroglossal duct cysts are most commonly of high T1 signal intensity consistent with high protein content. The tract leading to the base of the tongue is infrequently seen, the diagnosis being determined by the intimate relationship to the hyoid and strap muscles. Intralaryngeal extension in adult patients with TDC is more frequent than reported previously.
authors.affiliation: Department of Diagnostic Radiology and Organ Imaging, Faculty of Medicine, Chinese University of Hong Kong, Prince of Wales Hospital, Shatin, New Territories.
authors.forename: A D
authors.initials: AD
authors.lastname: King
authors.forename: A T
authors.initials: AT
authors.lastname: Ahuja
authors.forename: C O
authors.initials: CO
authors.lastname: Mok
authors.forename: C
authors.initials: C
authors.lastname: Metreweli
mesh_terms: D000328:Adult; D000368:Aged; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D013955:Thyroglossal Cyst / Q000175:diagnosis* / Q000473:pathology; D013961:Thyroid Gland / Q000473:pathology